# Tropical Medicine publications 2011

et al. 2011. Plasmodium vivax lineages: geographical distribution, tandem repeat polymorphism, and phylogenetic relationship. Malar J, 10 (1), pp. 374. | Citations: 7 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Multi-drug resistance and severe/complicated cases are the emerging phenotypes of vivax malaria, which may deteriorate current anti-malarial control measures. The emergence of these phenotypes could be associated with either of the two Plasmodium vivax lineages. The two lineages had been categorized as Old World and New World, based on geographical sub-division and genetic and phenotypical markers. This study revisited the lineage hypothesis of P. vivax by typing the distribution of lineages among global isolates and evaluated their genetic relatedness using a panel of new mini-satellite markers. METHODS: 18S SSU rRNA S-type gene was amplified from 420 Plasmodium vivax field isolates collected from different geographical regions of India, Thailand and Colombia as well as four strains each of P. vivax originating from Nicaragua, Panama, Thailand (Pak Chang), and Vietnam (ONG). A mini-satellite marker panel was then developed to understand the population genetic parameters and tested on a sample subset of both lineages. RESULTS: 18S SSU rRNA S-type gene typing revealed the distribution of both lineages (Old World and New World) in all geographical regions. However, distribution of Plasmodium vivax lineages was highly variable in every geographical region. The lack of geographical sub-division between lineages suggests that both lineages are globally distributed. Ten mini-satellites were scanned from the P. vivax genome sequence; these tandem repeats were located in eight of the chromosomes. Mini-satellites revealed substantial allelic diversity (7-21, AE = 14.6 ± 2.0) and heterozygosity (He = 0.697-0.924, AE = 0.857 ± 0.033) per locus. Mini-satellite comparison between the two lineages revealed high but similar pattern of genetic diversity, allele frequency, and high degree of allele sharing. A Neighbour-Joining phylogenetic tree derived from genetic distance data obtained from ten mini-satellites also placed both lineages together in every cluster. CONCLUSIONS: The global lineage distribution, lack of genetic distance, similar pattern of genetic diversity, and allele sharing strongly suggested that both lineages are a single species and thus new emerging phenotypes associated with vivax malaria could not be clearly classified as belonging to a particular lineage on basis of their geographical origin.

. 2011. ISCB Africa ASBCB Conference on Bioinformatics and eBioKit Workshop EMBnet.journal, 17 (2), pp. 7-7. | Read more

et al. 2011. Poor quality vital anti-malarials in Africa - an urgent neglected public health priority. Malar J, 10 (1), pp. 352. | Citations: 57 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Plasmodium falciparum malaria remains a major public health problem. A vital component of malaria control rests on the availability of good quality artemisinin-derivative based combination therapy (ACT) at the correct dose. However, there are increasing reports of poor quality anti-malarials in Africa. METHODS: Seven collections of artemisinin derivative monotherapies, ACT and halofantrine anti-malarials of suspicious quality were collected in 2002/10 in eleven African countries and in Asia en route to Africa. Packaging, chemical composition (high performance liquid chromatography, direct ionization mass spectrometry, X-ray diffractometry, stable isotope analysis) and botanical investigations were performed. RESULTS: Counterfeit artesunate containing chloroquine, counterfeit dihydroartemisinin (DHA) containing paracetamol (acetaminophen), counterfeit DHA-piperaquine containing sildenafil, counterfeit artemether-lumefantrine containing pyrimethamine, counterfeit halofantrine containing artemisinin, and substandard/counterfeit or degraded artesunate and artesunate+amodiaquine in eight countries are described. Pollen analysis was consistent with manufacture of counterfeits in eastern Asia. These data do not allow estimation of the frequency of poor quality anti-malarials in Africa. CONCLUSIONS: Criminals are producing diverse harmful anti-malarial counterfeits with important public health consequences. The presence of artesunate monotherapy, substandard and/or degraded and counterfeit medicines containing sub-therapeutic amounts of unexpected anti-malarials will engender drug resistance. With the threatening spread of artemisinin resistance to Africa, much greater investment is required to ensure the quality of ACTs and removal of artemisinin monotherapies. The International Health Regulations may need to be invoked to counter these serious public health problems.

. 2011. Molecular detection and speciation of pathogenic Leptospira spp. in blood from patients with culture-negative leptospirosis. BMC Infect Dis, 11 (1), pp. 338. | Citations: 20 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Pathogenic Leptospira spp. present in the blood of patients with leptospirosis during the first week of symptoms can be detected using culture or PCR. A proportion of patients who are positive by PCR are negative by culture. Leptospira spp. are fastidious bacteria, and we hypothesized that a false-negative culture result may represent infection with a distinct bacterial subset that fail to grow in standard culture medium. METHODS: We evaluated our hypothesis during a prospective study of 418 consecutive patients presenting to a hospital in northeast Thailand with an acute febrile illness. Admission blood samples were taken for Leptospira culture and PCR. A single tube nested PCR that amplified a region of the rrs gene was developed and applied, amplicons sequenced and a phylogenetic tree reconstructed. RESULTS: 39/418 (9%) patients were culture-positive for Leptospira spp., and 81/418 (19%) patients were culture-negative but rrs PCR-positive. The species associated with culture-positive leptospirosis (37 L. interrogans and 2 L. borgpetersenii) were comparable to those associated with culture-negative, PCR-positive leptospirosis (76 L. interrogans, 4 L. borgpetersenii, 1 unidentified, possibly new species). CONCLUSION: Molecular speciation failed to identify a unique bacterial subset in patients with culture-negative, PCR-positive leptospirosis. The rate of false-negative culture was high, and we speculate that antibiotic pre-treatment is the most likely explanation for this.

et al. 2011. Dexamethasone and Long-Term Outcome of Tuberculous Meningitis in Vietnamese Adults and Adolescents PLOS ONE, 6 (12), | Citations: 34 (Web of Science Lite) | Read more

. 2011. Explaining the effects of a multifaceted intervention to improve inpatient care in rural Kenyan hospitals--interpretation based on retrospective examination of data from participant observation, quantitative and qualitative studies. Implement Sci, 6 (1), pp. 124. | Citations: 24 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: We have reported the results of a cluster randomized trial of rural Kenyan hospitals evaluating the effects of an intervention to introduce care based on best-practice guidelines. In parallel work we described the context of the study, explored the process and perceptions of the intervention, and undertook a discrete study on health worker motivation because this was felt likely to be an important contributor to poor performance in Kenyan public sector hospitals. Here, we use data from these multiple studies and insights gained from being participants in and observers of the intervention process to provide our explanation of how intervention effects were achieved as part of an effort to better understand implementation in low-income hospital settings. METHODS: Initial hypotheses were generated to explain the variation in intervention effects across place, time, and effect measure (indicator) based on our understanding of theory and informed by our implementation experience and participant observations. All data sources available for hospitals considered as cases for study were then examined to determine if hypotheses were supported, rejected, or required modification. Data included transcriptions of interviews and group discussions, field notes and that from the detailed longitudinal quantitative investigation. Potentially useful explanatory themes were identified, discussed by the implementing and research team, revised, and merged as part of an iterative process aimed at building more generic explanatory theory. At the end of this process, findings were mapped against a recently reported comprehensive framework for implementation research. RESULTS: A normative re-educative intervention approach evolved that sought to reset norms and values concerning good practice and promote 'grass-roots' participation to improve delivery of correct care. Maximal effects were achieved when this strategy and external support supervision helped create a soft-contract with senior managers clarifying roles and expectations around desired performance. This, combined with the support of facilitators acting as an expert resource and 'shop-floor' change agent, led to improvements in leadership, accountability, and resource allocation that enhanced workers' commitment and capacity and improved clinical microsystems. Provision of correct care was then particularly likely if tasks were simple and a good fit to existing professional routines. Our findings were in broad agreement with those defined as part of recent work articulating a comprehensive framework for implementation research. CONCLUSIONS: Using data from multiple studies can provide valuable insight into how an intervention is working and what factors may explain variability in effects. Findings clearly suggest that major intervention strategies aimed at improving child and newborn survival in low-income settings should go well beyond the fixed inputs (training, guidelines, and job aides) that are typical of many major programmes. Strategies required to deliver good care in low-income settings should recognize that this will need to be co-produced through engagement often over prolonged periods and as part of a directive but adaptive, participatory, information-rich, and reflective process.

et al. 2011. Performance of the CareStart™ G6PD deficiency screening test, a point-of-care diagnostic for primaquine therapy screening. PLoS One, 6 (12), pp. e28357. | Citations: 51 (Web of Science Lite) | Show Abstract | Read more

Development of reliable, easy-to-use, rapid diagnostic tests (RDTs) to detect glucose-6-phosphate dehydrogenase (G6PD) deficiency at point of care is essential to deploying primaquine therapies as part of malaria elimination strategies. We assessed a kit under research and development called CareStart™ G6PD deficiency screening test (Access Bio, New Jersey, USA) by comparing its performance to quantitative G6PD enzyme activity using a standardized spectrophotometric method ('gold standard'). Blood samples (n = 903) were collected from Cambodian adults living in Pailin province, western Cambodia. G6PD enzyme activities ranged from 0 to 20.5 U/g Hb (median 12.0 U/g Hg). Based on a normal haemoglobin concentration and wild-type G6PD gene, the normal values of G6PD enzymatic activity for this population was 3.6 to 20.5 U/g Hg (95(th) percentiles from 5.5 to 17.2 U/g Hg). Ninety-seven subjects (10.7%) had <3.6 U/g Hg and were classified as G6PD deficient. Prevalence of deficiency was 15.0% (64/425) among men and 6.9% (33/478) among women. Genotype was analyzed in 66 G6PD-deficient subjects and 63 of these exhibited findings consistent with Viangchang genotype. The sensitivity and specificity of the CareStart™ G6PD deficiency screening test was 0.68 and 1.0, respectively. Its detection threshold was <2.7 U/g Hg, well within the range of moderate and severe enzyme deficiencies. Thirteen subjects (1.4%, 12 males and 1 female) with G6PD enzyme activities <2 U/g Hg were falsely classified as "normal" by RDT. This experimental RDT test here evaluated outside of the laboratory for the first time shows real promise, but safe application of it will require lower rates of falsely "normal" results.

. 2011. Adaptive trial design: could we use this approach to improve clinical trials in the field of global health? Am J Trop Med Hyg, 85 (6), pp. 967-970. | Citations: 14 (Scopus) | Show Abstract | Read more

We need more clinical trials in the world's poorest regions to evaluate new drugs and vaccines, and also to find better ways to manage health issues. Clinical trials are expensive, time consuming, and cumbersome. However, in wealthier regions these limiting factors are being addressed to make trials less administrative and improve the designs. A good example is adaptive trial design. This innovation is becoming accepted by the regulators and has been taken up by the pharmaceutical industry to reduce product development times and costs. If this approach makes trials easier and less expensive surely we should be implementing this approach in the field of tropical medicine and international health? As yet this has rarely been proposed and there are few examples. There is a need for raising the awareness of these design approaches because they could be used to make dramatic improvements to clinical research in developing countries.

. 2011. Review: Improving the therapeutic index of 8-aminoquinolines by the use of drug combinations: review of the literature and proposal for future investigations. Am J Trop Med Hyg, 85 (6), pp. 1010-1014. | Citations: 21 (Web of Science Lite) | Show Abstract | Read more

Because 8-aminoquinolines affect critical survival stages of Plasmodium parasites, treatment and control of malaria could be markedly improved by more widespread use of these drugs; however, hemolytic toxicity, which is widely prevalent in G6PD-deficient patients, severely constrains this use. Primaquine was approved more than 50 years ago after extensive clinical testing. Review of the mid-20th century literature in the light of present understanding of pharmacokinetics and metabolism suggests that manipulation of these factors might dissociate 8-aminoquinoline efficacy from toxicity and lead to an improved therapeutic index.

. 2011. The primacy of public health considerations in defining poor quality medicines. PLoS Med, 8 (12), pp. e1001139. | Citations: 48 (Scopus) | Read more

. 2011. "The dirty hand in the latex glove": a study of hand hygiene compliance when gloves are worn. Infect Control Hosp Epidemiol, 32 (12), pp. 1194-1199. | Citations: 51 (Scopus) | Show Abstract | Read more

BACKGROUND AND OBJECTIVE: Wearing of gloves reduces transmission of organisms by healthcare workers' hands but is not a substitute for hand hygiene. Results of previous studies have varied as to whether hand hygiene is worse when gloves are worn. Most studies have been small and used nonstandardized assessments of glove use and hand hygiene. We sought to observe whether gloves were worn when appropriate and whether hand hygiene compliance differed when gloves were worn. DESIGN: Observational study. PARTICIPANTS AND SETTING: Healthcare workers in 56 medical or care of the elderly wards and intensive care units in 15 hospitals across England and Wales. METHODS: We observed hand hygiene and glove usage (7,578 moments for hand hygiene) during 249 one-hour sessions. Observers also recorded whether gloves were or were not worn for individual contacts. RESULTS: Gloves were used in 1,983 (26.2%) of the 7,578 moments for hand hygiene and in 551 (16.7%) of 3,292 low-risk contacts; gloves were not used in 141 (21.1%) of 669 high-risk contacts. The rate of hand hygiene compliance with glove use was 41.4% (415 of 1,002 moments), and the rate without glove use was 50.0% (1,344 of 2,686 moments). After adjusting for ward, healthcare worker type, contact risk level, and whether the hand hygiene opportunity occurred before or after a patient contact, glove use was strongly associated with lower levels of hand hygiene (adjusted odds ratio, 0.65 [95% confidence interval, 0.54-0.79]; P < .0001). CONCLUSION: The rate of glove usage is lower than previously reported. Gloves are often worn when not indicated and vice versa. The rate of compliance with hand hygiene was significantly lower when gloves were worn. Hand hygiene campaigns should consider placing greater emphasis on the World Health Organization indications for gloving and associated hand hygiene. TRIAL REGISTRATION: National Research Register N0256159318.

. 2011. OPTIMISING STRATEGIES FOR MALARIA ELIMINATION: PRIMAQUINE, MASS DRUG ADMINISTRATION AND ARTEMISININ RESISTANCECATEGORY: SCIENTIFIC FREE PAPER JOURNAL OF INFECTION, 63 (6), pp. E77-E77. | Read more

et al. 2011. MALARIAL RETINOPATHY IN ADULTS JOURNAL OF INFECTION, 63 (6), pp. 494-495. | Read more

et al. 2011. TIMING OF ENTERAL FEEDING IN CEREBRAL MALARIA IN RESOURCE-POOR SETTINGS: A RANDOMIZED TRIALCATEGORY: SCIENTIFIC FREE PAPER JOURNAL OF INFECTION, 63 (6), pp. E101-E101. | Read more

. 2011. Assessing health system interventions: key points when considering the value of randomization. Bull World Health Organ, 89 (12), pp. 907-912. | Show Abstract | Read more

Research is needed to help identify interventions that will improve the capacity or functioning of health systems and thereby contribute to achieving global health goals. Well conducted, randomized controlled trials (RCTs), insofar as they reduce bias and confounding, provide the strongest evidence for identifying which interventions delivered directly to individuals are safe and effective. When ethically feasible, they can also help reduce bias and confounding when assessing interventions targeting entire health systems. However, additional challenges emerge when research focuses on interventions that target the multiple units of organization found within health systems. Hence, one cannot complacently assume that randomization can reduce or eliminate bias and confounding to the same degree in every instance. While others have articulated arguments in favour of alternative designs, this paper is intended to help people understand why the potential value afforded by RCTs may be threatened. Specifically, it suggests six points to be borne in mind when exploring the challenges entailed in designing or evaluating RCTs on health system interventions: (i) the number of units available for randomization; (ii) the complexity of the organizational unit under study; (iii) the complexity of the intervention; (iv) the complexity of the cause-effect pathway, (v) contamination; and (vi) outcome heterogeneity. The authors suggest that the latter may be informative and that the reasons behind it should be explored and not ignored. Based on improved understanding of the value and possible limitations of RCTs on health system interventions, the authors show why we need broader platforms of research to complement RCTs.

. 2011. Experience in the use of social media in medical and health education. Contribution of the IMIA Social Media Working Group. Yearb Med Inform, 6 (1), pp. 21-29. | Citations: 20 (Scopus) | Show Abstract

OBJECTIVES: Social media are online tools that allow collaboration and community building. Succinctly, they can be described as applications where "users add value". This paper aims to show how five educators have used social media tools in medical and health education to attempt to add value to the education they provide. METHODS: We conducted a review of the literature about the use of social media tools in medical and health education. Each of the authors reported on their use of social media in their educational projects and collaborated on a discussion of the advantages and disadvantages of this approach to delivering educational projects. RESULTS: We found little empirical evidence to support the use of social media tools in medical and health education. Social media are, however, a rapidly evolving range of tools, websites and online experiences and it is likely that the topic is too broad to draw definitive conclusions from any particular study. As practitioners in the use of social media, we have recognised how difficult it is to create evidence of effectiveness and have therefore presented only our anecdotal opinions based on our personal experiences of using social media in our educational projects. CONCLUSION: The authors feel confident in recommending that other educators use social media in their educational projects. Social media appear to have unique advantages over non-social educational tools. The learning experience appears to be enhanced by the ability of students to virtually build connections, make friends and find mentors. Creating a scientific analysis of why these connections enhance learning is difficult, but anecdotal and preliminary survey evidence appears to be positive and our experience reflects the hypothesis that learning is, at heart, a social activity.

et al. 2011. Risk and causes of paediatric hospital-acquired bacteraemia in Kilifi District Hospital, Kenya: a prospective cohort study. Lancet, 378 (9808), pp. 2021-2027. | Citations: 54 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: In sub-Saharan Africa, community-acquired bacteraemia is an important cause of illness and death in children. Our aim was to establish the magnitude and causes of hospital-acquired (nosocomial) bacteraemia in African children. METHODS: We reviewed prospectively collected surveillance data of 33,188 admissions to Kilifi District Hospital, Kenya, between April 16, 2002, and Sept 30, 2009. We defined bacteraemia as nosocomial if it occurred 48 h or more after admission. We estimated the per-admission risk, daily rate, effect on mortality, and microbial cause of nosocomial bacteraemia and analysed risk factors by multivariable Cox regression. The effect on morbidity was measured as the increase in hospital stay by comparison with time-matched patients without bacteraemia. FINDINGS: The overall risk of nosocomial bacteraemia during this period was 5·9/1000 admissions (95% CI 5·2-6·9) but we recorded an underlying rise in risk of 27% per year. The incidence was 1·0/1000 days in hospital (0·87-1·14), which is about 40 times higher than that of community-acquired bacteraemia in the same region. Mortality in patients with nosocomial bacteraemia was 53%, compared with 24% in community-acquired bacteraemia and 6% in patients without bacteraemia. In survivors, nosocomial bacteraemia lengthened hospital stay by 10·1 days (3·0-17·2). Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, Acinetobacter spp, group D streptococci, and Pseudomonas aeruginosa accounted for three-quarters of nosocomial infections. Nosocomial bacteraemia was significantly associated with severe malnutrition (hazard ratio 2·52, 95% CI 1·79-3·57) and blood transfusion in children without severe anaemia (4·99; 3·39-7·37). INTERPRETATION: Our findings show that although nosocomial bacteraemia is rare, it has serious effects on morbidity and mortality, and the microbiological causes are distinct from those of community-acquired bacteraemia. Nosocomial infections are largely unrecognised or undocumented as a health risk in low-income countries, but they are likely to become public health priorities as awareness of their occurrence increases and as other prominent childhood diseases are progressively controlled. FUNDING: Wellcome Trust.

et al. 2011. First results of phase 3 trial of RTS,S/AS01 malaria vaccine in African children. N Engl J Med, 365 (20), pp. 1863-1875. | Citations: 471 (Scopus) | Show Abstract | Read more

BACKGROUND: An ongoing phase 3 study of the efficacy, safety, and immunogenicity of candidate malaria vaccine RTS,S/AS01 is being conducted in seven African countries. METHODS: From March 2009 through January 2011, we enrolled 15,460 children in two age categories--6 to 12 weeks of age and 5 to 17 months of age--for vaccination with either RTS,S/AS01 or a non-malaria comparator vaccine. The primary end point of the analysis was vaccine efficacy against clinical malaria during the 12 months after vaccination in the first 6000 children 5 to 17 months of age at enrollment who received all three doses of vaccine according to protocol. After 250 children had an episode of severe malaria, we evaluated vaccine efficacy against severe malaria in both age categories. RESULTS: In the 14 months after the first dose of vaccine, the incidence of first episodes of clinical malaria in the first 6000 children in the older age category was 0.32 episodes per person-year in the RTS,S/AS01 group and 0.55 episodes per person-year in the control group, for an efficacy of 50.4% (95% confidence interval [CI], 45.8 to 54.6) in the intention-to-treat population and 55.8% (97.5% CI, 50.6 to 60.4) in the per-protocol population. Vaccine efficacy against severe malaria was 45.1% (95% CI, 23.8 to 60.5) in the intention-to-treat population and 47.3% (95% CI, 22.4 to 64.2) in the per-protocol population. Vaccine efficacy against severe malaria in the combined age categories was 34.8% (95% CI, 16.2 to 49.2) in the per-protocol population during an average follow-up of 11 months. Serious adverse events occurred with a similar frequency in the two study groups. Among children in the older age category, the rate of generalized convulsive seizures after RTS,S/AS01 vaccination was 1.04 per 1000 doses (95% CI, 0.62 to 1.64). CONCLUSIONS: The RTS,S/AS01 vaccine provided protection against both clinical and severe malaria in African children. (Funded by GlaxoSmithKline Biologicals and the PATH Malaria Vaccine Initiative; RTS,S ClinicalTrials.gov number, NCT00866619 .).

. 2011. Highly effective therapy for maternal malaria associated with a lower risk of vertical transmission. J Infect Dis, 204 (10), pp. 1613-1619. | Citations: 14 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: The epidemiology of congenital malaria was investigated in a hospital-based malaria surveillance study in Papua, Indonesia. METHODS: From April 2005 to January 2010, 4878 delivering women and their newborns underwent prospective clinical review and malaria screening by peripheral blood microscopy. FINDINGS: Congenital malaria occurred in 8 per 1000 (38/4884) live births, with Plasmodium falciparum accounting for 76.3% (29) and P. vivax for 15.8% (6) of infections. Maternal malaria at delivery (adjusted odds ratio [AOR], 9.5; 95% confidence interval [CI], 4.2-21.5; P < .001), age ≤ 16 years (AOR, 4; 95% CI, 1.4-12.1; P = .011), and prior malaria during pregnancy (AOR, 2.2; 95% CI, 1.1-4.4, P = .022) were independent risk factors for vertical transmission. Of 29 mothers and neonates with contemporaneous peripheral parasitemia, 17% (5) had discordant parasite species, suggesting possible antenatal malaria transmission. Newborns with malaria were at significantly greater risk of low birth weight (AOR, 2.8; 95% CI, 1.2-6.6; P = .002). Following introduction of dihydroartemisinin-piperaquine for uncomplicated malaria in the second and third trimesters of pregnancy, congenital malaria incidence fell from 3.2% to 0.2% (odds ratio, 0.07; 95% CI, .03-.15; P < .001). CONCLUSIONS: Congenital malaria is an important cause of neonatal morbidity in this region co-endemic for P. falciparum and P. vivax malaria. The introduction of artemisinin-combination therapy was associated with a significant risk reduction in the vertical transmission of malaria.

. 2011. Ethics in practice: the state of the debate on promoting the social value of global health research in resource poor settings particularly Africa. BMC Med Ethics, 12 (1), pp. 22. | Citations: 20 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Promoting the social value of global health research undertaken in resource poor settings has become a key concern in global research ethics. The consideration for benefit sharing, which concerns the elucidation of what if anything, is owed to participants, their communities and host nations that take part in such research, and the obligations of researchers involved, is one of the main strategies used for promoting social value of research. In the last decade however, there has been intense debate within academic bioethics literature seeking to define the benefits, the beneficiaries, and the scope of obligations for providing these benefits. Although this debate may be indicative of willingness at the international level to engage with the responsibilities of researchers involved in global health research, it remains unclear which forms of benefits or beneficiaries should be considered. International and local research ethics guidelines are reviewed here to delineate the guidance they provide. METHODS: We reviewed documents selected from the international compilation of research ethics guidelines by the Office for Human Research Protections under the US Department of Health and Human Services. RESULTS: Access to interventions being researched, the provision of unavailable health care, capacity building for individuals and institutions, support to health care systems and access to medical and public health interventions proven effective, are the commonly recommended forms of benefits. The beneficiaries are volunteers, disease or illness affected communities and the population in general. Interestingly however, there is a divide between "global opinion" and the views of particular countries within resource poor settings as made explicit by differences in emphasis regarding the potential benefits and the beneficiaries. CONCLUSION: Although in theory benefit sharing is widely accepted as one of the means for promoting the social value of international collaborative health research, there is less agreement amongst major guidelines on the specific responsibilities of researchers over what is ethical in promoting the social value of research. Lack of consensus might have practical implications for efforts aimed at enhancing the social value of global health research undertaken in resource poor settings. Further developments in global research ethics require more reflection, paying attention to the practical realities of implementing the ethical principles in real world context.

et al. 2011. Central venous catheter use in severe malaria: time to reconsider the World Health Organization guidelines? Malar J, 10 (1), pp. 342. | Citations: 6 (Scopus) | Show Abstract | Read more

BACKGROUND: To optimize the fluid status of adult patients with severe malaria, World Health Organization (WHO) guidelines recommend the insertion of a central venous catheter (CVC) and a target central venous pressure (CVP) of 0-5 cmH2O. However there are few data from clinical trials to support this recommendation. METHODS: Twenty-eight adult Indian and Bangladeshi patients admitted to the intensive care unit with severe falciparum malaria were enrolled in the study. All patients had a CVC inserted and had regular CVP measurements recorded. The CVP measurements were compared with markers of disease severity, clinical endpoints and volumetric measures derived from transpulmonary thermodilution. RESULTS: There was no correlation between the admission CVP and patient outcome (p = 0.67) or disease severity (p = 0.33). There was no correlation between the baseline CVP and the concomitant extravascular lung water (p = 0.62), global end diastolic volume (p = 0.88) or cardiac index (p = 0.44). There was no correlation between the baseline CVP and the likelihood of a patient being fluid responsive (p = 0.37). On the occasions when the CVP was in the WHO target range patients were usually hypovolaemic and often had pulmonary oedema by volumetric measures. Seven of 28 patients suffered a complication of the CVC insertion, although none were fatal. CONCLUSION: The WHO recommendation for the routine insertion of a CVC, and the maintenance of a CVP of 0-5 cmH2O in adults with severe malaria, should be reconsidered.

. 2011. Ecology. Mosquito trials. Science, 334 (6057), pp. 771-772. | Citations: 20 (Scopus) | Show Abstract | Read more

Field trials of modified mosquitoes present complex but manageable challenges.

et al. 2011. Quality of hospital care for sick newborns and severely malnourished children in Kenya: a two-year descriptive study in 8 hospitals. BMC Health Serv Res, 11 (1), pp. 307. | Citations: 14 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Given the high mortality associated with neonatal illnesses and severe malnutrition and the development of packages of interventions that provide similar challenges for service delivery mechanisms we set out to explore how well such services are provided in Kenya. METHODS: As a sub-component of a larger study we evaluated care during surveys conducted in 8 rural district hospitals using convenience samples of case records. After baseline hospitals received either a full multifaceted intervention (intervention hospitals) or a partial intervention (control hospitals) aimed largely at improving inpatient paediatric care for malaria, pneumonia and diarrhea/dehydration. Additional data were collected to: i) examine the availability of routine information at baseline and their value for morbidity, mortality and quality of care reporting, and ii) compare the care received against national guidelines disseminated to all hospitals. RESULTS: Clinical documentation for neonatal and malnutrition admissions was often very poor at baseline with case records often entirely missing. Introducing a standard newborn admission record (NAR) form was associated with an increase in median assessment (IQR) score to 25/28 (22-27) from 2/28 (1-4) at baseline. Inadequate and incorrect prescribing of penicillin and gentamicin were common at baseline. For newborns considerable improvements in prescribing in the post baseline period were seen for penicillin but potentially serious errors persisted when prescribing gentamicin, particularly to low-birth weight newborns in the first week of life. Prescribing essential feeds appeared almost universally inadequate at baseline and showed limited improvement after guideline dissemination. CONCLUSION: Routine records are inadequate to assess newborn care and thus for monitoring newborn survival interventions. Quality of documented inpatient care for neonates and severely malnourished children is poor with limited improvement after the dissemination of clinical practice guidelines. Further research evaluating approaches to improving care for these vulnerable groups is urgently needed. We also suggest pre-service training curricula should be better aligned to help improve newborn survival particularly.

. 2011. Standardizing the measurement of parasite clearance in falciparum malaria: the parasite clearance estimator. Malar J, 10 (1), pp. 339. | Citations: 123 (Scopus) | Show Abstract | Read more

BACKGROUND: A significant reduction in parasite clearance rates following artesunate treatment of falciparum malaria, and increased failure rates following artemisinin combination treatments (ACT), signaled emergent artemisinin resistance in Western Cambodia. Accurate measurement of parasite clearance is therefore essential to assess the spread of artemisinin resistance in Plasmodium falciparum. The slope of the log-parasitaemia versus time relationship is considered to be the most robust measure of anti-malarial effect. However, an initial lag phase of numerical instability often precedes a steady exponential decline in the parasite count after the start of anti-malarial treatment. This lag complicates the clearance estimation, introduces observer subjectivity, and may influence the accuracy and consistency of reported results. METHODS: To address this problem, a new approach to modelling clearance of malaria parasites from parasitaemia-time profiles has been explored and validated. The methodology detects when a lag phase is present, selects the most appropriate model (linear, quadratic or cubic) to fit log-transformed parasite data, and calculates estimates of parasite clearance adjusted for this lag phase. Departing from previous approaches, parasite counts below the level of detection are accounted for and not excluded from the calculation. RESULTS: Data from large clinical studies with frequent parasite counts were examined. The effect of a lag phase on parasite clearance rate estimates is discussed, using individual patient data examples. As part of the World Wide Antimalarial Resistance Network's (WWARN) efforts to make innovative approaches available to the malaria community, an automated informatics tool: the parasite clearance estimator has been developed. CONCLUSIONS: The parasite clearance estimator provides a consistent, reliable and accurate method to estimate the lag phase and malaria parasite clearance rate. It could be used to detect early signs of emerging resistance to artemisinin derivatives and other compounds which affect ring-stage clearance.

. 2011. Bayesian modeling to unmask and predict influenza A/H1N1pdm dynamics in London. Proc Natl Acad Sci U S A, 108 (45), pp. 18238-18243. | Citations: 58 (Scopus) | Show Abstract | Read more

The tracking and projection of emerging epidemics is hindered by the disconnect between apparent epidemic dynamics, discernible from noisy and incomplete surveillance data, and the underlying, imperfectly observed, system. Behavior changes compound this, altering both true dynamics and reporting patterns, particularly for diseases with nonspecific symptoms, such as influenza. We disentangle these effects to unravel the hidden dynamics of the 2009 influenza A/H1N1pdm pandemic in London, where surveillance suggests an unusual dominant peak in the summer. We embed an age-structured model into a bayesian synthesis of multiple evidence sources to reveal substantial changes in contact patterns and health-seeking behavior throughout the epidemic, uncovering two similar infection waves, despite large differences in the reported levels of disease. We show how this approach, which allows for real-time learning about model parameters as the epidemic progresses, is also able to provide a sequence of nested projections that are capable of accurately reflecting the epidemic evolution.

. 2011. Dihydroartemisinin-piperaquine versus chloroquine in the treatment of Plasmodium vivax malaria in Thailand: a randomized controlled trial. Clin Infect Dis, 53 (10), pp. 977-984. | Citations: 44 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Chloroquine (CQ) remains the treatment of choice for Plasmodium vivax malaria. Initially confined to parts of Indonesia and Papua, resistance of P. vivax to CQ seems to be spreading, and alternative treatments are required. METHODS: We conducted a randomized controlled study to compare the efficacy and the tolerability of CQ and dihydroartemisinin-piperaquine (DP) in 500 adults and children with acute vivax malaria on the Northwestern border of Thailand. RESULTS: Both drugs were well tolerated. Fever and parasite clearance times were slower in the CQ than in the DP group (P < .001). By day 28, recurrent infections had emerged in 18 of 207 CQ recipients compared with 5 of 230 treated with DP (relative risk, 4.0; 95% confidence interval [CI], 1.51-10.58; P = .0046). The cumulative risk of recurrence with P. vivax at 9 weeks was 79.1% (95% CI, 73.5%-84.8%) in patients treated with CQ compared with 54.9% (95% CI, 48.2%-61.6%) in those receiving DP (hazard ratio [HR], 2.27; 95% CI, 1.8-2.9; P < .001). Children <5 years old were at greater risk of recurrent P. vivax infection (74.4%; 95% CI, 63.2%-85.6%) than older patients (55.3% [95% CI, 50.2%-60.4%]; HR, 1.58 [95% CI, 1.1-2.2]; P = .005). In vitro susceptibility testing showed that 13% of the tested isolates had a CQ median inhibitory concentration >100 nmol/L, suggesting reduced susceptibility. CONCLUSIONS: The efficacy of CQ in the treatment of P. vivax infections is declining on the Thai-Myanmar border. DP is an effective alternative treatment.

. 2011. Impact of non-health policies on infant mortality through the social determinants pathway. Bull World Health Organ, 89 (11), pp. 778. | Citations: 2 (Web of Science Lite) | Read more

et al. 2011. An In-Depth Analysis of Original Antigenic Sin in Dengue Virus Infection (vol 85, pg 410, 2011) JOURNAL OF VIROLOGY, 85 (22), pp. 12100-12100. | Citations: 52 (Scopus) | Read more

et al. 2011. [National Campaign of Vaccination against the flu A (H1N1)v: National Follow-up of Pharmacovigilance]. Therapie, 66 (6), pp. 527-540. | Citations: 4 (Scopus) | Show Abstract | Read more

OBJECTIVES: The present study was performed to evaluate safety data collected by the French Network of Pharmacovigilance centres network, from October 21, 2009 to June 15, 2010. METHODS: French Health Authorities (Afssaps [Agence française de sécurité sanitaire des produits de santé]) heightened awareness to extensive notifications with online health practitioners' reports and patients' reports via the Regional Centre concerned. RESULTS: During the campaign, 4.1 millions doses of Pandemrix(®) and 1.6 million doses of Panenza(®) were administered. Following Pandemrix(®), 4 183 adverse effects (AEs) were reported including 193 "serious" AEs. Concerning Panenza(®), 591 AEs were reported including 70 "serious" AE. The most frequently reported "serious" AEs were neurological for both Pandemrix(®) (38.9%, mainly isolated ascending paresthesia without any other neurological symptom and complication) and Panenza(®) (28.9%). Febrile convulsions were the most common neurological AEs with Panenza(®) in children. All reported deaths (n = 22) described causes other than recent A(H1N1)v vaccination. No causal relationship was established between these AEs and vaccination. Among AEs of "special" interest, 13 reports of confirmed GBS and 15 reports of demyelinating disorders were notified. No report of narcolepsy was made during the study period. CONCLUSION: For both vaccines, neurological AEs (isolated ascending paresthesia with Pandemrix(®) and febrile convulsions with Panenza(®)) were among the most frequently reported "serious" AEs. Despite limits of this survey based on spontaneous reporting, the study did not detect any safety signals, at least with an 8-month follow-up.

. 2011. Considerations on the use of nucleic acid-based amplification for malaria parasite detection. Malar J, 10 (1), pp. 323. | Citations: 21 (Scopus) | Show Abstract | Read more

BACKGROUND: Nucleic acid amplification provides the most sensitive and accurate method to detect and identify pathogens. This is primarily useful for epidemiological investigations of malaria because the infections, often with two or more Plasmodium species present simultaneously, are frequently associated with microscopically sub-patent parasite levels and cryptic mixed infections. Numerous distinct equally adequate amplification-based protocols have been described, but it is unclear which to select for epidemiological surveys. Few comparative studies are available, and none that addresses the issue of inter-laboratory variability. METHODS: Blood samples were collected from patients attending malaria clinics on the Thai-Myanmar border. Frozen aliquots from 413 samples were tested independently in two laboratories by nested PCR assay. Dried blood spots on filter papers from the same patients were also tested by the nested PCR assay in one laboratory and by a multiplex PCR assay in another. The aim was to determine which protocol best detected parasites below the sensitivity level of microscopic examination. RESULTS: As expected PCR-based assays detected a substantial number of infected samples, or mixed infections, missed by microscopy (27 and 42 for the most sensitive assay, respectively). The protocol that was most effective at detecting these, in particular mixed infections, was a nested PCR assay with individual secondary reactions for each of the species initiated with a template directly purified from the blood sample. However, a lesser sensitivity in detection was observed when the same protocol was conducted in another laboratory, and this significantly altered the data obtained on the parasite species distribution. CONCLUSIONS: The sensitivity of a given PCR assay varies between laboratories. Although, the variations are relatively minor, they primarily diminish the ability to detect low-level and mixed infections and are sufficient to obviate the main rationale to use PCR assays rather than microscopy or rapid diagnostic tests. The optimal approach to standardise methodologies is to provide PCR template standards. These will help researchers in different settings to ensure that the nucleic acid amplification protocols they wish to use provide the requisite level of sensitivity, and will permit comparison between sites.

et al. 2011. Decreasing incidence of severe malaria and community-acquired bacteraemia among hospitalized children in Muheza, north-eastern Tanzania, 2006-2010. Malar J, 10 (1), pp. 320. | Citations: 24 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: The annual incidence and temporal trend of severe malaria and community-acquired bacteraemia during a four-year period in Muheza, Tanzania was assessed. METHODS: Data on severely ill febrile children aged 2 months to 14 years from three prospective studies conducted at Muheza District Hospital from 2006 to 2010 was pooled and analysed. On admission, each enrolled child had a thin and thick blood film and at least one rapid diagnostic test for falciparum malaria, as well as a blood culture. The annual incidence of bacteraemia and severe malaria among children coming from Muheza was calculated and their temporal trend was assessed. RESULTS: Overall, 1, 898 severe falciparum malaria and 684 bacteraemia cases were included. Of these, 1, 356 (71%) and 482 (71%), respectively, were from the referral population of Muheza. The incidence of falciparum malaria and all-cause bacteraemia in Muheza decreased five-fold and three-fold, respectively, from the first to the fourth year of surveillance (p < 0.0001). During this period, the median ages of children from Muheza admitted with severe malaria increased from 1.7 to 2.5 years (p < 0.0001). The reduction in all-cause bacteraemia was mainly driven by the 11-fold decline in the incidence of non-typhoidal salmonellosis. The annual incidences of Haemophilus influenzae and pneumococcal invasive bacterial infections decreased as well but were much fewer in number. CONCLUSIONS: These results add to the growing evidence of the decline in malaria associated with a decrease in non-typhoidal salmonellosis and possibly other bacteraemias. Malarial prevention and control strategies may provide a greater benefit than the mere reduction of malaria alone.

. 2011. Genomic medicine has failed the poor. Nature, 478 (7369), pp. 287. | Citations: 3 (Web of Science Lite) | Read more

. 2011. Evaluation of six commercial point-of-care tests for diagnosis of acute dengue infections: the need for combining NS1 antigen and IgM/IgG antibody detection to achieve acceptable levels of accuracy. Clin Vaccine Immunol, 18 (12), pp. 2095-2101. | Citations: 68 (Scopus) | Show Abstract | Read more

Six assays were evaluated in this study to determine their suitability for the diagnosis of acute dengue infection using samples from 259 Sri Lankan patients with acute fevers (99 confirmed dengue cases and 160 patients with other confirmed acute febrile illnesses): (i) the Merlin dengue fever IgG & IgM combo device (Merlin), (ii) the Standard Diagnostics Dengue Duo nonstructural 1 (NS1) antigen and IgG/IgM combo device (Standard Diagnostics, South Korea), (iii) the Biosynex Immunoquick dengue fever IgG and IgM (Biosynex, France) assay, (iv) the Bio-Rad NS1 antigen strip (Bio-Rad, France), (v) the Panbio Dengue Duo IgG/IgM Cassette (Inverness, Australia), and (vi) the Panbio dengue NS1 antigen strip (Inverness, Australia). The median number of days of fever prior to admission sample collection was 5 days (interquartile range, 3 to 7 days). Sensitivity and specificity of the NS1 antigen tests ranged from 49 to 59% and from 93 to 99%, respectively, and sensitivity and sensitivity of the IgM antibody test ranged from 71 to 80% and from 46 to 90%, respectively. Combining the NS1 antigen and IgM antibody results from the Standard Diagnostics Dengue Duo test gave the best compromise of sensitivity and specificity (93% and 89%, respectively) and provided the best sensitivity in patients presenting at different times after fever onset. The Merlin IgM/IgG antibody tests correctly classified 64% and 86% of the primary and secondary dengue infection cases, respectively, and the Standard Diagnostics IgM/IgG antibody tests correctly classified 71% and 83% of the primary and secondary dengue infection cases, respectively. This study provides strong evidence of the value of combining dengue antigen- and antibody-based test results in the rapid diagnostic test (RDT) format for the acute diagnosis of dengue.

. 2011. A vaccine for malaria. N Engl J Med, 365 (20), pp. 1926-1927. | Citations: 21 (Scopus) | Read more

et al. 2011. Genome-wide association study identifies susceptibility loci for dengue shock syndrome at MICB and PLCE1. Nat Genet, 43 (11), pp. 1139-1141. | Citations: 97 (Web of Science Lite) | Show Abstract | Read more

Hypovolemic shock (dengue shock syndrome (DSS)) is the most common life-threatening complication of dengue. We conducted a genome-wide association study of 2,008 pediatric cases treated for DSS and 2,018 controls from Vietnam. Replication of the most significantly associated markers was carried out in an independent Vietnamese sample of 1,737 cases and 2,934 controls. SNPs at two loci showed genome-wide significant association with DSS. We identified a susceptibility locus at MICB (major histocompatibility complex (MHC) class I polypeptide-related sequence B), which was within the broad MHC region on chromosome 6 but outside the class I and class II HLA loci (rs3132468, P(meta) = 4.41 × 10(-11), per-allele odds ratio (OR) = 1.34 (95% confidence interval: 1.23-1.46)). We identified associated variants within PLCE1 (phospholipase C, epsilon 1) on chromosome 10 (rs3765524, P(meta) = 3.08 × 10(-10), per-allele OR = 0.80 (95% confidence interval: 0.75-0.86)). We identify two loci associated with susceptibility to DSS in people with dengue, suggesting possible mechanisms for this severe complication of dengue.

et al. 2011. Time from human immunodeficiency virus seroconversion to reaching CD4+ cell count thresholds <200, <350, and <500 Cells/mm³: assessment of need following changes in treatment guidelines. Clin Infect Dis, 53 (8), pp. 817-825. | Citations: 87 (Scopus) | Show Abstract | Read more

BACKGROUND: Recent updates of human immunodeficiency virus (HIV) treatment guidelines have raised the CD4+ cell count thresholds for antiretroviral therapy initiation from 350 to 500 cells/mm(3) in the United States and from 200 to 350 cells/mm³ in mid- and low-income countries. Robust data of time from HIV seroconversion to CD4+ cell counts of 200, 350, and 500 cells/mm³ are lacking but are needed to inform health care planners of the likely impact and cost effectiveness of these and possible future changes in CD4+ cell count initiation threshold. METHODS: Using Concerted Action on Seroconversion to AIDS and Death in Europe data from individuals with well-estimated dates of HIV seroconversion, we fitted mixed models on the square root of CD4+ cell counts measured before combined antiretroviral therapy (cART) initiation. Restricting analyses to adults (age >16 years), we predicted time between seroconversion and CD4+ cell count <200, <350, and <500 cells/mm³ as well as CD4+ cell count distribution and proportions reaching these thresholds at 1, 2, and 5 years after seroconversion. RESULTS: Median (interquartile range [IQR]) follow-up for the 18495 eligible individuals from seroconversion while cART-free was 3.7 years (1.5, 7). Most of the subjects were male (78%), had a median age at seroconversion of 30 years (IQR, 25-37 years), and were infected through sex between men (55%). Estimated median times (95% confidence interval [CI]) from seroconversion to CD4+ cell count <500, <350, and <200 cells/mm(3) were 1.19 (95% CI, 1.12-1.26), 4.19 (95% CI, 4.09-4.28), and 7.93 (95% CI, 7.76-8.09) years, respectively. Almost half of infected individuals would require treatment within 1 year of seroconversion for guidelines recommending its initiation at 500 cells/mm³, compared with 26% and 9% for guidelines recommending initiation at 350 and 200 cells/mm³, respectively. CONCLUSIONS: These data suggest substantial increases in the number of individuals who require treatment and call for early HIV testing.

. 2011. A rapid and robust tri-color flow cytometry assay for monitoring malaria parasite development. Sci Rep, 1 (1), pp. 118. | Citations: 77 (Scopus) | Show Abstract | Read more

Microscopic examination of Giemsa-stained thin blood smears remains the gold standard method used to quantify and stage malaria parasites. However, this technique is tedious, and requires trained microscopists. We have developed a fast and simple flow cytometry method to quantify and stage, various malaria parasites in red blood cells in whole blood or in vitro cultured Plasmodium falciparum. The parasites were stained with dihydroethidium and Hoechst 33342 or SYBR Green I and leukocytes were identified with an antibody against CD45. Depending on the DNA stains used, samples were analyzed using different models of flow cytometers. This protocol, which does not require any washing steps, allows infected red blood cells to be distinguished from leukocytes, as well as allowing non-infected reticulocytes and normocytes to be identified. It also allows assessing the proportion of parasites at different developmental stages. Lastly, we demonstrate how this technique can be applied to antimalarial drug testing.

et al. 2011. Antimicrobial resistance to ceftazidime involving loss of penicillin-binding protein 3 in Burkholderia pseudomallei. Proc Natl Acad Sci U S A, 108 (41), pp. 17165-17170. | Citations: 46 (Scopus) | Show Abstract | Read more

Known mechanisms of resistance to β-lactam antibiotics include β-lactamase expression, altered drug target, decreased bacterial permeability, and increased drug efflux. Here, we describe a unique mechanism of β-lactam resistance in the biothreat organism Burkholderia pseudomallei (the cause of melioidosis), associated with treatment failure during prolonged ceftazidime therapy of natural infection. Detailed comparisons of the initial ceftazidime-susceptible infecting isolate and subsequent ceftazidime-resistant variants from six patients led us to identify a common, large-scale genomic loss involving a minimum of 49 genes in all six resistant strains. Mutational analysis of wild-type B. pseudomallei demonstrated that ceftazidime resistance was due to deletion of a gene encoding a penicillin-binding protein 3 (BPSS1219) present within the region of genomic loss. The clinical ceftazidime-resistant variants failed to grow using commonly used laboratory culture media, including commercial blood cultures, rendering the variants almost undetectable in the diagnostic laboratory. Melioidosis is notoriously difficult to cure and clinical treatment failure is common in patients treated with ceftazidime, the drug of first choice across most of Southeast Asia where the majority of cases are reported. The mechanism described here represents an explanation for ceftazidime treatment failure, and may be a frequent but undetected resistance event.

. 2011. Plasmodium vivax treatments: what are we looking for? Curr Opin Infect Dis, 24 (6), pp. 578-585. | Citations: 35 (Web of Science Lite) | Show Abstract | Read more

PURPOSE OF REVIEW: For over 50 years, the treatment of Plasmodium vivax has relied on a combination of chloroquine and primaquine, but this strategy is under threat. Chloroquine efficacy is now compromised across much of the vivax endemic world and there are significant operational difficulties in deploying primaquine. We review the recent advances in P. vivax chemotherapy that may influence the future management of this neglected pathogen. RECENT FINDINGS: New-generation artemisinin combination therapies (ACTs) have shown potent efficacy against the erythrocytic stages of both drug-resistant P. vivax and Plasmodium falciparum. Antimalarial regimens containing slowly eliminated drugs provide a measure of protection against the first, and possibly second, relapse of tropical strains of P. vivax, but reliable radical cure is needed to prevent future relapses. Primaquine is currently the only licensed hypnozoitocidal treatment, but requires long treatment courses and its effectiveness in different endemic settings remains largely unknown. SUMMARY: In regions coendemic for P. vivax and P. falciparum, a unified treatment policy for malaria of any parasitological cause is likely to confer the greatest individual and public health benefit. Optimizing the safety and effectiveness of primaquine through the development of rapid diagnostic tests for glucose-6-phosphate dehydrogenase deficiency and improving drug adherence will be crucial endeavors in the fight against vivax malaria.

. 2011. Diabetes does not influence activation of coagulation, fibrinolysis or anticoagulant pathways in Gram-negative sepsis (melioidosis). Thromb Haemost, 106 (6), pp. 1139-1148. | Citations: 9 (Scopus) | Show Abstract | Read more

Diabetes is associated with a disturbance of the haemostatic balance and is an important risk factor for sepsis, but the influence of diabetes on the pathogenesis of sepsis remains unclear. Melioidosis ( Burkholderia pseudomallei infection) is a common cause of community-acquired sepsis in Southeast Asia and northern Australia. We sought to investigate the impact of pre-existing diabetes on the coagulation and fibrinolytic systems during sepsis caused by B.pseudomallei . We recruited a cohort of 44 patients (34 with diabetes and 10 without diabetes) with culture-proven melioidosis. Diabetes was defined as a pre-admission diagnosis of diabetes or an HbA₁c>7.8% at enrolment. Thirty healthy blood donors and 52 otherwise healthy diabetes patients served as controls. Citrated plasma was collected from all subjects; additionally in melioidosis patients follow-up specimens were collected seven and ≥ 28 days after enrolment where possible. Relative to uninfected healthy controls, diabetes per se (i.e. in the absence of infection) was characterised by a procoagulant effect. Melioidosis was associated with activation of coagulation (thrombin-antithrombin complexes (TAT), prothrombin fragment F₁+₂ and fibrinogen concentrations were elevated; PT and PTT prolonged), suppression of anti-coagulation (antithrombin, protein C, total and free protein S levels were depressed) and abnormalities of fibrinolysis (D-dimer and plasmin-antiplasmin complex [PAP] were elevated). Remarkably, none of these haemostatic alterations were influenced by pre-existing diabetes. In conclusion, although diabetes is associated with multiple abnormalities of coagulation, anticoagulation and fibrinolysis, these changes are not detectable when superimposed on the background of larger abnormalities attributable to B. pseudomallei sepsis.

. 2011. Screening, isolation, and decolonisation strategies in the control of meticillin resistant Staphylococcus aureus in intensive care units: cost effectiveness evaluation BRITISH MEDICAL JOURNAL, 343 (oct05 3), pp. d5694-d5694. | Citations: 43 (Web of Science Lite) | Read more

. 2011. Stakeholders understanding of the concept of benefit sharing in health research in Kenya: a qualitative study. BMC Med Ethics, 12 (1), pp. 20. | Citations: 6 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: The concept of benefit sharing to enhance the social value of global health research in resource poor settings is now a key strategy for addressing moral issues of relevance to individuals, communities and host countries in resource poor settings when they participate in international collaborative health research.The influence of benefit sharing framework on the conduct of collaborative health research is for instance evidenced by the number of publications and research ethics guidelines that require prior engagement between stakeholders to determine the social value of research to the host communities. While such efforts as the production of international guidance on how to promote the social value of research through such strategies as benefit sharing have been made, the extent to which these ideas and guidelines have been absorbed by those engaged in global health research especially in resource poor settings remains unclear. We examine this awareness among stakeholders involved in health related research in Kenya. METHODS: We conducted in-depth interviews with key informants drawn from within the broader health research system in Kenya including researchers from the mainstream health research institutions, networks and universities, teaching hospitals, policy makers, institutional review boards, civil society organisations and community representative groups. RESULTS: Our study suggests that although people have a sense of justice and the moral aspects of research, this was not articulated in terms used in the literature and the guidelines on the ethics of global health research. CONCLUSION: This study demonstrates that while in theory several efforts can be made to address the moral issues of concern to research participants and their communities in resource poor settings, quick fixes such as benefit sharing are not going to be straightforward. We suggest a need to pay closer attention to the processes through which ethical principles are enacted in practice and distil lessons on how best to involve individuals and communities in promoting ethical conduct of global health research in resource poor settings.

. 2011. Ultrastructural and real-time microscopic changes in P. falciparum-infected red blood cells following treatment with antimalarial drugs. Ultrastruct Pathol, 35 (5), pp. 214-225. | Citations: 8 (Scopus) | Show Abstract | Read more

Ultrastructural changes to P. falciparum-infected red blood cells were examined in vitro after treatment with antimalarial drugs. Artesunate had the most rapid parasitocidal effect. All three drugs caused structural changes within the parasite, including dilatation of the parasitophorus vacuole membrane, depletion of ribosomes, mitochondrial swelling, and decreased formation of hemozoin crystals. The structure of surface knobs and Maurer's clefts were similar to controls but reduced in number. Only depletion of free ribosomes correlated with antimalarial drug exposure. Drug treatment decreased movement of hemozoin granules within parasites on real-time microscopy, before recognizable morphological changes of parasite death.

. 2011. Pneumococcal conjugate vaccine given shortly after birth stimulates effective antibody concentrations and primes immunological memory for sustained infant protection. Clin Infect Dis, 53 (7), pp. 663-670. | Citations: 24 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: In developing countries, newborn immunization with pneumococcal conjugate vaccines (PCVs) could protect young infants who are at high risk of invasive pneumococcal disease (IPD) but might lead to immune tolerance. METHODS: In a randomized trial, young infants received 7-valent PCV at 6, 10, and 14 weeks (Expanded Programme on Immunization [EPI] group) or 0, 10, and 14 weeks (newborn group). Safety was monitored actively at 2-7 days and then passively. Serum samples obtained at birth and 6, 10, 14, 18, 36, and 37 weeks were assayed by enzyme-linked immunosorbent assay for anticapsular immunoglobulin G concentration and avidity. Infants were boosted with either 7-valent PCV or one-fifth dose of pneumococcal polysaccharide vaccine at 36 weeks. Nasopharyngeal swab samples were obtained at 18 and 36 weeks. RESULTS: Three-hundred neonates and young infants were enrolled. Newborn vaccination was well tolerated. Adverse events occurred equally in each group; none was related to immunization. One infant, immunized at birth, died of unrelated neonatal sepsis. At 18 weeks, protective concentrations (≥0.35 μg/mL) were achieved against each serotype by ≥87% of infants with no significant differences between groups. Geometric mean concentrations were higher in the EPI group for serotypes 4, 9V, 18C, and 19F at 18 weeks and for serotype 4 at 36 weeks. Avidity was greater in the newborn group for serotypes 4, 6B, and 19F at 18 weeks and for serotype 19F at 36 weeks. Booster responses and vaccine-type/nonvaccine-type carriage prevalence did not differ between groups. CONCLUSIONS: PCV was safe, immunogenic, and primed for memory when given at birth. There was no evidence of immune tolerance. Vaccination beginning at birth offers an alternative to control IPD in vulnerable young infants.

et al. 2011. The emergence of rotavirus G12 and the prevalence of enteric viruses in hospitalized pediatric diarrheal patients in southern Vietnam. Am J Trop Med Hyg, 85 (4), pp. 768-775. | Citations: 18 (Scopus) | Show Abstract | Read more

Diarrhea is a major cause of childhood morbidity and mortality in developing countries, and the majority of infections are of viral etiology. We aimed to compare the etiological prevalence of the major enteric viruses in an urban and a rural setting in southern Vietnam. We simultaneously screened fecal specimens from 362 children in Ho Chi Minh City and Dong Thap province that were hospitalized with acute diarrhea over a 1-month-long period for four viral gastrointestinal pathogens. Rotavirus was the most common pathogen identified, but there was a differential prevalence of rotavirus and norovirus between the urban and rural locations. Furthermore, rotavirus genotyping and phylogenetic analysis again differentiated the genotypes by the sampling location. Our data show a disproportional distribution of enteric viral pathogens in urban and rural locations, and we provide evidence of continual importation of new rotavirus strains into southern Vietnam and report the emergence of rotavirus genotype G12.

et al. 2011. Excess child mortality after discharge from hospital in Kilifi, Kenya: a retrospective cohort analysis. Bull World Health Organ, 89 (10), pp. 725-732A. | Citations: 23 (Scopus) | Show Abstract | Read more

OBJECTIVE: To explore excess paediatric mortality after discharge from Kilifi District Hospital, Kenya, and its duration and risk factors. METHODS: Hospital and demographic data were used to describe post-discharge mortality and survival probability in children aged < 15 years, by age group and clinical syndrome. Cox regression models were developed to identify risk factors. FINDINGS: In 2004-2008, approximately 111,000 children were followed for 555,000 person-years. We analysed 14,971 discharges and 535 deaths occurring within 365 days of discharge. Mortality was higher in the post-discharge cohort than in the community cohort (age-adjusted rate ratio, RR: 7.7; 95% confidence interval, CI: 6.6-8.9) and declined little over time. An increased post-discharge mortality hazard was found in children aged < 5 years with the following: weight-for-age Z score < -4 (hazard ratio, HR: 6.5); weight-for-age Z score > -4 but < -3 (HR: 3.4); hypoxia (HR: 2.3); bacteraemia (HR: 1.8); hepatomegaly (HR: 2.3); jaundice (HR: 1.8); hospital stay > 13 days (HR: 1.8). Older age was protective (reference < 1 month): 6-23 months, HR: 0.8; 2-4 years, HR: 0.6. Children with at least one risk factor accounted for 545 (33%) of the 1655 annual discharges and for 39 (47%) of the 83 discharge-associated deaths. CONCLUSION: Hospital admission selects vulnerable children with a sustained increased risk of dying. The risk factors identified provide an empiric basis for effective outpatient follow-up.

. 2011. Chloroquine resistance in Haiti: lessons learned from imported cases TROPICAL MEDICINE & INTERNATIONAL HEALTH, 16 pp. 130-130.

. 2011. Impact of malaria in pregnancy on gestational age, birth weight and infant growth: a cohort study in Uganda TROPICAL MEDICINE & INTERNATIONAL HEALTH, 16 pp. 135-135.

. 2011. Mortality and causes of death in children with sickle cell disease in the Netherlands, before the introduction of neonatal screening. Br J Haematol, 155 (1), pp. 106-110. | Citations: 12 (Scopus) | Show Abstract | Read more

This study analyzed the mortality and causes of death in sickle cell disease patients in the Netherlands, to provide a baseline for monitoring the effect of the recently introduced neonatal screening programme and to indicate areas of improvement in the care for these patients. All children (<18 years) diagnosed with sickle cell disease in a tertiary hospital from 1985 to 2007 were included. Vital status was determined up to March 2008. A total of 298 children were included: 189 (63%) patients had HbSS, 17 (6%) HbSβ(0) thalassaemia, 72 (24%) HbSC and 20 (7%) HbSβ(+) thalassaemia. Twelve patients (4%) died during a total follow-up of 3896 patient years. All known deaths were sickle cell disease-related. Meningitis/sepsis (n=4; 33%), stroke (n=3; 25%) and death during a visit to the country of origin (n=3; 25%) were the most common causes of death. The overall mortality rate was 0·27 deaths/100 patient years [95% confidence interval (CI): 0·15-0·43]. The estimated survival at the age of 18 years was 97·3% (95% CI: 95-99%). This report confirms that the burden of mortality in sickle cell disease is increasingly shifting to adults. It is recommended that compliance to antibiotic prophylaxis, thorough counselling and support for patients travelling abroad and specialized peri-operative care should receive continuous attention.

. 2011. A frequentist approach to estimating the force of infection for a respiratory disease using repeated measurement data from a birth cohort. Stat Methods Med Res, 20 (5), pp. 551-570. | Citations: 1 (Web of Science Lite) | Show Abstract | Read more

This article aims to develop a probability-based model involving the use of direct likelihood formulation and generalised linear modelling (GLM) approaches useful in estimating important disease parameters from longitudinal or repeated measurement data. The current application is based on infection with respiratory syncytial virus. The force of infection and the recovery rate or per capita loss of infection are the parameters of interest. However, because of the limitation arising from the study design and subsequently, the data generated only the force of infection is estimable. The problem of dealing with time-varying disease parameters is also addressed in the article by fitting piecewise constant parameters over time via the GLM approach. The current model formulation is based on that published in White LJ, Buttery J, Cooper B, Nokes DJ and Medley GF. Rotavirus within day care centres in Oxfordshire, UK: characterization of partial immunity. Journal of Royal Society Interface 2008; 5: 1481-1490 with an application to rotavirus transmission and immunity.

et al. 2011. HIV-1 drug resistance in antiretroviral-naive individuals in sub-Saharan Africa after rollout of antiretroviral therapy: a multicentre observational study. Lancet Infect Dis, 11 (10), pp. 750-759. | Citations: 179 (Scopus) | Show Abstract | Read more

BACKGROUND: There are few data on the epidemiology of primary HIV-1 drug resistance after the roll-out of antiretroviral treatment (ART) in sub-Saharan Africa. We aimed to assess the prevalence of primary resistance in six African countries after ART roll-out and if wider use of ART in sub-Saharan Africa is associated with rising prevalence of drug resistance. METHODS: We did a cross-sectional study in antiretroviral-naive adults infected with HIV-1 who had not started first-line ART, recruited between 2007 and 2009 from 11 regions in Kenya, Nigeria, South Africa, Uganda, Zambia, and Zimbabwe. We did population-based sequencing of the pol gene on plasma specimens with greater than 1000 copies per mL of HIV RNA. We identified drug-resistance mutations with the WHO list for transmitted resistance. The prevalence of sequences containing at least one drug-resistance mutation was calculated accounting for the sampling weights of the sites. We assessed the risk factors of resistance with multilevel logistic regression with random coefficients. FINDINGS: 2436 (94.1%) of 2590 participants had a pretreatment genotypic resistance result. 1486 participants (57.4%) were women, 1575 (60.8%) had WHO clinical stage 3 or 4 disease, and the median CD4 count was 133 cells per μL (IQR 62-204). Overall sample-weighted drug-resistance prevalence was 5.6% (139 of 2436; 95% CI 4.6-6.7), ranging from 1.1% (two of 176; 0.0-2.7) in Pretoria, South Africa, to 12.3% (22 of 179; 7.5-17.1) in Kampala, Uganda. The pooled prevalence for all three Ugandan sites was 11.6% (66 of 570; 8.9-14.2), compared with 3.5% (73 of 1866; 2.5-4.5) for all other sites. Drug class-specific resistance prevalence was 2.5% (54 of 2436; 1.8-3.2) for nucleoside reverse-transcriptase inhibitors (NRTIs), 3.3% (83 of 2436; 2.5-4.2) for non-NRTIs (NNRTIs), 1.3% (31 of 2436; 0.8-1.8) for protease inhibitors, and 1.2% (25 of 2436; 0.7-1.7) for dual-class resistance to NRTIs and NNRTIs. The most common drug-resistance mutations were K103N (43 [1.8%] of 2436), thymidine analogue mutations (33 [1.6%] of 2436), M184V (25 [1.2%] of 2436), and Y181C/I (19 [0.7%] of 2436). The odds ratio for drug resistance associated with each additional year since the start of the ART roll-out in a region was 1.38 (95% CI 1.13-1.68; p=0.001). INTERPRETATION: The higher prevalence of primary drug resistance in Uganda than in other African countries is probably related to the earlier start of ART roll-out in Uganda. Resistance surveillance and prevention should be prioritised in settings where ART programmes are scaled up. FUNDING: Ministry of Foreign Affairs of the Netherlands.

. 2011. H5N1-SeroDetect EIA and rapid test: a novel differential diagnostic assay for serodiagnosis of H5N1 infections and surveillance. J Virol, 85 (23), pp. 12455-12463. | Citations: 7 (Web of Science Lite) | Show Abstract | Read more

Continuing evolution of highly pathogenic (HP) H5N1 influenza viruses in wild birds with transmission to domestic poultry and humans poses a pandemic threat. There is an urgent need for a simple and rapid serological diagnostic assay which can differentiate between antibodies to seasonal and H5N1 strains and that could provide surveillance tools not dependent on virus isolation and nucleic acid technologies. Here we describe the establishment of H5N1 SeroDetect enzyme-linked immunosorbent assay (ELISA) and rapid test assays based on three peptides in HA2 (488-516), PB1-F2 (2-75), and M2e (2-24) that are highly conserved within H5N1 strains. These peptides were identified by antibody repertoire analyses of H5N1 influenza survivors in Vietnam using whole-genome-fragment phage display libraries (GFPDLs). To date, both platforms have demonstrated high levels of sensitivity and specificity in detecting H5N1 infections (clade 1 and clade 2.3.4) in Vietnamese patients as early as 7 days and up to several years postinfection. H5N1 virus-uninfected individuals in Vietnam and the United States, including subjects vaccinated with seasonal influenza vaccines or with confirmed seasonal virus infections, did not react in the H5N1-SeroDetect assays. Moreover, sera from individuals vaccinated with H5N1 subunit vaccine with moderate anti-H5N1 neutralizing antibody titers did not react positively in the H5N1-SeroDetect ELISA or rapid test assays. The simple H5N1-SeroDetect ELISA and rapid tests could provide an important tool for large-scale surveillance for potential exposure to HP H5N1 strains in both humans and birds.

et al. 2011. Pharmacokinetics of dihydroartemisinin and piperaquine in pregnant and nonpregnant women with uncomplicated falciparum malaria. Antimicrob Agents Chemother, 55 (12), pp. 5500-5506. | Citations: 34 (Web of Science Lite) | Show Abstract | Read more

Dihydroartemisinin-piperaquine is a fixed-dose artemisinin-based combination treatment. Some antimalarials have altered pharmacokinetics in pregnancy. Pregnant women in the 2nd or 3rd trimester and matched nonpregnant women with uncomplicated falciparum malaria were treated with a total of 6.4 mg/kg of body weight dihydroartemisinin and 51.2 mg/kg piperaquine once daily for 3 days. Venous blood samples were drawn at prespecified time points over 9 weeks. Plasma dihydroartemisinin and piperaquine concentrations were analyzed by liquid chromatography-mass spectrometry. Piperaquine and dihydroartemisinin pharmacokinetics were well described. There were no significant differences in total piperaquine exposure (P = 0.80) or drug exposure during the terminal elimination phase (72 h to infinity) (P = 0.64) between the two groups. The apparent volume of distribution of piperaquine was significantly smaller (602 liters/kg versus 877 liters/kg) in pregnant women than in nonpregnant women (P = 0.0057), and the terminal elimination half-life was significantly shorter (17.8 days versus 25.6 days; P = 0.0023). Dihydroartemisinin exposure after the first dose was significantly lower (844 h × ng/ml versus 1,220 h × ng/ml, P = 0.0021) in pregnant women, but there were no significant differences in total dihydroartemisinin exposure or maximum concentrations between the two groups. There were no significant differences in any pharmacokinetic parameters between the second and third trimester. These results obtained through noncompartmental analysis suggest that in the treatment of falciparum malaria, there are no clinically important differences in the pharmacokinetics of dihydroartemisinin or piperaquine between pregnant and nonpregnant women. However, a more detailed analysis using population pharmacokinetic modeling is needed to fully investigate the differences found for some of the pharmacokinetic parameters, such as the terminal half-life.

et al. 2011. Correlation of susceptibility of Cryptococcus neoformans to amphotericin B with clinical outcome. Antimicrob Agents Chemother, 55 (12), pp. 5624-5630. | Citations: 11 (Scopus) | Show Abstract | Read more

Testing of Cryptococcus neoformans for susceptibility to antifungal drugs by standard microtiter methods has not been shown to correlate with clinical outcomes. This report describes a modified quantitative broth macrodilution susceptibility method showing a correlation with both the patient's quantitative biological response in the cerebrospinal fluid (CSF) and the survival of 85 patients treated with amphotericin B (AMB). The Spearman rank correlation between the quantitative in vitro measure of susceptibility and the quantitative measure of the number of organisms in the patient's CSF was 0.37 (P < 0.01; 95% confidence interval [95% CI], 0.20, 0.60) for the first susceptibility test replicate and 0.46 (P < 0.001; 95% CI, 0.21, 0.62) for the second susceptibility test replicate. The median in vitro estimated response (defined as the fungal burden after AMB treatment) at 1.5 mg/liter AMB for patients alive at day 14 was 5 CFU (95% CI, 3, 8), compared to 57 CFU (95% CI, 4, 832) for those who died before day 14. These exploratory results suggest that patients whose isolates show a quantitative in vitro susceptibility response below 10 CFU/ml were more likely to survive beyond day 14.

. 2011. Adherence to prescribed artemisinin-based combination therapy in Garissa and Bunyala districts, Kenya. Malar J, 10 (1), pp. 281. | Citations: 27 (Scopus) | Show Abstract | Read more

. 2011. Health facility committees and facility management - exploring the nature and depth of their roles in Coast Province, Kenya. BMC Health Serv Res, 11 (1), pp. 229. | Citations: 13 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Community participation has been emphasized internationally as a way of enhancing accountability, as well as a means to enhance health goals in terms of coverage, access and effective utilization. In rural health facilities in Kenya, initiatives to increase community accountability have focused on Health Facility Committees (HFCs). In Coast Province the role of HFCs has been expanded with the introduction of direct funding of rural facilities. We explored the nature and depth of managerial engagement of HFCs at the facility level in two rural districts in this Coastal setting, and how this has contributed to community accountability METHODS: We conducted structured interviews with the health worker in-charge and with patients in 30 health centres and dispensaries. These data were supplemented with in-depth interviews with district managers, and with health workers and HFC members in 12 health centres and dispensaries. In-depth interviews with health workers and HFC members included a participatory exercise to stimulate discussion of the nature and depth of their roles in facility management. RESULTS: HFCs were generally functioning well and played an important role in facility operations. The breadth and depth of engagement had reportedly increased after the introduction of direct funding of health facilities which allowed HFCs to manage their own budgets. Although relations with facility staff were generally good, some mistrust was expressed between HFC members and health workers, and between HFC members and the broader community, partially reflecting a lack of clarity in HFC roles. Moreover, over half of exit interviewees were not aware of the HFC's existence. Women and less well-educated respondents were particularly unlikely to know about the HFC. CONCLUSIONS: There is potential for HFCs to play an active and important role in health facility management, particularly where they have control over some facility level resources. However, to optimise their contribution, efforts are needed to improve their training, clarify their roles, and improve engagement with the wider community.

. 2011. The threat of artemisinin-resistant malaria. N Engl J Med, 365 (12), pp. 1073-1075. | Citations: 147 (Scopus) | Read more

. 2011. Public Health in Practice: translating theory into action. Med Educ, 45 (11), pp. 1142. | Citations: 2 (Web of Science Lite) | Read more

. 2011. Temperature and malaria trends in highland East Africa. PLoS One, 6 (9), pp. e24524. | Citations: 29 (Scopus) | Show Abstract | Read more

There has been considerable debate on the existence of trends in climate in the highlands of East Africa and hypotheses about their potential effect on the trends in malaria in the region. We apply a new robust trend test to mean temperature time series data from three editions of the University of East Anglia's Climatic Research Unit database (CRU TS) for several relevant locations. We find significant trends in the data extracted from newer editions of the database but not in the older version for periods ending in 1996. The trends in the newer data are even more significant when post-1996 data are added to the samples. We also test for trends in the data from the Kericho meteorological station prepared by Omumbo et al. We find no significant trend in the 1979-1995 period but a highly significant trend in the full 1979-2009 sample. However, although the malaria cases observed at Kericho, Kenya rose during a period of resurgent epidemics (1994-2002) they have since returned to a low level. A large assembly of parasite rate surveys from the region, stratified by altitude, show that this decrease in malaria prevalence is not limited to Kericho.

et al. 2011. Mycobacterium tuberculosis lineage influences innate immune response and virulence and is associated with distinct cell envelope lipid profiles. PLoS One, 6 (9), pp. e23870. | Citations: 49 (Web of Science Lite) | Show Abstract | Read more

The six major genetic lineages of Mycobacterium tuberculosis are strongly associated with specific geographical regions, but their relevance to bacterial virulence and the clinical consequences of infection are unclear. Previously, we found that in Vietnam, East Asian/Beijing and Indo-Oceanic strains were significantly more likely to cause disseminated tuberculosis with meningitis than those from the Euro-American lineage. To investigate this observation we characterised 7 East Asian/Beijing, 5 Indo-Oceanic and 6 Euro-American Vietnamese strains in bone-marrow-derived macrophages, dendritic cells and mice. East Asian/Beijing and Indo-Oceanic strains induced significantly more TNF-α and IL-1β from macrophages than the Euro-American strains, and East Asian/Beijing strains were detectable earlier in the blood of infected mice and grew faster in the lungs. We hypothesised that these differences were induced by lineage-specific variation in cell envelope lipids. Whole lipid extracts from East Asian/Beijing and Indo-Oceanic strains induced higher concentrations of TNF-α from macrophages than Euro-American lipids. The lipid extracts were fractionated and compared by thin layer chromatography to reveal a distinct pattern of lineage-associated profiles. A phthiotriol dimycocerosate was exclusively produced by East Asian/Beijing strains, but not the phenolic glycolipid previously associated with the hyper-virulent phenotype of some isolates of this lineage. All Indo-Oceanic strains produced a unique unidentified lipid, shown to be a phenolphthiocerol dimycocerosate dependent upon an intact pks15/1 for its production. This was described by Goren as the 'attenuation indictor lipid' more than 40 years ago, due to its association with less virulent strains from southern India. Mutation of pks15/1 in a representative Indo-Oceanic strain prevented phenolphthiocerol dimycocerosate synthesis, but did not alter macrophage cytokine induction. Our findings suggest that the early interactions between M. tuberculosis and host are determined by the lineage of the infecting strain; but we were unable to show these differences are driven by lineage-specific cell-surface expressed lipids.

. 2011. The plasma concentration of the B cell activating factor is increased in children with acute malaria. J Infect Dis, 204 (6), pp. 962-970. | Citations: 27 (Web of Science Lite) | Show Abstract | Read more

Malaria-specific antibody responses in children often appear to be short-lived but the mechanisms underlying this phenomenon are not well understood. In this study, we investigated the relationship between the B-cell activating factor (BAFF) and its receptors expressed on B cells with antibody responses during and after acute malaria in children. Our results demonstrate that BAFF plasma levels increased during acute malarial disease and reflected disease severity. The expression profiles for BAFF receptors on B cells agreed with rapid activation and differentiation of a proportion of B cells to plasma cells. However, BAFF receptor (BAFF-R) expression was reduced on all peripheral blood B cells during acute infection, but those children with the highest level of BAFF-R expression on B cells maintained schizont-specific immunoglobin G (IgG) over a period of 4 months, indicating that dysregulation of BAFF-R expression on B cells may contribute to short-lived antibody responses to malarial antigens in children. In summary, this study suggests a potential role for BAFF during malaria disease, both as a marker for disease severity and in shaping the differentiation pattern of antigen-specific B cells.

. 2011. 10 Travel-related opportunistic infections. HIV Med, 12 Suppl 2 pp. 88-101. | Citations: 4 (Web of Science Lite) | Read more

. 2011. Kinetics of viremia and NS1 antigenemia are shaped by immune status and virus serotype in adults with dengue. PLoS Negl Trop Dis, 5 (9), pp. e1309. | Citations: 78 (Scopus) | Show Abstract | Read more

BACKGROUND: Dengue is a major public health problem in tropical and subtropical countries. Exploring the relationships between virological features of infection with patient immune status and outcome may help to identify predictors of disease severity and enable rational therapeutic strategies. METHODS: Clinical features, antibody responses and virological markers were characterized in Vietnamese adults participating in a randomised controlled treatment trial of chloroquine. RESULTS: Of the 248 patients with laboratory-confirmed dengue and defined serological and clinical classifications 29 (11.7%) had primary DF, 150 (60.5%) had secondary DF, 4 (1.6%) had primary DHF and 65 (26.2%) had secondary DHF. DENV-1 was the commonest serotype (57.3%), then DENV-2 (20.6%), DENV-3 (15.7%) and DENV-4 (2.8%). DHF was associated with secondary infection (Odds ratio = 3.13, 95% CI 1.04-12.75). DENV-1 infections resulted in significantly higher viremia levels than DENV-2 infections. Early viremia levels were higher in DENV-1 patients with DHF than with DF, even if the peak viremia level was often not observed because it occurred prior to enrolment. Peak viremias were significantly less often observed during secondary infections than primary for all disease severity grades (P = 0.001). The clearance of DENV viremia and NS1 antigenemia occurs earlier and faster in patients with secondary dengue (P<0.0001). The maximum daily rate of viremia clearance was significantly higher in patients with secondary infections than primary (P<0.00001). CONCLUSIONS: Collectively, our findings suggest that the early magnitude of viremia is positively associated with disease severity. The clearance of DENV is associated with immune status, and there are serotype dependent differences in infection kinetics. These findings are relevant for the rational design of randomized controlled trials of therapeutic interventions, especially antivirals.

. 2011. Impact of guidelines and enhanced antibiotic stewardship on reducing broad-spectrum antibiotic usage and its effect on incidence of Clostridium difficile infection. J Antimicrob Chemother, 66 (9), pp. 2168-2174. | Citations: 87 (Web of Science Lite) | Show Abstract | Read more

OBJECTIVES: To evaluate the impact of an 'intervention' consisting of revised antibiotic guidelines for empirical treatment of common infections and enhanced stewardship on reducing broad-spectrum antibiotic usage and its effect on incidence of Clostridium difficile infection (CDI). METHODS: This was a retrospective, quasi-experimental study using interrupted time series (ITS) over 12 months before and after the intervention. The setting was adult medical and surgical wards in University Hospital Lewisham, an acute general hospital in London. The intervention was introduced in April 2006. Revised guidelines avoided broad-spectrum antibiotics, e.g. fluoroquinolones, cephalosporins, clindamycin, amoxicillin and co-amoxiclav, as they were considered to be 'high risk' for CDI. Instead, 'low risk' antibiotics such as penicillin, clarithromycin, doxycycline, gentamicin, vancomycin, trimethoprim and nitrofurantoin were recommended. Changes in antibiotic usage and incidence of CDI before and after the intervention were compared using segmented regression analysis. The negative binomial model was used to analyse the time series to estimate the CDI incidence rate ratio (IRR) following the intervention. RESULTS: The intervention was associated with a significant reduction in the use of fluoroquinolones by 105.33 defined daily doses (DDDs)/1000 occupied bed-days (OBDs) per month [95% confidence interval (CI) 34.18-176.48, P < 0.001] and cephalosporins by 45.93 DDDs/1000 OBDs/month (95% CI 24.11-67.74, P < 0.0001). There was no significant change in total antibiotic, clindamycin, amoxicillin or co-amoxiclav use. There was a significant decrease in CDI following the intervention [IRR 0.34 (0.20-0.58), P < 0.0001]. CONCLUSIONS: Revised antibiotic guidelines and enhanced stewardship was associated with a significant stepwise reduction in the use of cephalosporins and fluoroquinolones and a significant decrease in the incidence of CDI.

. 2011. Ex vivo drug susceptibility of ferroquine against chloroquine-resistant isolates of Plasmodium falciparum and P. vivax. Antimicrob Agents Chemother, 55 (9), pp. 4461-4464. | Citations: 26 (Scopus) | Show Abstract | Read more

Ferroquine (FQ; SSR97193), a ferrocene-containing 4-aminoquinoline derivate, has potent in vitro efficacy against chloroquine (CQ)-resistant Plasmodium falciparum and CQ-sensitive P. vivax. In the current study, ex vivo FQ activity was tested in multidrug-resistant P. falciparum and P. vivax field isolates using a schizont maturation assay. Although FQ showed excellent activity against CQ-sensitive and -resistant P. falciparum and P. vivax (median 50% inhibitory concentrations [IC(50)s], 9.6 nM and 18.8 nM, respectively), there was significant cross-susceptibility with the quinoline-based drugs chloroquine, amodiaquine, and piperaquine (for P. falciparum, r = 0.546 to 0.700, P < 0.001; for P. vivax, r = 0.677 to 0.821, P < 0.001). The observed ex vivo cross-susceptibility is likely to reflect similar mechanisms of drug uptake/efflux and modes of drug action of this drug class. However, the potent activity of FQ against resistant isolates of both P. falciparum and P. vivax highlights a promising role for FQ as a lead antimalarial against CQ-resistant Plasmodium and a useful partner drug for artemisinin-based combination therapy.

et al. 2011. Strengthening the informed consent process in international health research through community engagement: The KEMRI-Wellcome Trust Research Programme Experience. PLoS Med, 8 (9), pp. e1001089. | Citations: 17 (Scopus) | Read more

. 2011. Highly Sensitive Direct Detection and Quantification of Burkholderia pseudomallei Bacteria in Environmental Soil Samples by Using Real-Time PCR APPLIED AND ENVIRONMENTAL MICROBIOLOGY, 77 (18), pp. 6486-6494. | Citations: 24 (Scopus) | Show Abstract | Read more

The soil bacterium and potential biothreat agent Burkholderia pseudomallei causes the infectious disease melioidosis, which is naturally acquired through environmental contact with the bacterium. Environmental detection of B. pseudomallei represents the basis for the development of a geographical risk map for humans and livestock. The aim of the present study was to develop a highly sensitive, culture-independent, DNA-based method that allows direct quantification of B. pseudomallei from soil. We established a protocol for B. pseudomallei soil DNA isolation, purification, and quantification by quantitative PCR (qPCR) targeting a type three secretion system 1 single-copy gene. This assay was validated using 40 soil samples from Northeast Thailand that underwent parallel bacteriological culture. All 26 samples that were B. pseudomallei positive by direct culture were B. pseudomallei qPCR positive, with a median of 1.84 × 10 4 genome equivalents (range, 3.65 × 10 2 to 7.85 × 10 5 ) per gram of soil, assuming complete recovery of DNA. This was 10.6-fold (geometric mean; range, 1.1- to 151.3-fold) higher than the bacterial count defined by direct culture. Moreover, the qPCR detected B. pseudomallei in seven samples (median, 36.9 genome equivalents per g of soil; range, 9.4 to 47.3) which were negative by direct culture. These seven positive results were reproduced using a nested PCR targeting a second, independent B. pseudomallei-specific sequence. Two samples were direct culture and qPCR negative but nested PCR positive. Five samples were negative by both PCR methods and culture. In conclusion, our PCR-based system provides a highly specific and sensitive tool for the quantitative environmental surveillance of B. pseudomallei. © 2011, American Society for Microbiology.

. 2011. Melioidosis: a clinical overview BRITISH MEDICAL BULLETIN, 99 (1), pp. 125-139. | Citations: 114 (Scopus) | Show Abstract | Read more

Introduction: melioidosis, an infection caused by the environmental Gram-negative bacillus Burkholderia pseudomallei, has emerged as an important cause of morbidity and mortality in Southeast Asia and northern Australia. Sources of data: a review of the literature using PubMed. Areas of agreement: approaches to diagnosis and antimicrobial therapy. Areas of controversy: whether seroconversion signals the presence of a quiescent bacterial focus and an increase in long-term risk of melioidosis. Areas timely for developing research: melioidosis is potentially preventable, but there is a striking lack of evidence on which to base an effective prevention programme. An accurate map defining the global distribution of B. pseudomallei is needed, together with studies on the relative importance of different routes of infection. There is a marked difference in mortality from melioidosis in high-income versus lower income countries, and affordable strategies that reduce death from severe sepsis (from any cause) in resource-restricted settings are needed. © The Author 2010. Published by Oxford University Press. All rights reserved.

. 2011. Diagnostic accuracy of a loop-mediated isothermal PCR assay for detection of Orientia tsutsugamushi during acute Scrub Typhus infection. PLoS Negl Trop Dis, 5 (9), pp. e1307. | Citations: 32 (Scopus) | Show Abstract | Read more

BACKGROUND: There is an urgent need to develop rapid and accurate point-of-care (POC) technologies for acute scrub typhus diagnosis in low-resource, primary health care settings to guide clinical therapy. METHODOLOGY/PRINCIPAL FINDINGS: In this study we present the clinical evaluation of loop-mediated isothermal PCR assay (LAMP) in the context of a prospective fever study, including 161 patients from scrub typhus-endemic Chiang Rai, northern Thailand. A robust reference comparator set comprising following 'scrub typhus infection criteria' (STIC) was used: a) positive cell culture isolate and/or b) an admission IgM titer ≥1∶12,800 using the 'gold standard' indirect immunofluorescence assay (IFA) and/or c) a 4-fold rising IFA IgM titer and/or d) a positive result in at least two out of three PCR assays. Compared to the STIC criteria, all PCR assays (including LAMP) demonstrated high specificity ranging from 96-99%, with sensitivities varying from 40% to 56%, similar to the antibody based rapid test, which had a sensitivity of 47% and a specificity of 95%. CONCLUSIONS/SIGNIFICANCE: The diagnostic accuracy of the LAMP assay was similar to realtime and nested conventional PCR assays, but superior to the antibody-based rapid test in the early disease course. The combination of DNA- and antibody-based detection methods increased sensitivity with minimal reduction of specificity, and expanded the timeframe of adequate diagnostic coverage throughout the acute phase of scrub typhus.

. 2011. Impact of a clonal outbreak of extended-spectrum β-lactamase-producing Klebsiella pneumoniae in the development and evolution of bloodstream infections by K. pneumoniae and Escherichia coli: an 11 year experience in Oxfordshire, UK. J Antimicrob Chemother, 66 (9), pp. 2126-2135. | Citations: 20 (Web of Science Lite) | Show Abstract | Read more

OBJECTIVES: The objectives of this study were: (i) to describe an outbreak of multidrug-resistant Klebsiella pneumoniae in our population; (ii) to identify the potential source of this outbreak by examining antibiotic resistance trends in urocultures; (iii) to evaluate the contribution of this outbreak to resistance patterns over time in the two commonest Gram-negative blood culture isolates, namely K. pneumoniae and Escherichia coli; and (iv) to assess risk factors for multidrug resistance and the impact of this resistance on mortality and length of stay. METHODS: We searched Microbiology and Patient Administration Service databases retrospectively and describe resistance trends in E. coli and K. pneumoniae bloodstream infections (BSIs) in Oxfordshire, UK, over an 11 year period. RESULTS: An outbreak of a multidrug-resistant, CTX-M-15 extended-spectrum β-lactamase (ESBL)-producing K. pneumoniae clone was identified and shown by multilocus sequence typing to belong to a novel sequence type designated ST490. This was associated with a sporadic change in resistance rates in K. pneumoniae BSIs with rates of multidrug resistance (defined as resistance to three or more antibiotic classes) reaching 40%. A case-control study showed prior antibiotic exposure as a risk factor for infection with this organism. During the same time period, rates of ESBL-producing Klebsiella spp. isolated from urocultures increased from 0.5% to almost 6%. By contrast, the rate of multidrug resistance in E. coli rose more steadily from 0% in 2000 to 10% in 2010. CONCLUSIONS: Changes in resistance rates may be associated with outbreaks of resistant clones in K. pneumoniae. Changing resistance patterns may affect important health economic issues such as length of stay.

. 2011. Full loss of residual renal function causes higher mortality in dialysis patients; findings from a marginal structural model. Nephrol Dial Transplant, 26 (9), pp. 2978-2983. | Citations: 63 (Scopus) | Show Abstract | Read more

BACKGROUND: Declining residual renal function, as indicated by the glomerular filtration rate (GFR), is associated with an increased mortality risk in patients with end-stage renal disease (ESRD) on dialysis. METHODS: We monitored GFR and mortality in 1800 haemodialysis (HD) and peritoneal dialysis (PD) patients in 1996-2006. We used a marginal structural model to estimate the causal effects both of GFR when it was not completely lost and of the subsequent full loss of GFR on mortality, avoiding the drawbacks of standard regression models that include covariates to adjust for confounding. Instead, effect estimates were adjusted for possible baseline and time-varying confounders using inverse probability weighting. RESULTS: We estimated a hazard ratio (HR) corresponding to the effect of the full loss of GFR on mortality, as compared to not having fully lost GFR, of 1.50 [95% confidence interval (CI) 1.09-2.07]. The HR corresponding to the effect of GFR when GFR is not (yet) fully lost on mortality was 0.97 (95% CI 0.92-1.02) (per mL/min/1.73 m(2)). We found no significant difference in the effect of GFR on mortality between patients starting on PD and HD. CONCLUSIONS: Preventing or delaying the full loss of GFR can improve survival in dialysis patients. This supports the importance that is given to the effect of treatment options for patients with ESRD on the rate of decline of the residual renal function.

. 2011. Symptoms of infectious diseases in immunocompromised travelers: a prospective study with matched controls. J Travel Med, 18 (5), pp. 318-326. | Citations: 23 (Scopus) | Show Abstract | Read more

BACKGROUND: Immunocompromised travelers to developing countries are thought to have symptomatic infectious diseases more often and longer than non-immunocompromised travelers. Evidence for this is lacking. This study evaluates whether immunocompromised short-term travelers are at increased risk of diseases. METHODS: A prospective study was performed between October 2003 and May 2010 among adult travelers using immunosuppressive agents (ISA) and travelers with inflammatory bowel disease (IBD), with their non-immunocompromised travel companions serving as matched controls with comparable exposure to infection. Data on symptoms of infectious diseases were recorded by using a structured diary. RESULTS: Among 75 ISA, the incidence of travel-related diarrhea was 0.76 per person-month, and the number of symptomatic days 1.32 per month. For their 75 controls, figures were 0.66 and 1.50, respectively (p > 0.05). Among 71 IBD, the incidence was 1.19, and the number of symptomatic days was 2.48. For their 71 controls, figures were 0.73 and 1.31, respectively (p > 0.05). These differences also existed before travel. ISA had significantly more and longer travel-related signs of skin infection and IBD suffered more and longer from vomiting. As for other symptoms, no significant travel-related differences were found. Only 21% of immunocompromised travelers suffering from diarrhea used their stand-by antibiotics. CONCLUSIONS: ISA and IBD did not have symptomatic infectious diseases more often or longer than non-immunocompromised travelers, except for signs of travel-related skin infection among ISA. Routine prescription of stand-by antibiotics for these immunocompromised travelers to areas with good health facilities is probably not more useful than for healthy travelers.

et al. 2011. Unnecessary antiretroviral treatment switches and accumulation of HIV resistance mutations; two arguments for viral load monitoring in Africa. J Acquir Immune Defic Syndr, 58 (1), pp. 23-31. | Citations: 102 (Scopus) | Show Abstract | Read more

OBJECTIVES: This study aimed to investigate the consequences of using clinicoimmunological criteria to detect antiretroviral treatment (ART) failure and guide regimen switches in HIV-infected adults in sub-Saharan Africa. Frequencies of unnecessary switches, patterns of HIV drug resistance, and risk factors for the accumulation of nucleoside reverse transcriptase inhibitor (NRTI)-associated mutations were evaluated. METHODS: Cross-sectional analysis of adults switching ART regimens at 13 clinical sites in 6 African countries was performed. Two types of failure identification were compared: diagnosis of clinicoimmunological failure without viral load testing (CIF only) or CIF with local targeted viral load testing (targeted VL). After study enrollment, reference HIV RNA and genotype were determined retrospectively. Logistic regression assessed factors associated with multiple thymidine analogue mutations (TAMs) and NRTI cross-resistance (≥2 TAMs or Q151M or K65R/K70E). RESULTS: Of 250 patients with CIF switching to second-line ART, targeted VL was performed in 186. Unnecessary switch at reference HIV RNA <1000 copies per milliliter occurred in 46.9% of CIF only patients versus 12.4% of patients with targeted VL (P < 0.001). NRTI cross-resistance was observed in 48.0% of 183 specimens available for genotypic analysis, comprising ≥2 TAMs (37.7%), K65R (7.1%), K70E (3.3%), or Q151M (3.3%). The presence of NRTI cross-resistance was associated with the duration of ART exposure and zidovudine use. CONCLUSIONS: Clinicoimmunological monitoring without viral load testing resulted in frequent unnecessary regimen switches. Prolonged treatment failure was indicated by extensive NRTI cross-resistance. Access to virological monitoring should be expanded to prevent inappropriate switches, enable early failure detection and preserve second-line treatment options in Africa.

. 2011. A review of mixed malaria species infections in anopheline mosquitoes. Malar J, 10 (1), pp. 253. | Citations: 25 (Scopus) | Show Abstract | Read more

BACKGROUND: In patients with malaria mixed species infections are common and under reported. In PCR studies conducted in Asia mixed infection rates often exceed 20%. In South-East Asia, approximately one third of patients treated for falciparum malaria experience a subsequent Plasmodium vivax infection with a time interval suggesting relapse. It is uncertain whether the two infections are acquired simultaneously or separately. To determine whether mixed species infections in humans are derived from mainly from simultaneous or separate mosquito inoculations the literature on malaria species infection in wild captured anopheline mosquitoes was reviewed. METHODS: The biomedical literature was searched for studies of malaria infection and species identification in trapped wild mosquitoes and artificially infected mosquitoes. The study location and year, collection methods, mosquito species, number of specimens, parasite stage examined (oocysts or sporozoites), and the methods of parasite detection and speciation were tabulated. The entomological results in South East Asia were compared with mixed infection rates documented in patients in clinical studies. RESULTS: In total 63 studies were identified. Individual anopheline mosquitoes were examined for different malaria species in 28 of these. There were 14 studies from Africa; four with species evaluations in individual captured mosquitoes (SEICM). One study, from Ghana, identified a single mixed infection. No mixed infections were identified in Central and South America (seven studies, two SEICM). 42 studies were conducted in Asia and Oceania (11 from Thailand; 27 SEICM). The proportion of anophelines infected with Plasmodium falciparum parasites only was 0.51% (95% CI: 0.44 to 0.57%), for P. vivax only was 0.26% (95% CI: 0.21 to 0.30%), and for mixed P. falciparum and P. vivax infections was 0.036% (95% CI: 0.016 to 0.056%). The proportion of mixed infections in mosquitoes was significantly higher than expected by chance (P < 0.001), but was one fifth of that sufficient to explain the high rates of clinical mixed infections by simultaneous inoculation. CONCLUSIONS: There are relatively few data on mixed infection rates in mosquitoes from Africa. Mixed species malaria infections may be acquired by simultaneous inoculation of sporozoites from multiply infected anopheline mosquitoes but this is relatively unusual. In South East Asia, where P. vivax infection follows P. falciparum malaria in one third of cases, the available entomological information suggests that the majority of these mixed species malaria infections are acquired from separate inoculations.

. 2011. Survey of antimicrobial resistance in clinical Burkholderia pseudomallei isolates over two decades in Northeast Thailand. Antimicrob Agents Chemother, 55 (11), pp. 5388-5391. | Citations: 25 (Scopus) | Show Abstract | Read more

A 21-year survey conducted in northeast Thailand of antimicrobial resistance to parenteral antimicrobial drugs used to treat melioidosis identified 24/4,021 (0.6%) patients with one or more isolates resistant to ceftazidime (n = 8), amoxicillin-clavulanic acid (n = 4), or both drugs (n = 12). Two cases were identified at admission, and the remainder were detected a median of 15 days after starting antimicrobial therapy. Resistance to carbapenem drugs was not detected. These findings support the current prescribing recommendations for melioidosis.

. 2011. Poor diagnostic accuracy of commercial antibody-based assays for the diagnosis of acute Chikungunya infection. Clin Vaccine Immunol, 18 (10), pp. 1773-1775. | Citations: 28 (Scopus) | Show Abstract | Read more

A Sri Lankan fever cohort (n = 292 patients; 17.8% prevalence) was used to assess two standard diagnostic Chikungunya IgM tests. The immunochromatographic test (ICT) acute sample sensitivity (SN) was 1.9 to 3.9%, and specificity (SP) was 92.5 to 95.0%. The enzyme-linked immunosorbent assay (ELISA) gave an acute sample SN of 3.9% and an SP of 92.5% and a convalescent sample SN of 84% and an SP of 91%. These assays are not suitable for the acute diagnosis of Chikungunya virus infection.

. 2011. Validation of an internally controlled one-step real-time multiplex RT-PCR assay for the detection and quantitation of dengue virus RNA in plasma. J Virol Methods, 177 (2), pp. 168-173. | Citations: 10 (Web of Science Lite) | Show Abstract | Read more

Dengue is mosquito-borne virus infection that annually causes ~50 million clinically apparent cases worldwide. An internally controlled one-step real-time multiplex RT-PCR assay was developed for detection and quantitation of DENV RNA in plasma sample by using specific primers and fluorogenic TaqMan probes. All primers and probes targeted sequences near the 3' end of the NS5 gene. The method comprised two multiplex assays and was validated for sensitivity, specificity, linearity, reproducibility and precision. An internal control template was spiked into each clinical specimen to provide quality assurance for each experimental step. The assay allowed for detection of between 0.5 and 3 infectious particles per mL, is rapid and has been operationally characterized in 287 Vietnamese dengue patients from two therapeutic intervention trials at the Hospital for Tropical Diseases, Ho Chi Minh City, Viet Nam.

. 2011. Direct membrane binding by bacterial actin MreB. Mol Cell, 43 (3), pp. 478-487. | Citations: 101 (Scopus) | Show Abstract | Read more

Bacterial actin MreB is one of the key components of the bacterial cytoskeleton. It assembles into short filaments that lie just underneath the membrane and organize the cell wall synthesis machinery. Here we show that MreB from both T. maritima and E. coli binds directly to cell membranes. This function is essential for cell shape determination in E. coli and is proposed to be a general property of many, if not all, MreBs. We demonstrate that membrane binding is mediated by a membrane insertion loop in TmMreB and by an N-terminal amphipathic helix in EcMreB and show that purified TmMreB assembles into double filaments on a membrane surface that can induce curvature. This, the first example of a membrane-binding actin filament, prompts a fundamental rethink of the structure and dynamics of MreB filaments within cells.

et al. 2011. Assessment of severe malaria in a multicenter, phase III, RTS, S/AS01 malaria candidate vaccine trial: case definition, standardization of data collection and patient care. Malar J, 10 (1), pp. 221. | Citations: 21 (Scopus) | Show Abstract | Read more

BACKGROUND: An effective malaria vaccine, deployed in conjunction with other malaria interventions, is likely to substantially reduce the malaria burden. Efficacy against severe malaria will be a key driver for decisions on implementation. An initial study of an RTS, S vaccine candidate showed promising efficacy against severe malaria in children in Mozambique. Further evidence of its protective efficacy will be gained in a pivotal, multi-centre, phase III study. This paper describes the case definitions of severe malaria used in this study and the programme for standardized assessment of severe malaria according to the case definition. METHODS: Case definitions of severe malaria were developed from a literature review and a consensus meeting of expert consultants and the RTS, S Clinical Trial Partnership Committee, in collaboration with the World Health Organization and the Malaria Clinical Trials Alliance. The same groups, with input from an Independent Data Monitoring Committee, developed and implemented a programme for standardized data collection.The case definitions developed reflect the typical presentations of severe malaria in African hospitals. Markers of disease severity were chosen on the basis of their association with poor outcome, occurrence in a significant proportion of cases and on an ability to standardize their measurement across research centres. For the primary case definition, one or more clinical and/or laboratory markers of disease severity have to be present, four major co-morbidities (pneumonia, meningitis, bacteraemia or gastroenteritis with severe dehydration) are excluded, and a Plasmodium falciparum parasite density threshold is introduced, in order to maximize the specificity of the case definition. Secondary case definitions allow inclusion of co-morbidities and/or allow for the presence of parasitaemia at any density. The programmatic implementation of standardized case assessment included a clinical algorithm for evaluating seriously sick children, improvements to care delivery and a robust training and evaluation programme for clinicians. CONCLUSIONS: The case definition developed for the pivotal phase III RTS, S vaccine study is consistent with WHO recommendations, is locally applicable and appropriately balances sensitivity and specificity in the diagnosis of severe malaria. Processes set up to standardize severe malaria data collection will allow robust assessment of the efficacy of the RTS, S vaccine against severe malaria, strengthen local capacity and benefit patient care for subjects in the trial. TRIAL REGISTRATION: Clinicaltrials.gov NCT00866619.

et al. 2011. Artemisinin resistance in Plasmodium falciparum is associated with an altered temporal pattern of transcription. BMC Genomics, 12 (1), pp. 391. | Citations: 71 (Scopus) | Show Abstract | Read more

BACKGROUND: Artemisinin resistance in Plasmodium falciparum malaria has emerged in Western Cambodia. This is a major threat to global plans to control and eliminate malaria as the artemisinins are a key component of antimalarial treatment throughout the world. To identify key features associated with the delayed parasite clearance phenotype, we employed DNA microarrays to profile the physiological gene expression pattern of the resistant isolates. RESULTS: In the ring and trophozoite stages, we observed reduced expression of many basic metabolic and cellular pathways which suggests a slower growth and maturation of these parasites during the first half of the asexual intraerythrocytic developmental cycle (IDC). In the schizont stage, there is an increased expression of essentially all functionalities associated with protein metabolism which indicates the prolonged and thus increased capacity of protein synthesis during the second half of the resistant parasite IDC. This modulation of the P. falciparum intraerythrocytic transcriptome may result from differential expression of regulatory proteins such as transcription factors or chromatin remodeling associated proteins. In addition, there is a unique and uniform copy number variation pattern in the Cambodian parasites which may represent an underlying genetic background that contributes to the resistance phenotype. CONCLUSIONS: The decreased metabolic activities in the ring stages are consistent with previous suggestions of higher resilience of the early developmental stages to artemisinin. Moreover, the increased capacity of protein synthesis and protein turnover in the schizont stage may contribute to artemisinin resistance by counteracting the protein damage caused by the oxidative stress and/or protein alkylation effect of this drug. This study reports the first global transcriptional survey of artemisinin resistant parasites and provides insight to the complexities of the molecular basis of pathogens with drug resistance phenotypes in vivo.

et al. 2011. Laboratory prediction of the requirement for renal replacement in acute falciparum malaria. Malar J, 10 (1), pp. 217. | Citations: 12 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Acute renal failure is a common complication of severe malaria in adults, and without renal replacement therapy (RRT), it carries a poor prognosis. Even when RRT is available, delaying its initiation may increase mortality. Earlier identification of patients who will need RRT may improve outcomes. METHOD: Prospectively collected data from two intervention studies in adults with severe malaria were analysed focusing on laboratory features on presentation and their association with a later requirement for RRT. In particular, laboratory indices of acute tubular necrosis (ATN) and acute kidney injury (AKI) that are used in other settings were examined. RESULTS: Data from 163 patients were available for analysis. Whether or not the patients should have received RRT (a retrospective assessment determined by three independent reviewers) was used as the reference. Forty-three (26.4%) patients met criteria for dialysis, but only 19 (44.2%) were able to receive this intervention due to the limited availability of RRT. Patients with impaired renal function on admission (creatinine clearance < 60 ml/min) (n = 84) had their laboratory indices of ATN/AKI analysed. The plasma creatinine level had the greatest area under the ROC curve (AUC): 0.83 (95% confidence interval 0.74-0.92), significantly better than the AUCs for, urinary sodium level, the urea to creatinine ratio (UCR), the fractional excretion of urea (FeUN) and the urinary neutrophil gelatinase-associated lipocalcin (NGAL) level. The AUC for plasma creatinine was also greater than the AUC for blood urea nitrogen level, the fractional excretion of sodium (FeNa), the renal failure index (RFI), the urinary osmolality, the urine to plasma creatinine ratio (UPCR) and the creatinine clearance, although the difference for these variables did not reach statistical significance. CONCLUSIONS: In adult patients with severe malaria and impaired renal function on admission, none of the evaluated laboratory indices was superior to the plasma creatinine level when used to predict a later requirement for renal replacement therapy.

. 2011. The effect of mobile phone text-message reminders on Kenyan health workers' adherence to malaria treatment guidelines: a cluster randomised trial. Lancet, 378 (9793), pp. 795-803. | Citations: 154 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Health workers' malaria case-management practices often differ from national guidelines. We assessed whether text-message reminders sent to health workers' mobile phones could improve and maintain their adherence to treatment guidelines for outpatient paediatric malaria in Kenya. METHODS: From March 6, 2009, to May 31, 2010, we did a cluster-randomised controlled trial at 107 rural health facilities in 11 districts in coastal and western Kenya. With a computer-generated sequence, health facilities were randomly allocated to either the intervention group, in which all health workers received text messages on their personal mobile phones on malaria case-management for 6 months, or the control group, in which health workers did not receive any text messages. Health workers were not masked to the intervention, although patients were unaware of whether they were in an intervention or control facility. The primary outcome was correct management with artemether-lumefantrine, defined as a dichotomous composite indicator of treatment, dispensing, and counselling tasks concordant with Kenyan national guidelines. The primary analysis was by intention to treat. The trial is registered with Current Controlled Trials, ISRCTN72328636. FINDINGS: 119 health workers received the intervention. Case-management practices were assessed for 2269 children who needed treatment (1157 in the intervention group and 1112 in the control group). Intention-to-treat analysis showed that correct artemether-lumefantrine management improved by 23·7 percentage-points (95% CI 7·6-40·0; p=0·004) immediately after intervention and by 24·5 percentage-points (8·1-41·0; p=0·003) 6 months later. INTERPRETATION: In resource-limited settings, malaria control programmes should consider use of text messaging to improve health workers' case-management practices. FUNDING: The Wellcome Trust.

et al. 2011. Real-time PCR for detection of Streptococcus suis serotype 2 in cerebrospinal fluid of human patients with meningitis. Diagn Microbiol Infect Dis, 70 (4), pp. 461-467. | Citations: 22 (Scopus) | Show Abstract | Read more

Streptococcus suis serotype 2 is an emerging zoonotic pathogen and is the main cause of acute bacterial meningitis in adult patients in Vietnam. We developed an internally controlled real-time PCR for detection of S. suis serotype 2 in cerebrospinal fluid (CSF) samples targeted at the cps2J gene. Sensitivity and specificity in culture-confirmed clinical samples were 100%. The PCR detected S. suis serotype 2 infection in 101 of 238 (42.4%) prospectively collected CSF samples, of which 55 (23%) were culture positive. Culture-negative but PCR-positive CSF samples were significantly associated with the use of antimicrobial agents before admission. S. suis serotype 2 infection was more common than infections with Streptococcus pneumoniae and Neisseria meningitidis combined. Our results strikingly illustrate the additional diagnostic value of PCR in patients who are pretreated with antimicrobial agents and demonstrate the extremely high prevalence of S. suis infections among Vietnamese adult patients with bacterial meningitis.

. 2011. Use of filter paper as a transport medium for laboratory diagnosis of cholera under field conditions. J Clin Microbiol, 49 (8), pp. 3021-3023. | Citations: 5 (Web of Science Lite) | Show Abstract | Read more

Confirmation of a cholera epidemic is based on bacteriological identification of the agent and requires the sending of samples to a culture laboratory, often in countries with limited resources. Comparison of the use of filter paper with the use of Cary-Blair reference medium for stool transport showed that this simple transport medium is appropriate for the recovery of Vibrio cholerae.

. 2011. Urine antibiotic activity in patients presenting to hospitals in Laos: implications for worsening antibiotic resistance. Am J Trop Med Hyg, 85 (2), pp. 295-302. | Citations: 9 (Web of Science Lite) | Show Abstract | Read more

Widespread use of antibiotics may be important in the spread of antimicrobial resistance. We estimated the proportion of Lao in- and outpatients who had taken antibiotics before medical consultation by detecting antibiotic activity in their urine added to lawns of Bacillus stearothermophilus, Escherichia coli, and Streptococcus pyogenes. In the retrospective (N = 2,058) and prospective studies (N = 1,153), 49.7% (95% confidence interval [CI] = 47.4-52.0) and 36.2% (95% CI = 33.4-38.9), respectively, of Vientiane patients had urinary antibiotic activity detected. The highest frequency of estimated antibiotic pre-treatment was found in patients recruited with suspected central nervous system infections and community-acquired septicemia (both 56.8%). In Vientiane, children had a higher frequency of estimated antibiotic pre-treatment than adults (60.0% versus 46.5%; P < 0.001). Antibiotic use based on patients histories was significantly less frequent than when estimated from urinary antibiotic activity (P < 0.0001).

. 2011. Dextran fractional clearance studies in acute dengue infection. PLoS Negl Trop Dis, 5 (8), pp. e1282. | Citations: 5 (Scopus) | Show Abstract | Read more

BACKGROUND: Although increased capillary permeability is the major clinical feature associated with severe dengue infections the mechanisms underlying this phenomenon remain unclear. Dextran clearance methodology has been used to investigate the molecular sieving properties of the microvasculature in clinical situations associated with altered permeability, including during pregnancy and in various renal disorders. In order to better understand the characteristics of the vascular leak associated with dengue we undertook formal dextran clearance studies in Vietnamese dengue patients and healthy volunteers. METHODOLOGY/PRINCIPAL FINDINGS: We carried out serial clearance studies in 15 young adult males with acute dengue and evidence of vascular leakage a) during the phase of maximal leakage and b) one and three months later, as well as in 16 healthy control subjects. Interestingly we found no difference in the clearance profiles of neutral dextran solutions among the dengue patients at any time-point or in comparison to the healthy volunteers. CONCLUSIONS/SIGNIFICANCE: The surface glycocalyx layer, a fibre-matrix of proteoglycans, glycosaminoglycans, and plasma proteins, forms a complex with the underlying endothelial cells to regulate plasma volume within circumscribed limits. It is likely that during dengue infections loss of plasma proteins from this layer alters the permeability characteristics of the complex; physical and/or electrostatic interactions between the dextran molecules and the glycocalyx structure may temporarily restore normal function, rendering the technique unsuitable for assessing permeability in these patients. The implications for resuscitation of patients with dengue shock syndrome (DSS) are potentially important. It is possible that continuous low-dose infusions of dextran may help to stabilize the permeability barrier in patients with profound or refractory shock, reducing the need for repeated boluses, limiting the total colloid volume required. Formal clinical studies should help to assess this strategy as an alternative to conventional fluid resuscitation for severe DSS.

. 2011. The antimalarial ferroquine: from bench to clinic. Parasite, 18 (3), pp. 207-214. | Citations: 81 (Scopus) | Show Abstract | Read more

Ferroquine (FQ, SSR97193) is currently the most advanced organo-metallic drug candidate and about to complete phase II clinical trials as a treatment for uncomplicated malaria. This ferrocene-containing compound is active against both chloroquine-susceptible and chloroquine-resistant Plasmodium falciparum and P. vivax strains and/or isolates. This article focuses on the discovery of FQ, its antimalarial activity, the hypothesis of its mode of action, the current absence of resistance in vitro and recent clinical trials.

. 2011. Bacterial meningitis: frapper fort ou frapper doucement? Lancet Infect Dis, 11 (8), pp. 582-583. | Read more

. 2011. HIV diagnosis, linkage to HIV care, and HIV risk behaviors among newly diagnosed HIV-positive female sex workers in Kigali, Rwanda. J Acquir Immune Defic Syndr, 57 (4), pp. e70-e76. | Citations: 15 (Scopus) | Show Abstract | Read more

OBJECTIVE: To evaluate linkage-to-care, sexual behavior change, and psychosocial experiences among newly HIV-diagnosed female sex workers (FSWs) in Rwanda. METHODS: FSWs (n = 800) with unknown serostatus were screened for HIV during 2007/2008. Women testing HIV positive (n = 192) were referred to care and asked to return for interviews and laboratory testing 12-36 months postdiagnosis. One hundred fourty-one women (73%) returned for the postdiagnosis visit. RESULTS: Median CD4 count at diagnosis was 460 cells per microliter [interquartile range (IQR): 308-628], with 32% eligible for antiretroviral therapy (ART) per national CD4 criteria (median CD4: 235, IQR: 152-303). Postdiagnosis, 92% of women reported having disclosed their HIV status to a friend or relative, 85% reported having enrolled in HIV care (median 30 days after diagnosis, IQR: 7-360), including 89% among ART-eligible women. Among ART-eligible women in care, 87% had initiated ART, with a median follow-up CD4 count of 354 cells per microliter (IQR: 213-456). Women who did not initiate ART experienced a 6-month CD4 count change of -14 cells per microliter (IQR: -41 to 13). Three-quarters of women reported reduced sexual risk behavior postdiagnosis, with only 64% continuing to identify as FSWs. However, 53% reported past month condom use only "sometimes." CONCLUSIONS: Timely linkage to care and ART uptake were high in this group of Rwandan FSWs. However, risky sexual behaviors remained common after enrollment in care. HIV-positive FSWs are an important and receptive group for targeted efforts to increase HIV diagnosis and linkage to care/treatment. Once in care, intensified and sustained HIV prevention education is necessary.

. 2011. The incubation period distribution of tuberculosis estimated with a molecular epidemiological approach. Int J Epidemiol, 40 (4), pp. 964-970. | Citations: 32 (Scopus) | Show Abstract | Read more

BACKGROUND: There is limited information on the distribution of incubation periods of tuberculosis (TB). METHODS: In The Netherlands, patients whose Mycobacterium tuberculosis isolates have identical DNA fingerprints in the period 1993-2007 were interviewed to identify epidemiological links between cases. We determined the incubation period distribution in secondary cases. Survival analysis techniques were used to include secondary cases not yet symptomatic at diagnosis with weighting to adjust for lower capture probabilities of couples with longer time intervals between their diagnoses. In order to deal with missing data, we used multiple imputations. RESULTS: We identified 1095 epidemiologically linked secondary cases, attributed to 688 source cases with pulmonary TB. Of those developing disease within 15 years, the Kaplan-Meier probability to fall ill within 1 year was 45%, within 2 years 62% and within 5 years 83%. The incubation time was shorter in secondary cases who were men, young, those with extra-pulmonary TB and those not reporting previous TB or previous preventive therapy. CONCLUSIONS: Molecular epidemiological analysis has allowed a more precise description of the incubation period of TB than was possible in previous studies, including the identification of risk factors for shorter incubation periods.

. 2011. Ipw: An R package for inverse probability weighting Journal of Statistical Software, 43 (13), pp. 2-23. | Citations: 28 (Scopus) | Show Abstract

We describe the R package ipw for estimating inverse probability weights. We show how to use the package to fit marginal structural models through inverse probability weighting, to estimate causal effects. Our package can be used with data from a point treatment situation as well as with a time-varying exposure and time-varying confounders. It can be used with binomial, categorical, ordinal and continuous exposure variables.

. 2011. Highly sensitive direct detection and quantification of Burkholderia pseudomallei bacteria in environmental soil samples by using real-time PCR. Appl Environ Microbiol, 77 (18), pp. 6486-6494. | Show Abstract | Read more

The soil bacterium and potential biothreat agent Burkholderia pseudomallei causes the infectious disease melioidosis, which is naturally acquired through environmental contact with the bacterium. Environmental detection of B. pseudomallei represents the basis for the development of a geographical risk map for humans and livestock. The aim of the present study was to develop a highly sensitive, culture-independent, DNA-based method that allows direct quantification of B. pseudomallei from soil. We established a protocol for B. pseudomallei soil DNA isolation, purification, and quantification by quantitative PCR (qPCR) targeting a type three secretion system 1 single-copy gene. This assay was validated using 40 soil samples from Northeast Thailand that underwent parallel bacteriological culture. All 26 samples that were B. pseudomallei positive by direct culture were B. pseudomallei qPCR positive, with a median of 1.84 × 10(4) genome equivalents (range, 3.65 × 10(2) to 7.85 × 10(5)) per gram of soil, assuming complete recovery of DNA. This was 10.6-fold (geometric mean; range, 1.1- to 151.3-fold) higher than the bacterial count defined by direct culture. Moreover, the qPCR detected B. pseudomallei in seven samples (median, 36.9 genome equivalents per g of soil; range, 9.4 to 47.3) which were negative by direct culture. These seven positive results were reproduced using a nested PCR targeting a second, independent B. pseudomallei-specific sequence. Two samples were direct culture and qPCR negative but nested PCR positive. Five samples were negative by both PCR methods and culture. In conclusion, our PCR-based system provides a highly specific and sensitive tool for the quantitative environmental surveillance of B. pseudomallei.

. 2011. The pathogenesis of dengue. Vaccine, 29 (42), pp. 7221-7228. | Citations: 102 (Web of Science Lite) | Show Abstract | Read more

Dengue is an important cause of childhood and adult morbidity in Asian and Latin American countries and its geographic footprint is growing. The clinical manifestations of dengue are the expression of a constellation of host and viral factors, some acquired, others intrinsic to the individual. The virulence of the virus plus the flavivirus infection history, age, gender and genotype of the host all appear to help shape the severity of infection. Similarly, the characteristics of the innate and acquired host immune response subsequent to infection are also likely determinants of outcome. This review summarises recent developments in the understanding of dengue pathogenesis and their relevance to dengue vaccine development.

. 2011. Treatment of African children with severe malaria - towards evidence-informed clinical practice using GRADE. Malar J, 10 (1), pp. 201. | Citations: 2 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Severe malaria is a major contributor of deaths in African children up to five years of age. One valuable tool to support health workers in the management of diseases is clinical practice guidelines (CPGs) developed using robust methods. A critical assessment of the World Health Organization (WHO) and Kenyan paediatric malaria treatment guidelines with quinine was undertaken, with a focus on the quality of the evidence and transparency of the shift from evidence to recommendations. METHODS: Systematic reviews of the literature were conducted using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) tool to appraise included studies. The findings were used to evaluate the WHO and Kenyan recommendations for the management of severe childhood malaria. RESULTS: The WHO 2010 malaria guidance on severe malaria in children, which informed the Kenyan guidelines, only evaluated the evidence on one topic on paediatric care using the GRADE tool. Using the GRADE tool, this work explicitly demonstrated that despite the established use of quinine in the management of paediatric cases of severe malaria for decades, low or very low quality evidence of important outcomes, but not critical outcomes such as mortality, have informed national and international guidance on the paediatric quinine dosing, route of administration and adverse effects. CONCLUSIONS: Despite the foreseeable shift to artesunate as the primary drug for treatment of severe childhood malaria, the findings reported here reflect that the particulars of quinine therapeutics for the management of severe malaria in African children have historically been a neglected research priority. This work supports the application of the GRADE tool to make transparent recommendations and to inform advocacy efforts for a greater research focus in priority areas in paediatric care in Africa and other low-income settings.

. 2011. Survival of Burkholderia pseudomallei in distilled water for 16 years. Trans R Soc Trop Med Hyg, 105 (10), pp. 598-600. | Citations: 27 (Web of Science Lite) | Show Abstract | Read more

Burkholderia pseudomallei was examined after being maintained in distilled water at 25°C for 16 years. The Gram stain was atypical (pale pink cocci or coccobacilli). The estimated number of live and dead B. pseudomallei was 3.8×10(7) cells/ml and 1.4×10(5) cells/ml, respectively. A colony count on agar of 1.0×10(6) cfu/ml suggested that a proportion of cells were in a viable but non-culturable state. Colony morphology was different from the parental isolate for 84% of colonies. Pulsed-field gel electrophoresis analysis of AvrII DNA restriction fragments revealed six different but related banding patterns, which may represent genomic rearrangement.

. 2011. Modelling malaria elimination on the internet. Malar J, 10 (1), pp. 191. | Citations: 3 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Unprecedented efforts are underway to eliminate malaria. Mathematical modelling can help to determine the optimal strategies for malaria elimination in different epidemiological settings. This is necessary as there is limited scope for expensive and time-consuming field studies and failure of planned elimination strategies is likely to discourage ongoing investment by funders. However, there has been very little modelling of malaria elimination and little direct involvement of policymakers in its development. There is thus an urgent need for user-friendly and accessible models purpose-designed in collaboration with policymakers to answer pertinent questions arising from the field. RESULTS: An internet site is presented with a simple mathematical modelling platform for population level models of malaria elimination. It is freely accessible to all and designed to be flexible so both the platform and models can be developed through interaction with users. The site is an accessible introduction to modelling for a non-mathematical audience, and lessons learned from the project will help inform future development of mathematical models and improve communication of modelling results. Currently it hosts a simple model of strategies for malaria elimination and this will be developed, and more models added, over time. The iterative process of feedback and development will result in an educational and planning tool for non-modellers to assist with malaria elimination efforts worldwide. CONCLUSIONS: By collaboration with end users, iterative development of mathematical models of malaria elimination through this internet platform will maximize its potential as an educational and public health policy planning tool. It will also assist with preliminary optimisation of local malaria elimination strategies before commitment of valuable resources.

et al. 2011. Measurements of the properties of Lambda(c)(2595), Lambda(c)(2625), Sigma(c)(2455), and Sigma(c)(2520) baryons PHYSICAL REVIEW D, 84 (1), pp. 161. | Citations: 30 (Web of Science Lite) | Show Abstract | Read more

We perform a search for near-threshold $\Xi_b^0$ resonances decaying to $\Xi_b^- \pi^+$ in a sample of proton-proton collision data corresponding to an integrated luminosity of 3 fb$^{-1}$ collected by the LHCb experiment. We observe one resonant state, with the following properties: \begin{eqnarray*} m(\Xi_b^{*0}) - m(\Xi_b^-) - m(\pi^+) &=& 15.727 \pm 0.068 \, (\mathrm{stat}) \pm 0.023 \, (\mathrm{syst}) \, \mathrm{MeV}/c^2, \Gamma(\Xi_b^{*0}) &=& 0.90 \pm 0.16 \, (\mathrm{stat}) \pm 0.08 \, (\mathrm{syst}) \, \mathrm{MeV} . \end{eqnarray*} This confirms the previous observation by the CMS collaboration. The state is consistent with the $J^P=3/2^+$ $\Xi_b^{*0}$ resonance expected in the quark model. This is the most precise determination of the mass and the first measurement of the natural width of this state. We have also measured the ratio \begin{align*} \frac{\sigma(pp \to \Xi_b^{*0} X){\cal{B}}(\Xi_b^{*0} \to \Xi_b^- \pi^+)}{\sigma(pp \to \Xi_b^- X)} = 0.28 \pm 0.03 \, (\mathrm{stat}) \pm 0.01 \, (\mathrm{syst}) . \end{align*}

. 2011. Susceptibility of bacterial isolates from community-acquired infections in sub-Saharan Africa and Asia to macrolide antibiotics. Trop Med Int Health, 16 (10), pp. 1192-1205. | Citations: 8 (Web of Science Lite) | Show Abstract | Read more

OBJECTIVE: To review the literature on the susceptibility of common community pathogens in sub-Saharan Africa and Asia to the macrolide antibiotics. METHODS: Inclusion criteria required that isolates were collected since 2004 to ensure results were of contemporary relevance. The data were aggregated by region, age group and sterility of site of culture sample. RESULTS: A total of 51 studies were identified, which reported the macrolide antimicrobial susceptibilities of common bacterial pathogens isolated since 2004. In general, there was less macrolide resistance in African than in Asian isolates. Most African studies reported high levels of macrolide susceptibility in Streptococcus pneumoniae, whereas most Chinese studies reported high levels of resistance. There was very little information available for Gram-negative organisms. CONCLUSIONS: Susceptibility of the pneumococcus to macrolides in SSA remains high in many areas, and good activity of azithromycin has been shown against Salmonellae spp. in Asia. In urban areas where high antibiotic consumption is prevalent, there was evidence of increased resistance to macrolides. However, there is no information on susceptibility from large areas in both continents.

. 2011. Genetic diversity of Streptococcus suis isolates as determined by comparative genome hybridization. BMC Microbiol, 11 (1), pp. 161. | Citations: 26 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Streptococcus suis is a zoonotic pathogen that causes infections in young piglets. S. suis is a heterogeneous species. Thirty-three different capsular serotypes have been described, that differ in virulence between as well as within serotypes. RESULTS: In this study, the correlation between gene content, serotype, phenotype and virulence among 55 S. suis strains was studied using Comparative Genome Hybridization (CGH). Clustering of CGH data divided S. suis isolates into two clusters, A and B. Cluster A isolates could be discriminated from cluster B isolates based on the protein expression of extracellular factor (EF). Cluster A contained serotype 1 and 2 isolates that were correlated with virulence. Cluster B mainly contained serotype 7 and 9 isolates. Genetic similarity was observed between serotype 7 and serotype 2 isolates that do not express muramidase released protein (MRP) and EF (MRP⁻EF⁻), suggesting these isolates originated from a common founder. Profiles of 25 putative virulence-associated genes of S. suis were determined among the 55 isolates. Presence of all 25 genes was shown for cluster A isolates, whereas cluster B isolates lacked one or more putative virulence genes. Divergence of S. suis isolates was further studied based on the presence of 39 regions of difference. Conservation of genes was evaluated by the definition of a core genome that contained 78% of all ORFs in P1/7. CONCLUSIONS: In conclusion, we show that CGH is a valuable method to study distribution of genes or gene clusters among isolates in detail, yielding information on genetic similarity, and virulence traits of S. suis isolates.

et al. 2011. Effect of the pre-erythrocytic candidate malaria vaccine RTS,S/AS01E on blood stage immunity in young children. J Infect Dis, 204 (1), pp. 9-18. | Citations: 31 (Scopus) | Show Abstract | Read more

BACKGROUND: RTS,S/AS01(E) is the lead candidate malaria vaccine and confers pre-erythrocytic immunity. Vaccination may therefore impact acquired immunity to blood-stage malaria parasites after natural infection. METHODS: We measured, by enzyme-linked immunosorbent assay, antibodies to 4 Plasmodium falciparum merozoite antigens (AMA-1, MSP-1(42), EBA-175, and MSP-3) and by growth inhibitory activity (GIA) using 2 parasite clones (FV0 and 3D7) at 4 times on 860 children who were randomized to receive with RTS,S/AS01(E) or a control vaccine. RESULTS:  Antibody concentrations to AMA-1, EBA-175, and MSP-1(42) decreased with age during the first year of life, then increased to 32 months of age. Anti-MSP-3 antibody concentrations gradually increased, and GIA gradually decreased up to 32 months. Vaccination with RTS,S/AS01(E) resulted in modest reductions in AMA-1, EBA-175, MSP-1(42), and MSP-3 antibody concentrations and no significant change in GIA. Increasing anti-merozoite antibody concentrations and GIA were prospectively associated with increased risk of clinical malaria. CONCLUSIONS: Vaccination with RTS,S/AS01E reduces exposure to blood-stage parasites and, thus, reduces anti-merozoite antigen antibody concentrations. However, in this study, these antibodies were not correlates of clinical immunity to malaria. Instead, heterogeneous exposure led to confounded, positive associations between increasing antibody concentration and increasing risk of clinical malaria.

. 2011. Optimal designs for population pharmacokinetic studies of oral artesunate in patients with uncomplicated falciparum malaria. Malar J, 10 (1), pp. 181. | Citations: 10 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Currently, population pharmacokinetic (PK) studies of anti-malarial drugs are designed primarily by the logistical and ethical constraints of taking blood samples from patients, and the statistical models that are fitted to the data are not formally considered. This could lead to imprecise estimates of the target PK parameters, and/or designs insufficient to estimate all of the parameters. Optimal design methodology has been developed to determine blood sampling schedules that will yield precise parameter estimates within the practical constraints of sampling the study populations. In this work optimal design methods were used to determine sampling designs for typical future population PK studies of dihydroartemisinin, the principal biologically active metabolite of oral artesunate. METHODS: Optimal designs were derived using freely available software and were based on appropriate structural PK models from an analysis of data or the literature and key sampling constraints identified in a questionnaire sent to active malaria researchers (3-4 samples per patient, at least 15 minutes between samples). The derived optimal designs were then evaluated via simulation-estimation. RESULTS: The derived optimal sampling windows were 17 to 29 minutes, 30 to 57 minutes, 2.5 to 3.7 hours and 5.8 to 6.6 hours for non-pregnant adults; 16 to 29 minutes, 31 minutes to 1 hour, 2.0 to 3.4 hours and 5.5 to 6.6 hours for designs with non-pregnant adults and children and 35 to 59 minutes, 1.2 to 3.4 hours, 3.4 to 4.9 hours and 6.0 to 8.0 hours for pregnant women. The optimal designs resulted in acceptable precision of the PK parameters. CONCLUSIONS: The proposed sampling designs in this paper are robust and efficient and should be considered in future PK studies of oral artesunate where only three or four blood samples can be collected.

et al. 2011. Cost-effectiveness of parenteral artesunate for treating children with severe malaria in sub-Saharan Africa. Bull World Health Organ, 89 (7), pp. 504-512. | Citations: 24 (Web of Science Lite) | Show Abstract | Read more

OBJECTIVE: To explore the cost-effectiveness of parenteral artesunate for the treatment of severe malaria in children and its potential impact on hospital budgets. METHODS: The costs of inpatient care of children with severe malaria were assessed in four of the 11 sites included in the African Quinine Artesunate Malaria Treatment trial, conducted with over 5400 children. The drugs, laboratory tests and intravenous fluids provided to 2300 patients from admission to discharge were recorded, as was the length of inpatient stay, to calculate the cost of inpatient care. The data were matched with pooled clinical outcomes and entered into a decision model to calculate the cost per disability-adjusted life year (DALY) averted and the cost per death averted. FINDINGS: The mean cost of treating severe malaria patients was similar in the two study groups: 63.5 United States dollars (US$) (95% confidence interval, CI: 61.7-65.2) in the quinine arm and US$ 66.5 (95% CI: 63.7-69.2) in the artesunate arm. Children treated with artesunate had 22.5% lower mortality than those treated with quinine and the same rate of neurological sequelae: (artesunate arm: 2.3 DALYs per patient; quinine arm: 3.0 DALYs per patient). Compared with quinine as a baseline, artesunate showed an incremental cost per DALY averted and an incremental cost per death averted of US$3.8 and US$ 123, respectively. CONCLUSION: Artesunate is a highly cost-effective and affordable alternative to quinine for treating children with severe malaria. The budgetary implications of adopting artesunate for routine use in hospital-based care are negligible.

. 2011. Barriers to immunization among children of migrant workers from Myanmar living in Tak province, Thailand. Bull World Health Organ, 89 (7), pp. 528-531. | Citations: 14 (Web of Science Lite) | Show Abstract | Read more

PROBLEM: Immunization is a cost-effective means of improving child survival but implementation of programmes in low- and middle-income countries is variable. Children of migrants are less likely to be immunized. APPROACH: The qualitative study aimed to identify barriers to the successful implementation of migrant immunization programmes in Tak province, Thailand. We ran a total of 53 focus groups involving 371 participants in three sites. LOCAL SETTING: Tak province in Thailand borders Myanmar and has an estimated 200,000 migrants from Myanmar. Vaccine-preventable diseases are a documented cause of morbidity in this population but there is no systematic or coordinated immunization programme in the area. RELEVANT CHANGES: As a result of the findings, the subsequent immunization campaign targeted children in school to overcome those barriers of distance to immunization services, fear of arrest, not remembering immunization appointments, and the disruption of parental work. The campaigns also included immunization education for both parents and teachers. LESSONS LEARNT: Migrant parents identified similar barriers to accessing childhood immunization programmes as migrant populations elsewhere in the world, although a unique barrier identified by parents from Myanmar was "fear of arrest". The subsequent school-based strategy to overcome these barriers appears to be effective.

. 2011. Quantification of dihydroartemisinin, artesunate and artemisinin in human blood: overcoming the technical challenge of protecting the peroxide bridge. Bioanalysis, 3 (14), pp. 1613-1624. | Citations: 17 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Quantification of artemisinin (ARN) and its derivatives in whole blood has hitherto been thought impossible. RESULTS: A LC-MS/MS method for the analysis of artesunate (ARS), its metabolite dihydroartemisinin (DHA) and artemisinin in human whole blood has been developed and successfully validated. The method includes stabilization of the blood matrix at the time of collection and at the time of analysis. Addition of potassium dichromate to the blood samples deactivated the Fe(2+) core in hemoglobin, while deferoxamine chelated Fe(3+) and prevented back conversion into Fe(2+). A pilot study showed that the blood:plasma ratio for ARS and DHA is approximately 0.75, indicating a significantly lower uptake in red blood cells than had previously been estimated using radiolabeled drug methodology. CONCLUSIONS: The developed LC-MS/MS assay is the first method available for quantification of ARN and its derivatives in blood and opens up new possibilities of studying these drugs inside infected red blood cells.

et al. 2011. Emergence of a globally dominant IncHI1 plasmid type associated with multiple drug resistant typhoid. PLoS Negl Trop Dis, 5 (7), pp. e1245. | Citations: 49 (Scopus) | Show Abstract | Read more

Typhoid fever, caused by Salmonella enterica serovar Typhi (S. Typhi), remains a serious global health concern. Since their emergence in the mid-1970s multi-drug resistant (MDR) S. Typhi now dominate drug sensitive equivalents in many regions. MDR in S. Typhi is almost exclusively conferred by self-transmissible IncHI1 plasmids carrying a suite of antimicrobial resistance genes. We identified over 300 single nucleotide polymorphisms (SNPs) within conserved regions of the IncHI1 plasmid, and genotyped both plasmid and chromosomal SNPs in over 450 S. Typhi dating back to 1958. Prior to 1995, a variety of IncHI1 plasmid types were detected in distinct S. Typhi haplotypes. Highly similar plasmids were detected in co-circulating S. Typhi haplotypes, indicative of plasmid transfer. In contrast, from 1995 onwards, 98% of MDR S. Typhi were plasmid sequence type 6 (PST6) and S. Typhi haplotype H58, indicating recent global spread of a dominant MDR clone. To investigate whether PST6 conferred a selective advantage compared to other IncHI1 plasmids, we used a phenotyping array to compare the impact of IncHI1 PST6 and PST1 plasmids in a common S. Typhi host. The PST6 plasmid conferred the ability to grow in high salt medium (4.7% NaCl), which we demonstrate is due to the presence in PST6 of the Tn6062 transposon encoding BetU.

. 2011. Getting to grips with GRADE-perspective from a low-income setting. J Clin Epidemiol, 64 (7), pp. 708-710. | Citations: 17 (Web of Science Lite) | Read more

. 2011. Serial measurement of the C-reactive protein is a poor predictor of treatment outcome in prosthetic joint infection. J Antimicrob Chemother, 66 (7), pp. 1590-1593. | Citations: 13 (Scopus) | Show Abstract | Read more

OBJECTIVES: Prosthetic joint infection is usually treated using surgery and antibiotics. The response to the treatment regimen is often evaluated using serial monitoring of plasma C-reactive protein (CRP) concentrations. In order to examine how useful this monitoring is, we calculated the sensitivity and specificity of CRP concentrations for predicting treatment failure. PATIENTS AND METHODS: We examined 3732 CRP measurements from 260 patients who were treated by either two-stage revision or debridement and retention. We tested the association between CRP concentration and outcome using logistic regression models, and assessed sensitivity and specificity by using receiver operator curves. RESULTS: The areas under receiver operator curves for CRP concentrations predicting outcome ranged from 0.55 to 0.65. CONCLUSIONS: CRP concentrations did not accurately predict treatment failure. Serial monitoring may not be of benefit.

. 2011. Plasmodium falciparum malaria endemicity in Indonesia in 2010. PLoS One, 6 (6), pp. e21315. | Citations: 22 (Scopus) | Show Abstract | Read more

BACKGROUND: Malaria control programs require a detailed understanding of the contemporary spatial distribution of infection risk to efficiently allocate resources. We used model based geostatistics (MBG) techniques to generate a contemporary map of Plasmodium falciparum malaria risk in Indonesia in 2010. METHODS: Plasmodium falciparum Annual Parasite Incidence (PfAPI) data (2006-2008) were used to map limits of P. falciparum transmission. A total of 2,581 community blood surveys of P. falciparum parasite rate (PfPR) were identified (1985-2009). After quality control, 2,516 were included into a national database of age-standardized 2-10 year old PfPR data (PfPR(2-10)) for endemicity mapping. A Bayesian MBG procedure was used to create a predicted surface of PfPR(2-10) endemicity with uncertainty estimates. Population at risk estimates were derived with reference to a 2010 human population count surface. RESULTS: We estimate 132.8 million people in Indonesia, lived at risk of P. falciparum transmission in 2010. Of these, 70.3% inhabited areas of unstable transmission and 29.7% in stable transmission. Among those exposed to stable risk, the vast majority were at low risk (93.39%) with the reminder at intermediate (6.6%) and high risk (0.01%). More people in western Indonesia lived in unstable rather than stable transmission zones. In contrast, fewer people in eastern Indonesia lived in unstable versus stable transmission areas. CONCLUSION: While further feasibility assessments will be required, the immediate prospects for sustained control are good across much of the archipelago and medium term plans to transition to the pre-elimination phase are not unrealistic for P. falciparum. Endemicity in areas of Papua will clearly present the greatest challenge. This P. falciparum endemicity map allows malaria control agencies and their partners to comprehensively assess the region-specific prospects for reaching pre-elimination, monitor and evaluate the effectiveness of future strategies against this 2010 baseline and ultimately improve their evidence-based malaria control strategies.

et al. 2011. Pharmacokinetics of amodiaquine and desethylamodiaquine in pregnant and postpartum women with Plasmodium vivax malaria. Antimicrob Agents Chemother, 55 (9), pp. 4338-4342. | Citations: 21 (Web of Science Lite) | Show Abstract | Read more

In order to study the pharmacokinetic properties of amodiaquine and desethylamodiaquine during pregnancy, 24 pregnant women in the second and third trimesters of pregnancy and with Plasmodium vivax malaria were treated with amodiaquine (10 mg/kg of body weight/day) for 3 days. The same women were studied again at 3 months postpartum. Plasma was analyzed for amodiaquine and desethylamodiaquine by use of a liquid chromatography-tandem mass spectrometry method. Individual concentration-time data were evaluated using noncompartmental analysis. There were no clinically relevant differences in the pharmacokinetics of amodiaquine and desethylamodiaquine between pregnant (n = 24) and postpartum (n = 18) women. The results suggest that the current amodiaquine dosing regimen is adequate for the treatment of P. vivax infections during pregnancy.

. 2011. Antimicrobial susceptibility of bacterial isolates from community acquired infections in Sub-Saharan Africa and Asian low and middle income countries. Trop Med Int Health, 16 (9), pp. 1167-1179. | Citations: 23 (Web of Science Lite) | Show Abstract | Read more

OBJECTIVE: Antimicrobial resistance has arisen across the globe in both nosocomial and community settings as a consequence of widespread antibiotic consumption. Poor availability of laboratory diagnosis means that resistance frequently goes unrecognised and may only be detected as clinical treatment failure. In this review, we provide an overview of the reported susceptibility of common community acquired bacterial pathogens in Sub-Saharan Africa and Asia to the antibiotics that are most widely used in these areas. METHODS: We reviewed the literature for reports of the susceptibility of prevalent pathogens in the community in SSA and Asia to a range of commonly prescribed antibiotics. Inclusion criteria required that isolates were collected since 2004 and that they were obtained from either normally sterile sites or urine. The data were aggregated by region and by age group. RESULTS: Eighty-three studies were identified since 2004 which reported the antimicrobial susceptibilities of common bacterial pathogens. Different methods were used to assess in-vitro susceptibility in the different studies. The quality of testing (evidenced by resistance profiles) also varied considerably. For Streptococcus pneumoniae and Neisseria meningitidis most drugs maintained relatively high efficacy, apart from co-trimoxazole to which there were high levels of resistance in most of the pathogens surveyed. CONCLUSIONS: Compared with the enormous infectious disease burden and widespread use of antibiotics there are relatively few reliable data on antimicrobial susceptibility from tropical Asia and Africa upon which to draw firm conclusions, although it is evident that many commonly used antibiotics face considerable resistance in prevalent bacterial pathogens. This is likely to exacerbate morbidity and mortality. Investment in improved antimicrobial susceptibility testing and surveillance systems is likely to be a highly cost-effective strategy and should be complemented by centralized and readily accessible information resources.

. 2011. Responding to the evidence for the management of severe malaria. Trop Med Int Health, 16 (9), pp. 1085-1086. | Citations: 2 (Web of Science Lite) | Read more

et al. 2011. An open-label crossover study to evaluate potential pharmacokinetic interactions between oral oseltamivir and intravenous zanamivir in healthy Thai adults. Antimicrob Agents Chemother, 55 (9), pp. 4050-4057. | Citations: 8 (Web of Science Lite) | Show Abstract | Read more

There is no parenteral formulation of the neuraminidase inhibitor oseltamivir, the most widely used anti-influenza virus drug. Oseltamivir resistance is an increasing problem. Zanamivir is effective against the most prevalent oseltamivir-resistant influenza viruses. A parenteral formulation of zanamivir is in development for the treatment of severe influenza. It is not known if there is any pharmacokinetic interaction between the two drugs. Sixteen healthy Thai adult volunteers were studied in an open-label, four-period, randomized two-sequence crossover pharmacokinetic study in which zanamivir was given by constant-rate infusion or slow intravenous injection either alone or together with oral oseltamivir. Plasma concentration profiles of oseltamivir, the active metabolite oseltamivir carboxylate, and zanamivir were measured by liquid chromatography-mass spectrometry-mass spectrometry. Both drugs were well tolerated alone and in combination. The maximum plasma concentrations and the areas under the plasma concentration-time curves (AUC) of oseltamivir and oseltamivir carboxylate were not significantly different when oseltamivir was given separately or together with zanamivir. Maximum plasma concentrations of zanamivir were 10% (95% confidence interval, 7 to 12%) higher when zanamivir was infused concurrently with oral oseltamivir than with infusions before or after oral oseltamivir. The plasma zanamivir total AUC was positively correlated with the total oseltamivir carboxylate AUC (Pearson's correlation coefficient [r(P)] = 0.720, P = 0.002, n = 16) but not with the oseltamivir AUC (r(p) = 0.121, n = 16). There is no clinically significant pharmacokinetic interaction between oseltamivir and zanamivir.

. 2011. Improved pregnancy outcome in refugees and migrants despite low literacy on the Thai-Burmese border: results of three cross-sectional surveys. BMC Pregnancy Childbirth, 11 (1), pp. 45. | Citations: 21 (Scopus) | Show Abstract | Read more

BACKGROUND: Maternal and infant health has been associated with maternal education level, which is highly associated with literacy. We aimed at estimating literacy rates among reproductive age women attending antenatal clinics in camps for refugees and in migrant clinics in Tak province, north-western Thailand, to determine whether illiteracy had an impact on birth outcomes. METHODS: Three reading assessments were conducted using an identical method each time, in 1995-97, 2003 and 2008. Midwives chose at random one of four pre-set sentences. Each woman was asked to read aloud and scoring was based on a "pass/fail" system. Pregnancy outcomes were compared with maternal literacy rate. RESULTS: Overall, 47% (1149/2424) of women were able to read. A significant improvement was observed among migrant (34% in 2003 vs. 46% in 2008, p = 0.01), but not refugee (47% in 1995-97, 49% in 2003, and 51% in 2008) women. Literate women were significantly more likely to be of non-Karen ethnicity, primigravidae, non-smokers, to remain free from malaria during pregnancy and to deliver in a health clinic. Significant improvements in pregnancy outcome (reductions in premature births, low birth weight newborns and neonatal death) between 1995-97 and 2003 were unrelated to literacy. CONCLUSIONS: Significant reductions in poor pregnancy outcome over time have not been driven by changes in literacy rates, which have remained low. Access to early diagnosis and treatment of malaria in this population, and delivery with skilled birth attendants, despite ongoing low literacy, appears to have played a significant role.

. 2011. Do clinical guidelines reduce clinician dependent costs? Health Res Policy Syst, 9 (1), pp. 24. | Citations: 6 (Web of Science Lite) | Show Abstract | Read more

Clinician dependent costs are the costs of care that are under the discretion of the healthcare provider. These costs include the costs of drugs, tests and investigations, and discretionary outpatient visits and impatient stays. The purpose of this review was to summarize recent evidence, relevant to both developed and developing countries on whether evidence based clinical guidelines can change hospitals variable costs which are clinician dependent, and the degree of financial savings achieved at hospital level. Potential studies for inclusion were identified using structured searches of Econlit, J-Stor, and Pubmed databases. Two reviewers independently evaluated retrieved studies for inclusion. The methodological quality of the selected articles was assessed using the Oxford Centre for Evidence- Based Medicine (CEBM) levels of evidence. The results suggest that 10 of the 11 interventions were successful reducing financial costs. Most of the interventions, either in modeling studies or real interventions generate significant financial saving, although the former reported higher savings because the studies assumed 100 percent compliance.

. 2011. The challenges and opportunities of conducting a clinical trial in a low resource setting: the case of the Cameroon mobile phone SMS (CAMPS) trial, an investigator initiated trial. Trials, 12 (1), pp. 145. | Citations: 20 (Scopus) | Show Abstract | Read more

Conducting clinical trials in developing countries often presents significant ethical, organisational, cultural and infrastructural challenges to researchers, pharmaceutical companies, sponsors and regulatory bodies. Globally, these regions are under-represented in research, yet this population stands to gain more from research in these settings as the burdens on health are greater than those in developed resourceful countries. However, developing countries also offer an attractive setting for clinical trials because they often have larger treatment naive populations with higher incidence rates of disease and more advanced stages. These factors can present a reduction in costs and time required to recruit patients. So, balance needs to be found where research can be encouraged and supported in order to bring maximum public health benefits to these communities. The difficulties with such trials arise from problems with obtaining valid informed consent, ethical compensation mechanisms for extremely poor populations, poor health infrastructure and considerable socio-economic and cultural divides. Ethical concerns with trials in developing countries have received attention, even though many other non-ethical issues may arise. Local investigator initiated trials also face a variety of difficulties that have not been adequately reported in literature. This paper uses the example of the Cameroon Mobile Phone SMS trial to describe in detail, the specific difficulties encountered in an investigator-initiated trial in a developing country. It highlights administrative, ethical, financial and staff related issues, proposes solutions and gives a list of additional documentation to ease the organisational process.

et al. 2011. Timing of initiation of antiretroviral therapy in human immunodeficiency virus (HIV)--associated tuberculous meningitis. Clin Infect Dis, 52 (11), pp. 1374-1383. | Citations: 154 (Scopus) | Show Abstract | Read more

BACKGROUND: The optimal time to initiate antiretroviral therapy (ART) in human immunodeficiency virus (HIV)-associated tuberculous meningitis is unknown. METHODS: We conducted a randomized, double-blind, placebo-controlled trial of immediate versus deferred ART in patients with HIV-associated tuberculous meningitis to determine whether immediate ART reduced the risk of death. Antiretroviral drugs (zidovudine, lamivudine, and efavirenz) were started either at study entry or 2 months after randomization. All patients were treated with standard antituberculosis treatment, adjunctive dexamethasone, and prophylactic co-trimoxazole and were followed up for 12 months. We conducted intention-to-treat, per-protocol, and prespecified subgroup analyses. RESULTS: A total of 253 patients were randomized, 127 in the immediate ART group and 126 in the deferred ART group; 76 and 70 patients died within 9 months in the immediate and deferred ART groups, respectively. Immediate ART was not significantly associated with 9-month mortality (hazard ratio [HR], 1.12; 95% confidence interval [CI], .81-1.55; P = .50) or the time to new AIDS events or death (HR, 1.16; 95% CI, .87-1.55; P = .31). The percentage of patients with severe (grade 3 or 4) adverse events was high in both arms (90% in the immediate ART group and 89% in the deferred ART group; P = .84), but there were significantly more grade 4 adverse events in the immediate ART arm (102 in the immediate ART group vs 87 in the deferred ART group; P = .04). CONCLUSIONS: Immediate ART initiation does not improve outcome in patients presenting with HIV-associated tuberculous meningitis. There were significantly more grade 4 adverse events in the immediate ART arm, supporting delayed initiation of ART in HIV-associated tuberculous meningitis. Clinical Trials Registration. ISRCTN63659091.

. 2011. Repeat blood culture positive for B. pseudomallei indicates an increased risk of death from melioidosis. Am J Trop Med Hyg, 84 (6), pp. 858-861. | Citations: 7 (Scopus) | Show Abstract | Read more

Melioidosis, a bacterial infection caused by Burkholderia pseudomallei, is notoriously difficult to cure despite appropriate antimicrobial therapy and has a mortality rate of up to 40%. We demonstrate that a blood culture positive for B. pseudomallei taken at the end of the first and/or second week after hospitalization for melioidosis is a strong prognostic factor for death (adjusted odds ratio = 4.2, 95% confidence interval = 2.1-8.7, P < 0.001 and adjusted odds ratio = 2.6, 95% confidence interval = 1.1-6.0, P = 0.03, respectively). However, repeat cultures of respiratory secretions, urine, throat swabs, or pus/surface swabs provide no prognostic information. This finding highlights the need for follow-up blood cultures in patients with melioidosis.

et al. 2011. AIDS vaccines and preexposure prophylaxis: is synergy possible? AIDS Res Hum Retroviruses, 27 (6), pp. 669-680. | Citations: 21 (Scopus) | Show Abstract | Read more

While the long-term goal is to develop highly effective AIDS vaccines, first generation vaccines may be only partially effective. Other HIV prevention modalities such as preexposure prophylaxis with antiretrovirals (PrEP) may have limited efficacy as well. The combined administration of vaccine and PrEP (VAXPREP), however, may have a synergistic effect leading to an overall benefit that is greater than the sum of the individual effects. We propose two test-of-concept trial designs for an AIDS vaccine plus oral or topical ARV. In one design, evidence that PrEP reduces the risk of HIV acquisition is assumed to justify offering it to all participants. A two-arm study comparing PrEP alone to VAXPREP is proposed in which 30 to 60 incident infections are observed to assess the additional benefit of vaccination on risk of infection and setpoint viral load. The demonstrated superiority of VAXPREP does not imply vaccine alone is efficacious. Similarly, the lack of superiority does not imply vaccine alone is ineffective, as antagonism could exist between vaccine and PrEP. In the other design, PrEP is assumed not to be in general use. A 2 × 2 factorial design is proposed in which high-risk individuals are randomized to one of four arms: placebo vaccine given with placebo PrEP, placebo vaccine given with PrEP, vaccine given with placebo PrEP, or VAXPREP. Between 60 and 210 infections are required to detect a benefit of vaccination with or without PrEP on risk of HIV acquisition or setpoint viral load, with fewer infections needed when synergy is present.

. 2011. The utility of diagnostic tests for enteric fever in endemic locations. Expert Rev Anti Infect Ther, 9 (6), pp. 711-725. | Citations: 72 (Scopus) | Show Abstract | Read more

Enteric fever, an infection caused by Salmonella enterica serovar Typhi and serovar Paratyphi A, is common and endemic in many areas of the Asian and African continents. In endemic areas, diagnostic tests are needed to diagnose acute cases for clinical management, to detect convalescent and chronic fecal carriage and for contact tracing. A suitable test may also allow an assessment of disease burden in a community to determine the need for vaccination programs. Each specific role may warrant a dedicated test, utilizing different samples, targets and methods to serve their respective purpose. Current diagnostic methods are poor. Blood culture is insufficiently sensitive and technically demanding, and bone marrow culture, although more sensitive, is infrequently performed. Antibody- and antigen-detection tests lend themselves to point-of-care format but remain insufficiently sensitive and specific for this role. There are concerns about the sensitivity of nucleic acid amplification tests and they have not become widely adopted. However, new approaches using genomics, proteomics, transcriptomics, in vivo-induced antigen and immunoaffinity proteomics-based technologies are being employed to identify new antigens, gene targets and metabolic products that could be used as a basis for more effective diagnostic tests. If novel tests are to be credible and widely used they require rigorous evaluation in endemic areas in studies with appropriate selection of patients, adequate sample sizes and proper attention to a gold standard reference. Here, we discuss the range of methods currently used for diagnosing enteric fever in endemic locations and we suggest new technologies which may improve enteric fever diagnostics over the coming years.

. 2011. Added value of an oropharyngeal swab in detection of viruses in children hospitalized with lower respiratory tract infection. J Clin Microbiol, 49 (6), pp. 2318-2320. | Citations: 25 (Web of Science Lite) | Show Abstract | Read more

Paired nasopharyngeal and oropharyngeal swabs collected from 533 children hospitalized with lower respiratory tract infection were assessed by multiplex reverse transcription-PCR. Oropharyngeal swabs increased the number of viral infections detected by 15%, compared to collection of a nasopharyngeal swab alone. This advantage was most pronounced for detection of influenza, parainfluenza, and adenovirus.

. 2011. Ethnic differences in the health of women prisoners. Public Health, 125 (6), pp. 349-356. | Show Abstract | Read more

OBJECTIVES: The numbers of female and ethnic minority prisoners in the UK are increasing. Despite recent policy initiatives to improve both prison healthcare and the status of women and ethnic minority groups, there are few data with which to inform service development. This is the first study in the UK to examine differences in subjective health status and health behaviours between Black and White female prisoners. STUDY DESIGN: Retrospective secondary analysis of data from the Health of Women in Prison Study by the University of Oxford. The latter was a longitudinal survey. METHODS: Participants were given a questionnaire containing the Short Form 36 (SF-36) and questions about cigarette smoking, alcohol consumption, illicit drug use, physical exercise, diet, imprisonment history and ethnicity. Data from Black and White participants were compared. Physical and mental component summary scores from the SF-36 were assessed using the independent t-test for means. Differences in health behaviours between the Black and White women were assessed using a paired samples t-test for continuous variables or Chi-squared test for categorical data. RESULTS: Black women were more likely to have stayed in full-time education for longer and to have been legally employed prior to imprisonment. The average length of their current sentence was significantly higher than that for White women. Black women scored higher in general health perception, but there were no other significant differences in subjective health status. Significantly fewer Black women smoked or drank to excess, or had used drugs in the 6 months prior to imprisonment. Black women ate more healthily, but were more likely to be overweight and to have higher blood pressure than their White counterparts. Both groups, however, demonstrated poor health and health behaviours overall. CONCLUSION: Black women entering prison are more likely to be educated, employed, drug free and, in some ways, healthier than White women. However, all the prisoners, regardless of ethnicity, had poorer levels of mental and physical health than the general population; thus, a need exists for researchers and policy makers alike to examine the health of these groups within and out of prison.

. 2011. The influence of reduced susceptibility to fluoroquinolones in Salmonella enterica serovar Typhi on the clinical response to ofloxacin therapy. PLoS Negl Trop Dis, 5 (6), pp. e1163. | Citations: 39 (Scopus) | Show Abstract | Read more

BACKGROUND: Infection with Salmonella enterica serovar Typhi (S. Typhi) with reduced susceptibility to fluoroquinolones has been associated with fluoroquinolone treatment failure. We studied the relationship between ofloxacin treatment response and the ofloxacin minimum inhibitory concentration (MIC) of the infecting isolate. Individual patient data from seven randomised controlled trials of antimicrobial treatment in enteric fever conducted in Vietnam in which ofloxacin was used in at least one of the treatment arms was studied. Data from 540 patients randomised to ofloxacin treatment was analysed to identify an MIC of the infecting organism associated with treatment failure. PRINCIPAL FINDINGS: The proportion of patients failing ofloxacin treatment was significantly higher in patients infected with S. Typhi isolates with an MIC≥0.25 µg/mL compared with those infections with an MIC of ≤0.125 µg/mL (p<0.001). Treatment success was 96% when the ofloxacin MIC was ≤0.125 µg/mL, 73% when the MIC was between 0.25 and 0.50 µg/mL and 53% when the MIC was 1.00 µg/mL. This was despite a longer duration of treatment at a higher dosage in patients infected with isolates with an MIC≥0.25 µg/mL compared with those infections with an MIC of ≤0.125 µg/mL. SIGNIFICANCE: There is a clear relationship between ofloxacin susceptibility and clinical outcome in ofloxacin treated patients with enteric fever. An ofloxacin MIC of ≥0.25 µg/mL, or the presence of nalidixic acid resistance, can be used to define S. Typhi infections in which the response to ofloxacin may be impaired.

. 2011. Coma associated with microscopy-diagnosed Plasmodium vivax: a prospective study in Papua, Indonesia. PLoS Negl Trop Dis, 5 (6), pp. e1032. | Citations: 30 (Scopus) | Show Abstract | Read more

BACKGROUND: Coma complicates Plasmodium falciparum infection but is uncommonly associated with P. vivax. Most series of vivax coma have been retrospective and have not utilized molecular methods to exclude mixed infections with P. falciparum. METHODS: We prospectively enrolled patients hospitalized in Timika, Indonesia, with a Glasgow Coma Score (GCS) ≤10 and P. vivax monoinfection on initial microscopy over a four year period. Hematological, biochemical, serological, radiological and cerebrospinal fluid (CSF) examinations were performed to identify other causes of coma. Repeat microscopy, antigen detection and polymerase chain reaction (PCR) were performed to exclude infections with other Plasmodium species. RESULTS: Of 24 patients fulfilling enrolment criteria, 5 had clear evidence for other non-malarial etiologies. PCR demonstrated 10 mixed infections and 3 P. falciparum monoinfections. 6 (25%) patients had vivax monoinfection and no apparent alternative cause, with a median GCS of 9 (range 8-10) and a median coma duration of 42 (range 36-48) hours. CSF leukocyte counts were <10/ul (n=3); 2 of the 3 patients without CSF examination recovered with antimalarial therapy alone. One patient had a tremor on discharge consistent with a post-malarial neurological syndrome. No patient had other organ dysfunction. The only death was associated with pure P. falciparum infection by PCR. Vivax monoinfection-associated risk of coma was estimated at 1 in 29,486 clinical vivax infections with no deaths. In comparison, the risk of falciparum-associated coma was estimated at 1 in 1,276 clinical infections with an 18.5% mortality rate. CONCLUSIONS: P. vivax-associated coma is rare, occurring 23 times less frequently than that seen with falciparum malaria, and is associated with a high proportion of non-malarial causes and mixed infections using PCR. The pathogenesis of coma associated with vivax malaria, particularly the role of comorbidities, is uncertain and requires further investigation.

. 2011. The diagnostic sensitivity of dengue rapid test assays is significantly enhanced by using a combined antigen and antibody testing approach. PLoS Negl Trop Dis, 5 (6), pp. e1199. | Citations: 78 (Scopus) | Show Abstract | Read more

BACKGROUND: Serological tests for IgM and IgG are routinely used in clinical laboratories for the rapid diagnosis of dengue and can differentiate between primary and secondary infections. Dengue virus non-structural protein 1 (NS1) has been identified as an early marker for acute dengue, and is typically present between days 1-9 post-onset of illness but following seroconversion it can be difficult to detect in serum. AIMS: To evaluate the performance of a newly developed Panbio® Dengue Early Rapid test for NS1 and determine if it can improve diagnostic sensitivity when used in combination with a commercial IgM/IgG rapid test. METHODOLOGY: The clinical performance of the Dengue Early Rapid was evaluated in a retrospective study in Vietnam with 198 acute laboratory-confirmed positive and 100 negative samples. The performance of the Dengue Early Rapid in combination with the IgM/IgG Rapid test was also evaluated in Malaysia with 263 laboratory-confirmed positive and 30 negative samples. KEY RESULTS: In Vietnam the sensitivity and specificity of the test was 69.2% (95% CI: 62.8% to 75.6%) and 96% (95% CI: 92.2% to 99.8) respectively. In Malaysia the performance was similar with 68.9% sensitivity (95% CI: 61.8% to 76.1%) and 96.7% specificity (95% CI: 82.8% to 99.9%) compared to RT-PCR. Importantly, when the Dengue Early Rapid test was used in combination with the IgM/IgG test the sensitivity increased to 93.0%. When the two tests were compared at each day post-onset of illness there was clear differentiation between the antigen and antibody markers. CONCLUSIONS: This study highlights that using dengue NS1 antigen detection in combination with anti-glycoprotein E IgM and IgG serology can significantly increase the sensitivity of acute dengue diagnosis and extends the possible window of detection to include very early acute samples and enhances the clinical utility of rapid immunochromatographic testing for dengue.

et al. 2011. Prevalence of specific neutralizing antibodies against Sendai virus in populations from different geographic areas: implications for AIDS vaccine development using Sendai virus vectors. Hum Vaccin, 7 (6), pp. 639-645. | Citations: 19 (Scopus) | Show Abstract | Read more

A Sendai virus (SeV) vector is being developed for delivery of an HIV immunogen. SeV is not known to cause disease in humans. Because it is genetically and antigenically related to human parainfluenza virus type 1 (hPIV-1), it is important to determine whether pre-existing hPIV-1 antibodies will affect immune responses elicited by a SeV vector-based vaccine. To quantify SeV neutralizing antibodies (NAb) in human serum, a sensitive virus neutralization assay was developed using a SeV vector encoding green fluorescent protein. Samples from 255 HIV-uninfected subjects from Africa, Europe, United States, and Japan, as well as from 12 confirmed hPIV-1-infected patients, were analyzed. SeV NAb titers did not vary significantly after serum was treated with receptor-destroying enzyme, indicating that non-specific hemagglutination inhibitors did not affect the assay sensitivity. A significant correlation was observed between hPIV-1 ELISA and SeV NAb titers. SeV NAb were detected in 92.5% subjects with a median titer of 60.6 and values ranging from 5.9- 11,324. The majority had titers < 1000 with 71.7% < 100 (< 5 considered negative). There was no significant difference in titer or prevalence by gender, age range or geographic origin. However, African males had a lower titer than non-Africans of either gender (p=0.007). Overall, the prevalence of SeV NAb is high and likely due to neutralization by cross-reactive hPIV-1 antibodies. Clinical trials will be needed to assess the influence of pre-existing SeV NAb on HIV-specific immune responses elicited by a SeV vaccine vector expressing HIV.

. 2011. Endemic dengue associated with the co-circulation of multiple viral lineages and localized density-dependent transmission. PLoS Pathog, 7 (6), pp. e1002064. | Citations: 56 (Scopus) | Show Abstract | Read more

Dengue is one of the most important infectious diseases of humans and has spread throughout much of the tropical and subtropical world. Despite this widespread dispersal, the determinants of dengue transmission in endemic populations are not well understood, although essential for virus control. To address this issue we performed a phylogeographic analysis of 751 complete genome sequences of dengue 1 virus (DENV-1) sampled from both rural (Dong Thap) and urban (Ho Chi Minh City) populations in southern Viet Nam during the period 2003-2008. We show that DENV-1 in Viet Nam exhibits strong spatial clustering, with likely importation from Cambodia on multiple occasions. Notably, multiple lineages of DENV-1 co-circulated in Ho Chi Minh City. That these lineages emerged at approximately the same time and dispersed over similar spatial regions suggests that they are of broadly equivalent fitness. We also observed an important relationship between the density of the human host population and the dispersion rate of dengue, such that DENV-1 tends to move from urban to rural populations, and that densely populated regions within Ho Chi Minh City act as major transmission foci. Despite these fluid dynamics, the dispersion rates of DENV-1 are relatively low, particularly in Ho Chi Minh City where the virus moves less than an average of 20 km/year. These low rates suggest a major role for mosquito-mediated dispersal, such that DENV-1 does not need to move great distances to infect a new host when there are abundant susceptibles, and imply that control measures should be directed toward the most densely populated urban environments.

. 2011. Climate variability and the outbreaks of cholera in Zanzibar, East Africa: a time series analysis. Am J Trop Med Hyg, 84 (6), pp. 862-869. | Citations: 32 (Scopus) | Show Abstract | Read more

Global cholera incidence is increasing, particularly in sub-Saharan Africa. We examined the impact of climate and ocean environmental variability on cholera outbreaks, and developed a forecasting model for outbreaks in Zanzibar. Routine cholera surveillance reports between 1997 and 2006 were correlated with remotely and locally sensed environmental data. A seasonal autoregressive integrated moving average (SARIMA) model determined the impact of climate and environmental variability on cholera. The SARIMA model shows temporal clustering of cholera. A 1°C increase in temperature at 4 months lag resulted in a 2-fold increase of cholera cases, and an increase of 200 mm of rainfall at 2 months lag resulted in a 1.6-fold increase of cholera cases. Temperature and rainfall interaction yielded a significantly positive association (P < 0.04) with cholera at a 1-month lag. These results may be applied to forecast cholera outbreaks, and guide public health resources in controlling cholera in Zanzibar.

. 2011. Safety surveillance of influenza A(H1N1)v monovalent vaccines during the 2009-2010 mass vaccination campaign in France. Eur J Clin Pharmacol, 67 (6), pp. 649-651. | Citations: 8 (Scopus) | Read more

. 2011. Pandemic response lessons from influenza H1N1 2009 in Asia. Respirology, 16 (6), pp. 876-882. | Citations: 21 (Scopus) | Show Abstract | Read more

During April 2009, a novel H1N1 influenza A virus strain was identified in Mexico and the USA. Within weeks the virus had spread globally and the first pandemic of the 21st Century had been declared. It is unlikely to be the last and it is crucial that real lessons are learned from the experience. Asia is considered a hot spot for the emergence of new pathogens including past influenza pandemics. On this occasion while preparing for an avian, highly virulent influenza virus (H5N1 like) originating in Asia in fact the pandemic originated from swine, and was less virulent. This discrepancy between what was planned for and what emerged created its own challenges. The H1N1 pandemic has tested national health-care infrastructures and exposed shortcomings in our preparedness as a region. Key health challenges include communication throughout the region, surge capacity, access to reliable information and access to quality care, health-care worker skills, quality, density and distribution, access to essential medicines and lack of organizational infrastructure for emergency response. Despite years of preparation the public health and clinical research community were not ready to respond and opportunities for an immediate research response were missed. Despite warm words and pledges efforts to engage the international community to ensure equitable sharing of limited resources such as antivirals and vaccines fell short and stockpiles in the main remained in the rich world. This manuscript with authors from across the region describes some of the major challenges faced by Asia in response to the pandemic and draws lessons for the future.

. 2011. Seroprevalence, predictors and estimated incidence of maternal and neonatal Herpes Simplex Virus type 2 infection in semi-urban women in Kilifi, Kenya. BMC Infect Dis, 11 (1), pp. 155. | Citations: 12 (Scopus) | Show Abstract | Read more

BACKGROUND: Herpes Simplex Virus type 2 (HSV-2) has public health importance as a leading cause of genital ulcers, a co-factor in HIV-1 acquisition and transmission and as a cause of neonatal herpes infections. Little is known of its epidemiology and burden in Coastal Kenya. METHODS: We screened plasma samples for HSV-2 infection from 826 women aged 15-34 years who participated in an HIV-1 survey in Kilifi in 2004. The sample comprised 563 women selected randomly from a demographic surveillance system (DSS) and 263 women who presented for voluntary counseling and testing (VCT). Predictors for HSV-2 seropositivity were determined using multivariate logistic regression. The incidence of HSV-2 infection and risk of neonatal herpes were estimated by a simple catalytic model fitted to age-seroprevalence data. RESULTS: HSV-2 prevalence was 32% in the DSS recruits vs. 44% in the VCT recruits (P < 0.001), while, HIV-1 prevalence was 8% in the DSS recruits vs. 12% in the VCT recruits (P = 0.12). Independent risk factors for HSV-2 infection in all women were: older age (30-34 years; odds ratio (OR) 10.5, 95% confidence interval (CI): 5.2 - 21.0), recruitment from VCT (OR 1.5, 95% CI: 1.1 - 2.1), history of genital ulcers (OR 1.7, 95% CI: 1.2 - 2.3) and HIV infection (OR 2.7, 95% CI: 1.6-4.6). Education beyond primary (OR 0.7, 95% CI: 0.5 - 0.9) was inversely associated with HSV-2 infection. In the DSS sample, HSV-2 incidence was estimated at 4 cases (95% CI: 3.3 - 4.4) per 100 women per year, 17 cases (95% CI: 16-18) per 1,000 pregnancies per year and 33 neonatal cases (95% CI: 31-36) per 100,000 births per year. CONCLUSIONS: HSV-2 transmission is rapid following the onset of sexual activity and likely to result in a significant burden of genital ulcer disease. Nevertheless, the burden of neonatal HSV-2 can be predicted to be low. Educating young women about HSV-2 infection may help in reducing its burden in this semi-urban population.

et al. 2011. Multicentre prospective study on dengue classification in four South-east Asian and three Latin American countries. Trop Med Int Health, 16 (8), pp. 936-948. | Citations: 91 (Web of Science Lite) | Show Abstract | Read more

OBJECTIVE: To evaluate the existing WHO dengue classification across all age groups and a wide geographical range and to develop a revised evidence-based classification that would better reflect clinical severity. METHODS: We followed suspected dengue cases daily in seven countries across South-east Asia and Latin America and then categorised them into one of three intervention groups describing disease severity according to the overall level of medical and nursing support required. Using a pre-defined analysis plan, we explored the clinical and laboratory profiles characteristic of these intervention categories and presented the most promising options for a revised classification scheme to an independent group of WHO dengue experts for consideration. Potential warning signs were also evaluated by comparing contemporaneous data of patients who progressed to severe disease with the data of those who did not. RESULTS: A total of 2259 patients were recruited during 2006-2007 and 230 (13%) of the 1734 laboratory-confirmed patients required major intervention. Applying the existing WHO system, 47/210 (22%) of patients with shock did not fulfil all the criteria for dengue haemorrhagic fever. However, no three-tier revision adequately described the different severity groups either. Inclusion of readily discernible complications (shock/severe vascular leakage and/or severe bleeding and/or severe organ dysfunction) was necessary to devise a system that identified patients requiring major intervention with sufficient sensitivity and specificity to be practically useful. Only a small number of subjects (5%) progressed to severe disease while under observation; several warning signs were identified, but much larger studies are necessary to fully characterize features associated with disease progression. CONCLUSIONS: Based on these results, a revised classification system comprised of two entities, 'Dengue' and 'Severe Dengue', was proposed and has now been incorporated into the new WHO guidelines.

. 2011. Modelling the global constraints of temperature on transmission of Plasmodium falciparum and P. vivax. Parasit Vectors, 4 (1), pp. 92. | Citations: 83 (Scopus) | Show Abstract | Read more

BACKGROUND: Temperature is a key determinant of environmental suitability for transmission of human malaria, modulating endemicity in some regions and preventing transmission in others. The spatial modelling of malaria endemicity has become increasingly sophisticated and is now central to the global scale planning, implementation, and monitoring of disease control and regional efforts towards elimination, but existing efforts to model the constraints of temperature on the malaria landscape at these scales have been simplistic. Here, we define an analytical framework to model these constraints appropriately at fine spatial and temporal resolutions, providing a detailed dynamic description that can enhance large scale malaria cartography as a decision-support tool in public health. RESULTS: We defined a dynamic biological model that incorporated the principal mechanisms of temperature dependency in the malaria transmission cycle and used it with fine spatial and temporal resolution temperature data to evaluate time-series of temperature suitability for transmission of Plasmodium falciparum and P. vivax throughout an average year, quantified using an index proportional to the basic reproductive number. Time-series were calculated for all 1 km resolution land pixels globally and were summarised to create high-resolution maps for each species delineating those regions where temperature precludes transmission throughout the year. Within suitable zones we mapped for each pixel the number of days in which transmission is possible and an integrated measure of the intensity of suitability across the year. The detailed evaluation of temporal suitability dynamics provided by the model is visualised in a series of accompanying animations. CONCLUSIONS: These modelled products, made available freely in the public domain, can support the refined delineation of populations at risk; enhance endemicity mapping by offering a detailed, dynamic, and biologically driven alternative to the ubiquitous empirical incorporation of raw temperature data in geospatial models; and provide a rich spatial and temporal platform for future biological modelling studies.

et al. 2011. Assessment and comparative analysis of a rapid diagnostic test (Tubex®) for the diagnosis of typhoid fever among hospitalized children in rural Tanzania. BMC Infect Dis, 11 (1), pp. 147. | Citations: 19 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Typhoid fever remains a significant health problem in many developing countries. A rapid test with a performance comparable to that of blood culture would be highly useful. A rapid diagnostic test for typhoid fever, Tubex®, is commercially available that uses particle separation to detect immunoglobulin M directed towards Salmonella Typhi O9 lipopolysaccharide in sera. METHODS: We assessed the sensitivity and specificity of the Tubex test among Tanzanian children hospitalized with febrile illness using blood culture as gold standard. Evaluation was done considering blood culture confirmed S. Typhi with non-typhi salmonella (NTS) and non - salmonella isolates as controls as well as with non-salmonella isolates only. RESULTS: Of 139 samples tested with Tubex, 33 were positive for S. Typhi in blood culture, 49 were culture-confirmed NTS infections, and 57 were other non-salmonella infections. Thirteen hemolyzed samples were excluded. Using all non - S. Typhi isolates as controls, we showed a sensitivity of 79% and a specificity of 89%. When the analysis was repeated excluding NTS from the pool of controls we showed a sensitivity of 79% and a specificity of 97%. There was no significant difference in the test performance using the two different control groups (p > 0.05). CONCLUSION: This first evaluation of the Tubex test in an African setting showed a similar performance to those seen in some Asian settings. Comparison with the earlier results of a Widal test using the same samples showed no significant difference (p > 0.05) for any of the performance indicators, irrespective of the applied control group.

et al. 2011. The initial pharmaceutical development of an artesunate/amodiaquine oral formulation for the treatment of malaria: a public-private partnership. Malar J, 10 (1), pp. 142. | Citations: 15 (Scopus) | Show Abstract | Read more

BACKGROUND: Artemisinin-based combination therapy is currently recommended worldwide for the treatment of uncomplicated malaria. Fixed-dose combinations are preferred as they favour compliance. This paper reports on the initial phases of the pharmaceutical development of an artesunate-amodiaquine (ASAQ) bilayer co-formulation tablet, undertaken following pre-formulation studies by a network of scientists and industrials from institutions of both industrialized and low income countries. METHODS: Pharmaceutical development was performed by a research laboratory at the University Bordeaux Segalen, School of Pharmacy, for feasibility and early stability studies of various drug formulations, further transferred to a company specialized in pharmaceutical development, and then provided to another company for clinical batch manufacturing. The work was conducted by a regional public-private not-for-profit network (TropiVal) within a larger Public Private partnership (the FACT project), set up by WHO/TDR, Médecins Sans Frontières and the Drugs for Neglected Disease initiative (DNDi). RESULTS: The main pharmaceutical goal was to combine in a solid oral form two incompatible active principles while preventing artesunate degradation under tropical conditions. Several options were attempted and failed to provide satisfactory stability results: incorporating artesunate in the external phase of the tablets, adding a pH regulator, alcoholic wet granulation, dry granulation, addition of an hydrophobic agent, tablet manufacturing in controlled conditions. However, long-term stability could be achieved, in experimental batches under GMP conditions, by physical separation of artesunate and amodiaquine in a bilayer co-formulation tablet in alu-alu blisters. Conduction of the workplan was monitored by DNDi. CONCLUSIONS: Collaborations between research and industrial groups greatly accelerated the process of development of the bi-layered ASAQ tablet. Lack of public funding was the main obstacle hampering the development process, and no intellectual property right was claimed. This approach resulted in a rapid technology transfer to the drug company Sanofi-Aventis, finalizing the process of development, registration and WHO pre-qualification of the fixed-dose co-formulation together with DNDi. The bi-layered tablet is made available under the names of Coarsucam® and Artesunate amodiaquine Winthrop®, Sanofi-Aventis. The issue related to the difficulty of public institutions to valorise their participation in such initiative by lack of priority and funding of applied research is discussed.

. 2011. The clinical burden of malaria in Nairobi: a historical review and contemporary audit. Malar J, 10 (1), pp. 138. | Citations: 14 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Widespread urbanization over the next 20 years has the potential to drastically change the risk of malaria within Africa. The burden of the disease, its management, risk factors and appropriateness of targeted intervention across varied urban environments in Africa remain largely undefined. This paper presents a combined historical and contemporary review of the clinical burden of malaria within one of Africa's largest urban settlements, Nairobi, Kenya. METHODS: A review of historical reported malaria case burdens since 1911 within Nairobi was undertaken using archived government and city council reports. Contemporary information on out-patient case burdens due to malaria were assembled from the National Health Management and Information System (HMIS). Finally, an audit of 22 randomly selected health facilities within Nairobi was undertaken covering 12 months 2009-2010. The audit included interviews with health workers, and a checklist of commodities and guidelines necessary to diagnose, treat and record malaria. RESULTS: From the 1930's through to the mid-1960's malaria incidence declined coincidental with rapid population growth. During this period malaria notification and prevention were a priority for the city council. From 2001-2008 reporting systems for malaria were inadequate to define the extent or distribution of malaria risk within Nairobi. A more detailed facility review suggests, however that malaria remains a common diagnosis (11% of all paediatric diagnoses made) and where laboratories (n = 15) exist slide positivity rates are on average 15%. Information on the quality of diagnosis, slide reading and whether those reported as positive were imported infections was not established. The facilities and health workers included in this study were not universally prepared to treat malaria according to national guidelines or identify foci of risks due to shortages of national first-line drugs, inadequate record keeping and a view among some health workers (17%) that slide negative patients could still have malaria. CONCLUSION: Combined with historical evidence there is a strong suggestion that very low risks of locally acquired malaria exist today within Nairobi's city limits and this requires further investigation. To be prepared for effective prevention and case-management of malaria among a diverse, mobile population in Nairobi requires a major paradigm shift and investment in improved quality of malaria diagnosis and case management, health system strengthening and case reporting.

et al. 2011. Recent avian influenza virus A/H5N1 evolution in vaccinated and unvaccinated poultry from farms in Southern Vietnam, January-March 2010. Transbound Emerg Dis, 58 (6), pp. 537-543. | Citations: 14 (Web of Science Lite) | Show Abstract | Read more

We report 15 new avian influenza virus A/H5N1 haemagglutinin (HA) sequences sampled from visibly sick domestic poultry in southern Vietnam, between 1 January 2010 and 6 March 2010. These HA sequences form a new sub-clade of the clade 1 H5N1 viruses that have been circulating in Vietnam since 2003/2004. The viruses are characterized by a change from isoleucine to valine at position 514 (I514V) and are 1.8% divergent at the nucleotide level from HA sequences sampled in Vietnam in 2007. Five new amino acid changes were observed at previously identified antigenic sites, and three were located within structural elements of the receptor-binding domain. One new mutation removed a potential N-linked glycosylation site, and a methionine insertion was observed in one virus at the polybasic cleavage site. Five of these viruses were sampled from farms where poultry were vaccinated against H5N1, but there was no association between observed amino acid changes and flock vaccination status. Despite the current lack of evidence for antigenic drift or immune escape in Vietnamese H5N1 viruses, continued surveillance remains a high priority.

et al. 2011. Trends in malaria research in 11 Asian Pacific countries: an analysis of peer-reviewed publications over two decades. Malar J, 10 (1), pp. 131. | Citations: 6 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Quantitative data are lacking on published malaria research. The purpose of the study is to characterize trends in malaria-related literature from 1990 to 2009 in 11 Asian-Pacific countries that are committed to malaria elimination as a national goal. METHODS: A systematic search was conducted for articles published from January 1990 to December 2009 in PubMed/MEDLINE using terms for malaria and 11 target countries (Bhutan, China, North Korea, Indonesia, Malaysia, Philippines, Solomon Islands, South Korea, Sri Lanka, Thailand and Vanuatu). The references were collated and categorized according to subject, Plasmodium species, and whether they contained original or derivative data. RESULTS: 2,700 articles published between 1990 and 2009 related to malaria in the target countries. The annual output of malaria-related papers increased linearly whereas the overall biomedical output from these countries grew exponentially. The percentage of malaria-related publications was nearly 3% (111/3741) of all biomedical publications in 1992 and decreased to less than 1% (118/12171; p < 0.001) in 2009. Thailand had the highest absolute output of malaria-related papers (n = 1211), followed by China (n = 609) and Indonesia (n = 346). Solomon Islands and Vanuatu had lower absolute numbers of publications, but both countries had the highest number of publications per capita (1.3 and 2.5 papers/1,000 population). The largest percentage of papers concerned the epidemiology and control of malaria (53%) followed by studies of drugs and drug resistance (47%). There was an increase in the proportion of articles relating to epidemiology, entomology, biology, molecular biology, pathophysiology and diagnostics from the first to the second decade, whereas the percentage of papers on drugs, clinical aspects of malaria, immunology, and social sciences decreased. CONCLUSIONS: The proportion of malaria-related publications out of the overall biomedical output from the 11 target Asian-Pacific countries is decreasing. The discovery and evaluation of new, safe and effective drugs and vaccines is paramount. In addition the elimination of malaria will require operational research to implement and scale up interventions.

. 2011. Low-cost portable fluorescein angiography. Br J Ophthalmol, 95 (9), pp. 1213-1215. | Citations: 2 (Web of Science Lite) | Show Abstract | Read more

Fundus fluorescein angiography has great potential as a unique non-invasive tool to investigate in vivo the microvascular pathogenesis of a wide variety of diseases affecting the central nervous system. However, because it requires a bulky and expensive tabletop retinal camera, it is normally limited to cooperative and alert seated patients in well-resourced settings. Recently completed and ongoing studies of the pathogenesis of severe malaria are using fluorescein angiography to examine in detail the postulated central role of microvascular obstruction. We describe a novel method of fluorescein angiography with a portable retinal camera that can be adapted at very low cost for use in sick patients at the bedside. This method greatly expands the scope of potential studies utilising fluorescein angiography.

. 2011. Valacyclovir for herpes simplex encephalitis. Antimicrob Agents Chemother, 55 (7), pp. 3624-3626. | Citations: 24 (Scopus) | Show Abstract | Read more

The recommended treatment for herpes simplex encephalitis (HSE) remains intravenous acyclovir. In resource-poor countries, however, intravenous formulations are usually unavailable or unaffordable. We report the penetration of acyclovir into the cerebrospinal fluid (CSF) in patients with HSE, treated with the oral prodrug valacyclovir at 1,000 mg three times daily. The oral therapy achieved adequate acyclovir concentrations in the CSF and may be an acceptable early treatment for suspected HSE in resource-limited settings.

et al. 2011. The hepatitis C epidemic among HIV-positive MSM: incidence estimates from 1990 to 2007. AIDS, 25 (8), pp. 1083-1091. | Citations: 94 (Scopus) | Show Abstract | Read more

BACKGROUND: Outbreaks of acute hepatitis C virus (HCV) infection among HIV-infected MSM have been described since 2000. However, phylogenetic analysis suggests that the spread of HCV started around 1996. We estimated the incidence of HCV in HIV-infected MSM with well estimated dates of HIV seroconversion from 1990 to 2007. METHODS: Data from 12 cohorts within the Concerted Action on SeroConversion to AIDS and Death in Europe (CASCADE) Collaboration were used. HCV incidence was estimated using standard incidence methods and methods for interval-censored data. We accounted for the fact that routine HCV data collection in each cohort started in different calendar years. RESULTS: Of 4724 MSM, 3014 had an HCV test result and were included. Of these, 124 (4%) had only positive HCV test results, 2798 (93%) had only negative results and 92 (3%) had both. In 1990, HCV incidence ranged from 0.9 to 2.2 per 1000 person-years, depending on the analysis strategy used. HCV incidence increased up to 1995 when it was estimated to range between 5.5 and 8.1 per 1000 person-years. From 2002 onwards, it increased substantially to values between 16.8 and 30.0 per 1000 person-years in 2005 and between 23.4 and 51.1 per 1000 person-years in 2007. CONCLUSION: Our data support phylodynamic findings that HCV incidence had already increased among HIV-infected MSM from the mid-1990s. However, the main expansion of the HCV epidemic started after 2002. Incidence estimates obtained from cohort studies may help identify changes in the spread of important infections earlier and should guide routine testing policies to minimize further disease burden.

. 2011. Melioidosis: a clinical overview. Br Med Bull, 99 (1), pp. 125-139. | Show Abstract | Read more

INTRODUCTION: Melioidosis, an infection caused by the environmental Gram-negative bacillus Burkholderia pseudomallei, has emerged as an important cause of morbidity and mortality in Southeast Asia and northern Australia. SOURCES OF DATA: a review of the literature using PubMed. AREAS OF AGREEMENT: Approaches to diagnosis and antimicrobial therapy. AREAS OF CONTROVERSY: Whether seroconversion signals the presence of a quiescent bacterial focus and an increase in long-term risk of melioidosis. AREAS TIMELY FOR DEVELOPING RESEARCH: Melioidosis is potentially preventable, but there is a striking lack of evidence on which to base an effective prevention programme. An accurate map defining the global distribution of B. pseudomallei is needed, together with studies on the relative importance of different routes of infection. There is a marked difference in mortality from melioidosis in high-income versus lower income countries, and affordable strategies that reduce death from severe sepsis (from any cause) in resource-restricted settings are needed.

. 2011. Health in southeast Asia. Lancet, 377 (9777), pp. 1571. | Citations: 1 (Web of Science Lite) | Read more

et al. 2011. Chloroquine resistant vivax malaria in a pregnant woman on the western border of Thailand. Malar J, 10 (1), pp. 113. | Citations: 37 (Scopus) | Show Abstract | Read more

Chloroquine (CQ) resistant vivax malaria is spreading. In this case, Plasmodium vivax infections during pregnancy and in the postpartum period were not satisfactorily cleared by CQ, despite adequate drug concentrations. A growth restricted infant was delivered. Poor susceptibility to CQ was confirmed in-vitro and molecular genotyping was strongly suggestive of true recrudescence of P. vivax. This is the first clinically and laboratory confirmed case of two high-grade CQ resistant vivax parasite strains from Thailand.

. 2011. Response to ordi et Al. J Infect Dis, 203 (11), pp. 1695-1696. | Read more

. 2011. Improved culture-based detection and quantification of Burkholderia pseudomallei from soil. Trans R Soc Trop Med Hyg, 105 (6), pp. 346-351. | Citations: 13 (Web of Science Lite) | Show Abstract | Read more

Environmental surveillance of the Gram-negative soil bacterium Burkholderia pseudomallei, the aetiological agent of melioidosis, is important in order to define human populations and livestock at risk of acquiring the infection. This study aimed to develop a more sensitive method for the detection of B. pseudomallei from soil samples in endemic areas compared with the currently used culture method based on soil dispersion in water. We report the development of a new protocol that involves soil dispersion in a polyethylene glycol (PEG) and sodium deoxycholate (DOC) solution to increase the yield of viable B. pseudomallei from soil samples. Comparative testing of soil samples from Northeast Thailand covering a wide range of B. pseudomallei concentrations demonstrated a significantly higher recovery (P<0.0001) of B. pseudomallei colony-forming units by the new method compared with the conventional method. The data indicate that using the detergents PEG and DOC not only results in a higher recovery of viable B. pseudomallei but also results in a shift in the bacterial species recovered from soil samples. Future studies on the geographical distribution and population structure of B. pseudomallei in soil are likely to benefit from the new protocol described here.

et al. 2011. Evaluation of a PfHRP2 and a pLDH-based rapid diagnostic test for the diagnosis of severe malaria in 2 populations of African children. Clin Infect Dis, 52 (9), pp. 1100-1107. | Citations: 25 (Scopus) | Show Abstract | Read more

BACKGROUND: Rapid diagnostic tests (RDTs) now play an important role in the diagnosis of falciparum malaria in many countries where the disease is endemic. Although these tests have been extensively evaluated in uncomplicated falciparum malaria, reliable data on their performance for diagnosing potentially lethal severe malaria is lacking. METHODS: We compared a Plasmodium falciparum histidine-rich-protein2 (PfHRP₂)-based RDT and a Plasmodium lactate dehydrogenase (pLDH)-based RDT with routine microscopy of a peripheral blood slide and expert microscopy as a reference standard for the diagnosis of severe malaria in 1898 children who presented with severe febrile illness at 2 centers in Mozambique and Tanzania. RESULTS: The overall sensitivity, specificity, positive predictive value, and negative predictive values of the PfHRP₂-based test were 94.0%, 70.9%, 85.4%, and 86.8%, respectively, and for the pLDH-based test, the values were 88.0%, 88.3%, 93.2%, and 80.3%, respectively. At parasite counts < 1000 parasites/μL (n = 173), sensitivity of the pLDH-based test was low (45.7%), compared with that of the PfHRP₂-based test (69.9%). Both RDTs performed better than did the routine slide reading in a clinical laboratory as assessed in 1 of the centers. CONCLUSION: The evaluated PfHRP2-based RDT is an acceptable alternative to routine microscopy for diagnosing severe malaria in African children and performed better than did the evaluated pLDH-based RDT.

. 2011. The impact of retail-sector delivery of artemether-lumefantrine on malaria treatment of children under five in Kenya: a cluster randomized controlled trial. PLoS Med, 8 (5), pp. e1000437. | Citations: 43 (Scopus) | Show Abstract | Read more

BACKGROUND: It has been proposed that artemisinin-based combination therapy (ACT) be subsidised in the private sector in order to improve affordability and access. This study in western Kenya aimed to evaluate the impact of providing subsidized artemether-lumefantrine (AL) through retail providers on the coverage of prompt, effective antimalarial treatment for febrile children aged 3-59 months. METHODS AND FINDINGS: We used a cluster-randomized, controlled design with nine control and nine intervention sublocations, equally distributed across three districts in western Kenya. Cross-sectional household surveys were conducted before and after the delivery of the intervention. The intervention comprised provision of subsidized packs of paediatric ACT to retail outlets, training of retail outlet staff, and community awareness activities. The primary outcome was defined as the proportion of children aged 3-59 months reporting fever in the past 2 weeks who started treatment with AL on the same day or following day of fever onset. Data were collected using structured questionnaires and analyzed based on cluster-level summaries, comparing control to intervention arms, while adjusting for other covariates. Data were collected on 2,749 children in the target age group at baseline and 2,662 at follow-up. 29% of children experienced fever within 2 weeks before the interview. At follow-up, the percentage of children receiving AL on the day of fever or the following day had risen by 14.6% points in the control arm (from 5.3% [standard deviation (SD): 3.2%] to 19.9% [SD: 10.0%]) and 40.2% points in the intervention arm (from 4.7% [SD: 3.4%] to 44.9% [SD: 11.7%]). The percentage of children receiving AL was significantly greater in the intervention arm at follow-up, with a difference between the arms of 25.0% points (95% confidence interval [CI]: 14.1%, 35.9%; unadjusted p = 0.0002, adjusted p = 0.0001). No significant differences were observed between arms in the proportion of caregivers who sought treatment for their child's fever by source, or in the child's adherence to AL. CONCLUSIONS: Subsidizing ACT in the retail sector can significantly increase ACT coverage for reported fevers in rural areas. Further research is needed on the impact and cost-effectiveness of such subsidy programmes at a national scale. TRIAL REGISTRATION: Current Controlled Trials ISRCTN59275137 and Kenya Pharmacy and Poisons Board Ethical Committee for Clinical Trials PPB/ECCT/08/07.

. 2011. Orally formulated artemisinin in healthy fasting Vietnamese male subjects: a randomized, four-sequence, open-label, pharmacokinetic crossover study. Clin Ther, 33 (5), pp. 644-654. | Citations: 8 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Artemisinin derivatives are used in antimalarial drug combination therapy. Artemisinin and piperaquine have recently been proven to be prospective candidates for combination therapy in the treatment of uncomplicated Plasmodium falciparum malaria. OBJECTIVE: The goal of this study was to evaluate the relative bioavailability and to characterize the pharmacokinetic properties of a new micronized powder formulation of artemisinin against the previous standard Vietnamese formulation when administered as a single oral dose or in combination with piperaquine. METHODS: This was a single-center, randomized, 4-sequence, open-label, crossover study conducted in 15 healthy male Vietnamese volunteers under fasting conditions with a washout period of 3 weeks between study visits. A single oral dose of 160 or 500 mg of artemisinin was administered alone or in combination with piperaquine. Potential adverse events were monitored daily by the clinician and by using laboratory test results. Frequent blood samples were drawn for 12 hours after dose. Artemisinin was quantified in plasma using LC-MS/MS. Pharmacokinetic parameters were computed from the plasma concentration-time profiles using a noncompartmental analysis method. RESULTS: Pharmacokinetic parameters T(max), C(max), AUC(0-∞), V(d)/F, CL/F, and t(1/2) (mean [SD]) for the new formulation of artemisinin were 1.83 (0.88) hours, 178 (97) ng/mL, 504 (210) h × ng/mL, 1270 (780) L, 401 (260) L/h, and 2.21 (0.29) hours, respectively. The mean percentage of the test/reference formulation ratio for the logarithmically transformed values of C(max), AUC(0-last,) and AUC(0-∞) were 121% (90% CI, 92.5-158), 122% (90% CI, 101-148), and 120% (90% CI, 98.0-146), respectively. CONCLUSIONS: This single-dose study found that the dose-normalized C(max), AUC(0-last), and AUC(0-∞) mean geometric differences between the test and reference formulations were relatively small (<40%) and will probably not have a clinical impact in the treatment of malaria infections.

. 2011. One hundred and twelve infected arthroplasties treated with 'DAIR' (debridement, antibiotics and implant retention): antibiotic duration and outcome (vol 63, pg 1264, 2009) JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY, 66 (5), pp. 1203-1203. | Citations: 2 (Web of Science Lite) | Read more

. 2011. Two-stage revision for prosthetic joint infection: predictors of outcome and the role of reimplantation microbiology (vol 65, 569, 2010) JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY, 66 (5), pp. 1204-1204. | Read more

et al. 2011. PROSPECTIVE STUDY OF MELIOIDOSIS AT ROYAL DARWIN HOSPITAL DURING THE 2009-2010 WET SEASON; COMPARISONS WITH THE PRECEDING 20 YEARS INTERNAL MEDICINE JOURNAL, 41 pp. 13-13.

. 2011. Work in hypoxic conditions--consensus statement of the Medical Commission of the Union Internationale des Associations d'Alpinisme (UIAA MedCom). Ann Occup Hyg, 55 (4), pp. 369-386. | Citations: 14 (Scopus) | Show Abstract | Read more

OBJECTIVES: The Commission gives recommendations on how to provide health and safety for employees in different kinds of low oxygen atmospheres. So far, no recommendations exist that take into account the several factors we have outlined in this report. METHODS: The health and safety recommendations of several countries were analysed for their strength and deficiencies. The scientific literature was checked (Medline, etc.) and evaluated for relevance of the topic. Typical situations of work in hypoxia were defined and their specific risks described. Specific recommendations are provided for any of these situations. RESULTS: We defined four main groups with some subgroups (main risk in brackets): short exposure (pressure change), limited exposure (acute altitude disease), expatriates (chronic altitude disease), and high-altitude populations (re-entry pulmonary oedema). For healthy unacclimatized persons, an acute but limited exposure down to 13% O(2) does not cause a health risk. Employees should be advised to leave hypoxic areas for any break, if possible. Detailed advice is given for any other situation and pre-existing diseases. CONCLUSIONS: If the specific risk of the respective type of hypoxia is taken into account, a pragmatic approach to provide health and safety for employees is possible. In contrast to other occupational exposures, a repeated exposure as often as possible is of benefit as it causes partial acclimatization. The consensus statement was approved by written consent in lieu of a meeting in July 2009.

. 2011. The cost-effectiveness of herpes simplex virus-2 suppressive therapy with daily aciclovir for delaying HIV disease progression among HIV-1-infected women in South Africa. Sex Transm Dis, 38 (5), pp. 401-409. | Citations: 7 (Scopus) | Show Abstract | Read more

BACKGROUND: The Partners in Prevention HSV/HIV transmission trial (Partners HSV/HIV Transmission Study) showed that herpes simplex virus-2 (HSV-2) suppressive therapy with daily aciclovir could decrease HIV disease progression amongst HIV-1/HSV-2 coinfected individuals. The cost-effectiveness of daily aciclovir for delaying HIV-1 disease progression in women not eligible for antiretroviral therapy (ART) is estimated. METHODS: Resource use/cost data for delivering daily aciclovir at a primary health care HIV clinic were collected in Johannesburg. Effectiveness estimates were obtained from the Partners HSV/HIV Transmission Study trial and epidemiologic data from South Africa. A Markov model simulated the cost-effectiveness of daily aciclovir on HIV-1 disease progression in ART-naive women. Therapy was given to all HIV-1-infected women. Cost-effectiveness was compared against cost per life-year gained (∼US $1200 per LYG) of ART provision in South Africa. RESULTS: For an ART eligibility criteria of CD4 count <200 cells/μL and the cheapest internationally available aciclovir (US$0.026 per day for 2 × 400 mg aciclovir), the median cost per LYG is US $1023 (95% confidence interval [CI]: 537-2842), whereas it decreases to US$737 (95% CI: 373-2489) if the ART eligibility criteria is CD4 count <350 cells/μL. Both these projections compare favorably with the estimated cost-effectiveness of ART in South Africa (∼US $1200 per LYG). The cost per LYG increases dramatically for the current aciclovir cost in South Africa (US$0.14 per day), if salary costs are higher and if HSV-2 prevalence amongst HIV-1-infected women are lower. Projections suggest HSV-2 suppressive therapy could dramatically increase the proportion of women initiating ART. CONCLUSIONS: HSV-2 suppressive therapy could be an affordable strategy for reducing HIV-1 disease progression and retaining women in care before ART initiation, but cheaply available aciclovir is needed.

. 2011. High human immunodeficiency virus incidence in a cohort of Rwandan female sex workers. Sex Transm Dis, 38 (5), pp. 385-394. | Citations: 39 (Scopus) | Show Abstract | Read more

BACKGROUND: Measurement of human immunodeficiency virus(HIV) incidence among female sex workers in Rwanda is a key part of preparing for HIV prevention trials. METHODS: HIV-negative, nonpregnant female sex workers (N =397) were tested for HIV-1, sexually transmitted infections, and pregnancy quarterly for 12 months, and again at a 1-time year 2 visit. Additional women (N=156) were tested for HIV at baseline and 6 to 12 months thereafter in a parallel study. RESULTS: A total of 19 participants seroconverted during follow-up,with 13 in the first 12 months. The 12-month HIV incidence rate (IR)was 3.5 (95% confidence interval: 1.6, 5.4) per 100 person-years (PY).There was a nonsignificant downward trend from 4.6/100 PY (1.6, 7.7)in the first 6 months to 2.2 (0.1, 4.4) in the second 6 months (IR ratio:2.1 [95% confidence interval: 0.7, 7.8]). The year 2 IR was 2.1 (0.4,3.7), and the HIV IR in the parallel study (in the absence of frequent study visits) was 3.3/100 PY (0, 7.0). HIV testing history, lifetime pregnancies, recent initiation of sex work, gonorrhea, syphilis, and change in reproductive intentions were associated with incident HIV infection. Incidence of pregnancy, herpes simplex virus-type 2,trichomoniasis, gonorrhea, chlamydia, and syphilis per 100 PY were as follows: 26.3 (21.9, 30.7), 8.7 (4.0, 13.4), 16.9 (12.7, 21.1), 12.1 (8.2,15.9), 8.1 (5.1, 11.2), and 6.2 (3.7, 8.7). CONCLUSIONS: The HIV/sexually transmitted infections burden int his group was high. HIV IR was highest in the first 6 months of the cohort, and in the parallel study in which there were no risk-reduction procedures. HIV prevention and family planning interventions are needed.

et al. 2011. Gatifloxacin versus chloramphenicol for uncomplicated enteric fever: an open-label, randomised, controlled trial. Lancet Infect Dis, 11 (6), pp. 445-454. | Citations: 34 (Scopus) | Show Abstract | Read more

BACKGROUND: We aimed to investigate whether gatifloxacin, a new generation and affordable fluoroquinolone, is better than chloramphenicol for the treatment of uncomplicated enteric fever in children and adults. METHODS: We did an open-label randomised superiority trial at Patan Hospital, Kathmandu, Nepal, to investigate whether gatifloxacin is more effective than chloramphenicol for treating uncomplicated enteric fever. Children and adults clinically diagnosed with enteric fever received either gatifloxacin (10 mg/kg) once a day for 7 days, or chloramphenicol (75 mg/kg per day) in four divided doses for 14 days. Patients were randomly allocated treatment (1:1) in blocks of 50, without stratification. Allocations were placed in sealed envelopes opened by the study physician once a patient was enrolled into the trial. Masking was not possible because of the different formulations and ways of giving the two drugs. The primary outcome measure was treatment failure, which consisted of at least one of the following: persistent fever at day 10, need for rescue treatment, microbiological failure, relapse until day 31, and enteric-fever-related complications. The primary outcome was assessed in all patients randomly allocated treatment and reported separately for culture-positive patients and for all patients. Secondary outcome measures were fever clearance time, late relapse, and faecal carriage. The trial is registered on controlled-trials.com, number ISRCTN 53258327. FINDINGS: 844 patients with a median age of 16 (IQR 9-22) years were enrolled in the trial and randomly allocated a treatment. 352 patients had blood-culture-confirmed enteric fever: 175 were treated with chloramphenicol and 177 with gatifloxacin. 14 patients had treatment failure in the chloramphenicol group, compared with 12 in the gatifloxacin group (hazard ratio [HR] of time to failure 0·86, 95% CI 0·40-1·86, p=0·70). The median time to fever clearance was 3·95 days (95% CI 3·68-4·68) in the chloramphenicol group and 3·90 days (3·58-4·27) in the gatifloxacin group (HR 1·06, 0·86-1·32, p=0·59). At 1 month only, three of 148 patients were stool-culture positive in the chloramphenicol group and none in the gatifloxacin group. At the end of 3 months only one person had a positive stool culture in the chloramphenicol group. There were no other positive stool cultures even at the end of 6 months. Late relapses were noted in three of 175 patients in the culture-confirmed chloramphenicol group and two of 177 in the gatifloxacin group. There were no culture-positive relapses after day 62. 99 patients (24%) experienced 168 adverse events in the chloramphenicol group and 59 (14%) experienced 73 events in the gatifloxacin group. INTERPRETATION: Although no more efficacious than chloramphenicol, gatifloxacin should be the preferred treatment for enteric fever in developing countries because of its shorter treatment duration and fewer adverse events. FUNDING: Wellcome Trust.

. 2011. Hepatitis E virus is prevalent in the pig population of Lao People's Democratic Republic and evidence exists for homogeneity with Chinese Genotype 4 human isolates. Infect Genet Evol, 11 (6), pp. 1306-1311. | Citations: 7 (Web of Science Lite) | Show Abstract | Read more

The objective of this study was to determine the prevalence and genotypic range of Hepatitis E virus (HEV) in the pig population of northern Lao People's Democratic Republic (PDR). We collected 181 faecal samples from indigenous-breed pigs ≤ 6 months of age and the faeces was stored in RNA stabilisation buffer due to cold-chain and transport limitations. Twenty-one (11.6%) pigs had detectable HEV RNA and 43.5% of village pig herds were infected. Based on a 240 base pair-nucleotide sequence flanking the junction of open reading frames 1, 2 and 3 (ORF1, ORF2 and ORF3) the isolates were phylogenetically classified within genotype 4. Phylogenetic analyses revealed distinct genetic groupings of the Lao HEV isolates and two groups clustered with human and pig HEV isolates from China. This was the first study to demonstrate genotype 4 HEV in Lao PDR and indicates pigs are a potential reservoir for human HEV infection.

. 2011. A prospective study of urinary pneumococcal antigen detection in healthy Karen mothers with high rates of pneumococcal nasopharyngeal carriage. BMC Infect Dis, 11 (1), pp. 108. | Citations: 10 (Scopus) | Show Abstract | Read more

BACKGROUND: Detection of Streptococcus pneumoniae C-polysaccharide in urine is a useful rapid diagnostic test for pneumococcal infections in adults. In young children, high rates of false positive results have been documented due to detection of concurrent nasopharyngeal pneumococcal carriage. The relationship between pneumococcal carriage and urinary antigen detection in adults from developing countries with high pneumococcal carriage prevalence has not been well established. METHODS: We nested an evaluation of the BinaxNOW S. pneumoniae test within a longitudinal mother-infant pneumococcal carriage study in Karen refugees on the Thailand-Myanmar border. Paired urine and nasopharyngeal swab specimens were collected from 98 asymptomatic women at a routine study follow-up visit. The urine specimens were analyzed with the BinaxNOW test and the nasopharyngeal swabs were semi-quantitatively cultured to identify pneumococcal colonization. RESULTS: 24/98 (25%) women were colonized by S. pneumoniae but only three (3%) had a positive BinaxNOW urine test. The sensitivity of the BinaxNOW test for detection of pneumococcal colonization was 4.2% (95% CI: 0.1-21.1%) with a specificity of 97.3% (95% CI: 90.6-99.7%). Pneumococcal colonization was not associated with having a positive BinaxNOW test (odds ratio 1.6; 95% CI: 0.0-12.7; p=0.7). CONCLUSIONS: Significant numbers of false positive results are unlikely to be encountered when using the BinaxNOW test to diagnose pneumococcal infection in adults from countries with moderate to high rates of pneumococcal colonization.

. 2011. Transmitted antiretroviral drug resistance among newly HIV-1 diagnosed young individuals in Kampala. AIDS, 25 (7), pp. 905-910. | Citations: 48 (Scopus) | Show Abstract | Read more

OBJECTIVE: To assess the emergence of transmitted HIV-1 drug resistance (TDR) in Kampala, Uganda, 10 years after the scale-up of antiretroviral treatment (ART) and to compare with a previous survey among antenatal clinic attendees in 2007 (reporting 0% TDR). DESIGN: A cross-sectional survey was conducted among newly HIV-1 diagnosed, antiretroviral-naive young adults attending two large voluntary counseling and testing centers within the geographic area of Kampala. METHODS: Proxy criteria for recent HIV-1 infection were used as defined by the WHO. Population sequencing of the pol gene was performed on plasma samples with HIV-1 RNA at least 1000 copies/ml. Surveillance drug resistance mutations (SDRMs) were identified according to the 2009 WHO list for surveillance of TDR. HIV-1 subtypes were designated using maximum likelihood phylogenetic reconstruction. RESULTS: : Genotypic test results were obtained for 70 of 77 (90.9%) participants. SDRMs were identified in six samples yielding a prevalence of TDR of 8.6% (95% confidence interval 3.2-17.7%). Two had SDRMs to nucleoside reverse-transcriptase inhibitors (D67G and L210W), three had SDRMs to nonnucleoside reverse transcriptase inhibitors (G190A, G190S, and K101E), and one had SDRMs to protease inhibitors (N88D). Frequencies of HIV-1 subtypes were A (36/70, 51.4%), C ( two of 70; 2.9%), D (23/70, 32.9%), and unique recombinant forms (nine of 70, 12.9%). CONCLUSION: This repeated survey suggests an increase in TDR in Kampala, compared with a previous survey. This finding justifies increased vigilance with respect to surveillance of TDR in areas in Africa where ART programs are rolled-out.

et al. 2011. Usefulness and applicability of the revised dengue case classification by disease: multi-centre study in 18 countries. BMC Infect Dis, 11 (1), pp. 106. | Citations: 79 (Scopus) | Show Abstract | Read more

BACKGROUND: In view of the long term discussion on the appropriateness of the dengue classification into dengue fever (DF), dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS), the World Health Organization (WHO) has outlined in its new global dengue guidelines a revised classification into levels of severity: dengue fever with an intermediary group of "dengue fever with warning sings", and severe dengue. The objective of this paper was to compare the two classification systems regarding applicability in clinical practice and surveillance, as well as user-friendliness and acceptance by health staff. METHODS: A mix of quantitative (prospective and retrospective review of medical charts by expert reviewers, formal staff interviews), semi-quantitative (open questions in staff interviews) and qualitative methods (focus group discussions) were used in 18 countries. Quality control of data collected was undertaken by external monitors. RESULTS: The applicability of the DF/DHF/DSS classification was limited, even when strict DHF criteria were not applied (13.7% of dengue cases could not be classified using the DF/DHF/DSS classification by experienced reviewers, compared to only 1.6% with the revised classification). The fact that some severe dengue cases could not be classified in the DF/DHF/DSS system was of particular concern. Both acceptance and perceived user-friendliness of the revised system were high, particularly in relation to triage and case management. The applicability of the revised classification to retrospective data sets (of importance for dengue surveillance) was also favourable. However, the need for training, dissemination and further research on the warning signs was highlighted. CONCLUSIONS: The revised dengue classification has a high potential for facilitating dengue case management and surveillance.

. 2011. Most adults seek urgent healthcare when acquiring HIV-1 and are frequently treated for malaria in coastal Kenya. AIDS, 25 (9), pp. 1219-1224. | Citations: 19 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Acute HIV-1 infection (AHI) may present with symptoms for which urgent healthcare is sought. However, little is known about healthcare seeking around the time of HIV-1 seroconversion in sub-Saharan Africa. METHODS: Review of clinical, counselling, treatment and laboratory records of previously HIV-1 seronegative at-risk adults, followed at monthly or 3-monthly visits, who seroconverted and enrolled in an AHI cohort. All HIV-seronegative plasma samples were tested for p24 antigen (p24) and stored preseroconversion samples for HIV-1 RNA (RNA). Factors associated with malaria treatment while acquiring HIV-1 were evaluated in multiple logistic regression. RESULTS: Sixty men and 12 women (95% of 75 seroconverters) were evaluated, including 43 (60%) with either p24-positive or RNA-positive or HIV-1 discordant rapid antibodies prior to seroconversion. Prior to diagnosis, 54 patients (75%) reported fever and 50 (69%) sought urgent care for symptomatic illness, including 23 (32%) who sought care in a nonresearch setting. Twenty-nine patients (40%) received presumptive malaria treatment. Only 24% of febrile patients were tested for malaria parasites. All documented smear results were negative. Malaria treatment was strongly associated with fever [adjusted odds ratio (aOR): 46, 95% confidence interval (CI): 3-725] and nonresearch setting (aOR: 5, 95% CI: 3-64). AHI was suspected in six (12%) patients who presented for urgent care during research evaluation. CONCLUSIONS: The majority of adults with AHI seek urgent healthcare. These individuals are often presumptively treated for malaria. Improved recognition of AHI in adults presenting for care may offer opportunities for optimizing HIV prevention strategies.

et al. 2011. A human Phase I/IIa malaria challenge trial of a polyprotein malaria vaccine. Vaccine, 29 (43), pp. 7514-7522. | Citations: 32 (Web of Science Lite) | Show Abstract | Read more

We examined the safety, immunogenicity and efficacy of a prime-boost vaccination regime involving two poxvirus malaria subunit vaccines, FP9-PP and MVA-PP, expressing the same polyprotein consisting of six pre-erythrocytic antigens from Plasmodium falciparum. Following safety assessment of single doses, 15 volunteers received a heterologous prime-boost vaccination regime and underwent malaria sporozoite challenge. The vaccines were safe but interferon-γ ELISPOT responses were low compared to other poxvirus vectors, despite targeting multiple antigens. There was no vaccine efficacy as measured by delay in time to parasitaemia. A number of possible explanations are discussed, including the very large insert size of the polyprotein transgene.

. 2011. Differential cellular recognition of antigens during acute Plasmodium falciparum and Plasmodium vivax malaria. J Infect Dis, 203 (8), pp. 1192-1199. | Citations: 4 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Plasmodium falciparum and Plasmodium vivax are co-endemic in the Asia-Pacific region. Their capacity to induce and sustain diverse T-cell responses underpins protective immunity. We compared T-cell responses to the largely conserved merozoite surface protein-5 (PfMSP5) during acute and convalescent falciparum and vivax malaria. METHODS: Lymphoproliferation and IFN--γ secretion to PfMSP5 and purified protein derivate were quantified in adults with falciparum (n=34), and vivax malaria (n=12) or asymptomatic residents (n=10) of Papua, Indonesia. Responses were reassessed 7-28 days following treatment. RESULTS: The frequency of IFN-γ responders to PfMSP5 was similar in acute falciparum (63%) or vivax (67%) malaria. However, significantly more IFN-γ-secreting cells were detectable during vivax compared with falciparum infection. Purified protein derivative responses showed a similarly enhanced pattern. While rapidly lost in vivax patients, PfMSP5-specific responses in falciparum malaria remained to day 28. By contrast, frequency and magnitude of lymphoproliferation to PfMSP5 were similar for falciparum and vivax infections. CONCLUSION: Cellular PfMSP5-specific responses are most frequent during either acute falciparum or vivax malaria, indicating functional T-cell responses to conserved antigens. Both effector and central memory T-cell functions are increased. Greater IFN-γ responses in acute P. vivax, suggest enhancement of pre-existing effector T-cells during acute vivax infection.

. 2011. Acute seizures attributable to falciparum malaria in an endemic area on the Kenyan coast. Brain, 134 (Pt 5), pp. 1519-1528. | Citations: 24 (Scopus) | Show Abstract | Read more

Falciparum malaria is an important cause of acute symptomatic seizures in children admitted to hospitals in sub-Saharan Africa, and these seizures are associated with neurological disabilities and epilepsy. However, it is difficult to determine the proportion of seizures attributable to malaria in endemic areas since a significant proportion of asymptomatic children have malaria parasitaemia. We studied children aged 0-13 years who had been admitted with a history of seizures to a rural Kenyan hospital between 2002 and 2008. We examined the changes in the incidence of seizures with the reduction of malaria. Logistic regression was used to model malaria-attributable fractions for seizures (the proportion of seizures caused by malaria) to determine if the observed decrease in acute symptomatic seizures was a measure of seizures that are attributable to malaria. The overall incidence of acute symptomatic seizures over the period was 651/100,000/year (95% confidence interval 632-670) and it was 400/100,000/year (95% confidence interval 385-415) for acute complex symptomatic seizures (convulsive status epilepticus, repetitive or focal) and 163/100,000/year (95% confidence interval 154-173) for febrile seizures. From 2002 to 2008, the incidence of all acute symptomatic seizures decreased by 809/100,000/year (69.2%) with 93.1% of this decrease in malaria-associated seizures. The decrease in the incidence of acute complex symptomatic seizures during the period was 111/100,000/year (57.2%) for convulsive status epilepticus, 440/100,000/year (73.7%) for repetitive seizures and 153/100,000/year (80.5%) for focal seizures. The adjusted malaria-attributable fractions for seizures with parasitaemia were 92.9% (95% confidence interval 90.4-95.1%) for all acute symptomatic seizures, 92.9% (95% confidence interval 89.4-95.5%) for convulsive status epilepticus, 93.6% (95% confidence interval 90.9-95.9%) for repetitive seizures and 91.8% (95% confidence interval 85.6-95.5%) for focal seizures. The adjusted malaria-attributable fractions for seizures in children above 6 months of age decreased with age. The observed decrease in all acute symptomatic seizures (809/100 000/year) was similar to the predicted decline (794/100,000/year) estimated by malaria-attributable fractions at the beginning of the study. In endemic areas, falciparum malaria is the most common cause of seizures and the risk for seizures in malaria decreases with age. The reduction in malaria has decreased the burden of seizures that are attributable to malaria and this could lead to reduced neurological disabilities and epilepsy in the area.

. 2011. How to minimise risk of acquiring tuberculosis when working in a high prevalence setting: a guide for healthcare workers. BMJ, 342 (mar16 2), pp. d1544. | Citations: 2 (Scopus) | Show Abstract | Read more

The risk of healthcare workers contracting tuberculosis while working in a high incidence area is real; all workers must be aware of the precautions needed to minimise risk.

. 2011. Interaction between antiretroviral drugs and acenocoumarol. Antivir Ther, 16 (2), pp. 249-252. | Citations: 6 (Scopus) | Show Abstract | Read more

The authors report a case of an HIV type-1-infected patient concomitantly using highly active antiretroviral therapy and acenocoumarol anticoagulant for secondary prevention of recurrent venous thromboembolism. This is the first report of a possible drug interaction between efavirenz and atazanavir/ritonavir with acenocoumarol and also of the uncomplicated concurrent use of raltegravir with acenocoumarol.

. 2011. Artesunate for severe malaria in African children Reply LANCET, 377 (9772), pp. 1154-1154. | Read more

et al. 2011. Predictors of bacterial pneumonia in Evaluation of Subcutaneous Interleukin-2 in a Randomized International Trial (ESPRIT). HIV Med, 12 (4), pp. 219-227. | Citations: 2 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND AND OBJECTIVES: Bacterial pneumonia still contributes to morbidity/mortality in HIV infection despite effective combination antiretroviral therapy (cART). Evaluation of Subcutaneous Interleukin-2 in a Randomized International Trial (ESPRIT), a trial of intermittent recombinant interleukin-2 (rIL-2) with cART vs. cART alone (control arm) in HIV-infected adults with CD4 counts ≥300cells/μL, offered the opportunity to explore associations between bacterial pneumonia and rIL-2, a cytokine that increases the risk of some bacterial infections. METHODS: Baseline and time-updated factors associated with first-episode pneumonia on study were analysed using multivariate proportional hazards regression models. Information on smoking/pneumococcal vaccination history was not collected. RESULTS: IL-2 cycling was most intense in years 1-2. Over ≈7 years, 93 IL-2 [rate 0.67/100 person-years (PY)] and 86 control (rate 0.63/100 PY) patients experienced a pneumonia event [hazard ratio (HR) 1.06; 95% confidence interval (CI) 0.79, 1.42; P=0.68]. Median CD4 counts prior to pneumonia were 570cells/μL (IL-2 arm) and 463cells/μL (control arm). Baseline risks for bacterial pneumonia included older age, injecting drug use, detectable HIV viral load (VL) and previous recurrent pneumonia; Asian ethnicity was associated with decreased risk. Higher proximal VL (HR for 1 log(10) higher VL 1.28; 95% CI 1.11, 1.47; P<0.001) was associated with increased risk; higher CD4 count prior to the event (HR per 100 cells/μL higher 0.94; 95% CI 0.89, 1.0; P=0.04) decreased risk. Compared with controls, the hazard for a pneumonia event was higher if rIL-2 was received <180 days previously (HR 1.66; 95% CI 1.07, 2.60; P=0.02) vs.≥180 days previously (HR 0.98; 95% CI 0.70, 1.37; P=0.9). Compared with the control group, pneumonia risk in the IL-2 arm decreased over time, with HRs of 1.41, 1.71, 1.16, 0.62 and 0.84 in years 1, 2, 3-4, 5-6 and 7, respectively. CONCLUSIONS: Bacterial pneumonia rates in cART-treated adults with moderate immunodeficiency are high. The mechanism of the association between bacterial pneumonia and recent IL-2 receipt and/or detectable HIV viraemia warrants further exploration.

. 2011. Working with Concepts: The Role of Community in International Collaborative Biomedical Research. Public Health Ethics, 4 (1), pp. 26-39. | Citations: 29 (Scopus) | Show Abstract | Read more

The importance of communities in strengthening the ethics of international collaborative research is increasingly highlighted, but there has been much debate about the meaning of the term 'community' and its specific normative contribution. We argue that 'community' is a contingent concept that plays an important normative role in research through the existence of morally significant interplay between notions of community and individuality. We draw on experience of community engagement in rural Kenya to illustrate two aspects of this interplay: (i) that taking individual informed consent seriously involves understanding and addressing the influence of communities in which individuals' lives are embedded; (ii) that individual participation can generate risks and benefits for communities as part of the wider implications of research. We further argue that the contingent nature of a community means that defining boundaries is generally a normative process itself, with ethical implications. Community engagement supports the enactment of normative roles; building mutual understanding and trust between researchers and community members have been important goals in Kilifi, requiring a broad range of approaches. Ethical dilemmas are continuously generated as part of these engagement activities, including the risks of perverse outcomes related to existing social relations in communities and conditions of 'half knowing' intrinsic to processes of developing new understandings.

. 2011. Epidemiology, seasonality, and predictors of outcome of AIDS-associated Penicillium marneffei infection in Ho Chi Minh City, Viet Nam. Clin Infect Dis, 52 (7), pp. 945-952. | Citations: 48 (Scopus) | Show Abstract | Read more

BACKGROUND: Penicillium marneffei is an important human immunodeficiency virus (HIV)-associated opportunistic pathogen in Southeast Asia. The epidemiology and the predictors of penicilliosis outcome are poorly understood. METHODS: We performed a retrospective study of culture-confirmed incident penicilliosis admissions during 1996-2009 at the Hospital for Tropical Diseases in Ho Chi Minh City, Viet Nam. Seasonality of penicilliosis was assessed using cosinor models. Logistic regression was used to assess predictors of death or worsening disease based on 10 predefined covariates, and Cox regression was performed to model time-to-antifungal initiation. RESULTS: A total of 795 patients were identified; hospital charts were obtainable for 513 patients (65%). Cases increased exponentially and peaked in 2007 (156 cases), mirroring the trends in AIDS admissions during the study period. A highly significant seasonality for penicilliosis (P<.001) but not for cryptococcosis (P=.63) or AIDS admissions (P=.83) was observed, with a 27% (95% confidence interval, 14%-41%) increase in incidence during rainy months. All patients were HIV infected; the median CD4 cell count (62 patients) was 7 cells/μL (interquartile range, 4-24 cells/μL). Hospital outcome was an improvement in 347 (68%), death in 101 (20%), worsening in 42 (8%), and nonassessable in 23 (5%) cases. Injection drug use, shorter history, absence of fever or skin lesions, elevated respiratory rates, higher lymphocyte count, and lower platelet count independently predicted poor outcome in both complete-case and multiple-imputation analyses. Time-to-treatment initiation was shorter for patients with skin lesions (hazard ratio, 3.78; 95% confidence interval, 2.96-4.84; P<.001). CONCLUSIONS: Penicilliosis incidence correlates with the HIV/AIDS epidemic in Viet nam. The number of cases increases during rainy months. Injection drug use, shorter history, absence of fever or skin lesions, respiratory difficulty, higher lymphocyte count, and lower platelet count predict poor in-hospital outcome.

. 2011. Accuracy of loop-mediated isothermal amplification for diagnosis of human leptospirosis in Thailand. Am J Trop Med Hyg, 84 (4), pp. 614-620. | Citations: 23 (Scopus) | Show Abstract | Read more

There is a lack of diagnostic tests for leptospirosis in technology-restricted settings. We developed loop-mediated isothermal amplification (LAMP) specific for the 16S ribosomal RNA gene (rrs) of pathogenic and intermediate group Leptospira species. The lower limit of detection was 10 genomic equivalents/reaction, and analytical specificity was high; we observed positive reactions for pathogenic/intermediate groups and negative reactions for non-pathogenic Leptospira species and other bacterial species. We evaluated this assay in Thailand by using a case-control study of 133 patients with laboratory-proven leptospirosis and 133 patients with other febrile illnesses. Using admission blood, we found that the rrs LAMP showed positive results in 58 of 133 cases (diagnostic sensitivity = 43.6, 95% confidence interval [CI] = 35.0-52.5) and in 22 of 133 controls (diagnostic specificity = 83.5, 95% CI = 76.0-89.3). Sensitivity was high for 39 patients who were culture positive for Leptospira spp. (84.6, 95% CI = 69.5-94.1). The rrs LAMP can provide an admission diagnosis in approximately half of patients with leptospirosis, but its clinical utility is reduced by a lower specificity.

. 2011. Enzyme-linked immunosorbent assay for the diagnosis of melioidosis: better than we thought. Clin Infect Dis, 52 (8), pp. 1024-1028. | Citations: 15 (Web of Science Lite) | Show Abstract | Read more

We used Bayesian latent-class models to generate receiver operating characteristic curves and to revise the cutoff values for an enzyme-linked immunosorbent assay that has been developed previously for melioidosis. The new cutoff was unbiased towards misclassification caused by an imperfect gold standard and resulted in an increase in both sensitivity (from 66.4% to 80.2%) and specificity (82.1% and 95.0%).

. 2011. Human immune responses to Burkholderia pseudomallei characterized by protein microarray analysis. J Infect Dis, 203 (7), pp. 1002-1011. | Citations: 33 (Scopus) | Show Abstract | Read more

BACKGROUND: We aimed to determine the antibody and T cell responses to Burkholderia pseudomallei of humans to select candidate vaccine antigens. METHODS: For antibody profiling, a protein microarray of 154 B. pseudomallei proteins was probed with plasma from 108 healthy individuals and 72 recovered patients. Blood from 20 of the healthy and 30 of the recovered individuals was also obtained for T cell assays. RESULTS: Twenty-seven proteins distinctively reacted with human plasma following environmental exposure or clinical melioidosis. We compared the responses according to the patient's history of subsequent relapse, and antibody response to BPSL2765 was higher in plasma from individuals who had only 1 episode of disease than in those with recurrent melioidosis. A comparison of antibody and T cell responses to 5 B. pseudomallei proteins revealed that BimA and flagellin-induced responses were similar but that BPSS0530 could induce T cell responses in healthy controls more than in recovered patients. CONCLUSIONS: By combining large-scale antibody microarrays and assays of T cell-mediated immunity, we identified a panel of novel B. pseudomallei proteins that show distinct patterns of reactivity in different stages of human melioidosis. These proteins may be useful candidates for development of subunit-based vaccines and in monitoring the risks of treatment failure and relapse.

. 2011. Snakebite mortality in India: a nationally representative mortality survey. PLoS Negl Trop Dis, 5 (4), pp. e1018. | Citations: 141 (Scopus) | Show Abstract | Read more

BACKGROUND: India has long been thought to have more snakebites than any other country. However, inadequate hospital-based reporting has resulted in estimates of total annual snakebite mortality ranging widely from about 1,300 to 50,000. We calculated direct estimates of snakebite mortality from a national mortality survey. METHODS AND FINDINGS: We conducted a nationally representative study of 123,000 deaths from 6,671 randomly selected areas in 2001-03. Full-time, non-medical field workers interviewed living respondents about all deaths. The underlying causes were independently coded by two of 130 trained physicians. Discrepancies were resolved by anonymous reconciliation or, failing that, by adjudication. A total of 562 deaths (0.47% of total deaths) were assigned to snakebites. Snakebite deaths occurred mostly in rural areas (97%), were more common in males (59%) than females (41%), and peaked at ages 15-29 years (25%) and during the monsoon months of June to September. This proportion represents about 45,900 annual snakebite deaths nationally (99% CI 40,900 to 50,900) or an annual age-standardised rate of 4.1/100,000 (99% CI 3.6-4.5), with higher rates in rural areas (5.4/100,000; 99% CI 4.8-6.0), and with the highest state rate in Andhra Pradesh (6.2). Annual snakebite deaths were greatest in the states of Uttar Pradesh (8,700), Andhra Pradesh (5,200), and Bihar (4,500). CONCLUSIONS: Snakebite remains an underestimated cause of accidental death in modern India. Because a large proportion of global totals of snakebites arise from India, global snakebite totals might also be underestimated. Community education, appropriate training of medical staff and better distribution of antivenom, especially to the 13 states with the highest prevalence, could reduce snakebite deaths in India.

et al. 2011. A multifaceted intervention to implement guidelines and improve admission paediatric care in Kenyan district hospitals: a cluster randomised trial. PLoS Med, 8 (4), pp. e1001018. | Citations: 63 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: In developing countries referral of severely ill children from primary care to district hospitals is common, but hospital care is often of poor quality. However, strategies to change multiple paediatric care practices in rural hospitals have rarely been evaluated. METHODS AND FINDINGS: This cluster randomized trial was conducted in eight rural Kenyan district hospitals, four of which were randomly assigned to a full intervention aimed at improving quality of clinical care (evidence-based guidelines, training, job aides, local facilitation, supervision, and face-to-face feedback; n  =  4) and the remaining four to control intervention (guidelines, didactic training, job aides, and written feedback; n  =  4). Prespecified structure, process, and outcome indicators were measured at baseline and during three and five 6-monthly surveys in control and intervention hospitals, respectively. Primary outcomes were process of care measures, assessed at 18 months postbaseline. In both groups performance improved from baseline. Completion of admission assessment tasks was higher in intervention sites at 18 months (mean  =  0.94 versus 0.65, adjusted difference 0.54 [95% confidence interval 0.05-0.29]). Uptake of guideline recommended therapeutic practices was also higher within intervention hospitals: adoption of once daily gentamicin (89.2% versus 74.4%; 17.1% [8.04%-26.1%]); loading dose quinine (91.9% versus 66.7%, 26.3% [-3.66% to 56.3%]); and adequate prescriptions of intravenous fluids for severe dehydration (67.2% versus 40.6%; 29.9% [10.9%-48.9%]). The proportion of children receiving inappropriate doses of drugs in intervention hospitals was lower (quinine dose >40 mg/kg/day; 1.0% versus 7.5%; -6.5% [-12.9% to 0.20%]), and inadequate gentamicin dose (2.2% versus 9.0%; -6.8% [-11.9% to -1.6%]). CONCLUSIONS: Specific efforts are needed to improve hospital care in developing countries. A full, multifaceted intervention was associated with greater changes in practice spanning multiple, high mortality conditions in rural Kenyan hospitals than a partial intervention, providing one model for bridging the evidence to practice gap and improving admission care in similar settings.

et al. 2011. The impact of enhanced cleaning within the intensive care unit on contamination of the near-patient environment with hospital pathogens: a randomized crossover study in critical care units in two hospitals. Crit Care Med, 39 (4), pp. 651-658. | Citations: 53 (Scopus) | Show Abstract | Read more

OBJECTIVES: To determine the effect of enhanced cleaning of the near-patient environment on the isolation of hospital pathogens from the bed area and staff hands. DESIGN: Prospective randomized crossover study over the course of 1 yr. SETTING: Intensive care units at two teaching hospitals. PATIENTS: There were 1252 patients staying during enhanced cleaning and 1331 staying during standard cleaning. INTERVENTIONS: In each of six 2-month periods, one unit was randomly selected for additional twice-daily enhanced cleaning of hand contact surfaces. MEASUREMENTS AND MAIN RESULTS: Agar contact samples were taken at five sites around randomly selected bed areas, from staff hands, and from communal sites three times daily for 12 bed days per week. Patients admitted in the year commencing April 2007 were analyzed for hospital-acquired colonization and infection. Over the course of 1152 bed days, 20,736 samples were collected. Detection of environmental methicillin-resistant Staphylococcus aureus per bed-area day was reduced during enhanced cleaning phases from 82 of 561 (14.6%) to 51 of 559 (9.1%) (adjusted odds ratio, 0.59; 95% confidence interval, 0.40-0.86; p = .006). Other targeted pathogens (Acinetobacter baumannii, extended-spectrum β-lactamase-producing Gram-negative bacteria, vancomycin-resistant enterococci, and Clostridium difficile) were rarely detected. Subgroup analyses showed reduced methicillin-resistant Staphylococcus aureus contamination on doctors' hands during enhanced cleaning (3 of 425; 0.7% vs. 11 of 423; 2.6%; adjusted odds ratio, 0.26; 95% confidence interval, 0.07-0.95; p = .025) and a trend to reduction on nurses' hands (16 of 1647; 1.0% vs. 28 of 1694; 1.7%; adjusted odds ratio 0.56; 95% confidence interval, 0.29-1.08; p = .077). All 1252 critical care patients staying during enhanced and 1,331 during standard cleaning were included, but no significant effect on patient methicillin-resistant Staphylococcus aureus acquisition was observed (adjusted odds ratio, 0.98; 95% confidence interval, 0.58-1.65; p = .93). CONCLUSIONS: Enhanced cleaning reduced environmental contamination and hand carriage, but no significant effect was observed on patient acquisition of methicillin-resistant Staphylococcus aureus. TRIAL REGISTRY: ISRCTN. Identifier: 06298448. http://www.controlled-trials.com/isrctn/.

. 2011. Risk factors for recurrence after Staphylococcus aureus bacteraemia. A retrospective matched case-control study (vol 58, pg 411, 2009) JOURNAL OF INFECTION, 62 (4), pp. 328-328. | Read more

. 2011. Infections of the nervous system. Pract Neurol, 11 (2), pp. 121-131. | Citations: 4 (Scopus) | Read more

. 2011. Community perceptions of bloody diarrhoea in an urban slum in South Asia: implications for introduction of a Shigella vaccine. Epidemiol Infect, 139 (4), pp. 599-605. | Citations: 6 (Scopus) | Show Abstract | Read more

Understanding local perceptions of disease causation could help public health officials improve strategies to prevent bloody diarrhoea. A cross-sectional survey was conducted in Dhaka, Bangladesh to elicit community beliefs about the causes of and prevention strategies for bloody diarrhoea. Between March and June 2003, we interviewed 541 randomly selected respondents. Overall, 507 (93%) respondents perceived that a vaccine could prevent bloody diarrhoea. If a vaccine provided lifetime protection, 445 (83%) respondents stated that they would opt to get the vaccine and would pay a median of $0·05 (range U.S.$0·01-0·15) for it, equivalent to <1% of their median weekly income. There was almost universal perception that an effective vaccine to prevent bloody diarrhoea was highly beneficial and acceptable. While respondents valued a vaccine for prevention of bloody diarrhoea, they were only willing to pay minimally for it. Therefore, achieving a high rate of Shigella vaccine coverage may require subsidy of vaccine purchase.

. 2011. Basic Molecular Evolution Workshop--A trans-African virtual training course: "Virtual Workshops": Is Africa ready to embrace the concept? Bioessays, 33 (4), pp. 243-247. | Read more

et al. 2011. Results of antiretroviral treatment interruption and intensification in advanced multi-drug resistant HIV infection from the OPTIMA trial. PLoS One, 6 (3), pp. e14764. | Citations: 84 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Guidance is needed on best medical management for advanced HIV disease with multidrug resistance (MDR) and limited retreatment options. We assessed two novel antiretroviral (ARV) treatment approaches in this setting. METHODS AND FINDINGS: We conducted a 2×2 factorial randomized open label controlled trial in patients with a CD4 count≤300 cells/µl who had ARV treatment (ART) failure requiring retreatment, to two options (a) re-treatment with either standard (≤4 ARVs) or intensive (≥5 ARVs) ART and b) either treatment starting immediately or after a 12-week monitored ART interruption. Primary outcome was time to developing a first AIDS-defining event (ADE) or death from any cause. Analysis was by intention to treat. From 2001 to 2006, 368 patients were randomized. At baseline, mean age was 48 years, 2% were women, median CD4 count was 106/µl, mean viral load was 4.74 log(10) copies/ml, and 59% had a prior AIDS diagnosis. Median follow-up was 4.0 years in 1249 person-years of observation. There were no statistically significant differences in the primary composite outcome of ADE or death between re-treatment options of standard versus intensive ART (hazard ratio 1.17; CI 0.86-1.59), or between immediate retreatment initiation versus interruption before re-treatment (hazard ratio 0.93; CI 0.68-1.30), or in the rate of non-HIV associated serious adverse events between re-treatment options. CONCLUSIONS: We did not observe clinical benefit or harm assessed by the primary outcome in this largest and longest trial exploring both ART interruption and intensification in advanced MDR HIV infection with poor retreatment options. TRIAL REGISTRATION: Clinicaltrials.gov NCT00050089.

. 2011. Use of deferred consent for severely ill children in a multi-centre phase III trial. Trials, 12 (1), pp. 90. | Citations: 31 (Scopus) | Show Abstract | Read more

BACKGROUND: Voluntary participation of a subject in research respects a subject's rights, strengthens its ethical conduct, and is formalized by the informed consent process. Clinical trials of life-saving interventions for medical emergencies often necessitate enrollment of patients where prior written individual informed consent is impossible. Although there are regulations and guidelines on protecting subjects in emergency research, these have been criticised for being limited and unnecessarily restrictive. Across Europe and the United States stringent regulations have resulted in a substantial decline of clinical trials involving emergency interventions. METHODS: We are conducting a trial of fluid resuscitation in children with hypovolaemic shock in six hospitals across three malaria-endemic African countries. The design is pragmatic as children are enrolled on clinical criteria alone and is being conducted in hospitals with facilities typical of many district hospitals across Africa. The trial aims to inform strategy for managing children with febrile illness and features of shock. In order to develop appropriate consent processes for the trial, we conducted a narrative review of current international recommendations for emergency consent. RESULTS: Practical or specific guidance was generally sparse or confusing with few examples in the literature to direct our informed consent process. For a sub-group of children who were critically sick or where parents themselves were otherwise too distressed to consider prior written consent, we opted for a modified form of deferred consent. This included verbal assent from guardians at the point of enrollment, with full written consent obtained after stabilising the child. For children who died prior to full written consent, ethical permission was received to waiver full consent. CONCLUSIONS: In light of the controversy around guidance and regulations in this area we report how and why we have used a modified system of deferred consent in an emergency intervention trial in children. Although approved by all relevant ethics committees and operational in 3 countries in Africa, formal research is now necessary to explore the perceptions and experiences of parents, health workers, researchers and ethics committees of the modified method of deferred consent.

. 2011. Detection of respiratory viruses by PCR assay of nasopharyngeal swabs stored in skim milk-tryptone-glucose-glycerol transport medium. J Clin Microbiol, 49 (6), pp. 2311-2313. | Citations: 5 (Web of Science Lite) | Show Abstract | Read more

We analyzed 129 paired nasopharyngeal aspirates (stored in viral transport medium [VTM]) and nasopharyngeal swabs (stored in skim milk-tryptone-glucose-glycerol [STGG] bacterial transport and storage medium) using PCRs to detect adenoviruses, influenza virus A or B, and respiratory syncytial virus (RSV). Overall, swabs stored in STGG medium without antimicrobials were found to be an acceptable alternative to aspirates stored in antimicrobial-containing VTM, with PCR agreement of 90.2% (kappa of 0.8).

. 2011. Rebound of plasma viremia following cessation of antiretroviral therapy despite profoundly low levels of HIV reservoir: implications for eradication. AIDS, 25 (6), pp. 871-872. | Citations: 3 (Scopus) | Read more

. 2011. Malaria-attributed death rates in India. Lancet, 377 (9770), pp. 993. | Citations: 3 (Web of Science Lite) | Read more

. 2011. Improved detection of nasopharyngeal cocolonization by multiple pneumococcal serotypes by use of latex agglutination or molecular serotyping by microarray. J Clin Microbiol, 49 (5), pp. 1784-1789. | Citations: 76 (Scopus) | Show Abstract | Read more

Identification of Streptococcus pneumoniae in the nasopharynx is critical for an understanding of transmission, estimates of vaccine efficacy, and possible replacement disease. Conventional nasopharyngeal swab (NPS) culture and serotyping (the WHO protocol) is likely to underestimate multiple-serotype carriage. We compared the WHO protocol with methods aimed at improving cocolonization detection. One hundred twenty-five NPSs from an infant pneumococcal-carriage study, containing ≥ 1 serotype by WHO culture, were recultured in duplicate. A sweep of colonies from one plate culture was serotyped by latex agglutination. DNA extracted from the second plate was analyzed by S. pneumoniae molecular-serotyping microarray. Multiple serotypes were detected in 11.2% of the swabs by WHO culture, 43.2% by sweep serotyping, and 48.8% by microarray. Sweep and microarray were more likely to detect multiple serotypes than WHO culture (P < 0.0001). Cocolonization detection rates were similar between microarray and sweep, but the microarray identified the greatest number of serotypes. A common serogroup type was identified in 95.2% of swabs by all methods. WHO methodology significantly underestimates multiple-serotype carriage compared to these alternate methods. Sweep serotyping is cost-effective and field deployable but may fail to detect serotypes at low abundance, whereas microarray serotyping is more costly and technology dependent but may detect these additional minor carried serotypes.

et al. 2011. Glyburide is anti-inflammatory and associated with reduced mortality in melioidosis. Clin Infect Dis, 52 (6), pp. 717-725. | Citations: 52 (Scopus) | Show Abstract | Read more

BACKGROUND: Patients with diabetes mellitus are more prone to bacterial sepsis, but there are conflicting data on whether outcomes are worse in diabetics after presentation with sepsis. Glyburide is an oral hypoglycemic agent used to treat diabetes mellitus. This K(ATP)-channel blocker and broad-spectrum ATP-binding cassette (ABC) transporter inhibitor has broad-ranging effects on the immune system, including inhibition of inflammasome assembly and would be predicted to influence the host response to infection. METHODS: We studied a cohort of 1160 patients with gram-negative sepsis caused by a single pathogen (Burkholderia pseudomallei), 410 (35%) of whom were known to have diabetes. We subsequently studied prospectively diabetics with B. pseudomallei infection (n = 20) to compare the gene expression profile of peripheral whole blood leukocytes in patients who were taking glyburide against those not taking any sulfonylurea. RESULTS: Survival was greater in diabetics than in nondiabetics (38% vs 45%, respectively, P = .04), but the survival benefit was confined to the patient group taking glyburide (adjusted odds ratio .47, 95% confidence interval .28-.74, P = .005). We identified differential expression of 63 immune-related genes (P = .001) in patients taking glyburide, the sum effect of which we predict to be antiinflammatory in the glyburide group. CONCLUSIONS: We present observational evidence for a glyburide-associated benefit during human melioidosis and correlate this with an anti-inflammatory effect of glyburide on the immune system.

. 2011. Resistance to chloroquine unhinges vivax malaria therapeutics. Antimicrob Agents Chemother, 55 (5), pp. 1827-1830. | Citations: 33 (Web of Science Lite) | Read more

et al. 2011. Specific receptor usage in Plasmodium falciparum cytoadherence is associated with disease outcome. PLoS One, 6 (3), pp. e14741. | Citations: 70 (Scopus) | Show Abstract | Read more

Our understanding of the basis of severe disease in malaria is incomplete. It is clear that pathology is in part related to the pro-inflammatory nature of the host response but a number of other factors are also thought to be involved, including the interaction between infected erythrocytes and endothelium. This is a complex system involving several host receptors and a major parasite-derived variant antigen (PfEMP1) expressed on the surface of the infected erythrocyte membrane. Previous studies have suggested a role for ICAM-1 in the pathology of cerebral malaria, although these have been inconclusive. In this study we have examined the cytoadherence patterns of 101 patient isolates from varying clinical syndromes to CD36 and ICAM-1, and have used variant ICAM-1 proteins to further characterise this adhesive phenotype. Our results show that increased binding to CD36 is associated with uncomplicated malaria while ICAM-1 adhesion is raised in parasites from cerebral malaria cases.

. 2011. Plasmodium vivax recurrence following falciparum and mixed species malaria: risk factors and effect of antimalarial kinetics. Clin Infect Dis, 52 (5), pp. 612-620. | Citations: 67 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Plasmodium vivax malaria commonly follows treatment of falciparum malaria in regions of co-endemicity. This is an important cause of preventable morbidity. METHODS: We examined the factors contributing to the risk of recurrence of P. vivax infection after treatment of acute falciparum malaria in a series of clinical trials conducted on the Thai-Myanmar border from 1991 through 2005. RESULTS: Overall, 10,549 patients (4960 children aged <15 years and 5589 adults) were treated for falciparum malaria; of these patients, 9385 (89.0%) had Plasmodium falciparum monoinfection and 1164 (11.0%) had mixed P. falciparum/P. vivax infections according to microscopic examinations performed at screening. The cumulative proportion of patients with P. falciparum infection recurrence by day 63 was 21.5% (95% confidence interval [CI], 20.3%-22.8%), and the cumulative proportion with P. vivax infection recurrence was 31.5% (95% CI, 30.1%-33.0%). Significant risk factors for P. vivax infection recurrence were mixed infection at enrollment, male sex, younger age, lower hematocrit, higher asexual P. falciparum parasite density (P < .001 for all factors), and P. falciparum gametocytemia at enrollment (P = .001). By day 63, the cumulative risk of vivax malaria after P. falciparum monoinfection was 51.1% (95% CI, 46.1%-56.2%) after treatment with rapidly eliminated drugs (t(1/2) <1 day), 35.3% (95% CI, 31.8%-39.0%) after treatment with intermediate half-life drugs (t(1/2) 1-7 days), and 19.6% (95% CI, 18.1%-21.3%) after treatment with slowly eliminated drugs (t(1/2) > 7 days) (P < .001, by test for trend). Artemisinin-based combinations containing mefloquine or piperaquine, compared with the artemether-lumefantrine and artesunate-atovaquone-proguanil combinations, were associated with a 3.6-fold to 4.2-fold lower adjusted hazard ratio for P. vivax infection recurrence within 63 days after pure or mixed P. falciparum infections (P < .001, for comparisons with artesunate-mefloquine). CONCLUSIONS: On the Thai-Myanmar border, P. vivax is the most common cause of parasitological failure after treatment for falciparum malaria. Slowly eliminated antimalarials reduce the risk of early P. vivax infection recurrence.

. 2011. Radical cure: the case for anti-relapse therapy against all malarias. Clin Infect Dis, 52 (5), pp. 621-623. | Citations: 9 (Web of Science Lite) | Read more

. 2011. A randomized study comparing combined pneumococcal conjugate and polysaccharide vaccination schedules in adults. Clin Infect Dis, 52 (6), pp. 736-742. | Citations: 65 (Scopus) | Show Abstract | Read more

BACKGROUND: The widely used 23-valent plain polysaccharide vaccine (23vP) has limited effectiveness, produces short-lived immune responses, and induces attenuated antibody production after subsequent challenge with pneumococcal vaccines. Our goal was to examine whether priming with the 7-valent pneumococcal conjugate vaccine (PCV7) could enhance the immunogenicity of 23vP for the PCV7 serotypes and to investigate whether 23vP induced hyporesponsiveness could be overcome using PCV7. METHODS: We conducted an open-label randomized study that compared 3 vaccine schedules, each of which consisted of 2 doses of PCV7 and 1 dose of 23vP (23vP-PCV7-PCV7, PCV7-23vP-PCV7, PCV7-PCV7-23vP) administered over a 1-year period in a cohort of 348 adults 50-70 years of age. All vaccines were administered intramuscularly and were given 6 months apart. Blood samples were obtained prior to and 1 month after each vaccination. RESULTS: 23vP administered after priming with 2 doses of PCV7 produced significantly higher antibody concentrations for 3 of the 7 PCV7 serotypes, compared with vaccination with a single dose of 23vP; however, the same immunogenicity could be achieved with a single dose of PCV7. Prior vaccination with 23vP attenuated the antibody response to subsequent PCV7, which was not restored by additional doses of PCV7. CONCLUSION: In adults, vaccination schedules combining PCV7 and 23vP do not provide improved immunogenicity over the use of a single dose of 23vP for most of the serotypes contained in PCV7.

. 2011. Circulating red cell-derived microparticles in human malaria. J Infect Dis, 203 (5), pp. 700-706. | Citations: 61 (Web of Science Lite) | Show Abstract | Read more

In patients with falciparum malaria, plasma concentrations of cell-derived microparticles correlate with disease severity. Using flow cytometry, we quantified red blood cell-derived microparticles (RMPs) in patients with malaria and identified the source and the factors associated with production. RMP concentrations were increased in patients with Plasmodium falciparum (n = 29; median, 457 RMPs/μL [range, 13-4,342 RMPs/μL]), Plasmodium vivax (n = 5; median, 409 RMPs/μL [range, 281-503/μL]), and Plasmodium malariae (n = 2; median, 163 RMPs/μL [range, 127-200 RMPs/μL]) compared with those in healthy subjects (n = 11; median, 8 RMPs/μL [range, 3-166 RMPs/μL]; P = .01). RMP concentrations were highest in patients with severe falciparum malaria (P = .01). Parasitized red cells produced >10 times more RMPs than did unparasitized cells, but the overall majority of RMPs still derived from uninfected red blood cells (URBCs). In cultures, RMP production increased as the parasites matured. Hemin and parasite products induced RMP production in URBCs, which was inhibited by N-acetylcysteine, suggesting heme-mediated oxidative stress as a pathway for the generation of RMPs.

. 2011. Clinical management of Staphylococcus aureus bacteraemia. Lancet Infect Dis, 11 (3), pp. 208-222. | Citations: 98 (Scopus) | Show Abstract | Read more

Staphylococcus aureus bacteraemia is one of the most common serious bacterial infections worldwide. In the UK alone, around 12,500 cases each year are reported, with an associated mortality of about 30%, yet the evidence guiding optimum management is poor. To date, fewer than 1500 patients with S aureus bacteraemia have been recruited to 16 controlled trials of antimicrobial therapy. Consequently, clinical practice is driven by the results of observational studies and anecdote. Here, we propose and review ten unanswered clinical questions commonly posed by those managing S aureus bacteraemia. Our findings define the major areas of uncertainty in the management of S aureus bacteraemia and highlight just two key principles. First, all infective foci must be identified and removed as soon as possible. Second, long-term antimicrobial therapy is required for those with persistent bacteraemia or a deep, irremovable focus. Beyond this, the best drugs, dose, mode of delivery, and duration of therapy are uncertain, a situation compounded by emerging S aureus strains that are resistant to old and new antibiotics. We discuss the consequences on clinical practice, and how these findings define the agenda for future clinical research.

et al. 2011. Snake venomics of African spitting cobras: toxin composition and assessment of congeneric cross-reactivity of the pan-African EchiTAb-Plus-ICP antivenom by antivenomics and neutralization approaches. J Proteome Res, 10 (3), pp. 1266-1280. | Citations: 73 (Scopus) | Show Abstract | Read more

Venomic analysis of the venoms of Naja nigricollis, N. katiensis, N. nubiae, N. mossambica, and N. pallida revealed similar compositional trends. The high content of cytotoxins and PLA(2)s may account for the extensive tissue necrosis characteristic of the envenomings by these species. The high abundance of a type I α-neurotoxin in N. nubiae may be responsible for the high lethal toxicity of this venom (in rodents). The ability of EchiTAb-Plus-ICP antivenom to immunodeplete and neutralize the venoms of African spitting cobras was assessed by antivenomics and neutralization tests. It partially immunodepleted 3FTx and PLA(2)s and completely immunodepleted SVMPs and CRISPs in all venoms. The antivenom neutralized the dermonecrotic and PLA(2) activities of all African Naja venoms, whereas lethality was eliminated in the venoms of N. nigricollis, N. mossambica, and N. pallida but not in those of N. nubiae and N. katiensis. The lack of neutralization of lethality of N. nubiae venom may be of medical relevance only in relatively populous areas of the Saharan region. The impaired activity of EchiTAb-Plus-ICP against N. katiensis may not represent a major concern. This species is sympatric with N. nigricollis in many regions of Africa, although very few bites have been attributed to it.

. 2011. Implementing locally appropriate guidelines and training to improve care of serious illness in Kenyan hospitals: a story of scaling-up (and down and left and right). Arch Dis Child, 96 (3), pp. 285-290. | Citations: 22 (Scopus) | Read more

. 2011. Are bloodstream leukocytes Trojan Horses for the metastasis of Staphylococcus aureus? Nat Rev Microbiol, 9 (3), pp. 215-222. | Citations: 69 (Scopus) | Show Abstract | Read more

Staphylococcus aureus bacteraemia remains very difficult to treat, and a large proportion of cases result in potentially lethal metastatic infection. Unpredictable and persistent bacteraemia in the face of highly active, usually bactericidal antibiotics is the strongest predictor of death or disseminated disease. Although S. aureus has conventionally been considered an extracellular pathogen, much evidence demonstrates that it can survive intracellularly. In this Opinion article, we propose that phagocytes, and specifically neutrophils, represent a privileged site for S. aureus in the bloodstream, offering protection from most antibiotics and providing a mechanism by which the bacterium can travel to and infect distant sites. Furthermore, we suggest how this can be experimentally confirmed and how it may prompt a change in the current paradigm of S. aureus bacteraemia and identify better treatment options for improved clinical outcomes.

et al. 2011. A comparison of disease caused by Shigella and Campylobacter species: 24 months community based surveillance in 4 slums of Karachi, Pakistan. J Infect Public Health, 4 (1), pp. 12-21. | Citations: 9 (Scopus) | Show Abstract | Read more

Despite the efforts of the international community diarrheal diseases still pose a major threat to children in children less than five years of age. Bacterial diarrhea has also emerged as a public health concern due to the proliferation of drug resistant species in many parts of the world. There is a paucity of population-based data about the incidence of shigellosis and Campylobacter infections in Pakistan. We report country specific results for Shigella diarrhea that were derived from a multicenter study conducted in six Asian countries. Disease surveillance was conducted over a 24 month period in urban slums of Karachi, Pakistan, a city with a population of 59,584. Cases were detected through passive detection in study treatment centers. Stool specimens or rectal swabs were collected from all consenting patients. Between January 2002 and December 2003 10,540 enteric infection cases were detected. The incidence rate of treated diarrhea in children under 5 was 488/1000/year. In children, 5 years and older, the diarrhea rate was 22/1000/year. 576 (7%) Campylobacter isolates were detected. The pre-dominant Campylobacter species was C. jenuni with an increase of 29/1000 year in children under 5 years. Shigella species were isolated from 394 of 8032 children under 5 years of age. Shigella flexneri was the dominant species (10/1000/year in children under 5 years) followed by Shigella sonnei (3.9/1000/year), Shigella boydii (2.0/1000/year) and Shigella dysenteriae (1.3/1000/year). Shigellosis and Campylobacter infection rates peaked during the second year of life. The incidence rate of shigellosis increased in old age but such a trend was not observed in Campylobacter infections. Of 394 shigellosis patients 123 (31%) presented with dysentery in contrast to only 54 (9%) of 576 patients with Campylobacter infections (p<0.001). Both Campylobacter infections and shigellosis are common in community settings of Pakistan but shigellosis presented more frequently with abdominal pain and dysentery than Campylobacter infections indicating that shigellosis may be a more severe illness than Campylobacter infections. Due to the increased and disease severity, drug resistant shigella have become a significant health problem; moreover it is a disease of poor and impoverished people who do not have the access to standard water and sanitary conditions, health care services or optimal treatment. In the face of these facts it is empirically important to develop a low cost effective vaccine that can protect these populations for a longer duration.

. 2011. Cost-Effectiveness of Health Care Interventions to Address Intimate Partner Violence: What Do We Know and What Else Should We Look for? Violence Against Women, 17 (3), pp. 389-403. | Citations: 7 (Scopus) | Show Abstract | Read more

Intimate partner violence (IPV) creates a substantial burden of disease and significant costs to families, communities, and governments. Building the evidence for effective interventions to reduce violence and its sequelae requires increased use of economic evaluation to inform policy through the analysis of costs and potential savings of interventions. The authors review existing economic evaluations and present case studies of current research from the United Kingdom and Australia to illustrate the strengths and limitations of two approaches to generating economic evidence: economic evaluation alongside randomized controlled trials and economic modeling. Economic evaluation should always be considered in the design of IPV intervention research.

. 2011. Cause-specific cumulative incidence estimation and the fine and gray model under both left truncation and right censoring. Biometrics, 67 (1), pp. 39-49. | Citations: 68 (Scopus) | Show Abstract | Read more

Summary The standard estimator for the cause-specific cumulative incidence function in a competing risks setting with left truncated and/or right censored data can be written in two alternative forms. One is a weighted empirical cumulative distribution function and the other a product-limit estimator. This equivalence suggests an alternative view of the analysis of time-to-event data with left truncation and right censoring: individuals who are still at risk or experienced an earlier competing event receive weights from the censoring and truncation mechanisms. As a consequence, inference on the cumulative scale can be performed using weighted versions of standard procedures. This holds for estimation of the cause-specific cumulative incidence function as well as for estimation of the regression parameters in the Fine and Gray proportional subdistribution hazards model. We show that, with the appropriate filtration, a martingale property holds that allows deriving asymptotic results for the proportional subdistribution hazards model in the same way as for the standard Cox proportional hazards model. Estimation of the cause-specific cumulative incidence function and regression on the subdistribution hazard can be performed using standard software for survival analysis if the software allows for inclusion of time-dependent weights. We show the implementation in the R statistical package. The proportional subdistribution hazards model is used to investigate the effect of calendar period as a deterministic external time varying covariate, which can be seen as a special case of left truncation, on AIDS related and non-AIDS related cumulative mortality.

. 2011. Improved detection of canine Angiostrongylus vasorum infection using real-time PCR and indirect ELISA Parasitology Research, 109 (6), pp. 1577-1583. | Read more

. 2011. Castor Oil for Induction of Labor Obstetric Anesthesia Digest, 31 (1), pp. 37-38. | Read more

. 2011. Clearance of asymptomatic P. falciparum Infections Interacts with the number of clones to predict the risk of subsequent malaria in Kenyan children. PLoS One, 6 (2), pp. e16940. | Citations: 12 (Scopus) | Show Abstract | Read more

BACKGROUND: Protective immunity to malaria is acquired after repeated infections in endemic areas. Asymptomatic multiclonal P. falciparum infections are common and may predict host protection. Here, we have investigated the effect of clearing asymptomatic infections on the risk of clinical malaria. METHODS: Malaria episodes were continuously monitored in 405 children (1-6 years) in an area of moderate transmission, coastal Kenya. Blood samples collected on four occasions were assessed by genotyping the polymorphic P. falciparum merozoite surface protein 2 using fluorescent PCR and capillary electrophoresis. Following the second survey, asymptomatic infections were cleared with a full course of dihydroartemisinin. RESULTS: Children who were parasite negative by PCR had a lower risk of subsequent malaria regardless of whether treatment had been given. Children with ≥ 2 clones had a reduced risk of febrile malaria compared with 1 clone after clearance of asymptomatic infections, but not if asymptomatic infections were not cleared. Multiclonal infection was associated with an increased risk of re-infection after drug treatment. However, among the children who were re-infected, multiclonal infections were associated with a shift from clinical malaria to asymptomatic parasitaemia. CONCLUSION: The number of clones was associated with exposure as well as blood stage immunity. These effects were distinguished by clearing asymptomatic infection with anti-malarials. Exposure to multiple P. falciparum infections is associated with protective immunity, but there appears to be an additional effect in untreated multiclonal infections that offsets this protective effect.

et al. 2011. Likely health outcomes for untreated acute febrile illness in the tropics in decision and economic models; a Delphi survey. PLoS One, 6 (2), pp. e17439. | Citations: 26 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Modelling is widely used to inform decisions about management of malaria and acute febrile illnesses. Most models depend on estimates of the probability that untreated patients with malaria or bacterial illnesses will progress to severe disease or death. However, data on these key parameters are lacking and assumptions are frequently made based on expert opinion. Widely diverse opinions can lead to conflicting outcomes in models they inform. METHODS AND FINDINGS: A Delphi survey was conducted with malaria experts aiming to reach consensus on key parameters for public health and economic models, relating to the outcome of untreated febrile illnesses. Survey questions were stratified by malaria transmission intensity, patient age, and HIV prevalence. The impact of the variability in opinion on decision models is illustrated with a model previously used to assess the cost-effectiveness of malaria rapid diagnostic tests. Some consensus was reached around the probability that patients from higher transmission settings with untreated malaria would progress to severe disease (median 3%, inter-quartile range (IQR) 1-5%), and the probability that a non-malaria illness required antibiotics in areas of low HIV prevalence (median 20%). Children living in low transmission areas were considered to be at higher risk of progressing to severe malaria (median 30%, IQR 10-58%) than those from higher transmission areas (median 13%, IQR 7-30%). Estimates of the probability of dying from severe malaria were high in all settings (medians 60-73%). However, opinions varied widely for most parameters, and did not converge on resurveying. CONCLUSIONS: This study highlights the uncertainty around potential consequences of untreated malaria and bacterial illnesses. The lack of consensus on most parameters, the wide range of estimates, and the impact of variability in estimates on model outputs, demonstrate the importance of sensitivity analysis for decision models employing expert opinion. Results of such models should be interpreted cautiously. The diversity of expert opinion should be recognised when policy options are debated.

. 2011. Identifying residual foci of Plasmodium falciparum infections for malaria elimination: the urban context of Khartoum, Sudan. PLoS One, 6 (2), pp. e16948. | Citations: 16 (Scopus) | Show Abstract | Read more

BACKGROUND: Identifying the location and size of residual foci of infections is critical where malaria elimination is the primary goal. Here the spatial heterogeneity of Plasmodium falciparum infections within the urban extent of Khartoum state in Sudan is investigated using data from cross-sectional surveys undertaken from 1999 to 2008 to inform the Khartoum Malaria Free Initiative (KMFI). METHODS: From 1999-2008 the KMFI undertook cross-sectional surveys of 256 clusters across 203 random samples of residential blocks in the urban Khartoum state in September of each year. Within sampled blocks, at least five persons, including at least one child under the age of five years, were selected from each household. Blood smears were collected from the sampled individuals to examine the presence of P. falciparum parasites. Residential blocks were mapped. Data were analysed for spatial clustering using the Bernoulli model and the significance of clusters were tested using the Kulldorff scan statistic. RESULTS: A total of 128,510 malaria slide examinations were undertaken during the study period. In 1999, overall prevalence was 2.5%, rising to 3.2% in 2000 and consistently staying below 1% in subsequent years. From 2006, over 90% of all surveyed clusters reported no infections. Spatial clustering of infections was present in each year but not statistically significant in the years 2001, 2002, 2004 and 2008. Spatial clusters of high infection were often located at the junction of the Blue and White Niles. CONCLUSION: Persisting foci of malaria infection in Khartoum are likely to distort wide area assessments and disproportionately affect future transmission within the city limits. Improved investments in surveillance that combines both passive and active case detection linked to a geographic information system and a more detailed analysis of the location and stability of foci should be undertaken to facilitate and track malaria elimination in the state of Khartoum.

. 2011. Feasibility of malaria elimination. Lancet, 377 (9766), pp. 638. | Citations: 4 (Web of Science Lite) | Read more

. 2011. Malaria in pregnancy: the difficulties in measuring birthweight. BJOG, 118 (6), pp. 671-678. | Citations: 27 (Scopus) | Show Abstract | Read more

Recommendations for interventions to control malaria in pregnancy are often based on studies using birthweight as the primary endpoint. Differences in birthweight may be attributable partly to methodological difficulties. We performed a structured search of the literature using 'malaria', 'pregnancy' and 'birth weight' as search terms. Of the clinical trials reporting birthweight, only 33% (14/43) gave information about the timing of the measurement and details on the scales used. Seventy seven per cent explained how gestational age was estimated. We propose a standardised method for the measurement and reporting of birthweight in future studies.

. 2011. Clinical research: time for sensible global guidelines. Lancet, 377 (9777), pp. 1553-1555. | Citations: 17 (Web of Science Lite) | Read more

. 2011. Kinetics of plasma viremia and soluble nonstructural protein 1 concentrations in dengue: differential effects according to serotype and immune status. J Infect Dis, 203 (9), pp. 1292-1300. | Citations: 68 (Scopus) | Show Abstract | Read more

We describe the magnitude and kinetics of plasma viremia and nonstructural protein 1 (sNS1) levels in sequential samples from 167 children with acute dengue, enrolled early in a community study in Vietnam. All children recovered fully, and only 5 required hospitalization. Among those with dengue virus type 1 (DENV-1), plasma viremia was significantly greater in primary (49) than secondary (44) infections and took longer to resolve. In primary DENV-2 and 3 infections, viremia was significantly lower than among primary DENV-1 infections. Concentrations of sNS1 were significantly higher for DENV-1 than for DENV-2 after adjusting for viremia, with marked differences in the kinetic profiles between primary and secondary infections. Secondary infection and higher viremia were independent predictors of more severe thrombocytopenia, and higher viremia was associated with a small increase in hemoconcentration. Our findings identify clear serotype and immune-status related effects on the dynamics of dengue viremia and sNS1 responses, together with associations with important clinical parameters.

. 2011. Avidity of serogroup A meningococcal IgG antibodies after immunization with different doses of a tetravalent A/C/Y/W135 polysaccharide vaccine. Scand J Immunol, 74 (1), pp. 87-94. | Citations: 4 (Web of Science Lite) | Show Abstract | Read more

In the absence of an affordable conjugate meningococcal vaccine, mass vaccination campaigns with polysaccharide vaccines are the means to control meningitis epidemics in sub-Saharan Africa. Facing global vaccine shortage, the use of reduced doses, which have been shown to be protective by serum bactericidal activity, can save many lives. In this study, we investigated the antibody responses and avidity of IgG antibodies evoked against the serogroup A capsule of Neisseria meningitidis by different doses of an A/C/Y/W135 polysaccharide vaccine. Volunteers in Uganda were vaccinated with 1/10, 1/5 or a full dose (50 μg) and revaccinated with a full dose after 1 year. Specific IgG geometric mean concentrations and geometric mean avidity indices (GMAI) were determined by a modified enzyme-linked immunosorbent assay (ELISA) using thiocyanate as a chaotropic agent. After vaccination with 1/10 or 1/5 doses, the GMAI increased from 1 month to 1 year. One year following the initial dose, the GMAI levels were higher in the arm receiving reduced doses than for the arm receiving a full dose. Following the second full dose, avidity indices equalized at approximately the same level in the three arms. Although there are practical challenges to the use of reduced doses in the field, our findings suggest that reduced doses of polysaccharide vaccine are able to elicit antibodies of as good avidity against serogroup A polysaccharide as a full dose.

et al. 2011. Mortality in sickle cell anemia in Africa: a prospective cohort study in Tanzania. PLoS One, 6 (2), pp. e14699. | Citations: 82 (Scopus) | Show Abstract | Read more

BACKGROUND: The World Health Organization has declared Sickle Cell Anemia (SCA) a public health priority. There are 300,000 births/year, over 75% in Africa, with estimates suggesting that 6 million Africans will be living with SCA if average survival reaches half the African norm. Countries such as United States of America and United Kingdom have reduced SCA mortality from 3 to 0.13 per 100 person years of observation (PYO), with interventions such as newborn screening, prevention of infections and comprehensive care, but implementation of interventions in African countries has been hindered by lack of locally appropriate information. The objective of this study was to determine the incidence and factors associated with death from SCA in Dar-es-Salaam. METHODS AND FINDINGS: A hospital-based cohort study was conducted, with prospective surveillance of 1,725 SCA patients recruited from 2004 to 2009, with 209 (12%) lost to follow up, while 86 died. The mortality rate was 1.9 (95%CI 1.5, 2.9) per 100 PYO, highest under 5-years old [7.3 (4.8-11.0)], adjusting for dates of birth and study enrollment. Independent risk factors, at enrollment to the cohort, predicting death were low hemoglobin (<5 g/dL) [3.8 (1.8-8.2); p = 0.001] and high total bilirubin (≥102 µmol/L) [1.7 (1.0-2.9); p = 0.044] as determined by logistic regression. CONCLUSIONS: Mortality in SCA in Africa is high, with the most vulnerable period being under 5-years old. This is most likely an underestimate, as this was a hospital cohort and may not have captured SCA individuals with severe disease who died in early childhood, those with mild disease who are undiagnosed or do not utilize services at health facilities. Prompt and effective treatment for anemia in SCA is recommended as it is likely to improve survival. Further research is required to determine the etiology, pathophysiology and the most appropriate strategies for management of anemia in SCA.

. 2011. Multi-nucleoside reverse transcriptase inhibitor resistant HIV type-1 in a patient from Sierra Leone failing stavudine, lamivudine and nevirapine. Antivir Ther, 16 (1), pp. 115-118. | Citations: 5 (Scopus) | Show Abstract | Read more

We report a 33-year-old HIV type-1 (HIV-1)-infected male from Sierra Leone who harboured extensive drug resistance mutations to all nucleoside reverse transcriptase inhibitors (NRTIs) and non-NRTIs, including the multi-NRTI-resistance Q151M complex, K65R, M184I and Y181I, after using standard first-line generic fixed-dose stavudine, lamivudine and nevirapine (Triomune™) for 36 months. In the context of non-B subtypes in resource-limited countries, first-line stavudine-containing regimens have been associated with more extensive and complex mutation patterns, compared with subtype B viruses. Whether the extensive and complex NRTI resistance patterns found among African patients failing first-line antiretroviral therapy is explained by viral genetic diversity or by different patient monitoring strategies remains to be elucidated. Emerging multi-NRTI resistance in sub-Saharan Africa would not only compromise second-line treatment options and the success of antiretroviral rollout, but could also contribute to the spread of drug-resistant variants worldwide.

. 2011. Advancing global health research through digital technology and sharing data. Science, 331 (6018), pp. 714-717. | Citations: 38 (Scopus) | Show Abstract | Read more

The imperative for improving health in the world's poorest regions lies in research, yet there is no question that low participation, a lack of trained staff, and limited opportunities for data sharing in developing countries impede advances in medical practice and public health knowledge. Extensive studies are essential to develop new treatments and to identify better ways to manage healthcare issues. Recent rapid advances in availability and uptake of digital technologies, especially of mobile networks, have the potential to overcome several barriers to collaborative research in remote places with limited access to resources. Many research groups are already taking advantage of these technologies for data sharing and capture, and these initiatives indicate that increasing acceptance and use of digital technology could promote rapid improvements in global medical science.

. 2011. High prevalence of quinolone resistance in Neisseria gonorrhoeae in coastal Kenya. Sex Transm Infect, 87 (3), pp. 231. | Citations: 9 (Web of Science Lite) | Read more

et al. 2011. A molecular epidemiological study of var gene diversity to characterize the reservoir of Plasmodium falciparum in humans in Africa. PLoS One, 6 (2), pp. e16629. | Citations: 20 (Scopus) | Show Abstract | Read more

BACKGROUND: The reservoir of Plasmodium infection in humans has traditionally been defined by blood slide positivity. This study was designed to characterize the local reservoir of infection in relation to the diverse var genes that encode the major surface antigen of Plasmodium falciparum blood stages and underlie the parasite's ability to establish chronic infection and transmit from human to mosquito. METHODOLOGY/PRINCIPAL FINDINGS: We investigated the molecular epidemiology of the var multigene family at local sites in Gabon, Senegal and Kenya which differ in parasite prevalence and transmission intensity. 1839 distinct var gene types were defined by sequencing DBLα domains in the three sites. Only 76 (4.1%) var types were found in more than one population indicating spatial heterogeneity in var types across the African continent. The majority of var types appeared only once in the population sample. Non-parametric statistical estimators predict in each population at minimum five to seven thousand distinct var types. Similar diversity of var types was seen in sites with different parasite prevalences. CONCLUSIONS/SIGNIFICANCE: Var population genomics provides new insights into the epidemiology of P. falciparum in Africa where malaria has never been conquered. In particular, we have described the extensive reservoir of infection in local African sites and discovered a unique var population structure that can facilitate superinfection through minimal overlap in var repertoires among parasite genomes. Our findings show that var typing as a molecular surveillance system defines the extent of genetic complexity in the reservoir of infection to complement measures of malaria prevalence. The observed small scale spatial diversity of var genes suggests that var genetics could greatly inform current malaria mapping approaches and predict complex malaria population dynamics due to the import of var types to areas where no widespread pre-existing immunity in the population exists.

. 2011. Malaria distribution, prevalence, drug resistance and control in Indonesia. Adv Parasitol, 74 (C), pp. 41-175. | Citations: 40 (Scopus) | Show Abstract | Read more

Approximately 230 million people live in Indonesia. The country is also home to over 20 anopheline vectors of malaria which transmit all four of the species of Plasmodium that routinely infect humans. A complex mosaic of risk of infection across this 5000-km-long archipelago of thousands of islands and distinctive habitats seriously challenges efforts to control malaria. Social, economic and political dimensions contribute to these complexities. This chapter examines malaria and its control in Indonesia, from the earliest efforts by malariologists of the colonial Netherlands East Indies, through the Global Malaria Eradication Campaign of the 1950s, the tumult following the coup d'état of 1965, the global resurgence of malaria through the 1980s and 1990s and finally through to the decentralization of government authority following the fall of the authoritarian Soeharto regime in 1998. We detail important methods of control and their impact in the context of the political systems that supported them. We examine prospects for malaria control in contemporary decentralized and democratized Indonesia with multidrug-resistant malaria and greatly diminished capacities for integrated malaria control management programs.

et al. 2011. Intensified treatment with high dose rifampicin and levofloxacin compared to standard treatment for adult patients with tuberculous meningitis (TBM-IT): protocol for a randomized controlled trial. Trials, 12 (1), pp. 25. | Citations: 41 (Scopus) | Show Abstract | Read more

BACKGROUND: Tuberculous meningitis is the most severe form of tuberculosis. Mortality for untreated tuberculous meningitis is 100%. Despite the introduction of antibiotic treatment for tuberculosis the mortality rate for tuberculous meningitis remains high; approximately 25% for HIV-negative and 67% for HIV positive patients with most deaths occurring within one month of starting therapy. The high mortality rate in tuberculous meningitis reflects the severity of the condition but also the poor antibacterial activity of current treatment regimes and relatively poor penetration of these drugs into the central nervous system. Improving the antitubercular activity in the central nervous system of current therapy may help improve outcomes. Increasing the dose of rifampicin, a key drug with known poor cerebrospinal fluid penetration may lead to higher drug levels at the site of infection and may improve survival. Of the second generation fluoroquinolones, levofloxacin may have the optimal pharmacological features including cerebrospinal fluid penetration, with a ratio of Area Under the Curve (AUC) in cerebrospinal fluid to AUC in plasma of >75% and strong bactericidal activity against Mycobacterium tuberculosis. We propose a randomized controlled trial to assess the efficacy of an intensified anti-tubercular treatment regimen in tuberculous meningitis patients, comparing current standard tuberculous meningitis treatment regimens with standard treatment intensified with high-dose rifampicin and additional levofloxacin. METHODS/DESIGN: A randomized, double blind, placebo-controlled trial with two parallel arms, comparing standard Vietnamese national guideline treatment for tuberculous meningitis with standard treatment plus an increased dose of rifampicin (to 15 mg/kg/day total) and additional levofloxacin. The study will include 750 patients (375 per treatment group) including a minimum of 350 HIV-positive patients. The calculation assumes an overall mortality of 40% vs. 30% in the two arms, respectively (corresponding to a target hazard ratio of 0.7), a power of 80% and a two-sided significance level of 5%. Randomization ratio is 1:1. The primary endpoint is overall survival, i.e. time from randomization to death during a follow-up period of 9 months. Secondary endpoints are: neurological disability at 9 months, time to new neurological event or death, time to new or recurrent AIDS-defining illness or death (in HIV-positive patients only), severe adverse events, and rate of treatment interruption for adverse events. DISCUSSION: Currently very few options are available for the treatment of TBM and the mortality rate remains unacceptably high with severe disabilities seen in many of the survivors. This trial is based on the hypothesis that current anti-mycobacterial treatment schedules for TBM are not potent enough and that outcomes will be improved by increasing the CSF penetrating power of this regimen by optimising dosage and using additional drugs with better CSF penetration. TRIAL REGISTRATION: International Standard Randomised Controlled Trial Number ISRCTN61649292.

. 2011. Sample size requirements for separating out the effects of combination treatments: randomised controlled trials of combination therapy vs. standard treatment compared to factorial designs for patients with tuberculous meningitis. Trials, 12 (1), pp. 26. | Citations: 10 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: In certain diseases clinical experts may judge that the intervention with the best prospects is the addition of two treatments to the standard of care. This can either be tested with a simple randomized trial of combination versus standard treatment or with a 2 x 2 factorial design. METHODS: We compared the two approaches using the design of a new trial in tuberculous meningitis as an example. In that trial the combination of 2 drugs added to standard treatment is assumed to reduce the hazard of death by 30% and the sample size of the combination trial to achieve 80% power is 750 patients. We calculated the power of corresponding factorial designs with one- to sixteen-fold the sample size of the combination trial depending on the contribution of each individual drug to the combination treatment effect and the strength of an interaction between the two. RESULTS: In the absence of an interaction, an eight-fold increase in sample size for the factorial design as compared to the combination trial is required to get 80% power to jointly detect effects of both drugs if the contribution of the less potent treatment to the total effect is at least 35%. An eight-fold sample size increase also provides a power of 76% to detect a qualitative interaction at the one-sided 10% significance level if the individual effects of both drugs are equal. Factorial designs with a lower sample size have a high chance to be underpowered, to show significance of only one drug even if both are equally effective, and to miss important interactions. CONCLUSIONS: Pragmatic combination trials of multiple interventions versus standard therapy are valuable in diseases with a limited patient pool if all interventions test the same treatment concept, it is considered likely that either both or none of the individual interventions are effective, and only moderate drug interactions are suspected. An adequately powered 2 x 2 factorial design to detect effects of individual drugs would require at least 8-fold the sample size of the combination trial. TRIAL REGISTRATION: Current Controlled Trials ISRCTN61649292.

. 2011. Emergence of community-associated methicillin-resistant Staphylococcus aureus carriage in children in Cambodia. Am J Trop Med Hyg, 84 (2), pp. 313-317. | Citations: 16 (Scopus) | Show Abstract | Read more

We previously described the first reported isolation of methicillin-resistant Staphylococcus aureus (MRSA) (a case series of pediatric community-associated MRSA infections) in Cambodia. We define the rate of pediatric MRSA carriage in the same population and characterize the associated bacterial genotypes by using pulsed-field gel electrophoresis and multilocus sequence typing. A prospective cohort study of MRSA carriage conducted over one month at the Angkor Hospital for Children, Siem Reap, Cambodia, identified MRSA carriage in 87 (3.5%) of 2,485 children who came to the outpatient department, and 6 (4.1%) of 145 inpatients, including at least two with cases of nosocomial acquisition. Genotyping of all 93 MRSA isolates resolved 5 genotypes. Most (91%) isolates were assigned to sequence type 834. Only 28 (32%) of 87 MRSA carriers identified in the outpatient department had no history of recent healthcare contact. The study findings have important implications for healthcare in a setting where diagnostic microbiology and access to antimicrobial drugs with efficacy against MRSA are limited.

et al. 2011. Clinically unapparent infantile thiamin deficiency in Vientiane, Laos. PLoS Negl Trop Dis, 5 (2), pp. e969. | Citations: 21 (Scopus) | Show Abstract | Read more

BACKGROUND: Beriberi occurs in Vientiane, Lao PDR, among breastfed infants. Clinical disease may be the tip of an iceberg with subclinical thiamin deficiency contributing to other illnesses. Thiamin treatment could improve outcome. METHODOLOGY/PRINCIPAL FINDINGS: A cohort of 778 sick infants admitted during one year without clinical evidence of beriberi were studied prospectively and erythrocyte transketolase assays (ETK) performed. Biochemical thiamin deficiency was defined both in terms of the activation coefficient (α>31%) and basal ETK activity <0.59 micromoles/min/gHb. Of the 778 infants, median (range) age was 5 (0-12) months, 79.2% were breastfed, 5.1% had α>31% and 13.4 % basal ETK<0.59 micromoles/min/gHb. Infants≥2 months old had a higher frequency of biochemical markers of thiamin deficiency. Mortality was 5.5% but, among infants ≥2 months old, mortality was higher in those with basal ETK<0.59 micromoles/min/gHb (3/47, 6.4%) than in those with basal ETK≥0.59 micromoles/min/gHb (1/146, 0.7%) (P=0.045, relative risk=9.32 (95%CI 0.99 to 87.5)). Multivariate regression analysis indicated that infant age≥2 months and fewer maternal years of schooling were independently associated with infant basal ETK<0.59 micromoles/min/gHb. CONCLUSIONS/SIGNIFICANCE: Clinically unapparent thiamin deficiency is common among sick infants (≥2 months old) admitted to hospital in Vientiane. This may contribute to mortality and a low clinical threshold for providing thiamin to sick infants may be needed.

. 2011. Long-term outcome of Q fever endocarditis. Lancet Infect Dis, 11 (2), pp. 81. | Citations: 1 (Web of Science Lite) | Read more

. 2011. Sensitivity of hospital-based surveillance for severe disease: a geographic information system analysis of access to care in Kilifi district, Kenya. Bull World Health Organ, 89 (2), pp. 102-111. | Citations: 29 (Web of Science Lite) | Show Abstract | Read more

. 2011. Brain blood flow in Andean and Himalayan high-altitude populations: evidence of different traits for the same environmental constraint. J Cereb Blood Flow Metab, 31 (2), pp. 706-714. | Citations: 13 (Scopus) | Show Abstract | Read more

Humans have populated the Tibetan plateau much longer than the Andean Altiplano. It is thought that the difference in length of occupation of these altitudes has led to different responses to the stress of hypoxia. As such, Andean populations have higher hematocrit levels than Himalayans. In contrast, Himalayans have increased circulation to certain organ systems to meet tissue oxygen demand. In this study, we hypothesize that cerebral blood flow (CBF) is higher in Himalayans than in Andeans. Using a MEDLINE and EMBASE search, we included 10 studies that investigated CBF in Andeans and Himalayans between 3,658 and 4,330 m altitude. The CBF values were corrected for differences in hematocrit and arterial oxygen saturation. The data of these studies show a mean hematocrit of 50% in Himalayans and 54.1% in Andeans. Arterial oxygen saturation was 86.9% in Andeans and 88.4% in Himalayans. The CBF in Himalayans was slightly elevated compared with sea-level subjects, and was 24% higher compared with Andeans. After correction for hematorit and arterial oxygen saturation, CBF was ∼20% higher in Himalayans compared with Andeans. Altered brain metabolism in Andeans, and/or increased nitric oxide availability in Himalayans may have a role to explain this difference in brain blood flow.

. 2011. Differential phenotypic and genotypic characteristics of qnrS1-harboring plasmids carried by hospital and community commensal enterobacteria. Antimicrob Agents Chemother, 55 (4), pp. 1798-1802. | Citations: 7 (Scopus) | Show Abstract | Read more

The qnrS1 gene induces reduced susceptibility to fluoroquinolones in enterobacteria. We investigated the structure, antimicrobial susceptibility phenotype, and antimicrobial resistance gene characteristics of qnrS1 plasmids from hospitalized patients and community controls in southern Vietnam. We found that the antimicrobial susceptibilities, resistance gene characteristics, and plasmid structures of qnrS1 plasmids from the hospital differed from those from the community. Our data imply that the characteristics of the two plasmid groups are indicative of distinct selective pressures in the differing environments.

et al. 2011. Rapid pneumococcal evolution in response to clinical interventions. Science, 331 (6016), pp. 430-434. | Citations: 460 (Scopus) | Show Abstract | Read more

Epidemiological studies of the naturally transformable bacterial pathogen Streptococcus pneumoniae have previously been confounded by high rates of recombination. Sequencing 240 isolates of the PMEN1 (Spain(23F)-1) multidrug-resistant lineage enabled base substitutions to be distinguished from polymorphisms arising through horizontal sequence transfer. More than 700 recombinations were detected, with genes encoding major antigens frequently affected. Among these were 10 capsule-switching events, one of which accompanied a population shift as vaccine-escape serotype 19A isolates emerged in the USA after the introduction of the conjugate polysaccharide vaccine. The evolution of resistance to fluoroquinolones, rifampicin, and macrolides was observed to occur on multiple occasions. This study details how genomic plasticity within lineages of recombinogenic bacteria can permit adaptation to clinical interventions over remarkably short time scales.

. 2011. A Research Agenda for Malaria Eradication: Modeling PLOS MEDICINE, 8 (1), pp. e1000403-e1000403. | Citations: 1 (Web of Science Lite) | Read more

. 2011. Exploring the condom gap: is supply or demand the limiting factor - condom access and use in an urban and a rural setting in Kilifi district, Kenya. AIDS, 25 (2), pp. 247-255. | Citations: 17 (Scopus) | Show Abstract | Read more

OBJECTIVE: to explore the extent of the condom gap, investigating the relative roles of supply-side and demand-side factors in determining condom use. DESIGN: GPS mapping of condom outlets, and population-based survey. METHODS: an urban and a rural site were selected within the Epidemiological and Demographic Surveillance Site in Kilifi district, Kenya. Potential condom outlets (n = 281) were mapped and surveyed, and questionnaires on condom access and use (n = 630) were administered to a random sample of men and women aged 15-49. Multivariate logistic regression was performed to assess the relative roles of supply-side and demand-side barriers on condom use. RESULTS: the median straight-line distance to free condoms was 18-fold higher in the rural versus urban site. Among sexually active respondents, 42% had ever used a condom, and 23% had used a condom over the past 12 months, with lower levels among rural versus urban respondents (P < 0.05). The mean number of condoms used was 2.2/person per year among all sexually active individuals (condom users and nonusers), amounting to 8.2% protected sex acts/person per year. The adjusted odds of condom use (past 12 months) were 8.1 times greater among individuals experiencing no supply-side or demand-side barriers, compared with individuals experiencing both types of barriers. Despite low levels of usage and the presence of supply-side and demand-side barriers, reported unmet need for condoms was low. CONCLUSIONS: there is an urgent need for renewed condom promotion efforts aimed at building demand, in addition to improving physical access, in resource-limited settings with generalized HIV epidemics in sub-Saharan Africa.

. 2011. The contribution of the eBioKit to Bioinformatics Education in Southern Africa EMBnet.journal, 16 (1), pp. 29-29. | Read more

. 2011. Parasitological efficacy of antimalarials in the treatment and prevention of falciparum malaria in pregnancy 1998 to 2009: a systematic review. BJOG, 118 (2), pp. 123-135. | Citations: 27 (Scopus) | Show Abstract | Read more

BACKGROUND: Pregnant women are at increased risk from malaria. Resistance to all classes of antimalarials has affected the treatment and prevention of malaria in pregnancy. OBJECTIVES: To review the therapeutic efficacy of antimalarials used for treatment and intermittent preventive treatment (IPT) in pregnancy. SEARCH STRATEGY: We searched MEDLINE and the Cochrane Library between January 1998 and December 2009 for publications using the medical subject headings: efficacy, antimalarials, malaria, pregnancy, pharmacokinetics, treatment, IPT and placenta positive. In May 2010 we searched the register of clinical trials (http://clinicaltrials.gov/) and of WHO (http://apps.who.int/trialsearch/) using 'malaria', and 'pregnancy' and 'treatment'. SELECTION CRITERIA: We identified 233 abstracts, reviewed 83 full text articles and included 60 studies. DATA COLLECTION AND ANALYSIS: Two authors entered extracted data to an excel spreadsheet. MAIN RESULTS: Parasitological failure rates, placenta positivity rates (assessed by microscopy) or both were reported in 44% (21/48), 46% (22/48) and 10% (5/48) of articles, respectively. Most pharmacokinetic studies (9/12) suggested dose optimisation. In 23 treatment studies 17 different antimalarial drugs were delivered in 53 study arms; 43.4% (23/53) reported a failure rate of < 5%; 83.3% of sulphadoxine-pyrimethamine (SP) arms and 9% of artemisinin combination therapy (ACT) arms had failure rates ≥ 10%. Placenta-positive rates (mostly reported in the context of IPT in pregnancy) were > 10% in 68% (23/34) of SP trial arms and > 15% in all seven chloroquine arms. The ACT provided lower parasitological failure and gametocyte carriage rates. AUTHOR'S CONCLUSIONS: Drugs used in pregnancy should aim for 95% efficacy but many currently deployed regimens are associated with much lower cure rates.

. 2011. A prospective evaluation of diagnostic methodologies for the acute diagnosis of dengue virus infection on the Thailand-Myanmar border Transactions of the Royal Society of Tropical Medicine and Hygiene, 105 (1), pp. 32-37. | Citations: 18 (Scopus) | Show Abstract | Read more

Clinically useful diagnostic tests of dengue virus infection are lacking. We prospectively evaluated the performance of real-time reverse transcriptase (rRT)-PCR, NS-1 antigen and IgM antibody tests to confirm dengue virus infection in acute blood specimens from 162 patients presenting with undifferentiated febrile illness compatible with dengue infection. rRT-PCR was the most sensitive test (89%) and potentially could be used as a single test for confirmation of dengue infection. NS-1 antigen and IgM antibody were not sufficiently sensitive to be used as a single confirmatory test with sensitivities of 54% and 17% respectively. The specificities of rRT-PCR, NS-1 antigen and IgM antibody tests were 96%, 100% and 88% respectively. Combining NS-1 and rRT-PCR or the combination of all three tests resulted in the highest sensitivity (93%) but specificities dropped to 96% and 83% respectively. We conclude that at least the combination of two tests, either agent detection (rRT-PCR) or antigen detection (NS-1) plus IgM antibody detection should be used for laboratory confirmation of dengue infection. © 2010 Royal Society of Tropical Medicine and Hygiene.

. 2011. Social and environmental determinants of malaria in space and time in Viet Nam International Journal for Parasitology, 41 (1), pp. 109-116. | Citations: 29 (Scopus) | Show Abstract | Read more

The malaria burden in Viet Nam has been in decline in recent decades, but localised areas of high transmission remain. We used spatiotemporal analytical tools to determine the social and environmental drivers of malaria risk and to identify residual high-risk areas where control and surveillance resources can be targeted. Counts of reported Plasmodium falciparum and Plasmodium vivax malaria cases by month (January 2007-December 2008) and by district were assembled. Zero-inflated Poisson regression models were developed in a Bayesian framework. Models had the percentage of the district's population living below the poverty line, percent of the district covered by forest, median elevation, median long-term average precipitation, and minimum temperature included as fixed effects, and terms for temporal trend and residual district-level spatial autocorrelation. Strong temporal and spatial heterogeneity in counts of malaria cases was apparent. Poverty and forest cover were significantly associated with an increased count of malaria cases but the magnitude and direction of associations between climate and malaria varied by socio-ecological zone. There was a declining trend in counts of malaria cases during the study period. After accounting for the social and environmental fixed effects, substantial spatial heterogeneity was still evident. Unmeasured factors which may contribute to this residual variation include malaria control activities, population migration and accessibility to health care. Forest-related activities and factors encompassed by poverty indicators are major drivers of malaria incidence in Viet Nam. © 2010 Australian Society for Parasitology Inc.

. 2011. Consideration of ethics in primaquine therapy against malaria transmission Trends in Parasitology, 27 (1), pp. 11-16. | Citations: 44 (Scopus) | Show Abstract | Read more

Millions of people receive primaquine against sexual plasmodia responsible for malaria transmission. These gametocytes cause no symptoms and do not threaten the host, but they infect mosquitoes and threaten the community. Primaquine causes hemolysis in the small minority of patients with glucose-6-phosphate dehydrogenase deficiency (G6PDd). Clinical studies in the 1950s demonstrated gametocytocidal primaquine to be safe without G6PDd screening. However, the evaluated G6PDd variant, African A-, represents mild sensitivity to primaquine. The view of primaquine as a safe gametocytocide thus rests largely upon observations from a G6PDd variant that is unlikely to challenge safety. The early clinical work does not seem to afford an adequate assessment of safety in G6PDd patients. Potential risk of harm without clinical benefit to the patient raises ethical questions that should be examined. © 2010 Elsevier Ltd.

. 2011. Changes in health workers' malaria diagnosis and treatment practices in Kenya. Malar J, 10 (1), pp. 1. | Citations: 50 (Scopus) | Show Abstract | Read more

BACKGROUND: Change of Kenyan treatment policy for uncomplicated malaria from sulphadoxine-pyrimethamine to artemether-lumefantrine (AL) was accompanied by revised recommendations promoting presumptive malaria diagnosis in young children and, wherever possible, parasitological diagnosis and adherence to test results in older children and adults. Three years after the policy implementation, health workers' adherence to malaria diagnosis and treatment recommendations was evaluated. METHODS: A national cross-sectional, cluster sample survey was undertaken at public health facilities. Data were collected using quality-of-care assessment methods. Analysis was restricted to facilities with AL in stock. Main outcomes were diagnosis and treatment practices for febrile outpatients stratified by age, availability of diagnostics, use of malaria diagnostic tests, and test result. RESULTS: The analysis included 1,096 febrile patients (567 aged <5 years and 529 aged ≥5 years) at 88 facilities with malaria diagnostics, and 880 febrile patients (407 aged <5 years and 473 aged ≥5 years) at 71 facilities without malaria diagnostic capacity. At all facilities, 19.8% of young children and 28.7% of patients aged ≥5 years were tested, while at facilities with diagnostics, 33.5% and 53.7% were respectively tested in each age group. Overall, AL was prescribed for 63.6% of children aged <5 years and for 65.0% of patients aged ≥5 years, while amodiaquine or sulphadoxine-pyrimethamine monotherapies were prescribed for only 2.0% of children and 3.9% of older children and adults. In children aged <5 years, AL was prescribed for 74.7% of test positive, 40.4% of test negative and 60.7% of patients without test performed. In patients aged ≥5 years, AL was prescribed for 86.7% of test positive, 32.8% of test negative and 58.0% of patients without test performed. At least one anti-malarial treatment was prescribed for 56.6% of children and 50.4% of patients aged ≥5 years with a negative test result. CONCLUSIONS: Overall, malaria testing rates were low and, despite different age-specific recommendations, only moderate differences in testing rates between the two age groups were observed at facilities with available diagnostics. In both age groups, AL use prevailed, and prior ineffective anti-malarial treatments were nearly non-existent. The large majority of test positive patients were treated with recommended AL; however, anti-malarial treatments for test negative patients were widespread, with AL being the dominant choice. Recent change of diagnostic policy to universal testing in Kenya is an opportunity to improve upon the quality of malaria case management. This will be, however, dependent upon the delivery of a comprehensive case management package including large scale deployment of diagnostics, good quality of training, post-training follow-up, structured supervisory visits, and more intense monitoring.

et al. 2011. The antimicrobial resistance patterns and associated determinants in Streptococcus suis isolated from humans in southern Vietnam, 1997-2008. BMC Infect Dis, 11 (1), pp. 6. | Citations: 21 (Scopus) | Show Abstract | Read more

BACKGROUND: Streptococcus suis is an emerging zoonotic pathogen and is the leading cause of bacterial meningitis in adults in Vietnam. Systematic data on the antimicrobial susceptibility profiles of S. suis strains isolated from human cases are lacking. We studied antimicrobial resistance and associated resistance determinants in S. suis isolated from patients with meningitis in southern Vietnam. METHODS: S. suis strains isolated between 1997 and 2008 were investigated for their susceptibility to six antimicrobial agents. Strains were screened for the presence and expression of tetracycline and erythromycin resistance determinants and the association of tet(M) genes with Tn916- like transposons. The localization of tetracycline resistance gene tet(L) was determined by pulse field gel electrophoresis and Southern blotting. RESULTS: We observed a significant increase in resistance to tetracycline and chloramphenicol, which was concurrent with an increase in multi-drug resistance. In tetracycline resistance strains, we identified tet(M), tet(O), tet(W) and tet(L) and confirmed their expression. All tet(M) genes were associated with a Tn916-like transposon. The co-expression of tet(L) and other tetracycline resistance gene(s) encoding for ribosomal protection protein(s) was only detected in strains with a minimum inhibitory concentration (MIC) of tetracycline of ≥ 64 mg/L. CONCLUSIONS: We demonstrated that multi-drug resistance in S. suis causing disease in humans in southern Vietnam has increased over the 11-year period studied. We report the presence and expression of tet(L) in S. suis strains and our data suggest that co-expression of multiple genes encoding distinct mechanism is required for an MIC ≥ 64 mg/L to tetracycline.

. 2011. Epidemiological factors associated with dengue shock syndrome and mortality in hospitalized dengue patients in Ho Chi Minh City, Vietnam. Am J Trop Med Hyg, 84 (1), pp. 127-134. | Citations: 85 (Scopus) | Show Abstract | Read more

Understanding trends in dengue disease burden and risk factors for severe disease can inform health service allocation, clinical management, and planning for vaccines and therapeutics. Dengue admissions at three tertiary hospitals in Ho Chi Minh City, Vietnam, increased between 1996 and 2009, peaking at 22,860 in 2008. Children aged 6-10 years had highest risk of dengue shock syndrome (DSS); however, mortality was highest in younger children and decreased with increasing age (odds ratio [OR] = 0.52, 95% confidence interval [CI] = 0.36-0.75 in 6- to 10- year-old children and OR = 0.27, 95% CI = 0.16-0.44 in 11- to 15-year-old children compared with 1- to 5-year-old children). Males were overrepresented among dengue cases; however, girls had higher risk of DSS (OR = 1.19, 95% CI = 1.14-1.24) and death (OR = 1.57, 95% CI = 1.14-2.17). Young children with dengue had greatest risk of death and should be targeted in dengue vaccine and drug trials. The increased risk of severe outcomes in girls warrants further attention in studies of pathogenesis, health-seeking behavior, and clinical care.

. 2011. Malarial retinopathy in Bangladeshi adults. Am J Trop Med Hyg, 84 (1), pp. 141-147. | Citations: 13 (Scopus) | Show Abstract | Read more

To establish if assessment of malarial retinopathy in adult malaria using ophthalmoscopy by non-ophthalmologists has clinical and prognostic significance, 210 Bangladeshi adults were assessed by both direct and indirect ophthalmoscopy; 20 of 20 healthy subjects and 20 of 20 patients with vivax malaria showed no retinal changes, whereas in patients with falciparum malaria, indirect ophthalmoscopy revealed malarial retinopathy (predominantly retinal hemorrhages) in 18 of 21 (86%) fatal, 31 of 75 (41%) cerebral, 16 of 64 (25%) non-cerebral but severe, and 1 of 31 (3%) uncomplicated cases. Direct ophthalmoscopy missed retinopathy in one of these cases and found fewer retinal hemorrhages (mean difference = 3.09; 95% confidence interval = 1.50-4.68; P < 0.0001). Severity of retinopathy increased with severity of disease (P for trend < 0.0001), and renal failure, acidosis, and moderate/severe retinopathy were independent predictors of mortality by both ophthalmoscopic techniques. Direct ophthalmoscopy by non-ophthalmologists is an important clinical tool to aid diagnosis and prognosis in adults with severe malaria, and indirect ophthalmoscopy by non-ophthalmologists, although more sensitive, provides minimal additional prognostic information.

et al. 2011. Temporal fluctuation of multidrug resistant salmonella typhi haplotypes in the mekong river delta region of Vietnam. PLoS Negl Trop Dis, 5 (1), pp. e929. | Citations: 29 (Scopus) | Show Abstract | Read more

BACKGROUND: typhoid fever remains a public health problem in Vietnam, with a significant burden in the Mekong River delta region. Typhoid fever is caused by the bacterial pathogen Salmonella enterica serovar Typhi (S. Typhi), which is frequently multidrug resistant with reduced susceptibility to fluoroquinolone-based drugs, the first choice for the treatment of typhoid fever. We used a GoldenGate (Illumina) assay to type 1,500 single nucleotide polymorphisms (SNPs) and analyse the genetic variation of S. Typhi isolated from 267 typhoid fever patients in the Mekong delta region participating in a randomized trial conducted between 2004 and 2005. PRINCIPAL FINDINGS: the population of S. Typhi circulating during the study was highly clonal, with 91% of isolates belonging to a single clonal complex of the S. Typhi H58 haplogroup. The patterns of disease were consistent with the presence of an endemic haplotype H58-C and a localised outbreak of S. Typhi haplotype H58-E2 in 2004. H58-E2-associated typhoid fever cases exhibited evidence of significant geo-spatial clustering along the Sông H u branch of the Mekong River. Multidrug resistance was common in the established clone H58-C but not in the outbreak clone H58-E2, however all H58 S. Typhi were nalidixic acid resistant and carried a Ser83Phe amino acid substitution in the gyrA gene. SIGNIFICANCE: the H58 haplogroup dominates S. Typhi populations in other endemic areas, but the population described here was more homogeneous than previously examined populations, and the dominant clonal complex (H58-C, -E1, -E2) observed in this study has not been detected outside Vietnam. IncHI1 plasmid-bearing S. Typhi H58-C was endemic during the study period whilst H58-E2, which rarely carried the plasmid, was only transient, suggesting a selective advantage for the plasmid. These data add insight into the outbreak dynamics and local molecular epidemiology of S. Typhi in southern Vietnam.

et al. 2011. Efficacy of RTS,S/AS01E malaria vaccine and exploratory analysis on anti-circumsporozoite antibody titres and protection in children aged 5-17 months in Kenya and Tanzania: a randomised controlled trial. Lancet Infect Dis, 11 (2), pp. 102-109. | Citations: 97 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: RTS,S/AS01E is the lead candidate malaria vaccine. We recently showed efficacy against clinical falciparum malaria in 5-17 month old children, during an average of 8 months follow-up. We aimed to assess the efficacy of RTS,S/AS01E during 15 months of follow-up. METHODS: Between March, 2007, and October, 2008, we enrolled healthy children aged 5-17 months in Kilifi, Kenya, and Korogwe, Tanzania. Computer-generated block randomisation was used to randomly assign participants (1:1) to receive three doses (at month 0, 1, and 2) of either RTS,S/AS01E or human diploid-cell rabies vaccine. The primary endpoint was time to first clinical malaria episode, defined as the presence of fever (temperature ≥37·5°C) and a Plasmodium falciparum density of 2500/μL or more. Follow-up was 12 months for children from Korogwe and 15 months for children from Kilifi. Primary analysis was per protocol. In a post-hoc modelling analysis we characterised the associations between anti-circumsporozoite antibodies and protection against clinical malaria episodes. This study is registered with ClinicalTrials.gov, number NCT00380393. FINDINGS: 894 children were assigned, 447 in each treatment group. In the per-protocol analysis, 82 of 415 children in the RTS,S/AS01E group and 125 of 420 in the rabies vaccine group had first or only clinical malaria episode by 12 months, vaccine efficacy 39·2% (95% CI 19·5-54·1, p=0·0005). At 15 months follow-up, 58 of 209 children in the RTS,S/AS01E group and 85 of 206 in the rabies vaccine group had first or only clinical malaria episode, vaccine efficacy 45·8% (24·1-61·3, p=0·0004). At 12 months after the third dose, anti-circumsporozoite antibody titre data were available for 390 children in the RTS,S/AS01E group and 391 in the rabies group. A mean of 15 months (range 12-18 months) data were available for 172 children in the RTS,S/AS01E group and 155 in the rabies group. These titres at 1 month after the third dose were not associated with protection, but titres at 6·5 months were. The level of protection increased abruptly over a narrow range of antibody concentrations. The most common adverse events were pneumonia, febrile convulsion, gastroenteritis, and P falciparum malaria. INTERPRETATION: RTS,S/AS01E confers sustained efficacy for at least 15 months and shows promise as a potential public health intervention against childhood malaria in malaria endemic countries. FUNDING: PATH Malaria Vaccine Initiative (MVI), GlaxoSmithKline.

. 2011. Quantification of the anti-influenza drug zanamivir in plasma using high-throughput HILIC-MS/MS. Bioanalysis, 3 (2), pp. 157-165. | Citations: 10 (Scopus) | Show Abstract | Read more

BACKGROUND: parenteral zanamivir is a promising drug for the treatment of severe influenza. However, quantification of this polar drug in biological matrices has traditionally been difficult and the methods developed have been relatively insensitive. RESULTS: a high-throughput bioanalytical method for the analysis of zanamivir in human plasma using SPE in the 96-well plate format and LC coupled to positive MS/MS has been developed and validated according to US FDA guidelines. The method uses 50 microl of plasma and covers a large working range from 1-50, 000 ng/ml with a LOD of 0.50 ng/ml. CONCLUSION: this new LC-MS/MS assay is more sensitive than previous methods despite using a small plasma volume sample. It is particularly suitable for clinical studies on both parenteral and inhaled zanamivir.

. 2011. Diagnostic accuracy of real-time PCR assays targeting 16S rRNA and lipL32 genes for human leptospirosis in Thailand: a case-control study. PLoS One, 6 (1), pp. e16236. | Citations: 57 (Scopus) | Show Abstract | Read more

BACKGROUND: Rapid PCR-based tests for the diagnosis of leptospirosis can provide information that contributes towards early patient management, but these have not been adopted in Thailand. Here, we compare the diagnostic sensitivity and specificity of two real-time PCR assays targeting rrs or lipL32 for the diagnosis of leptospirosis in northeast Thailand. METHODS/PRINCIPAL FINDINGS: A case-control study of 266 patients (133 cases of leptospirosis and 133 controls) was constructed to evaluate the diagnostic sensitivity and specificity (DSe & DSp) of both PCR assays. The median duration of illness prior to admission of cases was 4 days (IQR 2-5 days; range 1-12 days). DSe and DSp were determined using positive culture and/or microscopic agglutination test (MAT) as the gold standard. The DSe was higher for the rrs assay than the lipL32 assay (56%, (95% CI 47-64%) versus 43%, (95% CI 34-52%), p<0.001). No cases were positive for the lipL32 assay alone. There was borderline evidence to suggest that the DSp of the rrs assay was lower than the lipL32 assay (90% (95% CI 83-94%) versus 93%, (95%CI 88-97%), p = 0.06). Nine controls gave positive reactions for both assays and 5 controls gave a positive reaction for the rrs assay alone. The DSe of the rrs and lipL32 assays were high in the subgroup of 39 patients who were culture positive for Leptospira spp. (95% and 87%, respectively, p = 0.25). CONCLUSIONS/SIGNIFICANCE: Early detection of Leptospira using PCR is possible for more than half of patients presenting with leptospirosis and could contribute to individual patient care.

. 2011. Methotrexate is highly potent against pyrimethamine-resistant Plasmodium vivax. J Infect Dis, 203 (2), pp. 207-210. | Citations: 13 (Scopus) | Show Abstract | Read more

Resistance of vivax malaria to treatment with antifolates, such as pyrimethamine (Pyr), is spreading as mutations in the dihydrofolatereductase (dhfr) genes are selected and disseminated. We tested the antitumor drug methotrexate (MTX), a potent competitive inhibitor of dhfr, against 11 Plasmodium vivax isolates ex vivo, 10 of which had multiple dhfr mutations associated with Pyr resistance. Despite high-grade resistance to Pyr (median 50% inhibitory concentration [IC₅₀], 13,345 nM), these parasites were all highly susceptible to MTX (median IC₅₀, 2.6 nM). Given its potency against Pyr-resistant P. vivax, the antimalarial potential of MTX deserves further investigation.

et al. 2011. Transmitted HIV type 1 drug resistance among individuals with recent HIV infection in East and Southern Africa. AIDS Res Hum Retroviruses, 27 (1), pp. 5-12. | Citations: 85 (Scopus) | Show Abstract | Read more

To characterize WHO-defined transmitted HIV drug resistance mutation (TDRM) data from recently HIV-infected African volunteers, we sequenced HIV (pol) and evaluated for TDRM the earliest available specimens from ARV-naive volunteers diagnosed within 1 year of their estimated date of infection at eight research centers in sub-Saharan Africa. TDRMs were detected in 19/408 (5%) volunteers. The prevalence of TDRMs varied by research center, from 5/26 (19%) in Entebbe, 6/78 (8%) in Kigali, 2/49 (4%) in Kilifi, to 3/106 (3%) in Lusaka. One of five volunteers from Cape Town (20%) had TDRMs. Despite small numbers, our data suggest an increase in DRMs by year of infection in Zambia (p = 0.004). The prevalence observed in Entebbe was high across the entire study. ARV history data from 12 (63%) HIV-infected sexual partners were available; 3 reported ARV use prior to transmission. Among four partners with sequence data available, transmission linkage was confirmed and two had the same TDRMs as the newly infected volunteer (both K103N). As ARV therapy continues to increase in availability throughout Africa, monitoring incident virus strains for the presence of TDRMs should be a priority. Early HIV infection cohorts provide an excellent and important platform to monitor the development of TDRMs to inform treatment guidelines, drug choices, and strategies for secondary prevention of TDRM transmission.

. 2011. Perasafe, Virkon and bleach are bactericidal for Burkholderia pseudomallei, a select agent and the cause of melioidosis Journal of Hospital Infection, 77 (2), pp. 183-184. | Citations: 1 (Scopus) | Read more

. 2011. Chromoblastomycosis after a leech bite complicated by myiasis: a case report. BMC Infect Dis, 11 (1), pp. 14. | Citations: 9 (Scopus) | Show Abstract | Read more

BACKGROUND: Chromoblastomycosis is a chronic mycotic infection, most common in the tropics and subtropics, following traumatic fungal implantation. CASE PRESENTATION: A 72 year-old farmer was admitted to Luang Namtha Provincial Hospital, northern Laos, with a growth on the left lower leg which began 1 week after a forefoot leech bite 10 years previously. He presented with a cauliflower-like mass and plaque-like lesions on his lower leg/foot and cellulitis with a purulent tender swelling of his left heel. Twenty-two Chrysomya bezziana larvae were extracted from his heel. PCR of a biopsy of a left lower leg nodule demonstrated Fonsecaea pedrosoi, monophora, or F. nubica. He was successfully treated with long term terbinafin plus itraconazole pulse-therapy and local debridement. CONCLUSIONS: Chromoblastomycosis is reported for the first time from Laos. It carries the danger of bacterial and myiasis superinfection. Leech bites may facilitate infection.

et al. 2011. Post-prostatic massage fluid/urine as an alternative to semen for studying male genitourinary HIV-1 shedding. Sex Transm Infect, 87 (3), pp. 232-237. | Citations: 3 (Web of Science Lite) | Show Abstract | Read more

OBJECTIVES: Genitourinary tract samples are required to investigate male HIV-1 infectivity. Because semen collection is often impractical, the acceptability, feasibility and validity of post-prostatic massage fluid/urine (post-PMF/U) was evaluated for studying male genitourinary HIV-1 shedding. METHODS: HIV-1-seropositive men were evaluated after 48 h of sexual abstinence. At each visit, a clinician performed prostatic massage, then post-PMF/U and blood were collected. Participants provided semen specimens 1 week later. An audio computer-assisted self-interview (ACASI) administered after each specimen collection evaluated acceptability, adherence to instructions and recent genitourinary symptoms. HIV-1 RNA was quantified using a real-time PCR assay. Detection and quantitation of HIV-1 RNA and stability over visits were compared for semen, post-PMF/U and blood. RESULTS: Post-PMF/U was successfully obtained at 106 visits (64%) and semen at 136 visits (81%, p<0.001). In ACASI, discomfort was rated higher for post-PMF/U collection (p=0.003), but there was no significant difference in acceptability. Detection of HIV-1 RNA in post-PMF/U was associated with detection in semen (p=0.02). Semen and post-PMF/U HIV-1-RNA levels were correlated (ρ=0.657, p<0.001). Concordance of results at repeat visits was 78.9% for post-PMF/U (κ=0.519, p=0.02) and 89.5% for both blood and semen (κ=0.774, p=0.001). CONCLUSIONS: Although semen collections were more successful, both post-PMF/U and semen collections were acceptable to many participants. HIV-1 RNA detection and levels were closely associated in semen and post-PMF/U, and results were relatively stable across visits. To assess male HIV-1 infectivity, post-PMF/U may represent a valid alternative when semen cannot be obtained.

et al. 2011. Social contact patterns in Vietnam and implications for the control of infectious diseases. PLoS One, 6 (2), pp. e16965. | Citations: 58 (Scopus) | Show Abstract | Read more

BACKGROUND: The spread of infectious diseases from person to person is determined by the frequency and nature of contacts between infected and susceptible members of the population. Although there is a long history of using mathematical models to understand these transmission dynamics, there are still remarkably little empirical data on contact behaviors with which to parameterize these models. Even starker is the almost complete absence of data from developing countries. We sought to address this knowledge gap by conducting a household based social contact diary in rural Vietnam. METHODS AND FINDINGS: A diary based survey of social contact patterns was conducted in a household-structured community cohort in North Vietnam in 2007. We used generalized estimating equations to model the number of contacts while taking into account the household sampling design, and used weighting to balance the household size and age distribution towards the Vietnamese population. We recorded 6675 contacts from 865 participants in 264 different households and found that mixing patterns were assortative by age but were more homogenous than observed in a recent European study. We also observed that physical contacts were more concentrated in the home setting in Vietnam than in Europe but the overall level of physical contact was lower. A model of individual versus household vaccination strategies revealed no difference between strategies in the impact on R(0). CONCLUSIONS AND SIGNIFICANCE: This work is the first to estimate contact patterns relevant to the spread of infections transmitted from person to person by non-sexual routes in a developing country setting. The results show interesting similarities and differences from European data and demonstrate the importance of context specific data.

. 2011. Performance of LED-based fluorescence microscopy to diagnose tuberculosis in a peripheral health centre in Nairobi. PLoS One, 6 (2), pp. e17214. | Citations: 24 (Scopus) | Show Abstract | Read more

BACKGROUND: Sputum microscopy is the only tuberculosis (TB) diagnostic available at peripheral levels of care in resource limited countries. Its sensitivity is low, particularly in high HIV prevalence settings. Fluorescence microscopy (FM) can improve performance of microscopy and with the new light emitting diode (LED) technologies could be appropriate for peripheral settings. The study aimed to compare the performance of LED-FM versus Ziehl-Neelsen (ZN) microscopy and to assess feasibility of LED-FM at a low level of care in a high HIV prevalence country. METHODS: A prospective study was conducted in an urban health clinic in Nairobi, Kenya. Three sputum specimens were collected over 2 days from suspected TB patients. Each sample was processed with Auramine O and ZN methods and a 4(th) specimen was collected for TB culture reference standard. Auramine smears were read using the same microscope, equipped with the FluoLED™ fluorescence illuminator. Inter-reader agreement, reading time and technicians' acceptability assessed feasibility. RESULTS: 497 patients were included and 1394 specimens were collected. The detection yields of LED-FM and ZN microscopy were 20.3% and 20.6% (p = 0.64), respectively. Sensitivity was 73.2% for LED-FM and 72% for ZN microscopy, p = 0.32. It was 96.7% and 95.9% for specificity, p = 0.53. Inter-reader agreement was high (kappa = 0.9). Mean reading time was three times faster than ZN microscopy with very good acceptance by technicians. CONCLUSIONS: Although it did not increase sensitivity, the faster reading time combined with very good acceptance and ease of use supports the introduction of LED-FM at the peripheral laboratory level of high TB and HIV burden countries.

et al. 2011. Erythrocyte transketolase activity, markers of cardiac dysfunction and the diagnosis of infantile beriberi. PLoS Negl Trop Dis, 5 (2), pp. e971. | Citations: 15 (Scopus) | Show Abstract | Read more

BACKGROUND: Infantile beriberi is a potentially lethal manifestation of thiamin deficiency, associated with traditional post-partum maternal food avoidance, which persists in the Lao PDR (Laos). There are few data on biochemical markers of infantile thiamin deficiency or indices of cardiac dysfunction as potential surrogate markers. METHODOLOGY/PRINCIPAL FINDINGS: A case control study of 47 infants with beriberi and age-matched afebrile and febrile controls was conducted in Vientiane, Laos. Basal and activated erythrocyte transketolase activities (ETK) and activation (α) coefficients were assayed along with plasma brain natriuretic peptide, N-terminal pro-brain natriuretic peptide and troponin T. Basal ETK (and to a lesser extent activated ETK) and plasma troponin T were the only infant biochemical markers that predicted infantile beriberi. A basal ETK ≤ 0.59 micromoles/min/gHb gave a sensitivity (95%CI) of 75.0 (47.6 to 92.7)% and specificity (95%CI) of 85.2 (66.3 to 95.8)% for predicting infantile beriberi (OR (95%CI) 15.9 (2.03-124.2); p = 0.008) (area under ROC curve = 0.80). In contrast, the α coefficient did not discriminate between cases and controls. Maternal basal ETK was linearly correlated with infant basal ETK (Pearson's r = 0.66, p < 0.001). The odds of beriberi in infants with detectable plasma troponin T was 3.4 times higher in comparison to infants without detectable troponin T (OR 3.4, 95%CI 1.22-9.73, p = 0.019). Detectable troponin T had a sensitivity (95%CI) of 78.6 (59.0 to 91.7) % and specificity (95%CI) of 56.1 (39.7 to 71.5) % for predicting infantile beriberi. CONCLUSIONS/SIGNIFICANCE: Basal ETK is a more accurate biochemical marker of infantile beriberi than the activation coefficient. Raised plasma troponin T may be a useful indicator of infantile beriberi in infants at risk and in the absence of other evident causes.

. 2011. Circulating red cell-derived microparticles in human malaria Journal of Infectious Diseases, 203 (5), pp. 700-706. | Citations: 64 (Scopus) | Show Abstract | Read more

In patients with falciparum malaria, plasma concentrations of cell-derived microparticles correlate with disease severity. Using flow cytometry, we quantified red blood cell-derived microparticles (RMPs) in patients with malaria and identified the source and the factors associated with production. RMP concentrations were increased in patients with Plasmodium falciparum (n = 29; median, 457 RMPs/μL [range, 13-4,342 RMPs/μL]), Plasmodium vivax (n = 5; median, 409 RMPs/μL [range, 281-503/μL] ), and Plasmodium malariae (n = 2; median, 163 RMPs/μL [range, 127-200 RMPs/μL]) compared with those in healthy subjects (n = 11; median, 8 RMPs/μL [range, 3-166 RMPs/μL] ; P = .01). RMP concentrations were highest in patients with severe falciparum malaria (P=.01). Parasitized red cells produced > 10 times more RMPs than did unparasitized cells, but the overall majority of RMPs still derived from uninfected red blood cells (URBCs). In cultures, RMP production increased as the parasites matured. Hemin and parasite products induced RMP production in URBCs, which was inhibited by N-acetylcysteine, suggesting heme-mediated oxidative stress as a pathway for the generation of RMPs. © The Author 2011.

et al. 2011. Virological and molecular epidemiological investigations into the role of wild birds in the epidemiology of influenza A/H5N1 in central Thailand Veterinary Microbiology, 148 (2-4), pp. 213-218. | Citations: 8 (Scopus) | Show Abstract | Read more

A serological and virological surveillance program to investigate the HPAI H5N1 virus in wild bird populations was undertaken from February 2007 to October 2008. The purpose of the survey was to investigate the infection status in free ranging wild birds in Banglane district, Nakhon Pathom province, central Thailand. Samples from wild birds were collected every two months. Choanal and cloacal swabs, serum and tissue samples were collected from 421 birds comprising 44 species. Sero-prevalence of the virus tested by H5N1 serum neutralization test (using a H5N1 virus clade 1; A/chicken/Thailand/vsmu-3-BKK/2004) was 2.1% (8 out of 385 samples; 95% CI 0.7, 3.5). Species that were antibody positive included rock pigeons (Columba livia), Asian pied starling (Gracupica contra), spotted dove (Streptopelia chinensis), oriental magpie robin (Copsychus saularis), blue-tailed bee-eater (Merops philippinus), myna (Acridotheres spp.), and pond heron (Ardeola spp.). Prevalence by H5N1 virus isolation was 0.5% (2 out of 421 samples; 95% CI 0.0, 1.1); the two H5N1 virus-positive samples were from Asian pied starling (Gracupica contra) and white vented myna (Acridotheres grandis). Positive virological samples were collected in June 2007 while all positive serology samples were collected between May and August except for one sample collected in December 2007. No positive samples were collected in 2008. Molecular studies revealed that the wild bird H5N1 viruses were closely related to poultry viruses isolated in other parts of Thailand. However, there was no poultry H5N1 prevalence study performed in the study site during the time of this wild bird survey. Interpretation of source of virus isolates would include spill-over of H5N1 viruses from contaminated sources due to movement of domestic poultry and/or fomites from other areas; or infection of wild birds within the outbreak locat ions and then translocation by wild bird movement and interaction with wild birds inhabiting distant locations. © 2010 Elsevier B.V.

et al. 2011. Comparison of adaptive pacing therapy, cognitive behaviour therapy, graded exercise therapy, and specialist medical care for chronic fatigue syndrome (PACE): a randomised trial. Lancet, 377 (9768), pp. 823-836. | Citations: 331 (Web of Science Lite) | Show Abstract | Read more

et al. 2011. Salmonella Typhi sense host neuroendocrine stress hormones and release the toxin haemolysin E. EMBO Rep, 12 (3), pp. 252-258. | Citations: 21 (Web of Science Lite) | Show Abstract | Read more

Salmonella enterica serovar Typhi (S. typhi) causes typhoid fever. We show that exposure of S. typhi to neuroendocrine stress hormones results in haemolysis, which is associated with the release of haemolysin E in membrane vesicles. This effect is attributed to increased expression of the small RNA micA and RNA chaperone Hfq, with concomitant downregulation of outer membrane protein A. Deletion of micA or the two-component signal-transduction system, CpxAR, abolishes the phenotype. The hormone response is inhibited by the β-blocker propranolol. We provide mechanistic insights into the basis of neuroendocrine hormone-mediated haemolysis by S. typhi, increasing our understanding of inter-kingdom signalling.

. 2011. CNS infection, CSF matrix metalloproteinase concentrations, and clinical/laboratory features. Neurology, 76 (6), pp. 577-579. | Citations: 12 (Scopus) | Read more

. 2011. Malaria: severe, life-threatening. BMJ Clin Evid, 2011 | Citations: 3 (Scopus) | Show Abstract

INTRODUCTION: Severe malaria mainly affects children under 5 years old, non-immune travellers, migrants to malarial areas, and people living in areas with unstable or seasonal malaria. Cerebral malaria, causing encephalopathy and coma, is fatal in around 20% of children and adults, and neurological sequelae may occur in some survivors. Severe malarial anaemia may have a mortality rate of over 13%. METHODS AND OUTCOMES: We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of antimalarial treatments and adjunctive treatment for complicated falciparum malaria in non-pregnant people? We searched: Medline, Embase, The Cochrane Library, and other important databases up to December 2009 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). RESULTS: We found 33 systematic reviews, RCTs, or observational studies that met our inclusion criteria. CONCLUSIONS: In this systematic review we present information relating to the effectiveness and safety of the following interventions: dexamethasone, exchange blood transfusion, initial blood transfusion, intramuscular artemether, intravenous and intramuscular artesunate, intravenous and intramuscular dihydroartemisinin, quinine, and rectal/intravenous/intramuscular artemisinin and its derivatives.

. 2011. Random PCR and ultracentrifugation increases sensitivity and throughput of VIDISCA for screening of pathogens in clinical specimens. J Infect Dev Ctries, 5 (2), pp. 142-148. | Citations: 8 (Scopus) | Show Abstract

INTRODUCTION: Virus discovery based on cDNA-AFLP (VIDISCA) is a sequence-independent virus discovery method that was recently developed and successfully used to characterize unknown viruses in cell cultures. Its applicability, however, is limited by its low sensitivity. METHODOLOGY: We evaluated whether the introduction of prior amplification of target sequences by random PCR (rPCR) increases the sensitivity of this method to improve its use on clinical specimens. In addition, ultracentrifugation was added to the protocol to allow for pooling of multiple samples, thereby increasing analytical throughput of the VIDSCA. RESULTS: We showed that rPCR enhanced the sensitivity of VIDISCA by 100-fold for two out of four viruses in different clinical samples, and that the ultracentrifugation step allowed for analyzing samples of large volumes (4 ml) and simultaneous processing of multiple (~40) clinical specimens. CONCLUSIONS: We conclude that this modified VIDISCA protocol is a relatively easy method to use for screening of large numbers of clinical samples that are suspected to contain previously unrecognized pathogens, in settings where ultradeep sequencing platforms are not available.

et al. 2011. Immunological and viral determinants of dengue severity in hospitalized adults in Ha Noi, Viet Nam. PLoS Negl Trop Dis, 5 (3), pp. e967. | Citations: 44 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: The relationships between the infecting dengue serotype, primary and secondary infection, viremia and dengue severity remain unclear. This cross-sectional study examined these interactions in adult patients hospitalized with dengue in Ha Noi. METHODS AND FINDINGS: 158 patients were enrolled between September 16 and November 11, 2008. Quantitative RT-PCR, serology and NS1 detection were used to confirm dengue infection, determine the serotype and plasma viral RNA concentration, and categorize infections as primary or secondary. 130 (82%) were laboratory confirmed. Serology was consistent with primary and secondary infection in 34% and 61%, respectively. The infecting serotype was DENV-1 in 42 (32%), DENV-2 in 39 (30%) and unknown in 49 (38%). Secondary infection was more common in DENV-2 infections (79%) compared to DENV-1 (36%, p<0.001). The proportion that developed dengue haemorrhagic fever (DHF) was 32% for secondary infection compared to 18% for primary infection (p = 0.14), and 26% for DENV-1 compared to 28% for DENV-2. The time until NS1 and plasma viral RNA were undetectable was shorter for DENV-2 compared to DENV-1 (p≤0.001) and plasma viral RNA concentration on day 5 was higher for DENV-1 (p = 0.03). Plasma viral RNA concentration was higher in secondary infection on day 5 of illness (p = 0.046). We didn't find an association between plasma viral RNA concentration and clinical severity. CONCLUSION: Dengue is emerging as a major public health problem in Ha Noi. DENV-1 and DENV-2 were the prevalent serotypes with similar numbers and clinical presentation. Secondary infection may be more common amongst DENV-2 than DENV-1 infections because DENV-2 infections resulted in lower plasma viral RNA concentrations and viral RNA concentrations were higher in secondary infection. The drivers of dengue emergence in northern Viet Nam need to be elucidated and public health measures instituted.

et al. 2011. Risk factors of Streptococcus suis infection in Vietnam. A case-control study. PLoS One, 6 (3), pp. e17604. | Citations: 34 (Scopus) | Show Abstract | Read more

BACKGROUND: Streptococcus suis infection, an emerging zoonosis, is an increasing public health problem across South East Asia and the most common cause of acute bacterial meningitis in adults in Vietnam. Little is known of the risk factors underlying the disease. METHODS AND FINDINGS: A case-control study with appropriate hospital and matched community controls for each patient was conducted between May 2006 and June 2009. Potential risk factors were assessed using a standardized questionnaire and investigation of throat and rectal S. suis carriage in cases, controls and their pigs, using real-time PCR and culture of swab samples. We recruited 101 cases of S. suis meningitis, 303 hospital controls and 300 community controls. By multivariate analysis, risk factors identified for S. suis infection as compared to either control group included eating "high risk" dishes, including such dishes as undercooked pig blood and pig intestine (OR(1) = 2.22; 95%CI = [1.15-4.28] and OR(2) = 4.44; 95%CI = [2.15-9.15]), occupations related to pigs (OR(1) = 3.84; 95%CI = [1.32-11.11] and OR(2) = 5.52; 95%CI = [1.49-20.39]), and exposures to pigs or pork in the presence of skin injuries (OR(1) = 7.48; 95%CI = [1.97-28.44] and OR(2) = 15.96; 95%CI = [2.97-85.72]). S. suis specific DNA was detected in rectal and throat swabs of 6 patients and was cultured from 2 rectal samples, but was not detected in such samples of 1522 healthy individuals or patients without S. suis infection. CONCLUSIONS: This case control study, the largest prospective epidemiological assessment of this disease, has identified the most important risk factors associated with S. suis bacterial meningitis to be eating 'high risk' dishes popular in parts of Asia, occupational exposure to pigs and pig products, and preparation of pork in the presence of skin lesions. These risk factors can be addressed in public health campaigns aimed at preventing S. suis infection.

. 2011. The effects of spatial population dataset choice on estimates of population at risk of disease Population Health Metrics, 9 | Citations: 37 (Scopus) | Show Abstract | Read more

Background: The spatial modeling of infectious disease distributions and dynamics is increasingly being undertaken for health services planning and disease control monitoring, implementation, and evaluation. Where risks are heterogeneous in space or dependent on person-to-person transmission, spatial data on human population distributions are required to estimate infectious disease risks, burdens, and dynamics. Several different modeled human population distribution datasets are available and widely used, but the disparities among them and the implications for enumerating disease burdens and populations at risk have not been considered systematically. Here, we quantify some of these effects using global estimates of populations at risk (PAR) of P. falciparum malaria as an example.Methods: The recent construction of a global map of P. falciparum malaria endemicity enabled the testing of different gridded population datasets for providing estimates of PAR by endemicity class. The estimated population numbers within each class were calculated for each country using four different global gridded human population datasets: GRUMP (~1 km spatial resolution), LandScan (~1 km), UNEP Global Population Databases (~5 km), and GPW3 (~5 km). More detailed assessments of PAR variation and accuracy were conducted for three African countries where census data were available at a higher administrative-unit level than used by any of the four gridded population datasets.Results: The estimates of PAR based on the datasets varied by more than 10 million people for some countries, even accounting for the fact that estimates of population totals made by different agencies are used to correct national totals in these datasets and can vary by more than 5% for many low-income countries. In many cases, these variations in PAR estimates comprised more than 10% of the total national population. The detailed country-level assessments suggested that none of the datasets was consistently more accurate than the others in estimating PAR. The sizes of such differences among modeled human populations were related to variations in the methods, input resolution, and date of the census data underlying each dataset. Data quality varied from country to country within the spatial population datasets.Conclusions: Detailed, highly spatially resolved human population data are an essential resource for planning health service delivery for disease control, for the spatial modeling of epidemics, and for decision-making processes related to public health. However, our results highlight that for the low-income regions of the world where disease burden is greatest, existing datasets display substantial variations in estimated population distributions, resulting in uncertainty in disease assessments that utilize them. Increased efforts are required to gather contemporary and spatially detailed demographic data to reduce this uncertainty, particularly in Africa, and to develop population distribution modeling methods that match the rigor, sophistication, and ability to handle uncertainty of contemporary disease mapping and spread modeling. In the meantime, studies that utilize a particular spatial population dataset need to acknowledge the uncertainties inherent within them and consider how the methods and data that comprise each will affect conclusions. © 2011 Tatem et al; licensee BioMed Central Ltd.

. 2011. Coverage of malaria protection in pregnant women in sub-Saharan Africa: A synthesis and analysis of national survey data The Lancet Infectious Diseases, 11 (3), pp. 190-207. | Citations: 76 (Scopus) | Show Abstract | Read more

Background: Insecticide-treated nets and intermittent preventive treatment with sulfadoxine-pyrimethamine are recommended for the control of malaria d uring pregnancy in endemic areas in Africa, but there has been no analysis of coverage data at a subnational level. We aimed to synthesise data from national surveys about these interventions, accounting for disparities in malaria risk within national borders. Methods: We extracted data for specific strategies for malaria control in pregnant women from national malaria policies from endemic countries in Africa. We identified the most recent national household cluster-sample surveys recording intermittent preventive treatment with sulfadoxine-pyrimethamine and use of insecticide-treated nets. We reconciled data to subnational administrative units to construct a model to estimate the number of pregnant women covered by a recommended intervention in 2007. Findings: 45 (96%) of 47 countries surveyed had a policy for distribution of insecticide-treated nets for pregnant women; estimated coverage in 2007 was 4·7 million (17%) of 27·7 million pregnancies at risk of malaria in 32 countries with data. 39 (83%) of 47 countries surveyed had an intermittent preventive treatment policy; in 2007, an estimated 6·4 million (25%) of 25·6 million pregnant women received at least one dose of treatment and 19·8 million (77%) visited an antenatal clinic (31 countries). Estimated coverage was lowest in areas of high-intensity transmission of malaria. Interpretation: Despite success in a few countries, coverage of insecticide-treated nets and intermittent preventive treatment in pregnant African women is inadequate; increased efforts towards scale-up are needed. Funding: The Malaria in Pregnancy Consortium and Wellcome Trust. © 2011 Elsevier Ltd.

. 2011. Effect of HIV infection on the acute antibody response to malaria antigens in children: an observational study. Malar J, 10 (1), pp. 55. | Citations: 10 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: In sub-Saharan Africa, the distributions of malaria and HIV widely overlap. Among pregnant and non-pregnant adults, HIV affects susceptibility to malaria, its clinical course and impairs antibody responses to malaria antigens. However, the relationship between the two diseases in childhood, when most deaths from malaria occur, is less clear. It was previously reported that HIV is associated with admission to hospital in rural Kenya with severe malaria among children, except in infancy. HIV-infected children with severe malaria were older, had higher parasite density and increased mortality, raising a hypothesis that HIV interferes with naturally acquired immunity to malaria, hence with little effect at younger ages (a shorter history of exposure). To test this hypothesis, levels of anti-merozoite and schizont extract antibodies were compared between HIV-infected and uninfected children who participated in the original study. METHODS: IgG responses to malaria antigens that are potential targets for immunity to malaria (AMA1, MSP2, MSP3 and schizont extract) were compared between 115 HIV-infected and 115 age-matched, HIV-uninfected children who presented with severe malaria. The children were classified as high and low responders for each antigen and assigned antibody-response breadth scores according to the number of antigens to which they were responsive. A predictive logistic regression model was used to test if HIV was an effect modifier on the age-related acquisition of antibody responses, with age as a continuous variable. RESULTS: Point estimates of the responses to all antigens were lower amongst HIV-infected children, but this was only statistically significant for AMA1 (P = 0.028). HIV-infected children were less likely to be high responders to AMA1 [OR 0.44 (95%CI, 0.2-0.90) P = 0.024]. HIV was associated with a reduced breadth of responses to individual merozoite antigens (P = 0.02). HIV strongly modified the acquisition of antibodies against schizont extract with increasing age (P < 0.0001), but did not modify the rate of age-related acquisition of responses to individual merozoite antigens. CONCLUSIONS: In children with severe malaria, HIV infection is associated with a lower magnitude and narrower breadth of IgG responses to merozoite antigens and stunting of age-related acquisition of the IgG antibody response to schizont extract.

et al. 2011. Salmonella Typhi sense host neuroendocrine stress hormones and release the toxin haemolysin e EMBO Reports, 12 (3), pp. 252-258. | Citations: 23 (Scopus) | Show Abstract | Read more

Salmonella enterica serovar Typhi (S. typhi) causes typhoid fever. We show that exposure of S. typhi to neuroendocrine stress hormones results in haemolysis, which is associated with the release of haemolysin E in membrane vesicles. This effect is attributed to increased expression of the small RNA micA and RNA chaperone Hfq, with concomitant downregulation of outer membrane protein A. Deletion of micA or the two-component signal-transduction system, CpxAR, abolishes the phenotype. The hormone response is inhibited by the β 2-blocker propranolol. We provide mechanistic insights into the basis of neuroendocrine hormone-mediated haemolysis by S. typhi, increasing our understanding of inter-kingdom signalling. © 2011 European Molecular Biology Organization Embo.

et al. 2011. Spironolactone does not prevent acute mountain sickness: a prospective, double-blind, randomized, placebo-controlled trial by SPACE Trial Group (spironolactone and acetazolamide trial in the prevention of acute mountain sickness group). Wilderness Environ Med, 22 (1), pp. 15-22. | Citations: 21 (Scopus) | Show Abstract | Read more

OBJECTIVES: Over the last 20 years a number of small trials have reported that spironolactone effectively prevents acute mountain sickness (AMS), but to date there have been no large randomized trials investigating the efficacy of spironolactone in prevention of AMS. Hence, a prospective, double-blind, randomized, placebo-controlled trial was conducted to evaluate the efficacy of spironolactone in the prevention of AMS. METHODS: Participants were sampled from a diverse population of western trekkers recruited at 4300 m on the Mount Everest base camp approach (Nepal side) en route to the study endpoint at 5000 m. Three hundred and eleven healthy trekkers were enrolled, and 251 completed the trial from October to November 2007. Participants were randomly assigned to receive at least 3 doses of spironolactone 50 mg BID, acetazolamide 250 mg BID, or visually matched placebo. A Lake Louise AMS Score of 3 or more, together with the presence of headache and 1 other symptom, was used to evaluate the incidence and severity of AMS. Secondary outcome measures were blood oxygen content and the incidence and severity of high altitude headache (HAH). RESULTS: Acetazolamide was more effective than spironolactone in preventing AMS (OR = 0.28, 95% CI 0.12-0.60, p < 0.01). Spironolactone was not significantly different from placebo in the prevention of AMS. AMS incidence for placebo was 20.3%, acetazolamide 10.5%, and spironolactone 29.4%. Oxygen saturation was also significantly increased in the acetazolamide group (83% ± 0.04) vs spironolactone group (80% ± 0.05, p < 0.01). CONCLUSIONS: Spironolactone (50 mg BID) was ineffective in comparison to acetazolamide (250 mg BID) in the prevention of AMS in partially acclimatized western trekkers ascending to 5000 m in the Nepali Himalaya.

et al. 2011. Comparison of adaptive pacing therapy, cognitive behaviour therapy, graded exercise therapy, and specialist medical care for chronic fatigue syndrome (PACE): A randomised trial The Lancet, 377 (9768), pp. 823-836. | Citations: 375 (Scopus) | Show Abstract | Read more

et al. 2011. Viral etiologies of acute respiratory infections among hospitalized Vietnamese children in Ho Chi Minh City, 2004-2008. PLoS One, 6 (3), pp. e18176. | Citations: 70 (Scopus) | Show Abstract | Read more

BACKGROUND: The dominant viral etiologies responsible for acute respiratory infections (ARIs) are poorly understood, particularly among hospitalized children in resource-limited tropical countries where morbidity and mortality caused by ARIs are highest. Improved etiological insight is needed to improve clinical management and prevention. OBJECTIVES: We conducted a three-year prospective descriptive study of severe respiratory illness among children from 2 months to 13 years of age within the largest referral hospital for infectious diseases in southern Vietnam. METHODS: Molecular detection for 15 viral species and subtypes was performed on three types of respiratory specimens (nose, throat swabs and nasopharyngeal aspirates) using a multiplex RT-PCR kit (Seeplex™ RV detection, Seegene) and additional monoplex real-time RT-PCRs. RESULTS: A total of 309 children were enrolled from November 2004 to January 2008. Viruses were identified in 72% (222/309) of cases, including respiratory syncytial virus (24%), influenza virus A and B (17%), human bocavirus (16%), enterovirus (9%), human coronavirus (8%), human metapneumovirus (7%), parainfluenza virus 1-3 (6%), adenovirus (5%), and human rhinovirus A (4%). Co-infections with multiple viruses were detected in 20% (62/309) of patients. When combined, diagnostic yields in nose and throat swabs were similar to nasopharyngeal aspirates. CONCLUSION: Similar to other parts in the world, RSV and influenza were the predominant viral pathogens detected in Vietnamese hospitalized children. Combined nasal and throat swabs are the specimens of choice for sensitive molecular detection of a broad panel of viral agents. Further research is required to better understand the clinical significance of single versus multiple viral coinfections and to address the role of bacterial (co-)infections involved in severe respiratory illness.

et al. 2011. Slaughterhouse pigs are a major reservoir of Streptococcus suis serotype 2 capable of causing human infection in southern Vietnam. PLoS One, 6 (3), pp. e17943. | Citations: 14 (Web of Science Lite) | Show Abstract | Read more

Streptococcus suis is a pathogen of major economic significance to the swine industry and is increasingly recognized as an emerging zoonotic agent in Asia. In Vietnam, S. suis is the leading cause of bacterial meningitis in adult humans. Zoonotic transmission is most frequently associated with serotype 2 strains and occupational exposure to pigs or consumption of infected pork. To gain insight into the role of pigs for human consumption as a reservoir for zoonotic infection in southern Vietnam, we determined the prevalence and diversity of S. suis carriage in healthy slaughterhouse pigs. Nasopharyngeal tonsils were sampled from pigs at slaughterhouses serving six provinces in southern Vietnam and Ho Chi Minh City area from September 2006 to November 2007. Samples were screened by bacterial culture. Isolates of S. suis were serotyped and characterized by multi locus sequence typing (MLST) and pulse field gel electrophoresis (PFGE). Antibiotic susceptibility profiles and associated genetic resistance determinants, and the presence of putative virulence factors were determined. 41% (222/542) of pigs carried S. suis of one or multiple serotypes. 8% (45/542) carried S. suis serotype 2 which was the most common serotype found (45/317 strains, 14%). 80% of serotype 2 strains belonged to the MLST clonal complex 1,which was previously associated with meningitis cases in Vietnam and outbreaks of severe disease in China in 1998 and 2005. These strains clustered with representative strains isolated from patients with meningitis in PFGE analysis, and showed similar antimicrobial resistance and virulence factor profiles. Slaughterhouse pigs are a major reservoir of S. suis serotype 2 capable of causing human infection in southern Vietnam. Strict hygiene at processing facilities, and health education programs addressing food safety and proper handling of pork should be encouraged.

. 2011. Bowel obstruction from wild bananas: a neglected health problem in Laos. Trop Doct, 41 (2), pp. 85-90. | Citations: 3 (Web of Science Lite) | Show Abstract | Read more

We investigated the significance and risk factors of bowel obstruction caused by the consumption of wild bananas (BOWB) in Laos. Of six patients with BOWB in Luang Namtha, North Laos, five required enterotomy for phytobezoars. All had eaten wild banana (WB) seeds. Of 227 other patients/relatives: 91.2% had eaten WB; 46.3% had also eaten the seeds and 45.4% knew of complications resulting from eating WB; 42.3% were aware of the complications of ingesting the seeds (constipation [37.9%], appendicitis/abdominal pain/vomiting [2.6% each] and bloated stomach/death [1.3% each]). Middle/highland Lao ethnicity was associated with WB and seed consumption (odds ratio [OR] 9.91 and 2.33), male sex with WB consumption and unawareness (OR 4.31 and 1.78). At all surgically-equipped hospitals in Laos, 33/44 doctors knew of BOWB, describing patients as young adults (16/30), male (24/30) and from middleland Lao (18/30). Countrywide, 46/48 patients with BOWB required laparotomy in 2009 (incidence 0.8/100,000). All consumed WB seeds. BOWB is widespread in Laos, especially among young middleland Lao men consuming WB seeds on an empty stomach.

. 2011. Mechanisms of artemisinin action and resistance: wider focus is needed. Trends Parasitol, 27 (1), pp. 2-3. | Citations: 8 (Scopus) | Read more

. 2011. Artesunate for severe malaria in African children – Authors' reply The Lancet, 377 (9772), pp. 1154-1154. | Citations: 1 (Scopus) | Read more

et al. 2011. A phase I trial to evaluate the safety and pharmacokinetics of low-dose methotrexate as an anti-malarial drug in Kenyan adult healthy volunteers. Malar J, 10 (1), pp. 63. | Citations: 12 (Scopus) | Show Abstract | Read more

. 2011. Analysis of Immunity to Febrile Malaria in Children That Distinguishes Immunity from Lack of Exposure (vol 77, pg 1917, 2009) INFECTION AND IMMUNITY, 79 (4), pp. 1804-1804. | Read more

. 2011. Novel polymorphisms in Plasmodium falciparum ABC transporter genes are associated with major ACT antimalarial drug resistance. PLoS One, 6 (5), pp. e20212. | Citations: 60 (Scopus) | Show Abstract | Read more

Chemotherapy is a critical component of malaria control. However, the most deadly malaria pathogen, Plasmodium falciparum, has repeatedly mounted resistance against a series of antimalarial drugs used in the last decades. Southeast Asia is an epicenter of emerging antimalarial drug resistance, including recent resistance to the artemisinins, the core component of all recommended antimalarial combination therapies. Alterations in the parasitic membrane proteins Pgh-1, PfCRT and PfMRP1 are believed to be major contributors to resistance through decreasing intracellular drug accumulation. The pfcrt, pfmdr1 and pfmrp1 genes were sequenced from a set of P.falciparum field isolates from the Thai-Myanmar border. In vitro drug susceptibility to artemisinin, dihydroartemisinin, mefloquine and lumefantrine were assessed. Positive correlations were seen between the in vitro susceptibility responses to artemisinin and dihydroartemisinin and the responses to the arylamino-alcohol quinolines lumefantrine and mefloquine. The previously unstudied pfmdr1 F1226Y and pfmrp1 F1390I SNPs were associated significantly with artemisinin, mefloquine and lumefantrine in vitro susceptibility. A variation in pfmdr1 gene copy number was also associated with parasite drug susceptibility of artemisinin, mefloquine and lumefantrine. Our work unveils new candidate markers of P. falciparum multidrug resistance in vitro, while contributing to the understanding of subjacent genetic complexity, essential for future evidence-based drug policy decisions.

. 2011. Spatio-temporal patterns of malaria infection in Bhutan: a country embarking on malaria elimination. Malar J, 10 (1), pp. 89. | Citations: 14 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: At the verge of elimination of malaria in Bhutan, this study was carried out to analyse the trend of malaria in the endemic districts of Bhutan and to identify malaria clusters at the sub-districts. The findings would aid in implementing the control activities. Poisson regression was performed to study the trend of malaria incidences at district level from 1994 to 2008. Spatial Empirical Bayesian smoothing was deployed to identify clusters of malaria at the sub-district level from 2004 to 2008. RESULTS: Trend of the overall districts and most of the endemic districts have decreased except Pemagatshel, which has an increase in the trend. Spatial cluster-outlier analysis showed that malaria clusters were mostly concentrated in the central and eastern Bhutan in three districts of Dagana, Samdrup Jongkhar and Sarpang. The disease clusters were reported throughout the year. Clusters extended to the non-transmission areas in the eastern Bhutan. CONCLUSIONS: There is significant decrease in the trend of malaria with the elimination at the sight. The decrease in the trend can be attributed to the success of the control and preventive measures. In order to realize the target of elimination of malaria, the control measure needs to be prioritized in these high-risk clusters of malaria.

. 2011. Increasing malaria hospital admissions in Uganda between 1999 and 2009. BMC Med, 9 (1), pp. 37. | Citations: 42 (Scopus) | Show Abstract | Read more

. 2011. Transmission of Plasmodium vivax in south-western Uganda: report of three cases in pregnant women. PLoS One, 6 (5), pp. e19801. | Citations: 12 (Scopus) | Show Abstract | Read more

Plasmodium vivax is considered to be rare in the predominantly Duffy negative populations of Sub-Saharan Africa, as this red blood cell surface antigen is essential for invasion by the parasite. However, despite only very few reports of molecularly confirmed P. vivax from tropical Africa, serological evidence indicated that 13% of the persons sampled in Congo had been exposed to P. vivax. We identified P. vivax by microscopy in 8 smears from Ugandan pregnant women who had been enrolled in a longitudinal study of malaria in pregnancy. A nested polymerase chain reaction (PCR) protocol was used to detect and identify the Plasmodium parasites present. PCR analysis confirmed the presence of P. vivax for three of the women and analysis of all available samples from these women revealed clinically silent chronic low-grade vivax infections for two of them. The parasites in one woman carried pyrimethamine resistance-associated double non-synonymous mutations in the P. vivax dihydrofolate reductase gene. The three women found infected with P. vivax were Duffy positive as were nine of 68 women randomly selected from the cohort. The data presented from these three case reports is consistent with stable transmission of malaria in a predominantly Duffy negative African population. Given the substantial morbidity associated with vivax infection in non-African endemic areas, it will be important to investigate whether the distribution and prevalence of P. vivax have been underestimated in Sub-Saharan Africa. This is particularly important in the context of the drive to eliminate malaria and its morbidity.

. 2011. Clinical research: Time for sensible global guidelines The Lancet, 377 (9777), pp. 1153-1555. | Citations: 16 (Scopus) | Read more

. 2011. Evaluation of combined LED-fluorescence microscopy and bleach sedimentation for diagnosis of tuberculosis at peripheral health service level. PLoS One, 6 (5), pp. e20175. | Citations: 12 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Sputum microscopy is the only diagnostic for tuberculosis (TB) available at peripheral levels of health service in resource-poor countries. Its sensitivity is reduced in high HIV-prevalence settings. Sodium hypochlorite (NaOCl) specimen sedimentation prior microscopy and light-emitting diode (LED)-fluorescence microscopy (FM) can individually improve performance of microscopy. This study aimed to evaluate the performance of combined LED-FM and NaOCl sputum sedimentation for TB detection at peripheral level of health services. METHODS: A prospective study was conducted in an urban health clinic in Nairobi, Kenya. Three sputum specimens were collected over 2 days from consecutive TB suspects. Smears were prepared and stained with auramine O and Ziehl-Neelsen (ZN) methods. Bleach (3.5%) was added to the remaining specimen before overnight sedimentation at room temperature. Auramine O staining was performed on smears of sediment. A 4(th) specimen was collected for TB culture. Auramine smears were read under the same microscope as used for ZN smears, but equipped with the LED FluoLED™ fluorescence illuminator. RESULTS: 497 patients were included, and 1394 specimens collected. The yield of positive specimen was significantly increased after NaOCl sedimentation (24.9%) compared to direct LED-FM (20.6%) and direct ZN (20.3%). In detecting smear-positive patients, sensitivity was 78.5% for LED-FM after NaOCl sedimentation compared to 73.2% and 72.0% for direct LED-FM (P = 0.06) and direct ZN (P = 0.06), respectively. Specificity was 87.8% for LED-FM after NaOCl sedimentation compared to 96.7% and 95.9% for direct LED-FM (P<0.01) and direct ZN (P<0.01), respectively. Inter-reading agreement (kappa = 0.7) and technicians' acceptability were good. CONCLUSION: NaOCl sedimentation did not improve the performance of LED-FM in the diagnosis of pulmonary TB at peripheral health service level.

. 2011. Self-reported fever, treatment actions and malaria infection prevalence in the northern states of Sudan. Malar J, 10 (1), pp. 128. | Citations: 9 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: The epidemiology of fevers and their management in areas of low malaria transmission in Africa is not well understood. The characteristics of fever, its treatment and association with infection prevalence from a national household sample survey in the northern states of Sudan, an area that represents historically low parasite prevalence, are examined in this study. METHODS: In October-November 2009, a cluster sample cross-sectional household malaria indicator survey was undertaken in the 15 northern states of the Sudan. Data on household assets and individual level information on age, sex, whether the individual had a fever in the last 14 days and on the day of survey, actions taken to treat the fever including diagnostic services and drugs used and their sources were collected. Consenting household members were asked to provide a finger-prick blood sample and examined for malaria parasitaemia using a rapid diagnostic test (RDT). All proportions and odds ratios were weighted and adjusted for clustering. RESULTS: Of 26,471 respondents 19% (n = 5,299) reported a history of fever within the last two weeks prior to the survey and 8% had fever on the day of the survey. Only 39% (n = 2,035) of individuals with fever in last two weeks took any action, of which 43% (n = 875) were treated with anti-malarials. About 44% (n = 382) of malaria treatments were done using the nationally recommended first-line therapy artesunate+sulphadoxine-pryrimethamine (AS+SP) and 13% (n = 122) with non-recommended chloroquine or SP. Importantly 33.9% (n = 296) of all malaria treatments included artemether monotherapy, which is internationally banned for the treatment of uncomplicated malaria. About 53% of fevers had some form of parasitological diagnosis before treatment. On the day of survey, 21,988 individuals provided a finger-prick blood sample and only 1.8% were found positive for Plasmodium falciparum. Infection prevalence was higher among individuals who had fever in the last two weeks (OR = 3.4; 95%CI = 2.6 - 4.4, p < 0.001) or reported fever on the day of survey (OR = 6.2; 95%CI = 4.4 - 8.7, p < 0.001) compared to those without a history of fever. CONCLUSION: Across the northern states of the Sudan, the period prevalence of fever is low. The proportion of fevers that are likely to be malaria is very low. Consequently, parasitological diagnosis of all fevers before treatment is an appropriate strategy for malaria case-management. Improved regulation and supervision of health workers is required to increase the use of diagnostics and remove the practice of prescribing artemisinin monotherapy.

et al. 2011. Population genetic analysis of Plasmodium falciparum parasites using a customized Illumina GoldenGate genotyping assay. PLoS One, 6 (6), pp. e20251. | Citations: 24 (Scopus) | Show Abstract | Read more

The diversity in the Plasmodium falciparum genome can be used to explore parasite population dynamics, with practical applications to malaria control. The ability to identify the geographic origin and trace the migratory patterns of parasites with clinically important phenotypes such as drug resistance is particularly relevant. With increasing single-nucleotide polymorphism (SNP) discovery from ongoing Plasmodium genome sequencing projects, a demand for high SNP and sample throughput genotyping platforms for large-scale population genetic studies is required. Low parasitaemias and multiple clone infections present a number of challenges to genotyping P. falciparum. We addressed some of these issues using a custom 384-SNP Illumina GoldenGate assay on P. falciparum DNA from laboratory clones (long-term cultured adapted parasite clones), short-term cultured parasite isolates and clinical (non-cultured isolates) samples from East and West Africa, Southeast Asia and Oceania. Eighty percent of the SNPs (n = 306) produced reliable genotype calls on samples containing as little as 2 ng of total genomic DNA and on whole genome amplified DNA. Analysis of artificial mixtures of laboratory clones demonstrated high genotype calling specificity and moderate sensitivity to call minor frequency alleles. Clear resolution of geographically distinct populations was demonstrated using Principal Components Analysis (PCA), and global patterns of population genetic diversity were consistent with previous reports. These results validate the utility of the platform in performing population genetic studies of P. falciparum.

et al. 2011. Establishing the extent of malaria transmission and challenges facing pre-elimination in the Republic of Djibouti. BMC Infect Dis, 11 (1), pp. 121. | Citations: 16 (Scopus) | Show Abstract | Read more

BACKGROUND: Countries aiming for malaria elimination require a detailed understanding of the current intensity of malaria transmission within their national borders. National household sample surveys are now being used to define infection prevalence but these are less efficient in areas of exceptionally low endemicity. Here we present the results of a national malaria indicator survey in the Republic of Djibouti, the first in sub-Saharan Africa to combine parasitological and serological markers of malaria, to evaluate the extent of transmission in the country and explore the potential for elimination. METHODS: A national cross-sectional household survey was undertaken from December 2008 to January 2009. A finger prick blood sample was taken from randomly selected participants of all ages to examine for parasitaemia using rapid diagnostic tests (RDTs) and confirmed using Polymerase Chain Reaction (PCR). Blood spots were also collected on filter paper and subsequently used to evaluate the presence of serological markers (combined AMA-1 and MSP-119) of Plasmodium falciparum exposure. Multivariate regression analysis was used to determine the risk factors for P. falciparum infection and/or exposure. The Getis-Ord G-statistic was used to assess spatial heterogeneity of combined infections and serological markers. RESULTS: A total of 7151 individuals were tested using RDTs of which only 42 (0.5%) were positive for P. falciparum infections and confirmed by PCR. Filter paper blood spots were collected for 5605 individuals. Of these 4769 showed concordant optical density results and were retained in subsequent analysis. Overall P. falciparum sero-prevalence was 9.9% (517/4769) for all ages; 6.9% (46/649) in children under the age of five years; and 14.2% (76/510) in the oldest age group (≥50 years). The combined infection and/or antibody prevalence was 10.5% (550/4769) and varied from 8.1% to 14.1% but overall regional differences were not statistically significant (χ2=33.98, p=0.3144). Increasing age (p<0.001) and decreasing household wealth status (p<0.001) were significantly associated with increasing combined P. falciparum infection and/or antibody prevalence. Significant P. falciparum hot spots were observed in Dikhil region. CONCLUSION: Malaria transmission in the Republic of Djibouti is very low across all regions with evidence of micro-epidemiological heterogeneity and limited recent transmission. It would seem that the Republic of Djibouti has a biologically feasible set of pre-conditions for elimination, however, the operational feasibility and the potential risks to elimination posed by P. vivax and human population movement across the sub-region remain to be properly established.

. 2011. Changes in health-related quality of life following imprisonment in 92 women in England: a three month follow-up study. Int J Equity Health, 10 (1), pp. 21. | Citations: 4 (Scopus) | Show Abstract | Read more

BACKGROUND: Despite the considerable changes in the provision of health care to prisoners in the UK there is little published literature that attempts to examine broader aspects of health and the impact of imprisonment on these, focusing instead on disease specific areas. This is surprising given that one of the main drivers behind the changes was the need for improvements in the quality of care; examining changes in health outcomes should be an important part of monitoring service developments. This study assessed the health-related quality of life of women on entry into prison and examined changes during a period of three months imprisonment. METHODS: This was a prospective longitudinal study involving 505 women prisoners in England. The SF-36 was contained within a questionnaire designed to examine many aspects of imprisoned women's health. Participants completed this questionnaire within 72 hours of entering prison. The researchers followed up all participants who were still imprisoned three months later. RESULTS: The study achieved good response rates: 82% of women agreed to participate initially (n = 505), and 93% of those still imprisoned participating three months later (n = 112). At prison entry, women prisoners have lower mental component summary score (MCS) and physical component summary score (PCS) compared to women within the general population. The mental well-being of those 112 women still imprisoned after three months improved over this period of imprisonment, although remained poorer than that of the general population. The PCS did not improve significantly and remained significantly lower than that of the general population. Multivariate analyses showed that the only independent predictor of change in component score was the score at baseline. CONCLUSIONS: The results highlight the poor health-related quality of life of women prisoners and highlight the scale of the challenge faced by those providing health care to prisoners. They also draw attention to the major health disadvantages of women offenders compared to women in general. While recent reforms may improve health services for prisoners, broader inequalities in the health of women are a more complex challenge.

. 2011. The use of positive serological tests as evidence of exposure to Burkholderia pseudomallei. Am J Trop Med Hyg, 84 (6), pp. 1021-1022. | Citations: 9 (Web of Science Lite) | Read more

. 2011. Ethnic differences in the health of women prisoners Public Health, 125 (6), pp. 349-356. | Citations: 4 (Scopus) | Show Abstract | Read more

Objectives: The numbers of female and ethnic minority prisoners in the UK are increasing. Despite recent policy initiatives to improve both prison healthcare and the status of women and ethnic minority groups, there are few data with which to inform service development. This is the first study in the UK to examine differences in subjective health status and health behaviours between Black and White female prisoners. Study design: Retrospective secondary analysis of data from the Health of Women in Prison Study by the University of Oxford. The latter was a longitudinal survey. Methods: Participants were given a questionnaire containing the Short Form 36 (SF-36) and questions about cigarette smoking, alcohol consumption, illicit drug use, physical exercise, diet, imprisonment history and ethnicity. Data from Black and White participants were compared. Physical and mental component summary scores from the SF-36 were assessed using the independent t-test for means. Differences in health behaviours between the Black and White women were assessed using a paired samples t-test for continuous variables or Chi-squared test for categorical data. Results: Black women were more likely to have stayed in full-time education for longer and to have been legally employed prior to imprisonment. The average length of their current sentence was significantly higher than that for White women. Black women scored higher in general health perception, but there were no other significant differences in subjective health status. Significantly fewer Black women smoked or drank to excess, or had used drugs in the 6 months prior to imprisonment. Black women ate more healthily, but were more likely to be overweight and to have higher blood pressure than their White counterparts. Both groups, however, demonstrated poor health and health behaviours overall. Conclusion: Black women entering prison are more likely to be educated, employed, drug free and, in some ways, healthier than White women. However, all the prisoners, regardless of ethnicity, had poorer levels of mental and physical health than the general population; thus, a need exists for researchers and policy makers alike to examine the health of these groups within and out of prison. © 2011 The Royal Society for Public Health.

et al. 2011. Randomized pharmacokinetic and pharmacodynamic comparison of fluoroquinolones for tuberculous meningitis. Antimicrob Agents Chemother, 55 (7), pp. 3244-3253. | Citations: 54 (Scopus) | Show Abstract | Read more

Tuberculous meningitis (TBM) is the most lethal form of tuberculosis, and new treatments that improve outcomes are required. We randomly assigned adults with TBM to treatment with standard antituberculosis treatment alone or in combination with ciprofloxacin (750 mg/12 h), levofloxacin (500 mg/12 h), or gatifloxacin (400 mg/24 h) for the first 60 days of therapy. Fluoroquinolone concentrations were measured with plasma and cerebrospinal fluid (CSF) specimens taken at predetermined, randomly assigned times throughout treatment. We aimed to describe the pharmacokinetics of each fluoroquinolone during TBM treatment and evaluate the relationship between drug exposure and clinical response over 270 days of therapy (Controlled Trials number ISRCTN07062956). Sixty-one patients with TBM were randomly assigned to treatment with no fluoroquinolone (n = 15), ciprofloxacin (n = 16), levofloxacin (n = 15), or gatifloxacin (n = 15). Cerebrospinal fluid penetration, measured by the ratio of the plasma area under the concentration-time curve from 0 to 24 h (AUC(0-24)) to the cerebrospinal fluid AUC(0-24), was greater for levofloxacin (median, 0.74; range, 0.58 to 1.03) than for gatifloxacin (median, 0.48; range, 0.47 to 0.50) or ciprofloxacin (median, 0.26; range, 0.11 to 0.77). Univariable and multivariable analyses of fluoroquinolone exposure against a range of different treatment responses revealed worse outcomes among patients with lower and higher plasma and CSF exposures than for patients with intermediate exposures (a U-shaped exposure-response). TBM patients most likely to benefit from fluoroquinolone therapy were identified, along with exposure-response relationships associated with improved outcomes. Fluoroquinolones add antituberculosis activity to the standard treatment regimen, but to improve outcomes of TBM, they must be started early, before the onset of coma.

et al. 2011. Ending the drought: New strategies for improving the flow of affordable, effective antivenoms in Asia and Africa Journal of Proteomics,

et al. 2011. Serological evidence of discrete spatial clusters of Plasmodium falciparum parasites. PLoS One, 6 (6), pp. e21711. | Citations: 21 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Malaria transmission may be considered to be homogenous with well-mixed parasite populations (as in the classic Ross/Macdonald models). Marked fine-scale heterogeneity of transmission has been observed in the field (i.e., over a few kilometres), but there are relatively few data on the degree of mixing. Since the Plasmodium falciparum Erythrocyte Membrane Protein 1 (PfEMP1) is highly polymorphic, the host's serological responses may be used to infer exposure to parasite sub-populations. METHODS AND FINDINGS: We measured the antibody responses to 46 individual PfEMP1 domains at four time points among 450 children in Kenya, and identified distinct spatial clusters of antibody responses to individual domains. 35 domains showed strongly significant sero-clusters at p = 0.001. Individuals within the high transmission hotspot showed the greatest diversity of anti-PfEMP1 responses. Individuals outside the hotspot had a less diverse range of responses, even if as individuals they were at relatively intense exposure. CONCLUSIONS: We infer that antigenically distinct sub-populations of parasites exist on a fine spatial scale in a study area of rural Kenya. Further studies should examine antigenic variation over longer periods of time and in different study areas.

. 2011. The seroprevalence and seroincidence of enterovirus71 infection in infants and children in Ho Chi Minh City, Viet Nam. PLoS One, 6 (7), pp. e21116. | Citations: 29 (Scopus) | Show Abstract | Read more

Enterovirus 71 (EV71)-associated hand, foot and mouth disease has emerged as a serious public health problem in South East Asia over the last decade. To better understand the prevalence of EV71 infection, we determined EV71 seroprevalence and seroincidence amongst healthy infants and children in Ho Chi Minh City, Viet Nam. In a cohort of 200 newborns, 55% of cord blood samples contained EV71 neutralizing antibodies and these decayed to undetectable levels by 6 months of age in 98% of infants. The EV71 neutralizing antibody seroconversion rate was 5.6% in the first year and 14% in the second year of life. In children 5-15 yrs of age, seroprevalence of EV71 neutralizing antibodies was 84% and in cord blood it was 55%. Taken together, these data suggest EV71 force of infection is high and highlights the need for more research into its epidemiology and pathogenesis in high disease burden countries.

. 2011. Melioidosis acquired by traveler to Nigeria. Emerg Infect Dis, 17 (7), pp. 1296-1298. | Citations: 13 (Web of Science Lite) | Show Abstract | Read more

We describe melioidosis associated with travel to Nigeria in a woman with diabetes, a major predisposing factor for this infection. With the prevalence of diabetes projected to increase dramatically in many developing countries, the global reach of melioidosis may expand.

. 2011. Transmission dynamics of methicillin-resistant Staphylococcus aureus in a medical intensive care unit in India PLoS ONE, 6 (7), | Citations: 11 (Scopus) | Show Abstract | Read more

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a global pathogen and an important but seldom investigated cause of morbidity and mortality in lower and middle-income countries where it can place a major burden on limited resources. Quantifying nosocomial transmission in resource-poor settings is difficult because molecular typing methods are prohibitively expensive. Mechanistic statistical models can overcome this problem with minimal cost. We analyse the transmission dynamics of MRSA in a hospital in south India using one such approach and provide conservative estimates of the organism's economic burden. Methods and Findings: Fifty months of MRSA infection data were collected retrospectively from a Medical Intensive Care Unit (MICU) in a tertiary hospital in Vellore, south India. Data were analysed using a previously described structured hidden Markov model. Seventy-two patients developed MRSA infections and, of these, 49 (68%) died in the MICU. We estimated that 4.2% (95%CI 1.0, 19.0) of patients were MRSA-positive when admitted, that there were 0.39 MRSA infections per colonized patient month (0.06, 0.73), and that the ward-level reproduction number for MRSA was 0.42 (0.08, 2.04). Anti-MRSA antibiotic treatment costs alone averaged $124/patient, over three times the monthly income of more than 40% of the Indian population. Conclusions: Our analysis of routine data provides the first estimate of the nosocomial transmission potential of MRSA in India. The high levels of transmission estimated underline the need for cost-effective interventions to reduce MRSA transmission in hospital settings in low and middle income countries. © 2011 Christopher et al. . 2011. Nutritional status, hospitalization and mortality among patients with sickle cell anemia in Tanzania. Haematologica, 96 (7), pp. 948-953. | Citations: 16 (Scopus) | Show Abstract | Read more BACKGROUND: Reduced growth is common in children with sickle cell anemia, but few data exist on associations with long-term clinical course. Our objective was to determine the prevalence of malnutrition at enrollment into a hospital-based cohort and whether poor nutritional status predicted morbidity and mortality within an urban cohort of Tanzanian sickle cell anemia patients. DESIGN AND METHODS: Anthropometry was conducted at enrollment into the sickle cell anemia cohort (n=1,618; ages 0.5-48 years) and in controls who attended screening (siblings, walk-ins and referrals) but who were found not to have sickle cell anemia (n=717; ages 0.5-64 years). Prospective surveillance recorded hospitalization at Muhimbili National Hospital and mortality between March 2004 and September 2009. RESULTS: Sickle cell anemia was associated with stunting (OR=1.92, P<0.001, 36.2%) and wasting (OR=1.66, P=0.002, 18.4%). The greatest growth deficits were observed in adolescents and in boys. Independent of age and sex, lower hemoglobin concentration was associated with increased odds of malnutrition in sickle cell patients. Of the 1,041 sickle cell anemia patients with a body mass index z-score at enrollment, 92% were followed up until September 2009 (n=908) or death (n=50). Body mass index and weight-for-age z-score predicted hospitalization (hazard ratio [HZR]=0.90, P=0.04 and HZR=0.88, P=0.02) but height-for-age z-score did not (HZR=0.93, NS). The mortality rate of 2.5 per 100 person-years was not associated with any of the anthropometric measures. CONCLUSIONS: In this non-birth-cohort of sickle cell anemia with significant associated undernutrition, wasting predicted an increased risk of hospital admission. Targeted nutritional interventions should prioritize treatment and prevention of wasting. . 2011. Temporal Association of Acute Hepatitis A and Plasmodium falciparum Malaria in Children PLOS ONE, 6 (7), pp. e21013-e21013. | Citations: 2 (Web of Science Lite) | Read more et al. 2011. Cost-effectiveness of parenteral artesunate for treating children with severe malaria in sub-saharan Africa Bulletin of the World Health Organization, 89 (7), pp. 504-512. | Citations: 24 (Scopus) | Show Abstract | Read more Objective To explore the cost-effectiveness of parenteral artesunate for the treatment of severe malaria in children and its potential impact on hospital budgets. Methods The costs of inpatient care of children with severe malaria were assessed in four of the 11 sites included in the African Quinine Artesunate Malaria Treatment trial, conducted with over 5400 children. The drugs, laboratory tests and intravenous fluids provided to 2300 patients from admission to discharge were recorded, as was the length of inpatient stay, to calculate the cost of inpatient care. The data were matched with pooled clinical outcomes and entered into a decision model to calculate the cost per disability-adjusted life year (DALY) averted and the cost per death averted. Findings The mean cost of treating severe malaria patients was similar in the two study groups: 63.5 United States dollars (US$) (95% confidence interval, CI: 61.7-65.2) in the quinine arm and US$66.5 (95% CI: 63.7-69.2) in the artesunate arm. Children treated with artesunate had 22.5% lower mortality than those treated with quinine and the same rate of neurological sequelae: (artesunate arm: 2.3 DALYs per patient; quinine arm: 3.0 DALYs per patient). Compared with quinine as a baseline, artesunate showed an incremental cost per DALY averted and an incremental cost per death averted of US$ 3.8 and US123, respectively. Conclusion Artesunate is a highly cost-effective and affordable alternative to quinine for treating children with severe malaria. The budgetary implications of adopting artesunate for routine use in hospital-based care are negligible. et al. 2011. Multicentre prospective study on dengue classification in four South-east Asian and three Latin American countries Tropical Medicine and International Health, 16 (8), pp. 936-948. | Citations: 89 (Scopus) | Show Abstract | Read more Objective To evaluate the existing WHO dengue classification across all age groups and a wide geographical range and to develop a revised evidence-based classification that would better reflect clinical severity. Methods We followed suspected dengue cases daily in seven countries across South-east Asia and Latin America and then categorised them into one of three intervention groups describing disease severity according to the overall level of medical and nursing support required. Using a pre-defined analysis plan, we explored the clinical and laboratory profiles characteristic of these intervention categories and presented the most promising options for a revised classification scheme to an independent group of WHO dengue experts for consideration. Potential warning signs were also evaluated by comparing contemporaneous data of patients who progressed to severe disease with the data of those who did not. Results A total of 2259 patients were recruited during 2006-2007 and 230 (13%) of the 1734 laboratory-confirmed patients required major intervention. Applying the existing WHO system, 47/210 (22%) of patients with shock did not fulfil all the criteria for dengue haemorrhagic fever. However, no three-tier revision adequately described the different severity groups either. Inclusion of readily discernible complications (shock/severe vascular leakage and/or severe bleeding and/or severe organ dysfunction) was necessary to devise a system that identified patients requiring major intervention with sufficient sensitivity and specificity to be practically useful. Only a small number of subjects (5%) progressed to severe disease while under observation; several warning signs were identified, but much larger studies are necessary to fully characterize features associated with disease progression. Conclusions Based on these results, a revised classification system comprised of two entities, 'Dengue' and 'Severe Dengue', was proposed and has now been incorporated into the new WHO guidelines. © 2011 Blackwell Publishing Ltd. . 2011. Effect of systemic antibiotics and topical chlorhexidine on meticillin-resistant Staphylococcus aureus carriage in intensive care unit patients Journal of Hospital Infection, . 2011. Hepatitis E virus is prevalent in the pig population of Lao People's Democratic Republic and evidence exists for homogeneity with Chinese Genotype 4 human isolates Infection, Genetics and Evolution, 11 (6), pp. 1306-1311. | Citations: 9 (Scopus) | Show Abstract | Read more The objective of this study was to determine the prevalence and genotypic range of Hepatitis E virus (HEV) in the pig population of northern Lao People's Democratic Republic (PDR). We collected 181 faecal samples from indigenous-breed pigs ≤6 months of age and the faeces was stored in RNA stabilisation buffer due to cold-chain and transport limitations. Twenty-one (11.6%) pigs had detectable HEV RNA and 43.5% of village pig herds were infected. Based on a 240 base pair-nucleotide sequence flanking the junction of open reading frames 1, 2 and 3 (ORF1, ORF2 and ORF3) the isolates were phylogenetically classified within genotype 4. Phylogenetic analyses revealed distinct genetic groupings of the Lao HEV isolates and two groups clustered with human and pig HEV isolates from China. This was the first study to demonstrate genotype 4 HEV in Lao PDR and indicates pigs are a potential reservoir for human HEV infection. © 2011 Elsevier B.V. et al. 2011. Slaughterhouse pigs are a major reservoir of Streptococcus suis serotype 2 capable of causing human infection in Southern Vietnam PLoS ONE, 6 (3), | Citations: 31 (Scopus) | Show Abstract | Read more Streptococcus suis is a pathogen of major economic significance to the swine industry and is increasingly recognized as an emerging zoonotic agent in Asia. In Vietnam, S. suis is the leading cause of bacterial meningitis in adult humans. Zoonotic transmission is most frequently associated with serotype 2 strains and occupational exposure to pigs or consumption of infected pork. To gain insight into the role of pigs for human consumption as a reservoir for zoonotic infection in southern Vietnam, we determined the prevalence and diversity of S. suis carriage in healthy slaughterhouse pigs. Nasopharyngeal tonsils were sampled from pigs at slaughterhouses serving six provinces in southern Vietnam and Ho Chi Minh City area from September 2006 to November 2007. Samples were screened by bacterial culture. Isolates of S. suis were serotyped and characterized by multi locus sequence typing (MLST) and pulse field gel electrophoresis (PFGE). Antibiotic susceptibility profiles and associated genetic resistance determinants, and the presence of putative virulence factors were determined. 41% (222/542) of pigs carried S. suis of one or multiple serotypes. 8% (45/542) carried S. suis serotype 2 which was the most common serotype found (45/317 strains, 14%). 80% of serotype 2 strains belonged to the MLST clonal complex 1,which was previously associated with meningitis cases in Vietnam and outbreaks of severe disease in China in 1998 and 2005. These strains clustered with representative strains isolated from patients with meningitis in PFGE analysis, and showed similar antimicrobial resistance and virulence factor profiles. Slaughterhouse pigs are a major reservoir of S. suis serotype 2 capable of causing human infection in southern Vietnam. Strict hygiene at processing facilities, and health education programs addressing food safety and proper handling of pork should be encouraged. © 2011 Hoa et al. . 2011. In Response The American Journal of Tropical Medicine and Hygiene, 84 (2), pp. 359-359. | Read more . 2011. What we learned about voluntariness and consent: incorporating "background situations" and understanding into analyses. Am J Bioeth, 11 (8), pp. 31-33. | Citations: 9 (Web of Science Lite) | Read more . 2011. Antimicrobial susceptibility of bacterial isolates from community acquired infections in Sub-Saharan Africa and Asian low and middle income countries Tropical Medicine and International Health, 16 (9), pp. 1167-1179. | Citations: 29 (Scopus) | Show Abstract | Read more Objective Antimicrobial resistance has arisen across the globe in both nosocomial and community settings as a consequence of widespread antibiotic consumption. Poor availability of laboratory diagnosis means that resistance frequently goes unrecognised and may only be detected as clinical treatment failure. In this review, we provide an overview of the reported susceptibility of common community acquired bacterial pathogens in Sub-Saharan Africa and Asia to the antibiotics that are most widely used in these areas. Methods We reviewed the literature for reports of the susceptibility of prevalent pathogens in the community in SSA and Asia to a range of commonly prescribed antibiotics. Inclusion criteria required that isolates were collected since 2004 and that they were obtained from either normally sterile sites or urine. The data were aggregated by region and by age group. Results Eighty-three studies were identified since 2004 which reported the antimicrobial susceptibilities of common bacterial pathogens. Different methods were used to assess in-vitro susceptibility in the different studies. The quality of testing (evidenced by resistance profiles) also varied considerably. For Streptococcus pneumoniae and Neisseria meningitidis most drugs maintained relatively high efficacy, apart from co-trimoxazole to which there were high levels of resistance in most of the pathogens surveyed. Conclusions Compared with the enormous infectious disease burden and widespread use of antibiotics there are relatively few reliable data o n antimicrobial susceptibility from tropical Asia and Africa upon which to draw firm conclusions, although it is evident that many commonly used antibiotics face considerable resistance in prevalent bacterial pathogens. This is likely to exacerbate morbidity and mortality. Investment in improved antimicrobial susceptibility testing and surveillance systems is likely to be a highly cost-effective strategy and should be complemented by centralized and readily accessible information resources. © 2011 Blackwell Publishing Ltd. . 2011. Responding to the evidence for the management of severe malaria Tropical Medicine and International Health, 16 (9), pp. 1085-1086. | Citations: 2 (Scopus) | Read more . 2011. Brain swelling and mannitol therapy in adult cerebral malaria: a randomized trial. Clin Infect Dis, 53 (4), pp. 349-355. | Citations: 37 (Scopus) | Show Abstract | Read more BACKGROUND: Coma is a frequent presentation of severe malaria in adults and an important cause of death. The role of cerebral swelling in its pathogenesis, and the possible benefit of intravenous mannitol therapy to treat this, is uncertain. METHODS: A computed tomographic (CT) scan of the cerebrum and lumbar puncture with measurement of cerebrospinal fluid (CSF) pressure were performed on admission for 126 consecutive adult Indian patients with cerebral malaria. Patients with brain swelling on CT scan were randomized to adjunctive treatment with intravenous mannitol (1.5 g/kg followed by 0.5 g/kg every 8 hours; n = 30) or no adjunctive therapy (n = 31). RESULTS: On CT scan 80 (63%) of 126 patients had cerebral swelling, of whom 36 (29%) had moderate or severe swelling. Extent of brain swelling was not related to coma depth or mortality. CSF pressures were elevated (≥200 mm H(2)O) in 43 (36%) of 120 patients and correlated with CT scan findings (P for trend = .001). Mortality with mannitol therapy was 9 (30%) of 30 versus 4 (13%) of 31 without adjunctive therapy (hazard ratio, 2.4 [95% confidence interval, 0.8-7.3]; P = .11). Median coma recovery time was 90 hours (range, 22-380 hours) with mannitol versus 32 hours (range, 5-168 hours) without (P = .02). CONCLUSIONS: Brain swelling on CT scan is a common finding in adult patients with cerebral malaria but is not related to coma depth or survival. Mannitol therapy as adjunctive treatment for brain swelling in adult cerebral malaria prolongs coma duration and may be harmful. . 2011. 'All her children are born that way': gendered experiences of stigma in families affected by sickle cell disorder in rural Kenya. Ethn Health, 16 (4-5), pp. 343-359. | Citations: 20 (Web of Science Lite) | Show Abstract | Read more OBJECTIVES: To explore early experiences of sickle cell disorder (SCD) in families with a young affected child, and the way these experiences influence relations within families. To consider ways in which stigma could be counteracted in health and research programmes in sub Saharan Africa. DESIGN: A qualitative study was conducted in a rural area of coastal Kenya including in-depth interviews with 13 families affected by SCD and 12 staff of a local biomedical research progamme. Purposive selection aimed to maximize diversity in socioeconomic and educational status, religion, severity of illness burden and religion amongst families and draw on relevant experience for staffs. Interviews were recorded, transcribed and analysed using the constant comparative method for family interviews and a thematic framework approach for staff data. RESULTS: Low initial recognition of SCD and its cause were associated with lay practices of surveillance within affected families, contributing to stigmatisation that occurred independently of genetic knowledge. Blame was often placed on mothers, including a risk of blame for misaligned paternity. Mothers are often particularly affected by SCD through the loss of independent livelihoods and their limited options in coping with this chronic condition. CONCLUSIONS: Mothers of children with SCD were particularly vulnerable to stigmatisation within families, with underlying structural influences that suggest these findings may apply to other similar settings in Africa, and have relevance for other genetic conditions. The potential, nature and form of stigmatisation point to the role of effective communication and SCD management in addressing for blame and discriminative effects of having a child with SCD. The findings highlight the importance of broader social programmes targeting underlying gender and economic inequalities. et al. 2011. A multi-center randomized trial to assess the efficacy of gatifloxacin versus ciprofloxacin for the treatment of shigellosis in Vietnamese children. PLoS Negl Trop Dis, 5 (8), pp. e1264. | Citations: 10 (Web of Science Lite) | Show Abstract | Read more BACKGROUND: The bacterial genus Shigella is the leading cause of dysentery. There have been significant increases in the proportion of Shigella isolated that demonstrate resistance to nalidixic acid. While nalidixic acid is no longer considered as a therapeutic agent for shigellosis, the fluoroquinolone ciprofloxacin is the current recommendation of the World Health Organization. Resistance to nalidixic acid is a marker of reduced susceptibility to older generation fluoroquinolones, such as ciprofloxacin. We aimed to assess the efficacy of gatifloxacin versus ciprofloxacin in the treatment of uncomplicated shigellosis in children. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a randomized, open-label, controlled trial with two parallel arms at two hospitals in southern Vietnam. The study was designed as a superiority trial and children with dysentery meeting the inclusion criteria were invited to participate. Participants received either gatifloxacin (10 mg/kg/day) in a single daily dose for 3 days or ciprofloxacin (30 mg/kg/day) in two divided doses for 3 days. The primary outcome measure was treatment failure; secondary outcome measures were time to the cessation of individual symptoms. Four hundred and ninety four patients were randomized to receive either gatifloxacin (n=249) or ciprofloxacin (n=245), of which 107 had a positive Shigella stool culture. We could not demonstrate superiority of gatifloxacin and observed similar clinical failure rate in both groups (gatifloxacin; 12.0% and ciprofloxacin; 11.0%, p=0.72). The median (inter-quartile range) time from illness onset to cessation of all symptoms was 95 (66-126) hours for gatifloxacin recipients and 93 (68-120) hours for the ciprofloxacin recipients (Hazard Ratio [95%CI]=0.98 [0.82-1.17], p=0.83). CONCLUSIONS: We conclude that in Vietnam, where nalidixic acid resistant Shigellae are highly prevalent, ciprofloxacin and gatifloxacin are similarly effective for the treatment of acute shigellosis. . 2011. What we learned about voluntariness and consent: Incorporating "background situations" and understanding into analyses American Journal of Bioethics, 11 (8), pp. 31-33. | Citations: 8 (Scopus) | Read more . 2011. Community and facility-level engagement in planning and budgeting for the government health sector - A district perspective from Kenya Health Policy, 99 (3), pp. 234-243. | Citations: 16 (Scopus) | Show Abstract | Read more Health systems reform processes have increasingly recognized the essential contribution of communities to the success of health programs and development activities in general. Here we examine the experience from Kilifi district in Kenya of implementing annual health sector planning guidelines that included community participation in problem identification, priority setting, and planning. We describe challenges in the implementation of national planning guidelines, how these were met, and how they influenced final plans and budgets.The broad-based community engagement envisaged in the guidelines did not take place due to the delay in roll out of the Ministry of Health-trained community health workers. Instead, community engagement was conducted through facility manage ment committees, though in a minority of facilities, even such committees were not involved. Some overlap was found in the priorities highlighted by facility staff, committee members and national indicators, but there were also many additional issues raised by committee members and not by other groups. The engagement of the community through committees influenced target and priority setting, but the emphasis on national health indicators left many local priorities unaddressed by the final work plans. Moreover, it appears that the final impact on budgets allocated at district and facility level was limited. The experience in Kilifi highlights the feasibility of engaging the community in the health planning process, and the challenges of ensuring that this engagement feeds into consolidated plans and future implementation. © 2010 Elsevier Ireland Ltd. . 2011. Urine antibiotic activity in patients presenting to Hospitals in Laos: Implications for worsening antibiotic resistance American Journal of Tropical Medicine and Hygiene, 85 (2), pp. 295-302. | Citations: 9 (Scopus) | Show Abstract | Read more Widespread use of antibiotics may be important in the spread of antimicrobial resistance. We estimated the proportion of Lao in- and outpatients who had taken antibiotics before medical consultation by detecting antibiotic activity in their urine added to lawns of Bacillus stearothermophilus, Escherichia coli, and Streptococcus pyogenes. In the retrospective (N = 2,058) and prospective studies (N = 1,153), 49.7% (95% confidence interv al [CI] = 47.4-52.0) and 36.2% (95% CI = 33.4-38.9), respectively, of Vientiane patients had urinary antibiotic activity detected. The highest frequency of estimated antibiotic pre-treatment was found in patients recruited with suspected central nervous system infections and community-acquired septicemia (both 56.8%). In Vientiane, children had a higher frequency of estimated antibiotic pre-treatment than adults (60.0% versus 46.5%; P < 0.001). Antibiotic use based on patients histories was significantly less frequent than when estimated from urinary antibiotic activity (P < 0.0001). Copyright © 2011 by The American Society of Tropical Medicine and Hygiene. et al. 2011. Ending the drought: new strategies for improving the flow of affordable, effective antivenoms in Asia and Africa. J Proteomics, 74 (9), pp. 1735-1767. | Citations: 90 (Scopus) | Show Abstract | Read more The development of snake antivenoms more than a century ago should have heralded effective treatment of the scourge of snakebite envenoming in impoverished, mostly rural populations around the world. That snakebite still exists today, as a widely untreated illness that maims, kills and terrifies men, women and children in vulnerable communities, is a cruel anachronism. Antivenom can be an effective, safe and affordable treatment for snakebites, but apathy, inaction and the politicisation of public health have marginalised both the problem (making snakebite arguably the most neglected of all neglected tropical diseases) and its solution. For lack of any coordinated approach, provision of antivenoms has been pushed off the public health agenda, leading to an incongruous decline in demand for these crucial antidotes, excused and fed by new priorities, an absence of epidemiological data, and a poor regulatory framework. These factors facilitated the infiltration of poor quality products that degrade user confidence and undermine legitimate producers. The result is that tens of thousands are denied an essential life-saving medicine, allowing a toll of human suffering that is a summation of many individual catastrophes. No strategy has been developed to address this problem and to overcome the intransigence and inaction responsible for the global tragedy of snakebite. Attempts to engage with the broader public health community through the World Health Organisation (WHO), GAVI, and other agencies have failed. Consequently, the toxinology community has taken on a leadership role in a new approach, the Global Snakebite Initiative, which seeks to mobilise the resources, skills and experience of scientists and clinicians for whom venoms, toxins, antivenoms, snakes and snakebites are already fields of interest. Proteomics is one such discipline, which has embraced the potential of using venoms in bio-discovery and systems biology. The fields of venomics and antivenomics have recently evolved from this discipline, offering fresh hope for the victims of snakebites by providing an exciting insight into the complexities, nature, fundamental properties and significance of venom constituents. Such a rational approach brings with it the potential to design new immunising mixtures from which to raise potent antivenoms with wider therapeutic ranges. This addresses a major practical limitation in antivenom use recognised since the beginning of the 20th century: the restriction of therapeutic effectiveness to the specific venom immunogen used in production. Antivenomic techniques enable the interactions between venoms and antivenoms to be examined in detail, and if combined with functional assays of specific activity and followed up by clinical trials of effectiveness and safety, can be powerful tools with which to evaluate the suitability of current and new antivenoms for meeting urgent regional needs. We propose two mechanisms through which the Global Snakebite Initiative might seek to end the antivenom drought in Africa and Asia: first by establishing a multidisciplinary, multicentre, international collaboration to evaluate currently available antivenoms against the venoms of medically important snakes from specific nations in Africa and Asia using a combination of proteomic, antivenomic and WHO-endorsed preclinical assessment protocols, to provide a validated evidence base for either recommending or rejecting individual products; and secondly by bringing the power of proteomics to bear on the design of new immunising mixtures to raise Pan-African and Pan-Asian polyvalent antivenoms of improved potency and quality. These products will be subject to rigorous clinical assessment. We propose radically to change the basis upon which antivenoms are produced and supplied for the developing world. Donor funding and strategic public health alliances will be sought to make it possible not only to sustain the financial viability of antivenom production partnerships, but also to ensure that patients are relieved of the costs of antivenom so that poverty is no longer a barrier to the treatment of this important, but grossly neglected public health emergency. et al. 2011. An open-label crossover study to evaluate potential pharmacokinetic interactions between oral oseltamivir and intravenous zanamivir in healthy thai adults Antimicrobial Agents and Chemotherapy, 55 (9), pp. 4050-4057. | Citations: 9 (Scopus) | Show Abstract | Read more There is no parenteral formulation of the neuraminidase inhibitor oseltamivir, the most widely used anti-influenza virus drug. Oseltamivir resistance is an increasing problem. Zanamivir is effective against the most prevalent oseltamivir-resistant influenza viruses. A parenteral formulation of zanamivir is in development for the treatment of severe influenza. It is not known if there is any pharmacokinetic interaction between the two drugs. Sixteen healthy Thai adult volunteers were studied in an open-label, four-period, randomized two-sequence crossover pharmacokinetic study in which zanamivir was given by constant-rate infusion or slow intravenous injection either alone or together with oral oseltamivir. Plasma concentration profiles of oseltamivir, the active metabolite oseltamivir carboxylate, and zanamivir were measured by liquid chromatography-mass spectrometry-mass spectrometry. Both drugs were well tolerated alone and in combination. The maximum plasma concentrations and the areas under the plasma concentration-time curves (AUC) of oseltamivir and oseltamivir carboxylate were not significantly different when oseltamivir was given separately or together with zanamivir. Maximum plasma concentrations of zanamivir were 10% (95% confidence interval, 7 to 12%) higher when zanamivir was infused concurrently with oral oseltamivir than with infusions before or after oral oseltamivir. The plasma zanamivir total AUC was positively correlated with the total oseltamivir carboxylate AUC (Pearson's correlation coefficient [rP] = 0.720, P = 0.002, n = 16) but not with the oseltamivir AUC (rp =0.121, n = 16). There is no clinically significant pharmacokinetic interaction between oseltamivir and zanamivir. Copyright © 2011, American Society for Microbiology. All Rights Reserved. . 2011. Factors associated with herpes simplex virus type 2 incidence in a cohort of human immunodeficiency virus type 1-seronegative Kenyan men and women reporting high-risk sexual behavior. Sex Transm Dis, 38 (9), pp. 837-844. | Citations: 17 (Scopus) | Show Abstract | Read more BACKGROUND: Herpes simplex virus type 2 (HSV-2) is an important cause of genital ulcers and can increase the risk for human immunodeficiency virus type 1 (HIV-1) transmission. Our objective was to determine the incidence and correlates of HSV-2 infection in HIV-1-seronegative Kenyan men reporting high-risk sexual behavior, compared with high-risk HIV-1-seronegative women in the same community. METHODS: Cohort participants were screened for prevalent HIV-1 infection. HIV-1-uninfected participants had regularly scheduled follow-up visits, with HIV counseling and testing and collection of demographic and behavioral data. Archived blood samples were tested for HSV-2. RESULTS: HSV-2 prevalence was 22.0% in men and 50.8% in women (P < 0.001). HSV-2 incidence in men was 9.0 per 100 person-years, and was associated with incident HIV-1 infection (adjusted incidence rate ratio [aIRR], 3.9; 95% confidence interval [CI], 1.3-12.4). Use of soap for genital washing was protective (aIRR, 0.3; 95% CI, 0.1-0.8). Receptive anal intercourse had a borderline association with HSV-2 acquisition in men (aIRR, 2.0; 95% CI, 1.0-4.1; P = 0.057), and weakened the association with incident HIV-1. Among women, HSV-2 incidence was 22.1 per 100 person-years (P < 0.001 compared with incidence in men), and was associated with incident HIV-1 infection (aIRR, 8.9; 95% CI, 3.6-21.8) and vaginal washing with soap (aIRR, 1.9; 95% CI, 1.0-3.4). CONCLUSIONS: HSV-2 incidence in these men and women is among the highest reported, and is associated with HIV-1 acquisition. Although vaginal washing with soap may increase HSV-2 risk in women, genital hygiene may be protective in men. . 2011. Microbiological diagnosis of prosthetic joint infections: a prospective evaluation of four bacterial culture media in the routine laboratory CLINICAL MICROBIOLOGY AND INFECTION, 17 (10), pp. 1528-1530. | Citations: 19 (Scopus) | Show Abstract | Read more The diagnosis of prosthetic joint infection (PJI) in the routine microbiology laboratory is labour-intensive, but semi-automated methods may be appropriate. We prospectively compared four microbiological culture methods on samples taken at prosthetic joint revision surgery. Automated BACTEC blood culture bottles and cooked meat enrichment broth were the most sensitive methods (87% and 83%, respectively, as compared with fastidious anaerobic broth (57%) and direct plates (39%)); all were highly specific (97-100%). To our knowledge, this is the first prospective study aimed at comparing culture methods in routine use in UK clinical laboratories for the diagnosis of PJI. © 2011 The Authors. Clinical Microbiology and Infection © 2011 European Society of Clinical Microbiology and Infectious Diseases. . 2011. A small amount of fat does not affect piperaquine exposure in patients with malaria. Antimicrob Agents Chemother, 55 (9), pp. 3971-3976. | Citations: 18 (Web of Science Lite) | Show Abstract | Read more Dihydroartemisinin-piperaquine is a new, highly effective, and well-tolerated combination treatment for uncomplicated falciparum malaria. The lipophilic characteristic of piperaquine suggests that administration together with fat will increase the oral bioavailability of the drug, and this has been reported for healthy volunteers. This pharmacokinetic study monitored 30 adult patients with uncomplicated falciparum malaria for 4.5 months to evaluate the effects of the concomitant intake of fat on the total piperaquine exposure. The fixed-drug combination of dihydroartemisinin-piperaquine was given with water to fasting patients (n = 15) or was coadministered with 200 ml milk containing 6.4 g fat (n = 15). The drug combination was generally well tolerated, and there were no severe adverse effects reported for either group during the study. Total piperaquine exposure (area under the concentration-time curve from zero to infinity [AUC(0-∞)]; results are given as medians [ranges]) were not statistically different between fed (29.5 h · μg/ml [20.6 to 58.7 h · μg/ml]) and fasting (23.9 h · μg/ml [11.9 to 72.9 h · μg/ml]) patients, but the interindividual variation was reduced in the fed group. Overall, none of the pharmacokinetic parameters differed statistically between the groups. Total piperaquine exposure correlated well with the day 7 concentrations in the fasted group, but the fed group showed a poor correlation. In conclusion, the coadministration of 6.4 g fat did not have any significant effect on piperaquine pharmacokinetics in the treatment of uncomplicated malaria. . 2011. Validation of an internally controlled one-step real-time multiplex RT-PCR assay for the detection and quantitation of dengue virus RNA in plasma Journal of Virological Methods, . 2011. Low-cost portable fluorescein angiography British Journal of Ophthalmology, 95 (9), pp. 1213-1215. | Citations: 2 (Scopus) | Show Abstract | Read more Fundus fluorescein angiography has great potential as a unique non-invasive tool to investigate in vivo the microvascular pathogenesis of a wide variety of diseases affecting the central nervous system. However, because it requires a bulky and expensive tabletop retinal camera, it is normally limited to cooperative and alert seated patients in well-resourced settings. Recently completed and ongoing studies of the pathogenesis of severe malaria are using fluorescein angiography to examine in detail the postulated central role of microvascular obstruction. We describe a novel method of fluorescein angiography with a portable retinal camera that can be adapted at very low cost for use in sick patients at the bedside. This method greatly expands the scope of potential studies utilising fluorescein angiography. . 2011. The plasma concentration of the B cell activating factor is increased in children with acute malaria Journal of Infectious Diseases, 204 (6), pp. 962-970. | Citations: 28 (Scopus) | Show Abstract | Read more Malaria-specific antibody responses in children often appear to be short-lived but the mechanisms underlying this phenomenon are not well understood. In this study, we investigated the relationship between the B-cell activating factor (BAFF) and its receptors expressed on B cells with antibody responses during and after acute malaria in children. Our results demonstrate that BAFF plasma levels increased during acute malarial disease and reflected disease severity. The expression profiles for BAFF receptors on B cells agreed with rapid activation and differentiation of a proportion of B cells to plasma cells. However, BAFF receptor (BAFF-R) expression was reduced on all peripheral blood B cells during acute infection, but those children with the highest level of BAFF-R expression on B cells maintained schizont-specific immunoglobin G (IgG) over a period of 4 months, indicating that dysregulation of BAFF-R expression on B cells may contribute to short-lived antibody responses to malarial antigens in children. In summary, this study suggests a potential role for BAFF during malaria disease, both as a marker for disease severity and in shaping the differentiation pattern of antigen-specific B cells. © The Author 2011. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. et al. 2011. Human leukocyte antigen variants B*44 and B*57 are consistently favorable during two distinct phases of primary HIV-1 infection in sub-Saharan Africans with several viral subtypes. J Virol, 85 (17), pp. 8894-8902. | Citations: 19 (Scopus) | Show Abstract | Read more As part of an ongoing study of early human immunodeficiency virus type 1 (HIV-1) infection in sub-Saharan African countries, we have identified 134 seroconverters (SCs) with distinct acute-phase (peak) and early chronic-phase (set-point) viremias. SCs with class I human leukocyte antigen (HLA) variants B*44 and B*57 had much lower peak viral loads (VLs) than SCs without these variants (adjusted linear regression beta values of -1.08 ± 0.26 log(10) [mean ± standard error] and -0.83 ± 0.27 log(10), respectively; P < 0.005 for both), after accounting for several nongenetic factors, including gender, age at estimated date of infection, duration of infection, and country of origin. These findings were confirmed by alternative models in which major viral subtypes (A1, C, and others) in the same SCs replaced country of origin as a covariate (P ≤ 0.03). Both B*44 and B*57 were also highly favorable (P ≤ 0.03) in analyses of set-point VLs. Moreover, B*44 was associated with relatively high CD4(+) T-cell counts during early chronic infection (P = 0.02). Thus, at least two common HLA-B variants showed strong influences on acute-phase as well as early chronic-phase VL, regardless of the infecting viral subtype. If confirmed, the identification of B*44 as another favorable marker in primary HIV-1 infection should help dissect mechanisms of early immune protection against HIV-1 infection. . 2011. The effect of mobile phone text-message reminders on Kenyan health workers' adherence to malaria treatment guidelines: A cluster randomised trial The Lancet, 378 (9793), pp. 795-803. | Citations: 169 (Scopus) | Show Abstract | Read more Health workers' malaria case-management practices often differ from national guidelines. We assessed whether text-message reminders sent to health workers' mobile phones could improve and maintain their adherence to treatment guidelines for outpatient paediatric malaria in Kenya. From March 6, 2009, to May 31, 2010, we did a cluster-randomised controlled trial at 107 rural health facilities in 11 districts in coastal and western Kenya. With a computer-generated sequence, health facilities were randomly allocated to either the intervention group, in which all health workers received text messages on their personal mobile phones on malaria case-management for 6 months, or the control group, in which health workers did not receive any text messages. Health workers were not masked to the intervention, although patients were unaware of whether they were in an intervention or control facility. The primary outcome was correct management with artemether-lumefantrine, defined as a dichotomous composite indicator of treatment, dispensing, and counselling tasks concordant with Kenyan national guidelines. The primary analysis was by intention to treat. The trial is registered with Current Controlled Trials, ISRCTN72328636. 119 health workers received the intervention. Case-management practices were assessed for 2269 children who needed treatment (1157 in the intervention group and 1112 in the control group). Intention-to-treat analysis showed that correct artemether-lumefantrine management improved by 23·7 percentage-points (95 CI 7·6-40·0; p=0·004) immediately after intervention and by 24·5 percentage-points (8·1-41·0; p=0·003) 6 months later. In resource-limited settings, malaria control programmes should consider use of text messaging to improve health workers' case-management practices. The Wellcome Trust. © 2011 Elsevier Ltd. et al. 2011. Long-term humoral and cellular immune responses elicited by a heterologous Plasmodium vivax apical membrane antigen 1 protein prime/adenovirus boost immunization protocol. Infect Immun, 79 (9), pp. 3642-3652. | Citations: 20 (Scopus) | Show Abstract | Read more Apical membrane antigen 1 (AMA-1) is an invasion-related Plasmodium antigen that is expressed during both intracellular and extracellular asexual stages of the parasite's life cycle, making it an ideal target for induction of humoral and cellular immune responses that can protect against malaria. We show here that when it is administered as a recombinant protein (P) in Montanide ISA720 adjuvant, followed by a recombinant human type 5 adenovirus (Ad), intense and long-lasting Plasmodium vivax AMA-1-specific antibody responses (including both IgG1 and IgG2a), as well as proliferative memory T cell responses, can be detected in immunized mice. Memory T cells displayed both central (CD44(hi) CD62L(hi)) and effector (CD44(hi) CD62L(lo)) phenotypes, with the central memory phenotype prevailing (56% of AMA-1-specific proliferating cells). Considering the main traits of the memory immune responses induced against AMA-1, this particular sequence of immunogens (P followed by Ad), but no others (Ad/Ad, Ad/P, or P/P), displayed an optimal synergistic effect. These results give further support to the need for preclinical studies of P. vivax vaccine candidate AMA-1 administered in prime/boost protocols that include recombinant proteins and adenoviral vectors. . 2011. The pathogenesis of dengue Vaccine, 29 (42), pp. 7221-7228. | Citations: 116 (Scopus) | Show Abstract | Read more Dengue is an important cause of childhood and adult morbidity in Asian and Latin American countries and its geographic footprint is growing. The clinical manifestations of dengue are the expression of a constellation of host and viral factors, some acquired, others intrinsic to the individual. The virulence of the virus plus the flavivirus infection history, age, gender and genotype of the host all appear to help shape the severity of infection. Similarly, the characteristics of the innate and acquired host immune response subsequent to infection are also likely determinants of outcome. This review summarises recent developments in the understanding of dengue pathogenesis and their relevance to dengue vaccine development. © 2011 Elsevier Ltd. . 2011. Pneumococcal conjugate vaccine given shortly after birth stimulates effective antibody concentrations and primes immunological memory for sustained infant protection Clinical Infectious Diseases, 53 (7), pp. 663-670. | Citations: 25 (Scopus) | Show Abstract | Read more Background.In developing countries, newborn immunization with pneumococcal conjugate vaccines (PCVs) could protect young infants who are at high risk of invasive pneumococcal disease (IPD) but might lead to immune tolerance.Methods.In a randomized trial, young infants received 7-valent PCV at 6, 10, and 14 weeks (Expanded Programme on Immunization [EPI] group) or 0, 10, and 14 weeks (newborn group). Safety was monitored actively at 2-7 days and then passively. Serum samples obtained at birth and 6, 10, 14, 18, 36, and 37 weeks were assayed by enzyme-linked immunosorbent assay for anticapsular immunoglobulin G concentration and avidity. Infants were boosted with either 7-valent PCV or one-fifth dose of pneumococcal pol ysaccharide vaccine at 36 weeks. Nasopharyngeal swab samples were obtained at 18 and 36 weeks.Results.Three-hundred neonates and young infants were enrolled. Newborn vaccination was well tolerated. Adverse events occurred equally in each group; none was related to immunization. One infant, immunized at birth, died of unrelated neonatal sepsis. At 18 weeks, protective concentrations (≥0.35 μg/mL) were achieved against each serotype by ≥87% of infants with no significant differences between groups. Geometric mean concentrations were higher in the EPI group for serotypes 4, 9V, 18C, and 19F at 18 weeks and for serotype 4 at 36 weeks. Avidity was greater in the newborn group for serotypes 4, 6B, and 19F at 18 weeks and for serotype 19F at 36 weeks. Booster responses and vaccine-type/nonvaccine-type carriage prevalence did not differ between groups.Conclusions.PCV was safe, immunogenic, and primed for memory when given at birth. There was no evidence of immune tolerance. Vaccination beginning at birth offers an alternative to control IPD in vulnerable young infants. The Author 2011. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please email:journals.permissions@oup.com.2011This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.5/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2011 The Author. . 2011. Malaria case-management following change of policy to universal parasitological diagnosis and targeted artemisinin-based combination therapy in Kenya. PLoS One, 6 (9), pp. e24781. | Citations: 27 (Web of Science Lite) | Show Abstract | Read more BACKGROUND: The change of malaria case-management policy in Kenya to recommend universal parasitological diagnosis and targeted treatment with artemether-lumefantrine (AL) is supported with activities aiming by 2013 at universal coverage and adherence to the recommendations. We evaluated changes in health systems and case-management indicators between the baseline survey undertaken before implementation of the policy and the follow-up survey following the first year of the implementation activities. METHODS/FINDINGS: National, cross-sectional surveys using quality-of-care methods were undertaken at public facilities. Baseline and follow-up surveys respectively included 174 and 176 facilities, 224 and 237 health workers, and 2,405 and 1,456 febrile patients. Health systems indicators showed variable changes between surveys: AL stock-out (27% to 21%; p = 0.152); availability of diagnostics (55% to 58%; p = 0.600); training on the new policy (0 to 22%; p = 0.001); exposure to supervision (18% to 13%; p = 0.156) and access to guidelines (0 to 6%; p = 0.001). At all facilities, there was an increase among patients tested for malaria (24% vs 31%; p = 0.090) and those who were both tested and treated according to test result (16% to 22%; p = 0.048). At facilities with AL and malaria diagnostics, testing increased from 43% to 50% (p = 0.196) while patients who were both, tested and treated according to test result, increased from 28% to 36% (p = 0.114). Treatment adherence improved for test positive patients from 83% to 90% (p = 0.150) and for test negative patients from 47% to 56% (p = 0.227). No association was found between testing and exposure to training, supervision and guidelines, however, testing was significantly associated with facility ownership, type of testing, and patients' caseload, age and clinical presentation. CONCLUSIONS: Most of the case-management indicators have shown some improvement trends; however differences were smaller than expected, rarely statistically significant and still leaving a substantial gap towards optimistic targets. The quantitative and qualitative improvement of interventions will ultimately determine the success of the new policy. . 2011. Susceptibility of bacterial isolates from community-acquired infections in sub-Saharan Africa and Asia to macrolide antibiotics Tropical Medicine and International Health, 16 (10), pp. 1192-1205. | Citations: 9 (Scopus) | Show Abstract | Read more Objective To review the literature on the susceptibility of common community pathogens in sub-Saharan Africa and Asia to the macrolide antibiotics. Methods Inclusion criteria required that isolates were collected since 2004 to ensure results were of contemporary relevance. The data were aggregated by region, age group and sterility of site of culture sample. Results A total of 51 studies were identified, which reported the macrolide antimicrobial susceptibilities of common bacterial pathogens isolated since 2004. In general, there was less macrolide resistance in African than in Asian isolates. Most African studies reported high levels of macrolide susceptibility in Streptococcus pneumoniae, whereas most Chinese studies reported high levels of resistance. There was very little information available for Gram-negative organisms. Conclusions Susceptibility of the pneumococcus to macrolides in SSA remains high in many areas, and good activity of azithromycin has been shown against Salmonellae spp. in Asia. In urban areas where high antibiotic consumption is prevalent, there was evidence of increased resistance to macrolides. However, there is no information on susceptibility from large areas in both continents. © 2011 Blackwell Publishing Ltd. . 2011. Are diagnostic criteria for acute malnutrition affected by hydration status in hospitalized children? A repeated measures study. Nutr J, 10 (1), pp. 92. | Citations: 23 (Web of Science Lite) | Show Abstract | Read more INTRODUCTION: Dehydration and malnutrition commonly occur together among ill children in developing countries. Dehydration (change in total body water) is known to alter weight. Although muscle tissue has high water content, it is not known whether mid-upper arm circumference (MUAC) may be altered by changes in tissue hydration. We aimed to determine whether rehydration alters MUAC, MUAC Z score (MUACz), weight-for-length Z-score (WFLz) and classification of nutritional status among hospitalised Kenyan children admitted with signs of dehydration. STUDY PROCEDURE: We enrolled children aged from 3 months to 5 years admitted to a rural Kenyan district hospital with clinical signs compatible with dehydration, and without kwashiorkor. Anthropometric measurements were taken at admission and repeated after 48 hours of treatment, which included rehydration by WHO protocols. Changes in weight observed during this period were considered to be due to changes in hydration status. RESULTS: Among 325 children (median age 11 months) the median weight gain (rehydration) after 48 hours was 0.21 kg, (an increase of 2.9% of admission body weight). Each 1% change in weight was associated with a 0.40 mm (95% CI: 0.30 to 0.44 mm, p < 0.001) change in MUAC, 0.035z (95% CI: 0.027 to 0.043z, P < 0.001) change in MUACz score and 0.115z (95% CI: 0.114 to 0.116 z, p < 0.001) change in WFLz. Among children aged 6 months or more with signs of dehydration at admission who were classified as having severe acute malnutrition (SAM) at admission by WFLz <-3 or MUAC <115 mm, 21% and 19% of children respectively were above these cut offs after 48 hours. CONCLUSION: MUAC is less affected by dehydration than WFLz and is therefore more suitable for nutritional assessment of ill children. However, both WFLz and MUAC misclassify SAM among dehydrated children. Nutritional status should be re-evaluated following rehydration, and management adjusted accordingly. . 2011. Validation of an internally controlled one-step real-time multiplex RT-PCR assay for the detection and quantitation of dengue virus RNA in plasma Journal of Virological Methods, 177 (2), pp. 168-173. | Citations: 53 (Scopus) | Show Abstract | Read more Dengue is mosquito-borne virus infection that annually causes ~50 million clinically apparent cases worldwide. An internally controlled one-step real-time multiplex RT-PCR assay was developed for detection and quantitation of DENV RNA in plasma sample by using specific primers and fluorogenic TaqMan probes. All primers and probes targeted sequences near the 3' end of the NS5 gene. The method comprised two multiplex assays and was validated for sensitivity, specificity, linearity, reproducibility and precision. An internal control template was spiked into each clinical specimen to provide quality assurance for each experimental step. The assay allowed for detection of between 0.5 and 3 infectious particles per mL, is rapid and has been operationally characterized in 287 Vietnamese dengue patients from two therapeutic intervention trials at the Hospital for Tropical Diseases, Ho Chi Minh City, Viet Nam. © 2011 Elsevier B.V. . 2011. Are diagnostic criteria for acute malnutrition affected by hydration status in hospitalized children? A repeated measures study Nutrition Journal, 10 (1), | Citations: 26 (Scopus) | Show Abstract | Read more Introduction. Dehydration and malnutrition commonly occur together among ill children in developing countries. Dehydration (change in total body water) is known to alter weight. Although muscle tissue has high water content, it is not known whether mid-upper arm circumference (MUAC) may be altered by changes in tissue hydration. We aimed to determine whether rehydration alters MUAC, MUAC Z score (MUACz), weight-for-length Z-score (WFLz) and classification of nutritional status among hospitalised Kenyan children admitted with signs of dehydration. Study procedure. We enrolled children aged from 3 months to 5 years admitted to a rural Kenyan district hospital with clinical signs compatible with dehydration, and without kwashiorkor. Anthropometric measurements were taken at admission and repeated after 48 hours of treatment, which included rehydration by WHO protocols. Changes in weight observed during this period were considered to be due to changes in hydration status. Results: Among 325 children (median age 11 months) the median weight gain (rehydration) after 48 hours was 0.21 kg, (an increase of 2.9% of admission body weight). Each 1% change in weight was associated with a 0.40 mm (95% CI: 0.30 to 0.44 mm, p < 0.001) change in MUAC, 0.035z (95% CI: 0.027 to 0.043z, P < 0.001) change in MUACz score and 0.115z (95% CI: 0.114 to 0.116 z, p < 0.001) change in WFLz. Among children aged 6 months or more with signs of dehydration at admission who were classified as having severe acute malnutrition (SAM) at admission by WFLz < -3 or MUAC < 115 mm, 21% and 19% of children respectively were above these cut offs after 48 hours. Conclusion: MUAC is less affected by dehydration than WFLz and is therefore more suitable for nutritional assessment of ill children. However, both WFLz and MUAC misclassify SAM among dehydrated children. Nutritional status should be re-evaluated following rehydration, and management adjusted accordingly. © 2011 Mwangome et al; licensee BioMed Central Ltd. . 2011. A review of parasitic zoonoses in a changing Southeast Asia. Vet Parasitol, 182 (1), pp. 22-40. | Citations: 45 (Scopus) | Show Abstract | Read more Parasitic zoonoses are common and widely distributed in the Southeast Asian region. However, the interactions between parasites, hosts and vectors are influenced by environmental, socio-cultural and livestock production changes that impact on the distribution, prevalence and severity of disease. In this review we provide an update on new knowledge in the context of ongoing changes for the food-borne pig associated zoonoses Taenia solium and Trichinella spp., the food-borne trematodes Opisthorchis viverrini and Clonorchis sinensis, the water-borne trematodes Schistosoma spp., the vector-borne zoonotic protozoa Plasmodium knowlesi and Leishmania spp. and the soil-borne zoonotic hookworm Ancylostoma ceylanicum. These various changes need to be considered when assessing or developing regional control programs or devising new research initiatives in a changing SE Asia. et al. 2011. Sustained low prevalence of meticillin-resistant Staphylococcus aureus upon admission to hospital in The Netherlands Journal of Hospital Infection, 79 (3), pp. 198-201. | Citations: 35 (Scopus) | Show Abstract | Read more The prevalence of meticillin-resistant Staphylococcus aureus (MRSA) carriage at hospital admission in The Netherlands was 0.03% in 1999-2000. The aim of the present study was to assess whether the prevalence of MRSA carriage in The Netherlands has changed over the last few years. In five Dutch hospitals, 6496 unique patients were screened for nasal S. aureus carriage at hospital admission by microbiological culture between 1 October 2005 and 7 June 2007. In total, 2036 of 6496 (31.3%) patients carried S. aureus in their nose, and seven of 6496 (0.11%) patients were nasal carriers of MRSA. Compared with 1999-2000, the prevalence of MRSA carriage in the Dutch population at hospital admission has increased more than three fold; however, this increase was not significant (P= 0.06, Fisher's exact test). This prevalence is still among the lowest in the world, probably as a result of the stringent Dutch infection control policy, and the restrictive use of antibiotics in The Netherlands. © 2011 The Healthcare Infection Society. . 2011. Effect of systemic antibiotics and topical chlorhexidine on meticillin-resistant Staphylococcus aureus carriage in intensive care unit patients. J Hosp Infect, 79 (3), pp. 222-226. | Citations: 1 (Web of Science Lite) | Show Abstract | Read more Antibiotics and antiseptics have the potential to influence carriage and transmission of meticillin-resistant Staphylococcus aureus (MRSA), although effects are likely to be complex, particularly in a setting where multiple agents are used. Here admission and weekly MRSA screens and daily antibiotic and antiseptic prescribing data from 544 MRSA carriers on an intensive care unit (ICU) are used to determine the effect of these agents on short-term within-host MRSA carriage dynamics. Longitudinal data were analysed using Markov models allowing patients to move between two states: MRSA positive (detectable MRSA carriage) and MRSA negative (no detectable carriage). The effect of concurrent systemic antibiotic and topical chlorhexidine (CHX) on movement between these states was assessed. CHX targeted to MRSA screen carriage sites increased transition from culture positive to negative and there was also weaker evidence that it decreased subsequent transition from negative back to positive. In contrast, there was only weak and inconsistent evidence that any antibiotic influenced transition in either direction. For example, whereas univariate analysis found quinolones to be strongly associated with both increased risk of losing and then reacquiring MRSA carriage over time intervals of one day, no effect was seen with weekly models. Similar studies are required to determine the generalisability of these findings. et al. 2011. A reliable ex vivo invasion assay of human reticulocytes by Plasmodium vivax. Blood, 118 (13), pp. e74-e81. | Citations: 64 (Scopus) | Show Abstract | Read more Currently, there are no reliable RBC invasion assays to guide the discovery of vaccines against Plasmodium vivax, the most prevalent malaria parasite in Asia and South America. Here we describe a protocol for an ex vivo P vivax invasion assay that can be easily deployed in laboratories located in endemic countries. The assay is based on mixing enriched cord blood reticulocytes with matured, trypsin-treated P vivax schizonts concentrated from clinical isolates. The reliability of this assay was demonstrated using a large panel of P vivax isolates freshly collected from patients in Thailand. . 2011. Quantifying the emergence of dengue in Hanoi, Vietnam: 1998-2009. PLoS Negl Trop Dis, 5 (9), pp. e1322. | Citations: 32 (Scopus) | Show Abstract | Read more BACKGROUND: An estimated 2.4 billion people live in areas at risk of dengue transmission, therefore the factors determining the establishment of endemic dengue in areas where transmission suitability is marginal is of considerable importance. Hanoi, Vietnam is such an area, and following a large dengue outbreak in 2009, we set out to determine if dengue is emerging in Hanoi. METHODS AND PRINCIPAL FINDINGS: We undertook a temporal and spatial analysis of 25,983 dengue cases notified in Hanoi between 1998 and 2009. Age standardized incidence rates, standardized age of infection, and Standardized Morbidity Ratios (SMR) were calculated. A quasi-Poisson regression model was used to determine if dengue incidence was increasing over time. Wavelet analysis was used to explore the periodicity of dengue transmission and the association with climate variables. After excluding the two major outbreak years of 1998 and 2009 and correcting for changes in population age structure, we identified a significant annual increase in the incidence of dengue cases over the period 1999-2008 (incidence rate ratio = 1.38, 95% confidence interval = 1.20-1.58, p value = 0.002). The age of notified dengue cases in Hanoi is high, with a median age of 23 years (mean 26.3 years). After adjusting for changes in population age structure, there was no statistically significant change in the median or mean age of dengue cases over the period studied. Districts in the central, highly urban, area of Hanoi have the highest incidence of dengue (SMR>3). CONCLUSIONS: Hanoi is a low dengue transmission setting where dengue incidence has been increasing year on year since 1999. This trend needs to be confirmed with serological surveys, followed by studies to determine the underlying drivers of this emergence. Such studies can provide insights into the biological, demographic, and environmental changes associated with vulnerability to the establishment of endemic dengue. . 2011. Coma in fatal adult human malaria is not caused by cerebral oedema. Malar J, 10 (1), pp. 267. | Citations: 28 (Web of Science Lite) | Show Abstract | Read more BACKGROUND: The role of brain oedema in the pathophysiology of cerebral malaria is controversial. Coma associated with severe Plasmodium falciparum malaria is multifactorial, but associated with histological evidence of parasitized erythrocyte sequestration and resultant microvascular congestion in cerebral vessels. To determine whether these changes cause breakdown of the blood-brain barrier and resultant perivascular or parenchymal cerebral oedema, histology, immunohistochemistry and image analysis were used to define the prevalence of histological patterns of oedema and the expression of specific molecular pathways involved in water balance in the brain in adults with fatal falciparum malaria. METHODS: The brains of 20 adult Vietnamese patients who died of severe malaria were examined for evidence of disrupted vascular integrity. Immunohistochemistry and image analysis was performed on brainstem sections for activation of the vascular endothelial growth factor (VEGF) receptor 2 and expression of the aquaporin 4 (AQP4) water channel protein. Fibrinogen immunostaining was assessed as evidence of blood-brain barrier leakage and perivascular oedema formation. Correlations were performed with clinical, biochemical and neuropathological parameters of severe malaria infection. RESULTS: The presence of oedema, plasma protein leakage and evidence of VEGF signalling were heterogeneous in fatal falciparum malaria and did not correlate with pre-mortem coma. Differences in vascular integrity were observed between brain regions with the greatest prevalence of disruption in the brainstem, compared to the cortex or midbrain. There was a statistically non-significant trend towards higher AQP4 staining in the brainstem of cases that presented with coma (P = .02). CONCLUSIONS: Histological evidence of cerebral oedema or immunohistochemical evidence of localised loss of vascular integrity did not correlate with the occurrence of pre-mortem coma in adults with fatal falciparum malaria. Enhanced expression of AQP4 water channels in the brainstem may, therefore, reflect a mix of both neuropathological or attempted neuroprotective responses to oedema formation. et al. 2011. Setting research priorities to reduce almost one million deaths from birth asphyxia by 2015. PLoS Med, 8 (1), pp. e1000389. | Citations: 49 (Scopus) | Read more . 2011. Viewpoint: Economic evaluation of package of care interventions employing clinical guidelines. Trop Med Int Health, 16 (1), pp. 97-104. | Citations: 8 (Scopus) | Show Abstract | Read more Increasingly attention is shifting towards delivering essential packages of care, often based on clinical practice guidelines, as a means to improve maternal, child and newborn survival in low-income settings. Cost effectiveness analysis (CEA), allied to the evaluation of less complex intervention, has become an increasingly important tool for priority setting. Arguably such analyses should be extended to inform decisions around the deployment of more complex interventions. In the discussion, we illustrate some of the challenges facing the extension of CEA to this area. We suggest that there are both practical and methodological challenges to overcome when conducting economic evaluation for packages of care interventions that incorporate clinical guidelines. Some might be overcome by developing specific guidance on approaches, for example clarity in identifying relevant costs. Some require consensus on methods. The greatest challenge, however, lies in how to incorporate, as measures of effectiveness, process measures of service quality. Questions on which measures to use, how multiple measures might be combined, how improvements in one area might be compared with those in another and what value is associated with improvement in health worker practices are yet to be answered. . 2011. Do clinical guidelines reduce clinician dependent costs? Health Research Policy and Systems, 9 | Citations: 7 (Scopus) | Show Abstract | Read more Clinician dependent costs are the costs of care that are under the discretion of the healthcare provider. These costs include the costs of drugs, tests and investigations, and discretionary outpatient visits and impatient stays. The purpose of this review was to summarize recent evidence, relevant to both developed and developing countries on whether evidence based clinical guidelines can change hospitals variable costs which are clinician dependent, and the degree of financial savings achieved at hospital level. Potential studies for inclusion were identified using structured searches of Econlit, J-Stor, and Pubmed databases. Two reviewers independently evaluated retrieved studies for inclusion. The methodological quality of the selected articles was assessed using the Oxford Centre for Evidence- Based Medicine (CEBM) levels of evidence. The results suggest that 10 of the 11 interventions were successful reducing financial costs. Most of the interventions, either in modeling studies or real interventions generate significant financial saving, although the former reported higher savings because the studies assumed 100 percent compliance. © 2011 Kosimbei et al; licensee BioMed Central Ltd. et al. 2011. A human phase I/IIa malaria challenge trial of a polyprotein malaria vaccine Vaccine, 29 (43), pp. 7514-7522. | Citations: 32 (Scopus) | Show Abstract | Read more We examined the safety, immunogenicity and efficacy of a prime-boost vaccination regime involving two poxvirus malaria subunit vaccines, FP9-PP and MVA-PP, expressing the same polyprotein consisting of six pre-erythrocytic antigens from Plasmodium falciparum. Following safety assessment of single doses, 15 volunteers received a heterologous prime-boost vaccination regime and underwent malaria sporozoite challenge. The vaccines were safe but interferon-γ ELISPOT responses were low compared to other poxvirus vectors, despite targeting multiple antigens. There was no vaccine efficacy as measured by delay in time to parasitaemia. A number of possible explanations are discussed, including the very large insert size of the polyprotein transgene. © 2011 Elsevier Ltd. et al. 2011. Circumsporozoite-specific T cell responses in children vaccinated with RTS,S/AS01E and protection against P falciparum clinical malaria. PLoS One, 6 (10), pp. e25786. | Citations: 52 (Scopus) | Show Abstract | Read more BACKGROUND: RTS,S/AS01(E) is the lead candidate pre-erythrocytic malaria vaccine. In Phase IIb field trials the safety profile was acceptable and the efficacy was 53% (95%CI 31%-72%) for protecting children against clinical malaria caused by P. falciparum. We studied CS-specific T cell responses in order to identify correlates of protection. METHODS AND FINDINGS: We used intracellular cytokine staining (for IL2, IFNγ, and TNFα), ex-vivo ELISPOTs (IFNγ and IL2) and IFNγ cultured ELISPOT assays to characterize the CS-specific cellular responses in 407 children (5-17 months of age) in a phase IIb randomized controlled trial of RTS,S/AS01(E) (NCT00380393). RTS,S/ AS01(E) vaccinees had higher frequencies of CS-specific CD4+ T cells producing IFNγ, TNFα or IL2 compared to control vaccinees. In a multivariable analysis TNFα(+) CD4(+) T cells were independently associated with a reduced risk for clinical malaria among RTS,S/AS01(E) vaccinees (HR = 0.64, 95%CI 0.49-0.86, p = 0.002). There was a non-significant tendency towards reduced risk among control vaccinees (HR = 0.80, 95%CI 0.62-1.03, p = 0.084), albeit with lower CS-specific T cell frequencies and higher rates of clinical malaria. When data from both RTS,S/AS01(E) vaccinees and control vaccinees were combined (with adjusting for vaccination group), the HR was 0.74 (95%CI 0.62-0.89, p = 0.001). After a Bonferroni correction for multiple comparisons (n-18), the finding was still significant at p = 0.018. There was no significant correlation between cultured or ex vivo ELISPOT data and protection from clinical malaria. The combination of TNFα(+) CD4(+) T cells and anti-CS antibody statistically accounted for the protective effect of vaccination in a Cox regression model. CONCLUSIONS: RTS,S/AS01(E) induces CS-specific Th1 T cell responses in young children living in a malaria endemic area. The combination of anti-CS antibody concentrations titers and CS-specific TNFα(+) CD4(+) T cells could account for the level of protection conferred by RTS,S/AS01(E). The correlation between CS-specific TNFα(+) CD4(+) T cells and protection needs confirmation in other datasets. et al. 2011. Relation between falciparum malaria and bacteraemia in Kenyan children: a population-based, case-control study and a longitudinal study. Lancet, 378 (9799), pp. 1316-1323. | Citations: 137 (Scopus) | Show Abstract | Read more BACKGROUND: Many investigators have suggested that malaria infection predisposes individuals to bacteraemia. We tested this hypothesis with mendelian randomisation studies of children with the malaria-protective phenotype of sickle-cell trait (HbAS). METHODS: This study was done in a defined area around Kilifi District Hospital, Kilifi, Kenya. We did a matched case-control study to identify risk factors for invasive bacterial disease, in which cases were children aged 3 months to 13 years who were admitted to hospital with bacteraemia between Sept 16, 1999, and July 31, 2002. We aimed to match two controls, by age, sex, location, and time of recruitment, for every case. We then did a longitudinal case-control study to assess the relation between HbAS and invasive bacterial disease as malaria incidence decreased. Cases were children aged 0-13 years who were admitted to hospital with bacteraemia between Jan 1, 1999, and Dec 31, 2007. Controls were born in the study area between Jan 1, 2006, and June 23, 2009. Finally, we modelled the annual incidence of bacteraemia against the community prevalence of malaria during 9 years with Poisson regression. RESULTS: In the matched case-control study, we recruited 292 cases-we recruited two controls for 236, and one for the remaining 56. Sickle-cell disease, HIV, leucocyte haemozoin pigment, and undernutrition were positively associated with bacteraemia and HbAS was strongly negatively associated with bacteraemia (odds ratio 0·36; 95% CI 0·20-0·65). In the longitudinal case-control study, we assessed data from 1454 cases and 10,749 controls. During the study period, the incidence of admission to hospital with malaria per 1000 child-years decreased from 28·5 to 3·45, with a reduction in protection afforded by HbAS against bacteraemia occurring in parallel (p=0·0008). The incidence of hospital admissions for bacteraemia per 1000 child-years also decreased from 2·59 to 1·45. The bacteraemia incidence rate ratio associated with malaria parasitaemia was 6·69 (95% CI 1·31-34·3) and, at a community parasite prevalence of 29% in 1999, 62% (8·2-91) of bacteraemia cases were attributable to malaria. INTERPRETATION: Malaria infection strongly predisposes individuals to bacteraemia and can account for more than half of all cases of bacteraemia in malaria-endemic areas. Interventions to control malaria will have a major additional benefit by reducing the burden of invasive bacterial disease. FUNDING: Wellcome Trust. et al. 2011. A retrospective analysis of the haemodynamic and metabolic effects of fluid resuscitation in Vietnamese adults with severe falciparum malaria. PLoS One, 6 (10), pp. e25523. | Citations: 4 (Web of Science Lite) | Show Abstract | Read more BACKGROUND: Optimising the fluid resuscitation of patients with severe malaria is a simple and potentially cost-effective intervention. Current WHO guidelines recommend central venous pressure (CVP) guided, crystalloid based, resuscitation in adults. METHODS: Prospectively collected haemodynamic data from intervention trials in Vietnamese adults with severe malaria were analysed retrospectively to assess the responses to fluid resuscitation. RESULTS: 43 patients were studied of whom 24 received a fluid load. The fluid load resulted in an increase in cardiac index (mean increase: 0.75 L/min/m(2) (95% Confidence interval (CI): 0.41 to 1.1)), but no significant change in acid-base status post resuscitation (mean increase base deficit 0.6 mmol/L (95% CI: -0.1 to 1.3). The CVP and PAoP (pulmonary artery occlusion pressure) were highly inter-correlated (r(s) = 0.7, p<0.0001), but neither were correlated with acid-base status (arterial pH, serum bicarbonate, base deficit) or respiratory status (PaO(2)/FiO(2) ratio). There was no correlation between the oxygen delivery (DO(2)) and base deficit at the 63 time-points where they were assessed simultaneously (r(s) = -0.09, p = 0.46). CONCLUSIONS: In adults with severe falciparum malaria there was no observed improvement in patient outcomes or acid-base status with fluid loading. Neither CVP nor PAoP correlated with markers of end-organ perfusion or respiratory status, suggesting these measures are poor predictors of their fluid resuscitation needs. . 2011. The parasite clearance curve. Malar J, 10 (1), pp. 278. | Citations: 88 (Scopus) | Show Abstract | Read more Parasite clearance rates are important measures of anti-malarial drug efficacy. They are particularly important in the assessment of artemisinin resistance. The slope of the log-linear segment in the middle of the parasite clearance curve has the least inter-individual variance and is the focus of therapeutic assessment. The factors affecting parasite clearance are reviewed. Methods of presentation and the approaches to analysis are discussed. . 2011. Protein-based signatures of functional evolution in Plasmodium falciparum. BMC Evol Biol, 11 (1), pp. 257. | Citations: 6 (Web of Science Lite) | Show Abstract | Read more BACKGROUND: It has been known for over a decade that Plasmodium falciparum proteins are enriched in non-globular domains of unknown function. The potential for these regions of protein sequence to undergo high levels of genetic drift provides a fundamental challenge to attempts to identify the molecular basis of adaptive change in malaria parasites. RESULTS: Evolutionary comparisons were undertaken using a set of forty P. falciparum metabolic enzyme genes, both within the hominid malaria clade (P. reichenowi) and across the genus (P. chabaudi). All genes contained coding elements highly conserved across the genus, but there were also a large number of regions of weakly or non-aligning coding sequence. These displayed remarkable levels of non-synonymous fixed differences within the hominid malaria clade indicating near complete release from purifying selection (dN/dS ratio at residues non-aligning across genus: 0.64, dN/dS ratio at residues identical across genus: 0.03). Regions of low conservation also possessed high levels of hydrophilicity, a marker of non-globularity. The propensity for such regions to act as potent sources of non-synonymous genetic drift within extant P. falciparum isolates was confirmed at chromosomal regions containing genes known to mediate drug resistance in field isolates, where 150 of 153 amino acid variants were located in poorly conserved regions. In contrast, all 22 amino acid variants associated with drug resistance were restricted to highly conserved regions. Additional mutations associated with laboratory-selected drug resistance, such as those in PfATPase4 selected by spiroindolone, were similarly restricted while mutations in another calcium ATPase (PfSERCA, a gene proposed to mediate artemisinin resistance) that reach significant frequencies in field isolates were located exclusively in poorly conserved regions consistent with genetic drift. CONCLUSION: Coding sequences of malaria parasites contain prospectively definable domains subject to neutral or nearly neutral evolution on a scale that appears unrivalled in biology. This distinct evolutionary landscape has potential to confound analytical methods developed for other genera. Against this tide of genetic drift, polymorphisms mediating functional change stand out to such an extent that evolutionary context provides a useful signal for identifying the molecular basis of drug resistance in malaria parasites, a finding that is of relevance to both genome-wide and candidate gene studies in this genus. . 2011. Decline of meticillin-resistant Staphylococcus aureus in Oxfordshire hospitals is strain-specific and preceded infection-control intensification. BMJ Open, 1 (1), pp. e000160. | Citations: 20 (Web of Science Lite) | Show Abstract | Read more Background In the past, strains of Staphylococcus aureus have evolved, expanded, made a marked clinical impact and then disappeared over several years. Faced with rising meticillin-resistant S aureus (MRSA) rates, UK government-supported infection control interventions were rolled out in Oxford Radcliffe Hospitals NHS Trust from 2006 onwards. Methods Using an electronic Database, the authors identified isolation of MRS among 611 434 hospital inpatients admitted to acute hospitals in Oxford, UK, 1 April 1998 to 30 June 2010. Isolation rates were modelled using segmented negative binomial regression for three groups of isolates: from blood cultures, from samples suggesting invasion (eg, cerebrospinal fluid, joint fluid, pus samples) and from surface swabs (eg, from wounds). Findings MRSA isolation rates rose rapidly from 1998 to the end of 2003 (annual increase from blood cultures 23%, 95% CI 16% to 30%), and then declined. The decline accelerated from mid-2006 onwards (annual decrease post-2006 38% from blood cultures, 95% CI 29% to 45%, p=0.003 vs previous decline). Rates of meticillin-sensitive S aureus changed little by comparison, with no evidence for declines 2006 onward (p=0.40); by 2010, sensitive S aureus was far more common than MRSA (blood cultures: 2.9 vs 0.25; invasive samples 14.7 vs 2.0 per 10 000 bedstays). Interestingly, trends in isolation of erythromycin-sensitive and resistant MRSA differed. Erythromycin-sensitive strains rose significantly faster (eg, from blood cultures p=0.002), and declined significantly more slowly (p=0.002), than erythromycin-resistant strains (global p<0.0001). Bacterial typing suggests this reflects differential spread of two major UK MRSA strains (ST22/36), ST36 having declined markedly 2006-2010, with ST22 becoming the dominant MRSA strain. Conclusions MRSA isolation rates were falling before recent intensification of infection-control measures. This, together with strain-specific changes in MRSA isolation, strongly suggests that incompletely understood biological factors are responsible for the much recent variation in MRSA isolation. A major, mainly meticillin-sensitive, S aureus burden remains. . 2011. Public Health in Practice: translating theory into action. Medical education, 45 (11), pp. 1142. | Citations: 1 (Scopus) . 2011. Protein-based signatures of functional evolution in Plasmodium falciparum BMC Evolutionary Biology, 11 (1), | Citations: 7 (Scopus) | Show Abstract | Read more Abstract. Background: It has been known for over a decade that Plasmodium falciparum proteins are enriched in non-globular domains of unknown function. The potential for these regions of protein sequence to undergo high levels of genetic drift provides a fundamental challenge to attempts to identify the molecular basis of adaptive change in malaria parasites. Results: Evolutionary comparisons were undertaken using a set of forty P. falciparum metabolic enzyme genes, both within the hominid malaria clade (P. reichenowi) and across the genus (P. chabaudi). All genes contained coding elements highly conserved across the genus, but there were also a large number of regions of weakly or non-aligning coding sequence. These displayed remarkable levels of non-synonymous fixed differences within the hominid malaria clade indicating near complete release from purifying selection (dN/dS ratio at residues non-aligning across genus: 0.64, dN/dS ratio at residues identical across genus: 0.03). Regions of low conservation also possessed high levels of hydrophilicity, a marker of non-globularity. The propensity for such regions to act as potent sources of non-synonymous genetic drift within extant P. falciparum isolates was confirmed at chromosomal regions containing genes known to mediate drug resistance in field isolates, where 150 of 153 amino acid variants were located in poorly conserved regions. In contrast, all 22 amino acid variants associated with drug resistance were restricted to highly conserved regions. Additional mutations associated with laboratory-selected drug resistance, such as those in PfATPase4 selected by spiroindolone, were similarly restricted while mutations in another calcium ATPase (PfSERCA, a gene proposed to mediate artemisinin resistance) that reach significant frequencies in field isolates were located exclusively in poorly conserved regions consistent with genetic drift. Conclusion: Coding sequences of malaria parasites contain prospectively definable domains subject to neutral or nearly neutral evolution on a scale that appears unrivalled in biology. This distinct evolutionary landscape has potential to confound analytical methods developed for other genera. Against this tide of genetic drift, polymorphisms mediating functional change stand out to such an extent that evolutionary context provides a useful signal for identifying the molecular basis of drug resistance in malaria parasites, a finding that is of relevance to both genome-wide and candidate gene studies in this genus. © 2011 Gardner et al; licensee BioMed Central Ltd. . 2011. What clinical signs best identify severe illness in young infants aged 0-59 days in developing countries? A systematic review. Arch Dis Child, 96 (11), pp. 1052-1059. | Citations: 7 (Web of Science Lite) | Show Abstract | Read more Despite recent overall improvement in the survival of under-five children worldwide, mortality among young infants remains high, and accounts for an increasing proportion of child deaths in resource-poor settings. In such settings, clinical decisions for appropriate management of severely ill infants have to be made on the basis of presenting clinical signs, and with limited or no laboratory facilities. This review summarises the evidence from observational studies of clinical signs of severe illnesses in young infants aged 0-59 days, with a particular focus on defining a minimum set of best predictors of the need for hospital-level care. Available moderate to high quality evidence suggests that, among sick infants aged 0-59 days brought to a health facility, the following clinical signs-alone or in combination-are likely to be the most valuable in identifying infants at risk of severe illness warranting hospital-level care: history of feeding difficulty, history of convulsions, temperature (axillary) ≥37.5°C or <35.5°C, change in level of activity, fast breathing/respiratory rate ≥60 breaths per minute, severe chest indrawing, grunting and cyanosis. . 2011. Clinical indicators of bacterial meningitis among neonates and young infants in rural Kenya. BMC Infect Dis, 11 (1), pp. 301. | Citations: 11 (Web of Science Lite) | Show Abstract | Read more BACKGROUND: Meningitis is notoriously difficult to diagnose in infancy because its clinical features are non-specific. World Health Organization (WHO) guidelines suggest several indicative signs, based on limited data. We aimed to identify indicators of bacterial meningitis in young infants in Kenya, and compared their performance to the WHO guidelines. We also examined the feasibility of developing a scoring system for meningitis. METHODS: We studied all admissions aged < 60 days to Kilifi District Hospital, 2001 through 2005. We evaluated clinical indicators against microbiological findings using likelihood ratios. We prospectively validated our findings 2006 through 2007. RESULTS: We studied 2,411 and 1,512 young infants during the derivation and validation periods respectively. During derivation, 31/1,031 (3.0%) neonates aged < 7 days and 67/1,380 (4.8%) young infants aged 7-59 days (p < 0.001) had meningitis. 90% of cases could be diagnosed macroscopically (turbidity) or by microscopic leukocyte counting. Independent indicators of meningitis were: fever, convulsions, irritability, bulging fontanel and temperature ≥ 39°C. Areas under the receiver operating characteristic curve in the validation period were 0.62 [95%CI: 0.49-0.75] age < 7 days and 0.76 [95%CI: 0.68-0.85] thereafter (P = 0.07), and using the WHO signs, 0.50 [95%CI 0.35-0.65] age < 7 days and 0.82 [95%CI: 0.75-0.89] thereafter (P = 0.0001). The number needed to LP to identify one case was 21 [95%CI: 15-35] for our signs, and 28 [95%CI: 18-61] for WHO signs. With a scoring system, a cut-off of ≥ 1 sign offered the best compromise on sensitivity and specificity. CONCLUSION: Simple clinical signs at admission identify two thirds of meningitis cases in neonates and young infants. Lumbar puncture is essential to diagnosis and avoidance of unnecessary treatment, and is worthwhile without CSF biochemistry or bacterial culture. The signs of Meningitis suggested by the WHO perform poorly in the first week of life. A scoring system for meningitis in this age group is not helpful. et al. 2011. Declining responsiveness of Plasmodium falciparum infections to artemisinin-based combination treatments on the Kenyan coast. PLoS One, 6 (11), pp. e26005. | Citations: 50 (Web of Science Lite) | Show Abstract | Read more BACKGROUND: The emergence of artemisinin-resistant P. falciparum malaria in South-East Asia highlights the need for continued global surveillance of the efficacy of artemisinin-based combination therapies. METHODS: On the Kenyan coast we studied the treatment responses in 474 children 6-59 months old with uncomplicated P. falciparum malaria in a randomized controlled trial of dihydroartemisinin-piperaquine vs. artemether-lumefantrine from 2005 to 2008. (ISRCTN88705995). RESULTS: The proportion of patients with residual parasitemia on day 1 rose from 55% in 2005-2006 to 87% in 2007-2008 (odds ratio, 5.4, 95%CI, 2.7-11.1; P<0.001) and from 81% to 95% (OR, 4.1, 95%CI, 1.7-9.9; P = 0.002) in the DHA-PPQ and AM-LM groups, respectively. In parallel, Kaplan-Meier estimated risks of apparent recrudescent infection by day 84 increased from 7% to 14% (P = 0.1) and from 6% to 15% (P = 0.05) with DHA-PPQ and AM-LM, respectively. Coinciding with decreasing transmission in the study area, clinical tolerance to parasitemia (defined as absence of fever) declined between 2005-2006 and 2007-2008 (OR body temperature >37.5°C, 2.8, 1.9-4.1; P<0.001). Neither in vitro sensitivity of parasites to DHA nor levels of antibodies against parasite extract accounted for parasite clearance rates or changes thereof. CONCLUSIONS: The significant, albeit small, decline through time of parasitological response rates to treatment with ACTs may be due to the emergence of parasites with reduced drug sensitivity, to the coincident reduction in population-level clinical immunity, or both. Maintaining the efficacy of artemisinin-based therapy in Africa would benefit from a better understanding of the mechanisms underlying reduced parasite clearance rates. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN88705995. et al. 2011. Timing of enteral feeding in cerebral malaria in resource-poor settings: a randomized trial. PLoS One, 6 (11), pp. e27273. | Citations: 17 (Scopus) | Show Abstract | Read more BACKGROUND: Early start of enteral feeding is an established treatment strategy in intubated patients in intensive care since it reduces invasive bacterial infections and length of hospital stay. There is equipoise whether early enteral feeding is also beneficial in non-intubated patients with cerebral malaria in resource poor settings. We hypothesized that the risk of aspiration pneumonia might outweigh the potential benefits of earlier recovery and prevention of hypoglycaemia. METHOD AND FINDINGS: A randomized trial of early (day of admission) versus late (after 60 hours in adults or 36 hours in children) start of enteral feeding was undertaken in patients with cerebral malaria in Chittagong, Bangladesh from May 2008 to August 2009. The primary outcome measures were incidence of aspiration pneumonia, hypoglycaemia and coma recovery time. The trial was terminated after inclusion of 56 patients because of a high incidence of aspiration pneumonia in the early feeding group (9/27 (33%)), compared to the late feeding group (0/29 (0%)), p = 0.001). One patient in the late feeding group, and none in the early group, had hypoglycaemia during admission. There was no significant difference in overall mortality (9/27 (33%) vs 6/29 (21%), p = 0.370), but mortality was 5/9 (56%) in patients with aspiration pneumonia. CONCLUSIONS: In conclusion, early start of enteral feeding is detrimental in non-intubated patients with cerebral malaria in many resource-poor settings. Evidence gathered in resource rich settings is not necessarily transferable to resource-poor settings. TRIAL REGISTRATION: Controlled-Trials.com ISRCTN57488577. . 2011. SIMULTANEOUS DETERMINATION OF ARTEMETHER AND AZITHROMYCIN IN SUPPOSITORIES BY REVERSED PHASE HPLC ANALYTICAL LETTERS, 44 (16), pp. 2732-2743. | Citations: 7 (Scopus) | Show Abstract | Read more Chromatographic parameter assessments for RP-HPLC-UV method development for the simultaneous analysis of artemether and azithromycin for the pharmaceutical analysis of a rectal coformulation currently under development for the treatment of malaria infected children. Using methanol based mobile phase for the analysis of both artemether and azithromycin provided a more robust method in terms of resolution and peak symmetry. The method validated for suppository used 80% methanol and 20% phosphate buffer 15 mM at pH 9. The UV detection was at 210 nm. The accuracy profiles indicated a method validation between 80-120% for both active pharmaceutical ingredients. The preparation process of the suppository was validated based on theoretical values of artemether and azithromycin present in the formulation; active pharmaceutical ingredients were homogenously distributed within the suppository. © 2011 Copyright Taylor and Francis Group, LLC. et al. 2011. Genome-wide association study identifies susceptibility loci for dengue shock syndrome at MICB and PLCE1 Nature Genetics, 43 (11), pp. 1139-1141. | Citations: 106 (Scopus) | Show Abstract | Read more Hypovolemic shock (dengue shock syndrome (DSS)) is the most common life-threatening complication of dengue. We conducted a genome-wide association study of 2,008 pediatric cases treated for DSS and 2,018 controls from Vietnam. Replication of the most significantly associated markers was carried out in an independent Vietnamese sample of 1,737 cases and 2,934 controls. SNPs at two loci showed genome-wide significant association with DSS. We identified a susceptibility locus at MICB (major histocompatibility complex (MHC) class I polypeptide-related sequence B), which was within the broad MHC region on chromosome 6 but outside the class I and class II HLA loci (rs3132468, P meta = 4.41 × 10 -11 , per-allele odds ratio (OR) = 1.34 (95% confidence interval: 1.23-1.46)). We identified associated variants within PLCE1 (phospholipase C, epsilon 1) on chromosome 10 (rs3765524, P meta = 3.08 × 10 -10 , per-allele OR = 0.80 (95% confidence interval: 0.75-0.86)). We identify two loci associated with susceptibility to DSS in people with dengue, suggesting possible mechanisms for this severe complication of dengue. © 2011 Nature America, Inc. All rights reserved. et al. 2011. Recent avian influenza virus A/H5N1 evolution in vaccinated and unvaccinated poultry from farms in Southern Vietnam, January-March 2010 Transboundary and Emerging Diseases, 58 (6), pp. 537-543. | Citations: 12 (Scopus) | Show Abstract | Read more We report 15 new avian influenza virus A/H5N1 haemagglutinin (HA) sequences sampled from visibly sick domestic poultry in southern Vietnam, between 1 January 2010 and 6 March 2010. These HA sequences form a new sub-clade of the clade 1 H5N1 viruses that have been circulating in Vietnam since 2003/2004. The viruses are characterized by a change from isoleucine to valine at position 514 (I514V) and are 1.8% divergent at the nucleotide level from HA sequences sampled in Vietnam in 2007. Five new amino acid changes were observed at previously identified antigenic sites, and three were located within structural elements of the receptor-binding domain. One new mutation removed a potential N-linked glycosylation site, and a methionine insertion was observed in one virus at the polybasic cleavage site. Five of these viruses were sampled from farms where poultry were vaccinated against H5N1, but there was no association between observed amino acid changes and flock vaccination status. Despite the current lack of evidence for antigenic drift or immune escape in Vietnamese H5N1 viruses, continued surveillance remains a high priority. © 2011 Blackwell Verlag GmbH. et al. 2011. Global burden of respiratory infections due to seasonal influenza in young children: a systematic review and meta-analysis The Lancet, . 2011. Determinants of relapse periodicity in Plasmodium vivax malaria. Malar J, 10 (1), pp. 297. | Citations: 194 (Scopus) | Show Abstract | Read more Plasmodium vivax is a major cause of febrile illness in endemic areas of Asia, Central and South America, and the horn of Africa. Plasmodium vivax infections are characterized by relapses of malaria arising from persistent liver stages of the parasite (hypnozoites) which can be prevented only by 8-aminoquinoline anti-malarials. Tropical P. vivax relapses at three week intervals if rapidly eliminated anti-malarials are given for treatment, whereas in temperate regions and parts of the sub-tropics P. vivax infections are characterized either by a long incubation or a long-latency period between illness and relapse - in both cases approximating 8-10 months. The epidemiology of the different relapse phenotypes has not been defined adequately despite obvious relevance to malaria control and elimination. The number of sporozoites inoculated by the anopheline mosquito is an important determinant of both the timing and the number of relapses. The intervals between relapses display a remarkable periodicity which has not been explained. Evidence is presented that the proportion of patients who have successive relapses is relatively constant and that the factor which activates hypnozoites and leads to regular interval relapse in vivax malaria is the systemic febrile illness itself. It is proposed that in endemic areas a large proportion of the population harbours latent hypnozoites which can be activated by a systemic illness such as vivax or falciparum malaria. This explains the high rates of vivax following falciparum malaria, the high proportion of heterologous genotypes in relapses, the higher rates of relapse in people living in endemic areas compared with artificial infection studies, and, by facilitating recombination between different genotypes, contributes to P. vivax genetic diversity particularly in low transmission settings. Long-latency P. vivax phenotypes may be more widespread and more prevalent than currently thought. These observations have important implications for the assessment of radical treatment efficacy and for malaria control and elimination. et al. 2011. Decreasing incidence of severe malaria and community-acquired bacteraemia among hospitalized children in Muheza, north-eastern Tanzania, 2006-2010 Malaria Journal, 10 | Citations: 37 (Scopus) | Show Abstract | Read more Background: The annual incidence and temporal trend of severe malaria and community-acquired bacteraemia during a four-year period in Muheza, Tanzania was assessed. Methods. Data on severely ill febrile children aged 2 months to 14 years from three prospective studies conducted at Muheza District Hospital from 2006 to 2010 was pooled and analysed. On admission, each enrolled child had a thin and thick blood film and at least one rapid diagnostic test for falciparum malaria, as well as a blood culture. The annual incidence of bacteraemia and severe malaria among children coming from Muheza was calculated and their temporal trend was assessed. Results: Overall, 1, 898 severe falciparum malaria and 684 bacteraemia cases were included. Of these, 1, 356 (71%) and 482 (71%), respectively, were from the referral population of Muheza. The incidence of falciparum malaria and all-cause bacteraemia in Muheza decreased five-fold and three-fold, respectively, from the first to the fourth year of surveillance (p < 0.0001). During this period, the median ages of children from Muheza admitted with severe malaria increased from 1.7 to 2.5 years (p < 0.0001). The reduction in all-cause bacteraemia was mainly driven by the 11-fold decline in the incidence of non-typhoidal salmonellosis. The annual incidences of Haemophilus influenzae and pneumococcal invasive bacterial infections decreased as well but were much fewer in number. Conclusions: These results add to the growing evidence of the decline in malaria associated with a decrease in non-typhoidal salmonellosis and possibly other bacteraemias. Malarial prevention and control strategies may provide a greater benefit than the mere reduction of malaria alone. © 2011Mtove et al; licensee BioMed Central Ltd. et al. 2011. Performance of the carestart™ G6PD deficiency screening test, a point-of-care diagnostic for primaquine therapy screening PLoS ONE, 6 (12), | Citations: 57 (Scopus) | Show Abstract | Read more Development of reliable, easy-to-use, rapid diagnostic tests (RDTs) to detect glucose-6-phosphate dehydrogenase (G6PD) deficiency at point of care is essential to deploying primaquine therapies as part of malaria elimination strategies. We assessed a kit under research and development called CareStart™ G6PD deficiency screening test (Access Bio, New Jersey, USA) by comparing its performance to quantitative G6PD enzyme activity using a standardized spectrophotometric method ('gold standard'). Blood samples (n = 903) were collected from Cambodian adults living in Pailin province, western Cambodia. G6PD enzyme activities ranged from 0 to 20.5 U/g Hb (median 12.0 U/g Hg). Based on a normal haemoglobin concentration and wild-type G6PD gene, the normal values of G6PD enzymatic activity for this population was 3.6 to 20.5 U/g Hg (95 th percentiles from 5.5 to 17.2 U/g Hg). Ninety-seven subjects (10.7%) had & 3.6 U/g Hg and were classified as G6PD deficient. Prevalence of deficiency was 15.0% (64/425) among men and 6.9% (33/478) among women. Genotype was analyzed in 66 G6PD-deficient subjects and 63 of these exhibited findings consistent with Viangchang genotype. The sensitivity and specificity of the CareStart™ G6PD deficiency screening test was 0.68 and 1.0, respectively. Its detection threshold was < 2.7 U/g Hg, well within the range of moderate and severe enzyme deficiencies. Thirteen subjects (1.4%, 12 males and 1 female) with G6PD enzyme activities < 2 U/g Hg were falsely classified as "normal" by RDT. This experimental RDT test here evaluated outside of the laboratory for the first time shows real promise, but safe application of it will require lower rates of falsely "normal" results. © 2011 Kim et al. et al. 2011. Dexamethasone and long-term outcome of tuberculous meningitis in Vietnamese adults and adolescents. PLoS One, 6 (12), pp. e27821. | Citations: 38 (Scopus) | Show Abstract | Read more BACKGROUND: Dexamethasone has been shown to reduce mortality in patients with tuberculous meningitis but the long-term outcome of the disease is unknown. METHODS: Vietnamese adults and adolescents with tuberculous meningitis recruited to a randomised, double-blind, placebo-controlled trial of adjunctive dexamethasone were followed-up at five years, to determine the effect of dexamethasone on long-term survival and neurological disability. RESULTS: 545 patients were randomised to receive either dexamethasone (274 patients) or placebo (271 patients). 50 patients (9.2%) were lost to follow-up at five years. In all patients two-year survival, probabilities tended to be higher in the dexamethasone arm (0.63 versus 0.55; p = 0.07) but five-year survival rates were similar (0.54 versus 0.51, p = 0.51) in both groups. In patients with grade 1 TBM, but not with grade 2 or grade 3 TBM, the benefit of dexamethasone treatment tended to persist over time (five-year survival probabilities 0.69 versus 0.55, p = 0.07) but there was no conclusive evidence of treatment effect heterogeneity by TBM grade (p = 0.36). The dexamethasone group had a similar proportion of severely disabled patients among survivors at five years as the placebo group (17/128, 13.2% vs. 17/116, 14.7%) and there was no significant association between dexamethasone treatment and disability status at five years (p = 0.32). CONCLUSIONS: Adjunctive dexamethasone appears to improve the probability of survival in patients with TBM, until at least two years of follow-up. We could not demonstrate a five-year survival benefit of dexamethasone treatment which may be confined to patients with grade 1 TBM. TRIAL REGISTRATION: ClinicalTrials.gov NCT01317654. . 2011. Diagnostic performance of visible severe wasting for identifying severe acute malnutrition in children admitted to hospital in Kenya. Bull World Health Organ, 89 (12), pp. 900-906. | Citations: 14 (Scopus) | Show Abstract | Read more OBJECTIVE: To determine the diagnostic value of visible severe wasting in identifying severe acute malnutrition at two public hospitals in Kenya. METHODS: This was a cross-sectional study of children aged 6 to 59.9 months admitted to one rural and one urban hospital. On admission, mid-upper arm circumference (MUAC), weight and height were measured and the presence of visible severe wasting was assessed. The diagnostic performance of visible severe wasting was evaluated against anthropometric criteria. FINDINGS: Of 11,166 children admitted, 563 (5%) had kwashiorkor and 1406 (12.5%) were severely wasted (MUAC < 11.5 cm). The combined sensitivity and specificity of visible severe wasting at the two hospitals, as assessed against a MUAC < 11.5 cm, were 54% (95% confidence interval, CI: 51-56) and 96% (95% CI: 96-97), respectively; at one hospital, its sensitivity and specificity against a weight-for-height z-score below -3 were 44.7% (95% CI: 42-48) and 96.5% (95% CI: 96-97), respectively. Severely wasted children who were correctly identified by visible severe wasting were consistently older, more severely wasted, more often having kwashiorkor, more often positive to the human immunodeficiency virus, ill for a longer period and at greater risk of death. Visible severe wasting had lower sensitivity for determining the risk of death than the anthropometric measures. There was no evidence to support measuring both MUAC and weight-for-height z-score. CONCLUSION: Visible severe wasting failed to detect approximately half of the children admitted to hospital with severe acute malnutrition diagnosed anthropometrically. Routine screening by MUAC is quick, simple and inexpensive and should be part of the standard assessment of all paediatric hospital admissions in the study setting. . 2011. Ethics in practice: The state of the debate on promoting the social value of global health research in resource poor settings particularly Africa BMC Medical Ethics, 12 (1), | Citations: 24 (Scopus) | Show Abstract | Read more Background: Promoting the social value of global health research undertaken in resource poor settings has become a key concern in global research ethics. The consideration for benefit sharing, which concerns the elucidation of what if anything, is owed to participants, their communities and host nations that take part in such research, and the obligations of researchers involved, is one of the main strategies used for promoting social value of research. In the last decade however, there has been intense debate within academic bioethics literature seeking to define the benefits, the beneficiaries, and the scope of obligations for providing these benefits. Although this debate may be indicative of willingness at the international level to engage with the responsibilities of researchers involved in global health research, it remains unclear which forms of benefits or beneficiaries should be considered. International and local research ethics guidelines are reviewed here to delineate the guidance they provide. Methods. We reviewed documents selected from the international compilation of research ethics guidelines by the Office for Human Research Protections under the US Department of Health and Human Services. Results: Access to interventions being researched, the provision of unavailable health care, capacity building for individuals and institutions, support to health care systems and access to medical and public health interventions proven effective, are the commonly recommended forms of benefits. The beneficiaries are volunteers, disease or illness affected communities and the population in general. Interestingly however, there is a divide between "global opinion" and the views of particular countries within resource poor settings as made explicit by differences in emphasis regarding the potential benefits and the beneficiaries. Conclusion: Although in theory benefit sharing is widely accepted as one of the means for promoting the social value of international collaborative health research, there is less agreement amongst major guidelines on the specific responsibilities of researchers over what is ethical in promoting the social value of research. Lack of consensus might have practical implications for efforts aimed at enhancing the social value of global health research undertaken in resource poor settings. Further developments in global research ethics require more reflection, paying attention to the practical realities of implementing the ethical principles in real world context. © 2011 Lairumbi et al; licensee BioMed Central Ltd. et al. 2011. Global burden of respiratory infections due to seasonal influenza in young children: a systematic review and meta-analysis. Lancet, 378 (9807), pp. 1917-1930. | Citations: 287 (Scopus) | Show Abstract | Read more BACKGROUND: The global burden of disease attributable to seasonal influenza virus in children is unknown. We aimed to estimate the global incidence of and mortality from lower respiratory infections associated with influenza in children younger than 5 years. METHODS: We estimated the incidence of influenza episodes, influenza-associated acute lower respiratory infections (ALRI), and influenza-associated severe ALRI in children younger than 5 years, stratified by age, with data from a systematic review of studies published between Jan 1, 1995, and Oct 31, 2010, and 16 unpublished population-based studies. We applied these incidence estimates to global population estimates for 2008 to calculate estimates for that year. We estimated possible bounds for influenza-associated ALRI mortality by combining incidence estimates with case fatality ratios from hospital-based reports and identifying studies with population-based data for influenza seasonality and monthly ALRI mortality. FINDINGS: We identified 43 suitable studies, with data for around 8 million children. We estimated that, in 2008, 90 million (95% CI 49-162 million) new cases of influenza (data from nine studies), 20 million (13-32 million) cases of influenza-associated ALRI (13% of all cases of paediatric ALRI; data from six studies), and 1 million (1-2 million) cases of influenza-associated severe ALRI (7% of cases of all severe paediatric ALRI; data from 39 studies) occurred worldwide in children younger than 5 years. We estimated there were 28,000-111,500 deaths in children younger than 5 years attributable to influenza-associated ALRI in 2008, with 99% of these deaths occurring in developing countries. Incidence and mortality varied substantially from year to year in any one setting. INTERPRETATION: Influenza is a common pathogen identified in children with ALRI and results in a substantial burden on health services worldwide. Sufficient data to precisely estimate the role of influenza in childhood mortality from ALRI are not available. FUNDING: WHO; Bill & Melinda Gates Foundation. . 2011. Performance of the MGIT TBc identification test and meta-analysis of MPT64 assays for identification of the Mycobacterium tuberculosis complex in liquid culture. J Clin Microbiol, 49 (12), pp. 4343-4346. | Citations: 23 (Scopus) | Show Abstract | Read more Rapid MPT64-based immunochromatographic tests (MPT64 ICTs) have been developed to detect Mycobacterium tuberculosis complex (MTBC) in culture. We demonstrated the noninferiority of one commercial MTP64 ICT, the MGIT TBc identification (TBcID) test, to GenoType line probe assays for MTBC identification in positive MGIT cultures. Meta-analysis of MPT64 ICT performance for identification of MTBC in liquid culture confirmed similar very high sensitivities and specificities for all three commercial MPT64 assays for which sufficient data were available. et al. 2011. Risk and causes of paediatric hospital-acquired bacteraemia in Kilifi District Hospital, Kenya: A prospective cohort study The Lancet, 378 (9808), pp. 2021-2027. | Citations: 51 (Scopus) | Show Abstract | Read more In sub-Saharan Africa, community-acquired bacteraemia is an important cause of illness and death in children. Our aim was to establish the magnitude and causes of hospital-acquired (nosocomial) bacteraemia in African children. We reviewed prospectively collected surveillance data of 33 188 admissions to Kilifi District Hospital, Kenya, between April 16, 2002, and Sept 30, 2009. We defined bacteraemia as nosocomial if it occurred 48 h or more after admission. We estimated the per-admission risk, daily rate, effect on mortality, and microbial cause of nosocomial bacteraemia and analysed risk factors by multivariable Cox regression. The effect on morbidity was measured as the increase in hospital stay by comparison with time-matched patients without bacteraemia. The overall risk of nosocomial bacteraemia during this period was 5·9/1000 admissions (95 CI 5·2-6·9) but we recorded an underlying rise in risk of 27 per year. The incidence was 1·0/1000 days in hospital (0·87-1·14), which is about 40 times higher than that of community-acquired bacteraemia in the same region. Mortality in patients with nosocomial bacteraemia was 53, compared with 24 in community-acquired bacteraemia and 6 in patients without bacteraemia. In survivors, nosocomial bacteraemia lengthened hospital stay by 10·1 days (3·0- 17·2). Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, Acinetobacter spp, group D streptococci, and Pseudomonas aeruginosa accounted for three-quarters of nosocomial infections. Nosocomial bacteraemia was significantly associated with severe malnutrition (hazard ratio 2·52, 95 CI 1·79-3·57) and blood transfusion in children without severe anaemia (4·99; 3·39-7·37). Our findings show that although nosocomial bacteraemia is rare, it has serious effects on morbidity and mortality, and the microbiological causes are distinct from those of community-acquired bacteraemia. Nosocomial infections are largely unrecognised or undocumented as a health risk in low-income countries, but they are likely to become public health priorities as awareness of their occurrence increases and as other prominent childhood diseases are progressively controlled. Wellcome Trust. © 2011 Elsevier Ltd. et al. 2011. Quality of hospital care for sick newborns and severely malnourished children in Kenya: A two-year descriptive study in 8 hospitals BMC Health Services Research, 11 | Citations: 12 (Scopus) | Show Abstract | Read more Background: Given the high mortality associated with neonatal illnesses and severe malnutrition and the development of packages of interventions that provide similar challenges for service delivery mechanisms we set out to explore how well such services are provided in Kenya. Methods. As a sub-component of a larger study we evaluated care during surveys conducted in 8 rural district hospitals using convenience samples of case records. After baseline hospitals received either a full multifaceted intervention (intervention hospitals) or a partial intervention (control hospitals) aimed largely at improving inpatient paediatric care for malaria, pneumonia and diarrhea/dehydration. Additional data were collected to: i) examine the availability of routine information at baseline and their value for morbidity, mortality and quality of care reporting, and ii) compare the care received against national guidelines disseminated to all hospitals. Results: Clinical documentation for neonatal and malnutrition admissions was often very poor at baseline with case records often entirely missing. Introducing a standard newborn admission record (NAR) form was associated with an increase in median assessment (IQR) score to 25/28 (22-27) from 2/28 (1-4) at baseline. Inadequate and incorrect prescribing of penicillin and gentamicin were common at baseline. For newborns considerable improvements in prescribing in the post baseline period were seen for penicillin but potentially serious errors persisted when prescribing gentamicin, particularly to low-birth weight newborns in the first week of life. Prescribing essential feeds appeared almost universally inadequate at baseline and showed limited improvement after guideline dissemination. Conclusion: Routine records are inadequate to assess newborn care and thus for monitoring newborn survival interventions. Quality of documented inpatient care for neonates and severely malnourished children is poor with limited improvement after the dissemination of clinical practice guidelines. Further research evaluating approaches to improving care for these vulnerable groups is urgently needed. We also suggest pre-service training curricula should be better aligned to help improve newborn survival particularly. © 2011 Gathara et al; licensee BioMed Central Ltd. . 2011. Statistical methodology for the evaluation of vaccine efficacy in a phase III multi-centre trial of the RTS, S/AS01 malaria vaccine in African children. Malar J, 10 (1), pp. 222. | Citations: 18 (Scopus) | Show Abstract | Read more BACKGROUND: There has been much debate about the appropriate statistical methodology for the evaluation of malaria field studies and the challenges in interpreting data arising from these trials. METHODS: The present paper describes, for a pivotal phase III efficacy of the RTS, S/AS01 malaria vaccine, the methods of the statistical analysis and the rationale for their selection. The methods used to estimate efficacy of the primary course of vaccination, and of a booster dose, in preventing clinical episodes of uncomplicated and severe malaria, and to determine the duration of protection, are described. The interpretation of various measures of efficacy in terms of the potential public health impact of the vaccine is discussed. CONCLUSIONS: The methodology selected to analyse the clinical trial must be scientifically sound, acceptable to regulatory authorities and meaningful to those responsible for malaria control and public health policy. . 2011. Erratum Clinical Infectious Diseases, 52 (9), pp. 1202-1202. | Read more . 2011. Erratum: Two-stage revision for prosthetic joint infection: Predictors of outcome and the role of reimplantation microbiology Journal of Antimicrobial Chemotherapy, 66 (5), pp. 1204. | Citations: 1 (Scopus) | Read more . 2011. Erratum: One hundred and twelve infected arthroplasties treated with 'DAIR' (debridement, antibiotics and implant retention): Antibiotic duration and outcome Journal of Antimicrobial Chemotherapy, 66 (5), pp. 1203. | Read more . 2011. Corrigendum to “Risk factors for recurrence after Staphylococcus aureus bacteraemia. A retrospective matched case-control study” [Journal of Infection 58 (2009) 411–416] Journal of Infection, 62 (4), pp. 328-328. | Read more . 2011. Correction: Multiple functions of human T cells generated by experimental malaria challenge European Journal of Immunology, 41 (4), pp. 1176-1176. | Read more . 2011. Correction: Malaria vaccine development: Lessons from the field European Journal of Immunology, 41 (4), pp. 1176-1176. | Read more et al. 2011. The blood-stage malaria antigen PfRH5 is susceptible to vaccine-inducible cross-strain neutralizing antibody. Nat Commun, 2 (1), pp. 601. | Citations: 119 (Web of Science Lite) | Show Abstract | Read more Current vaccine strategies against the asexual blood stage of Plasmodium falciparum are mostly focused on well-studied merozoite antigens that induce immune responses after natural exposure, but have yet to induce robust protection in any clinical trial. Here we compare human-compatible viral-vectored vaccines targeting ten different blood-stage antigens. We show that the full-length P. falciparum reticulocyte-binding protein homologue 5 (PfRH5) is highly susceptible to cross-strain neutralizing vaccine-induced antibodies, out-performing all other antigens delivered by the same vaccine platform. We find that, despite being susceptible to antibody, PfRH5 is unlikely to be under substantial immune selection pressure; there is minimal acquisition of anti-PfRH5 IgG antibodies in malaria-exposed Kenyans. These data challenge the widespread beliefs that any merozoite antigen that is highly susceptible to immune attack would be subject to significant levels of antigenic polymorphism, and that erythrocyte invasion by P. falciparum is a degenerate process involving a series of parallel redundant pathways. . 2011. Explaining the effects of a multifaceted intervention to improve inpatient care in rural Kenyan hospitals - interpretation based on retrospective examination of data from participant observation, quantitative and qualitative studies Implementation Science, 6 (1), | Citations: 26 (Scopus) | Show Abstract | Read more Background: We have reported the results of a cluster randomized trial of rural Kenyan hospitals evaluating the effects of an intervention to introduce care based on best-practice guidelines. In parallel work we described the context of the study, explored the process and perceptions of the intervention, and undertook a discrete study on health worker motivation because this was felt likely to be an important contributor to poor performance in Kenyan public sector hospitals. Here, we use data from these multiple studies and insights gained from being participants in and observers of the intervention process to provide our explanation of how intervention effects were achieved as part of an effort to better understan d implementation in low-income hospital settings.Methods: Initial hypotheses were generated to explain the variation in intervention effects across place, time, and effect measure (indicator) based on our understanding of theory and informed by our implementation experience and participant observations. All data sources available for hospitals considered as cases for study were then examined to determine if hypotheses were supported, rejected, or required modification. Data included transcriptions of interviews and group discussions, field notes and that from the detailed longitudinal quantitative investigation. Potentially useful explanatory themes were identified, discussed by the implementing and research team, revised, and merged as part of an iterative process aimed at building more generic explanatory theory. At the end of this process, findings were mapped against a recently reported comprehensive framework for implementation research.Results: A normative re-educative intervention approach evolved that sought to reset norms and values concerning good practice and promote 'grass-roots' participation to improve delivery of correct care. Maximal effects were achieved when this strategy and external support supervision helped create a soft-contract with senior managers clarifying roles and expectations around desired performance. This, combined with the support of facilitators acting as an expert resource and 'shop-floor' change agent, led to improvements in leadership, accountability, and resource allocation that enhanced workers' commitment and capacity and improved clinical microsystems. Provision of correct care was then particularly likely if tasks were simple and a good fit to existing professional routines. Our findings were in broad agreement with those defined as part of recent work articulating a comprehensive framework for implementation research.Conclusions: Using data from multiple studies can provide valuable insight into how an intervention is working and what factors may explain variability in effects. Findings clearly suggest that major intervention strategies aimed at improving child and newborn survival in low-income settings should go well beyond the fixed inputs (training, guidelines, and job aides) that are typical of many major programmes. Strategies required to deliver good care in low-income settings should recognize that this will need to be co-produced through engagement often over prolonged periods and as part of a directive but adaptive, participatory, information-rich, and reflective process. © 2011 English et al; licensee BioMed Central Ltd. . 2011. Prediction of serotypes causing invasive pneumococcal disease in unvaccinated and vaccinated populations. Epidemiology, 22 (2), pp. 199-207. | Citations: 22 (Scopus) | Show Abstract | Read more INTRODUCTION: Before the introduction of the heptavalent pneumococcal conjugate vaccine (Prevnar-7), the relative prevalence of serotypes of Streptococcus pneumoniae was fairly stable worldwide. We sought to develop a statistical tool to predict the relative frequency of different serotypes among disease isolates in the pre- and post-Prevnar-7 eras using the limited amount of data that is widely available. METHODS: We initially used pre-Prevnar-7 carriage prevalence and estimates of invasiveness derived from case-fatality data as predictors for the relative abundance of serotypes causing invasive pneumococcal disease during the pre- and post-Prevnar-7 eras, using negative binomial regression. We fit the model to pre-Prevnar-7 invasive pneumococcal disease data from England and Wales and used these data to (1) evaluate the performance of the model using several datasets and (2) evaluate the utility of the country-specific carriage data. We then fit an alternative model that used polysaccharide structure, a correlate of prevalence that does not require country-specific information and could be useful in determining the postvaccine population structure, as a predictor. RESULTS: Predictions from the initial model fit data from several pediatric populations in the pre-Prevnar-7 era. After the introduction of Prevnar-7, the model still had a good negative predictive value, though substantial unexplained variation remained. The alternative model had a good negative predictive value but poor positive predictive value. Both models demonstrate that the pneumococcal population follows a somewhat predictable pattern even after vaccination. CONCLUSIONS: This approach provides a preliminary framework to evaluate the potential patterns and impact of serotypes causing invasive pneumococcal disease. . 2011. The effects of spatial population dataset choice on estimates of population at risk of disease. Popul Health Metr, 9 (1), pp. 4. | Citations: 30 (Web of Science Lite) | Show Abstract | Read more BACKGROUND: The spatial modeling of infectious disease distributions and dynamics is increasingly being undertaken for health services planning and disease control monitoring, implementation, and evaluation. Where risks are heterogeneous in space or dependent on person-to-person transmission, spatial data on human population distributions are required to estimate infectious disease risks, burdens, and dynamics. Several different modeled human population distribution datasets are available and widely used, but the disparities among them and the implications for enumerating disease burdens and populations at risk have not been considered systematically. Here, we quantify some of these effects using global estimates of populations at risk (PAR) of P. falciparum malaria as an example. METHODS: The recent construction of a global map of P. falciparum malaria endemicity enabled the testing of different gridded population datasets for providing estimates of PAR by endemicity class. The estimated population numbers within each class were calculated for each country using four different global gridded human population datasets: GRUMP (~1 km spatial resolution), LandScan (~1 km), UNEP Global Population Databases (~5 km), and GPW3 (~5 km). More detailed assessments of PAR variation and accuracy were conducted for three African countries where census data were available at a higher administrative-unit level than used by any of the four gridded population datasets. RESULTS: The estimates of PAR based on the datasets varied by more than 10 million people for some countries, even accounting for the fact that estimates of population totals made by different agencies are used to correct national totals in these datasets and can vary by more than 5% for many low-income countries. In many cases, these variations in PAR estimates comprised more than 10% of the total national population. The detailed country-level assessments suggested that none of the datasets was consistently more accurate than the others in estimating PAR. The sizes of such differences among modeled human populations were related to variations in the methods, input resolution, and date of the census data underlying each dataset. Data quality varied from country to country within the spatial population datasets. CONCLUSIONS: Detailed, highly spatially resolved human population data are an essential resource for planning health service delivery for disease control, for the spatial modeling of epidemics, and for decision-making processes related to public health. However, our results highlight that for the low-income regions of the world where disease burden is greatest, existing datasets display substantial variations in estimated population distributions, resulting in uncertainty in disease assessments that utilize them. Increased efforts are required to gather contemporary and spatially detailed demographic data to reduce this uncertainty, particularly in Africa, and to develop population distribution modeling methods that match the rigor, sophistication, and ability to handle uncertainty of contemporary disease mapping and spread modeling. In the meantime, studies that utilize a particular spatial population dataset need to acknowledge the uncertainties inherent within them and consider how the methods and data that comprise each will affect conclusions. . 2011. Department of Error The Lancet, 377 (9759), pp. 30-30. | Read more . 2011. A comparison of pooled and individual bird sampling for detection of Salmonella in commercial egg laying flocks. Prev Vet Med, 99 (2-4), pp. 176-184. | Citations: 17 (Scopus) | Show Abstract | Read more The objective of this study was to determine the sensitivity of culturing pooled samples containing varying numbers of individual droppings for detection of Salmonella in commercial egg-laying flocks relative to the within-flock prevalence. A laboratory experiment was performed to directly measure the effect of diluting positive with negative faeces on the sensitivity of detection, and thus provide priors for a Bayesian model of pooled sampling. Pooled samples made up of different numbers of individual faecal droppings were collected from 20 flocks, and in addition bulked faeces and dust were also sampled using an in-house method that involved collecting 10 dust and 10 faeces samples into jars with buffered peptone water. The results from these flocks were analysed using Bayesian methods for diagnostic test evaluation in the absence of a gold standard, and the sensitivity of each pooled sample type was estimated relative to the within-flock prevalence. The sensitivity of pooled samples depended on the within-flock prevalence, and increased as the prevalence increased. The sensitivity of pooled sampling tended to increase with the number of droppings in the pool, and overall there was a higher proportion of positive samples from the pools of 20, 60 and the in-house faeces pooling method compared to the pools of 10, 5 and the individual droppings. Dust samples were more sensitive than the faeces samples, and so the inclusion of dust in sampling schemes is recommended. . 2011. A longitudinal study of Salmonella infection in different types of turkey flocks in Great Britain. Zoonoses Public Health, 58 (3), pp. 200-208. | Citations: 6 (Scopus) | Show Abstract | Read more Salmonella is, after Campylobacter, the most reported zoonotic pathogen in the EU. Poultry are a common source of infection to humans, and turkey flocks are commonly colonized with the organism. We investigated the prevalence and risk factors of Salmonella infection in 179 houses in 60 holdings representative of turkey meat and breeder production in Great Britain. From each holding, up to four houses were chosen, and two consecutive flocks per house were sampled/tested for Salmonella to investigate the persistence, elimination and introduction of Salmonella in consecutive crops. At the first sampling, the overall flock-level Salmonella prevalence was 32.8% and 8.9% for meat and breeding flocks respectively. There was a higher prevalence of Salmonella in flocks in the rearing stage than in the fattening and breeding stages. At the first sampling, the flock-level prevalence of Salmonella was 26.8% (95% CI: 20.7-33.7%), while the prevalence level in the subsequent flock was 20.5% (95% CI: 13.6-29.7%). No houses were positive for any of the EU-regulated serovars. The most commonly encountered serovars were S. Kottbus and S. Kedougou. Carry-over of infection was observed in 44.8% of the positive houses, and introduction of new infection occurred in 8.4% of houses. Data from the questionnaires and auditing of all holdings and houses were combined and used to calculate adjusted farm- and house-adjusted risk factors. Significant risk factors were feed from a source other than a national compounder (OR = 2.4), feeder type other than pan feeders (OR = 2.4) and hygiene practices other than terminal cleaning and disinfection using power-washing with sanitizer and anteroom with boot change (OR = 2.8). The study discusses the main challenges currently faced by the industry to control Salmonella in turkey production. . 2011. Survey of Salmonella prevalence on commercial turkey breeding and fattening farms in the UK in 2006 to 2007. Vet Rec, 169 (19), pp. 493. | Citations: 2 (Scopus) | Show Abstract | Read more A total of 29 breeding turkey holdings and 317 fattening turkey holdings were sampled between October 2006 and September 2007 in order to establish the baseline prevalence of Salmonella in turkeys in the UK. The weighted holding level Salmonella prevalence was found to be 20.1 per cent (95 per cent confidence interval [CI] 8.6 to 40.3 per cent) in breeding turkeys and 37.7 per cent (95 per cent CI 33.4 to 42.3 per cent) in fattening turkeys. For breeding turkeys, a weighted flock-level prevalence, as more than one flock per holding was sampled, was estimated at 7.1 per cent (95 per cent CI 3.2 to 14.8 per cent). A total of 13 different serovars were identified in the survey. The most frequent serovar in both turkey flock classes was Salmonella Kottbus, which was found on two breeding holdings and 63 of the fattening holdings giving weighted prevalences of 10.4 per cent (95 per cent CI 2.6 to 34.1 per cent) and 23.0 per cent (95 per cent CI 19.3 to 27.3 per cent), respectively. On breeding holdings, a single isolate of Salmonella Typhimurium, identified as DT12 (weighted prevalence 3.5 per cent [95 per cent CI 0.7 to 15.8 per cent] [holding], 0.7 per cent [95 per cent CI 0.1 to 3.7 per cent] [flock)], was found. On fattening holdings, there were 55 isolates of S Typhimurium from 16 holdings, giving a weighted prevalence of this serovar of 5.4 per cent (95 per cent CI 3.6 to 8.0 per cent). There were no isolates of Salmonella serovars Enteritidis, Hadar, Infantis or Virchow. . 2011. Oxford graduates' perceptions of a global health master's degree: a case study. Hum Resour Health, 9 (1), pp. 26. | Citations: 8 (Web of Science Lite) | Show Abstract | Read more INTRODUCTION: Low and middle-income countries suffer an ongoing deficit of trained public health workers, yet optimizing postgraduate education to best address these training needs remains a challenge. Much international public health education literature has focused on global capacity building and/or the description of innovative programmes, but less on quality and appropriateness. CASE DESCRIPTION: The MSc in Global Health Science at the University of Oxford is a relatively new, full-time one year master's degree in international public health. The programme is intended for individuals with significant evidence of commitment to health in low and middle income countries. The intake is small, with only about 25 students each year, but they are from diverse professional and geographical backgrounds. Given the diversity of their backgrounds, we wanted to determine the extent to which student background influenced their perceptions of the quality of their learning experience and their learning outcomes. We conducted virtual or face-to-face semi-structured individual interviews with students who had graduated from the course at least one year previously. Of the 2005 to 2007 intake years, 52 of 63 graduates (83%) were interviewed. We used thematic analysis to analyze the data, then linked results to student characteristics. DISCUSSION: The findings from the evaluation suggested that all MSc GHS graduates who spoke with us, irrespective of background, appreciated the curriculum structure drawing on the strengths of a small, diverse student group, and the contribution the programme had made to their breadth of understanding and their careers. This evaluation also demonstrated the feasibility of an educational evaluation conducted several years after programme completion and when graduates were 'in the field'. This is important in ensuring international public health programmes are relevant to the day-to-day work of public health practitioners and researchers in low and middle-income countries. CONCLUSIONS: Feedback from students, when they had either resumed their positions 'in the field' or pursued further training, was useful in identifying valuable and positive aspects of the programme and also in identifying areas for further action and development by the programme's management and by individual teaching staff. . 2011. Barriers to immunization among children of migrant workers from myanmar living in tak province, Thailand Bulletin of the World Health Organization, 89 (7), pp. 528-531. | Citations: 16 (Scopus) | Show Abstract | Read more Problem Immunization is a cost-effective means of improving child survival but implementation of programmes in low- and middleincome countries is variable. Children of migrants are less likely to be immunized. Approach The qualitative study aimed to identify barriers to the successful implementation of migrant immunization programmes in Tak province, Thailand. We ran a total of 53 focus groups involving 371 participants in three sites. Local setting Tak province in Thailand borders Myanmar and has an estimated 200 000 migrants from Myanmar. Vaccine-preventable diseases are a documented cause of morbidity in this population but there is no systematic or coordinated immunization programme in the area. Relevant changes As a result of the findings, the subsequent immunization campaign targeted children in school to overcome those barriers of distance to immunization services, fear of arrest, not remembering immunization appointments, and the disruption of parental work. The campaigns also included immunization education for both parents and teachers. Lessons learnt Migrant parents identified similar barriers to accessing childhood immunization programmes as migrant populations elsewhere in the world, although a unique barrier identified by parents from Myanmar was 'fear of arrest'. The subsequent schoolbased strategy to overcome these barriers appears to be effective. . 2011. Effect of a multi-faceted quality improvement intervention on inappropriate antibiotic use in children with non-bloody diarrhoea admitted to district hospitals in Kenya. BMC Pediatr, 11 (1), pp. 109. | Citations: 8 (Web of Science Lite) | Show Abstract | Read more BACKGROUND: There are few reports of interventions to reduce the common but irrational use of antibiotics for acute non-bloody diarrhoea amongst hospitalised children in low-income settings. We undertook a secondary analysis of data from an intervention comprising training of health workers, facilitation, supervision and face-to-face feedback, to assess whether it reduced inappropriate use of antibiotics in children with non-bloody diarrhoea and no co-morbidities requiring antibiotics, compared to a partial intervention comprising didactic training and written feedback only. This outcome was not a pre-specified end-point of the main trial. METHODS: Repeated cross-sectional survey data from a cluster-randomised controlled trial of an intervention to improve management of common childhood illnesses in Kenya were used to describe the prevalence of inappropriate antibiotic use in a 7-day period in children aged 2-59 months with acute non-bloody diarrhoea. Logistic regression models with random effects for hospital were then used to identify patient and clinician level factors associated with inappropriate antibiotic use and to assess the effect of the intervention. RESULTS: 9, 459 admission records of children were reviewed for this outcome. Of these, 4, 232 (44.7%) were diagnosed with diarrhoea, with 130 of these being bloody (dysentery) therefore requiring antibiotics. 1, 160 children had non-bloody diarrhoea and no co-morbidities requiring antibiotics-these were the focus of the analysis. 750 (64.7%) of them received antibiotics inappropriately, 313 of these being in the intervention hospitals vs. 437 in the controls. The adjusted logistic regression model showed the baseline-adjusted odds of inappropriate antibiotic prescription to children admitted to the intervention hospitals was 0.30 times that in the control hospitals (95%CI 0.09-1.02). CONCLUSION: We found some evidence that the multi-faceted, sustained intervention described in this paper led to a reduction in the inappropriate use of antibiotics in treating children with non-bloody diarrhoea. TRIAL REGISTRATION: International Standard Randomised Controlled Trial Number Register ISRCTN42996612. . 2011. Phenotyping clinical resistance to chloroquine in Plasmodium vivax in northeastern Papua, Indonesia. Int J Parasitol Drugs Drug Resist, 1 (1), pp. 28-32. | Citations: 3 (Web of Science Lite) | Show Abstract | Read more Chloroquine (CQ)-resistant Plasmodium vivax was first documented in 1989 and threatens much of eastern Indonesia, with > 50% of therapeutic failure rates. We screened 2236 subjects for malaria infection through active case detection and identified 232 infected cases with 100 subjects carried P. vivax mono infection. We prospectively evaluated therapeutic responses to CQ in 73 subjects infected by P. vivax in northeastern Papua, Indonesia. We phenotyped these infections as susceptible or resistant to CQ using a 28-day in vivo test format. Eighteen subjects (25%) had persistent or recurrent parasitemia during the test and were provisionally classified as resistant. Among the remainder, 46 (63%) subjects had no persistent or recurrent parasitemia and were classified as having infections sensitive to CQ, 4 were lost to follow up, and 5 dropped out. Among the 18 provisionally resistant cases, 1 subject (6%) had persistent parasitemia at Day 3 and was considered as a direct treatment failure, 2 subjects (11%) had recurrent parasitemia by Day 7 and were considered early treatment failures, and 7 (39%) and 8 (44%) had recurrent parasitemia by Days 14 and 28, respectively. Analysis of blood for CQ+N-desethylchloroquine (DCQ) levels on day of recurrence from 15 of the 18 with treatment failures showed 11 subjects having CQ+DCQ blood levels ⩾ 100 ng/ml and 2 with CQ+DCQ blood levels < 100 ng/ml. The 28-day cumulative incidence of therapeutic failure likely due to parasite resistance was 17.5%. These findings affirm P. vivax resistance to CQ in eastern Indonesia, albeit at lower levels than reported elsewhere. This simple means of phenotyping P. vivax infections could be implemented in other malaria endemic areas of Indonesia. et al. 2011. A retrospective analysis of the haemodynamic and metabolic effects of fluid resuscitation in vietnamese adults with severe falciparum malaria PLoS ONE, 6 (10), | Citations: 9 (Scopus) | Show Abstract | Read more Background: Optimising the fluid resuscitation of patients with severe malaria is a simple and potentially cost-effective intervention. Current WHO guidelines recommend central venous pressure (CVP) guided, crystalloid based, resuscitation in adults. Methods: Prospectively collected haemodynamic data from intervention trials in Vietnamese adults with severe malaria were analysed retrospectively to assess the responses to fluid resuscitation. Results: 43 patients were studied of whom 24 received a fluid load. The fluid load resulted in an increase in cardiac index (mean increase: 0.75 L/min/m 2 (95% Confidence interval (CI): 0.41 to 1.1)), but no significant change in acid-base status post resuscitation (mean increase base deficit 0.6 mmol/L (95% CI: -0.1 to 1.3). The CVP and PAoP (pulmonary artery occlusion pressure) were highly inter-correlated (r s = 0.7, p & 0.0001), but neither were correlated with acid-base status (arterial pH, serum bicarbonate, base deficit) or respiratory status (PaO 2 /FiO 2 ratio). There was no correlation between the oxygen delivery (DO 2 ) and base deficit at the 63 time-points where they were assessed simultaneously (r s =-0.09, p=0.46). Conclusions: In adults with severe falciparum malaria there was no observed improvement in patient outcomes or acid-base status with fluid loading. Neither CVP nor PAoP correlated with markers of end-organ perfusion or respiratory status, suggesting these measures are poor predictors of their fluid resuscitation needs. © 2011 Phu et al. . 2011. Snake bite: a neglected problem in twenty-first century India. Natl Med J India, 24 (6), pp. 321-324. | Citations: 9 (Web of Science Lite) et al. 2011. Impact of educational intervention concerning awareness and behaviors relating to avian influenza (H5N1) in a high-risk population in Vietnam. PLoS One, 6 (8), pp. e23711. | Show Abstract | Read more BACKGROUND: Early initiation of treatment is essential for treatment of avian influenza A/H5N1 viral infection in humans, as the disease can lead to rapid development of severe pneumonia which can result in death. Contact with infected poultry is known to be a significant risk factor for contraction of H5N1 infection. However, handling and encountering poultry are a part of most peoples' daily lives, especially in rural communities in Vietnam where epidemic outbreaks among poultry have been continuously reported. Enhancing proper knowledge relating to H5N1 and to the importance of early initiation of treatment are crucial. The aim of this study was to develop an effective educational program to enhance awareness of H5N1 and motivate people to access to health care earlier when H5N1 infection is suspected or likely. METHODOLOGY AND PRINCIPAL FINDINGS: A study was conducted in two agricultural communities (intervention and control groups) in the Ninh Binh province in Vietnam, where epidemic outbreaks of avian influenza have recently occurred in birds. A unique educational intervention was developed and provided to the intervention group, and no intervention was provided to the control group. A knowledge, attitude and practice (KAP) survey was conducted in both groups with a face-to-face interview by trained local healthcare workers at time points before and after the educational intervention. KAP scores were compared between the different time points and between the groups. How educational intervention influenced awareness relating to H5N1 and accessibility of healthcare in the population was analyzed. The study indicated an increased awareness of H5N1 and increased reliance on local health care workers. CONCLUSIONS: The novel educational program which was developed for this study impacted awareness of H5N1, and resulted in more people seeking early access to healthcare, and also resulted in earlier medical intervention for patients with H5N1 avian influenza infection in Vietnam. et al. 2011. Combined high-resolution genotyping and geospatial analysis reveals modes of endemic urban typhoid fever transmission. Open Biol, 1 (2), pp. 110008. | Citations: 43 (Scopus) | Show Abstract | Read more Typhoid is a systemic infection caused by Salmonella Typhi and Salmonella Paratyphi A, human-restricted bacteria that are transmitted faeco-orally. Salmonella Typhi and S. Paratyphi A are clonal, and their limited genetic diversity has precluded the identification of long-term transmission networks in areas with a high disease burden. To improve our understanding of typhoid transmission we have taken a novel approach, performing a longitudinal spatial case-control study for typhoid in Nepal, combining single-nucleotide polymorphism genotyping and case localization via global positioning. We show extensive clustering of typhoid occurring independent of population size and density. For the first time, we demonstrate an extensive range of genotypes existing within typhoid clusters, and even within individual households, including some resulting from clonal expansion. Furthermore, although the data provide evidence for direct human-to-human transmission, we demonstrate an overwhelming contribution of indirect transmission, potentially via contaminated water. Consistent with this, we detected S. Typhi and S. Paratyphi A in water supplies and found that typhoid was spatially associated with public water sources and low elevation. These findings have implications for typhoid-control strategies, and our innovative approach may be applied to other diseases caused by other monophyletic or emerging pathogens. . 2011. “Ten commandments” for the appropriate use of antibiotics by the practicing physician in an outpatient setting Frontiers in Microbiology, 2 (NOV), | Citations: 11 (Scopus) | Show Abstract | Read more A multi-national working group on antibiotic stewardship, from the International Society of Chemotherapy, put together ten recommendations to physicians prescribing antibiotics to outpatients. These recommendations are: (1) use antibiotics only when needed; teach the patient how to manage symptoms of non-bacterial infections; (2) select the adequate ATB; precise targeting is better than shotgun therapy; (3) consider pharmacokinetics and phar-macodynamics when selecting an ATB; use the shortest ATB course that has proven clinical efficacy; (4) encourage patients' compliance; (5) use antibiotic combinations only in specific situations; (6) avoid low quality and sub-standard drugs; prevent prescription changes at the drugstore; (7) discourage self-prescription; (8) follow only evidence-based guidelines; beware those sponsored by drug companies; (9) rely (rationally) upon the clinical microbiology lab; and (10) prescribe ATB empirically - but intelligently; know local susceptibility trends, and also surveillance limitations. © 2011 Lev-Hara, Amábile-Cuevas, Gould, Hutchinson, Abbo, Saxynger, Vlieghe, Cardoso, Methar, Kanj, Ohmagari, HarbarthandISC-ASW Group. . 2011. Temporal association of acute hepatitis A and Plasmodium falciparum malaria in children. PLoS One, 6 (7), pp. e21013. | Citations: 3 (Scopus) | Show Abstract | Read more BACKGROUND: In sub-Saharan Africa, Plasmodium falciparum and hepatitis A (HAV) infections are common, especially in children. Co-infections with these two pathogens may therefore occur, but it is unknown if temporal clustering exists. MATERIALS AND METHODS: We studied the pattern of co-infection of P. falciparum malaria and acute HAV in Kenyan children under the age of 5 years in a cohort of children presenting with uncomplicated P. falciparum malaria. HAV status was determined during a 3-month follow-up period. DISCUSSION: Among 222 cases of uncomplicated malaria, 10 patients were anti-HAV IgM positive. The incidence of HAV infections during P. falciparum malaria was 1.7 (95% CI 0.81-3.1) infections/person-year while the cumulative incidence of HAV over the 3-month follow-up period was 0.27 (95% CI 0.14-0.50) infections/person-year. Children with or without HAV co-infections had similar mean P. falciparum asexual parasite densities at presentation (31,000/µL vs. 34,000/µL, respectively), largely exceeding the pyrogenic threshold of 2,500 parasites/µL in this population and minimizing risk of over-diagnosis of malaria as an explanation. CONCLUSION: The observed temporal association between acute HAV and P. falciparum malaria suggests that co-infections of these two hepatotrophic human pathogens may result from changes in host susceptibility. Testing this hypothesis will require larger prospective studies. . 2011. "Venomous" Bites from Non-Venomous Snakes "Venomous" Bites from Non-Venomous Snakes, | Citations: 24 (Scopus) | Show Abstract This book is the first significant contribution to thoroughly examine the potential hazards associated with snakes of the former family, Colubridae. This family contained >65% of living snake species (approximately 3,000 taxa) and has recently been split into multiple families. Many of these snakes produce oral secretions that contain toxins and other biologically-active substances. A large variety of these snakes figure in the pet industry, yet little documented information or formal study of their potential medical importance has been published. Therefore, although the possible medical importance of many of these species has been subjected to speculation since the mid-nineteenth century, there is a limited amount of useful descriptive information regarding the real hazard (or lack thereof) of snakes belonging to this diverse, artificial family. There is a need for "one-stop shopping" offering information regarding their possible toxicity and clinical relevance as well as recommendations for medical management of their bites. This book is the first synthesis of this information and includes evidence-based risk assessment, hazard rankings and specific recommendations regarding important species, many common in captivity. Fills a gap in the toxinological, medical and herpetological literature by providing a comprehensive review of this entire assemblage of snakes, with particular attention given to their capacity, real or rumored, to cause harm to humans A patient-centered, evidence-based approach is applied to analyzing documented case reports of bites inflicted by approximately 100 species. Clinical management of medically significant bites from non-front-fanged colubroids is methodically reviewed, and specific recommendations are provided. © 2011 Elsevier Inc. All rights reserved. . 2011. The case for reactive mass oral cholera vaccinations. PLoS Negl Trop Dis, 5 (1), pp. e952. | Citations: 43 (Scopus) | Show Abstract | Read more INTRODUCTION: The outbreak of cholera in Zimbabwe intensified interest in the control and prevention of cholera. While there is agreement that safe water, sanitation, and personal hygiene are ideal for the long term control of cholera, there is controversy about the role of newer approaches such as oral cholera vaccines (OCVs). In October 2009 the Strategic Advisory Group of Experts advised the World Health Organization to consider reactive vaccination campaigns in response to large cholera outbreaks. To evaluate the potential benefit of this pivotal change in WHO policy, we used existing data from cholera outbreaks to simulate the number of cholera cases preventable by reactive mass vaccination. METHODS: Datasets of cholera outbreaks from three sites with varying cholera endemicity--Zimbabwe, Kolkata (India), and Zanzibar (Tanzania)--were analysed to estimate the number of cholera cases preventable under differing response times, vaccine coverage, and vaccine doses. FINDINGS: The large cholera outbreak in Zimbabwe started in mid August 2008 and by July 2009, 98,591 cholera cases had been reported with 4,288 deaths attributed to cholera. If a rapid response had taken place and half of the population had been vaccinated once the first 400 cases had occurred, as many as 34,900 (40%) cholera cases and 1,695 deaths (40%) could have been prevented. In the sites with endemic cholera, Kolkata and Zanzibar, a significant number of cases could have been prevented but the impact would have been less dramatic. A brisk response is required for outbreaks with the majority of cases occurring during the early weeks. Even a delayed response can save a substantial number of cases and deaths in long, drawn-out outbreaks. If circumstances prevent a rapid response there are good reasons to roll out cholera mass vaccination campaigns well into the outbreak. Once a substantial proportion of a population is vaccinated, outbreaks in subsequent years may be reduced if not prevented. A single dose vaccine would be of advantage in short, small outbreaks. CONCLUSIONS: We show that reactive vaccine use can prevent cholera cases and is a rational response to cholera outbreaks in endemic and non-endemic settings. In large and long outbreaks a reactive vaccination with a two-dose vaccine can prevent a substantial proportion of cases. To make mass vaccination campaigns successful, it would be essential to agree when to implement reactive vaccination campaigns and to have a dynamic and determined response team that is familiar with the logistic challenges on standby. Most importantly, the decision makers in donor and recipient countries have to be convinced of the benefit of reactive cholera vaccinations. . 2011. CMV retinitis screening and treatment in a resource-poor setting: three-year experience from a primary care HIV/AIDS programme in Myanmar. J Int AIDS Soc, 14 (1), pp. 41. | Citations: 17 (Scopus) | Show Abstract | Read more BACKGROUND: Cytomegalovirus retinitis is a neglected disease in resource-poor settings, in part because of the perceived complexity of care and because ophthalmologists are rarely accessible. In this paper, we describe a pilot programme of CMV retinitis management by non-ophthalmologists. The programme consists of systematic screening of all high-risk patients (CD4 <100 cells/mm3) by AIDS clinicians using indirect ophthalmoscopy, and treatment of all patients with active retinitis by intravitreal injection of ganciclovir. Prior to this programme, CMV retinitis was not routinely examined for, or treated, in Myanmar. METHODS: This is a retrospective descriptive study. Between November 2006 and July 2009, 17 primary care AIDS clinicians were trained in indirect ophthalmoscopy and diagnosis of CMV retinitis; eight were also trained in intravitreal injection. Evaluation of training by a variety of methods documented high clinical competence. Systematic screening of all high-risk patients (CD4 <100 cells/mm3) was carried out at five separate AIDS clinics throughout Myanmar. RESULTS: A total of 891 new patients (1782 eyes) were screened in the primary area (Yangon); the majority of patients were male (64.3%), median age was 32 years, and median CD4 cell count was 38 cells/mm3. CMV retinitis was diagnosed in 24% (211/891) of these patients. Bilateral disease was present in 36% of patients. Patients with active retinitis were treated with weekly intravitreal injection of ganciclovir, with patients typically receiving five to seven injections per eye. A total of 1296 injections were administered. CONCLUSIONS: A strategy of management of CMV retinitis at the primary care level is feasible in resource-poor settings. With appropriate training and support, CMV retinitis can be diagnosed and treated by AIDS clinicians (non-ophthalmologists), just like other major opportunistic infections. et al. 2011. Measurement of the diffractive longitudinal structure functionF_{L}^{D}\$ at HERA The European Physical Journal C, 71 (12), | Show Abstract | Read more

© The Author(s) 2011. First measurements are presented of the diffrac-tive cross section σ < inf > ep→e < /inf > XY at centre-of-mass energies √s of 225 and 252 GeV, together with a precise new measurement at √s of 319 GeV, using data taken with the H1 detector in the years 2006 and 2007. Together with previous H1 data at √s of 301 GeV, the measurements are used to extract the diffractive longitudinal structure function FD in the range of photon virtualities 4.0 < Q < sup > 2 < /sup > < 44.0 GeV < sup > 2 < /sup > and fractional proton longitudinal momentum loss 5 x 10- < sup > 4 < /sup > ≤xp ≤ 3×10 < sup > −3 < /sup > . The measured F < sup > D < /sup > < inf > L < /inf > is compared with leading twist predictions based on diffractive parton densities extracted in NLO QCD fits to previous measurements of diffractive Deep-Inelastic Scattering and with a model which additionally includes a higher twist contribution derived from a colour dipole approach. The ratio of the diffractive cross section induced by longitudinally polarised photons to that for transversely polarised photons is extracted and compared with the analogous quantity for inclusive Deep-Inelastic Scattering.

. 2011. TparvaDB: a database to support Theileria parva vaccine development. Database (Oxford), 2011 pp. bar015. | Show Abstract | Read more

We describe the development of TparvaDB, a comprehensive resource to facilitate research towards development of an East Coast fever vaccine, by providing an integrated user-friendly database of all genome and related data currently available for Theileria parva. TparvaDB is based on the Generic Model Organism Database (GMOD) platform. It contains a complete reference genome sequence, Expressed Sequence Tags (ESTs), Massively Parallel Signature Sequencing (MPSS) expression tag data and related information from both public and private repositories. The Artemis annotation workbench provides online annotation functionality. TparvaDB represents a resource that will underpin and promote ongoing East Coast fever vaccine development and biological research. Database URL: http://tparvadb.ilri.cgiar.org.

et al. 2011. The epidemiology of human papillomavirus infection in HIV-positive and HIV-negative high-risk women in Kigali, Rwanda. BMC Infect Dis, 11 (1), pp. 333. | Citations: 21 (Scopus) | Show Abstract | Read more

BACKGROUND: The prevalence, incidence and persistence of human papillomavirus (HPV) types in sub-Saharan Africa are not well established. The objectives of the current study are to describe (predictors of) the epidemiology of HPV among high-risk women in Kigali, Rwanda. METHODS: HIV-negative, high-risk women were seen quarterly for one year, and once in Year 2. HIV serostatus, clinical, and behavioral information were assessed at each visit, HPV types at Month 6 and Year 2, and other sexually transmitted infections (STI) at selected visits. HPV prevalence was also assessed in HIV-positive, high-risk women. RESULTS: Prevalence of any HPV was 47.0% in HIV-negative women (median age 25 years) compared to 72.2% in HIV-positive women (median age 27 years; OR 2.9, 95% CI 1.9-4.6). Among HIV-negative women, cumulative incidence of high-risk (HR)-HPV was 28.0% and persistence 32.0% after a mean period of 16.6 and 16.9 months, respectively. Prior Chlamydia trachomatis and Neisseria gonorrhoeae infection, concurrent low-risk (LR)-HPV infection and incident HSV-2 were associated with HR-HPV prevalence among HIV-negative women; prior C. trachomatis infection and co-infection with LR-HPV and HPV16-related HPV types with HR-HPV acquisition. HPV16-related types were the most prevalent and persistent. CONCLUSIONS: High HPV prevalence, incidence and persistence were found among high-risk women in Kigali. HPV52 had the highest incidence; and, together with HPV33 and HPV58, were strongly associated with acquisition of other HR-HPV types in HIV-negative women.

. 2011. Prevalence of Gram-negative bacilli resistance in adult critically ill patients at admission screening Critical Care, 15 (Suppl 1), pp. P225-P225. | Read more

et al. 2011. The presence of leukocytes in ex vivo assays significantly increases the 50-percent inhibitory concentrations of artesunate and chloroquine against Plasmodium vivax and Plasmodium falciparum. Antimicrob Agents Chemother, 55 (3), pp. 1300-1304. | Citations: 8 (Scopus) | Show Abstract | Read more

Plasmodium species ex vivo sensitivity assay protocols differ in the requirement for leukocyte removal before culturing. This study shows that the presence of leukocytes significantly increases the 50% inhibitory concentration (IC₅₀) of P. vivax and P. falciparum to artesunate and chloroquine relative to results with the paired leukocyte-free treatment. Although leukocyte removal is not an essential requirement for the conduct of ex vivo assays, its use has important implications for the interpretation of temporal and spatial antimalarial sensitivity data.

et al. 2011. Intrahost modeling of artemisinin resistance in Plasmodium falciparum. Proc Natl Acad Sci U S A, 108 (1), pp. 397-402. | Citations: 86 (Scopus) | Show Abstract | Read more

Artemisinin-resistant Plasmodium falciparum malaria has emerged in western Cambodia. Resistance is characterized by prolonged in vivo parasite clearance times (PCTs) following artesunate treatment. The biological basis is unclear. The hypothesis that delayed parasite clearance results from a stage-specific reduction in artemisinin sensitivity of the circulating young asexual parasite ring stages was examined. A mathematical model was developed, describing the intrahost parasite stage-specific pharmacokinetic-pharmacodynamic relationships. Model parameters were estimated using detailed pharmacokinetic and parasite clearance data from 39 patients with uncomplicated falciparum malaria treated with artesunate from Pailin (western Cambodia) where artemisinin resistance was evident and 40 patients from Wang Pha (northwestern Thailand) where efficacy was preserved. The mathematical model reproduced the observed parasite clearance for each patient with an accurate goodness of fit (rmsd: 0.03-0.67 in log(10) scale). The parameter sets that provided the best fits with the observed in vivo data consist of a highly conserved concentration-effect relationship for the trophozoite and schizont parasite stages, but a variable relationship for the ring stages. The model-derived assessment suggests that the efficacy of artesunate on ring stage parasites is reduced significantly in Pailin. This result supports the hypothesis that artemisinin resistance mainly reflects reduced ring-stage susceptibility and predicts that doubling the frequency of dosing will accelerate clearance of artemisinin-resistant parasites.

et al. 2011. Most cases of cryptococcal meningitis in HIV-uninfected patients in Vietnam are due to a distinct amplified fragment length polymorphism-defined cluster of Cryptococcus neoformans var. grubii VN1. J Clin Microbiol, 49 (2), pp. 658-664. | Citations: 17 (Web of Science Lite) | Show Abstract | Read more

Cryptococcal disease most commonly occurs in patients with an underlying immune deficit, most commonly HIV infection, and is due to Cryptococcus neoformans var. grubii. Occasionally disease due to this variety occurs in apparently immunocompetent patients. The relationship between strains infecting immunosuppressed and immunocompetent patients is not clear. Amplified fragment length polymorphism (AFLP) analysis was used to characterize the relationship between strains infecting HIV-infected and uninfected patients. Isolates from 51 HIV-uninfected patients and 100 HIV-infected patients with cryptococcal meningitis were compared. C. neoformans var. grubii VNI was responsible for infections in 73% of HIV-uninfected and 100% of HIV-infected patients. AFLP analysis defined two distinct clusters, VNIγ and VNIδ. The majority (84%) of isolates from HIV-uninfected patients were VNIγ, compared with only 38% of isolates from HIV-infected patients (odds ratio, 8.30; 95% confidence interval [CI], 3.04 to 26.6; P < 0.0001). In HIV-uninfected patients, underlying disease was less frequent in those with VNIγ infections. Two clusters of C. neoformans var. grubii VN1 are responsible for the majority of cases of cryptococcal meningitis in Vietnam. The distribution of these clusters differs according to the immune status of the host.

. 2011. Ex vivo activity of histone deacetylase inhibitors against multidrug-resistant clinical isolates of Plasmodium falciparum and P. vivax. Antimicrob Agents Chemother, 55 (3), pp. 961-966. | Citations: 29 (Scopus) | Show Abstract | Read more

Histone acetylation plays an important role in regulating gene transcription and silencing in Plasmodium falciparum. Histone deacetylase (HDAC) inhibitors, particularly those of the hydroxamate class, have been shown to have potent in vitro activity against drug-resistant and -sensitive laboratory strains of P. falciparum, raising their potential as a new class of antimalarial compounds. In the current study, stage-specific ex vivo susceptibility profiles of representative hydroxamate-based HDAC inhibitors suberoylanilide hydroxamic acid (SAHA), 2-ASA-9, and 2-ASA-14 (2-ASA-9 and 2-ASA-14 are 2-aminosuberic acid-based HDAC inhibitors) were assessed in multidrug-resistant clinical isolates of P. falciparum (n = 24) and P. vivax (n = 25) from Papua, Indonesia, using a modified schizont maturation assay. Submicromolar concentrations of SAHA, 2-ASA-9, and 2-ASA-14 inhibited the growth of both P. falciparum (median 50% inhibitory concentrations [IC₅₀s] of 310, 533, and 266 nM) and P. vivax (median IC₅₀s of 170, 503, and 278 nM). Inverse correlation patterns between HDAC inhibitors and chloroquine for P. falciparum and mefloquine for P. vivax indicate species-specific susceptibility profiles for HDAC inhibitors. These HDAC inhibitors were also found to be potent ex vivo against P. vivax schizont maturation, comparable to that in P. falciparum, suggesting that HDAC inhibitors may be promising candidates for antimalarial therapy in geographical locations where both species are endemic. Further studies optimizing the selectivity and in vivo efficacy of HDAC inhibitors in Plasmodium spp. and defining drug interaction with common antimalarial compounds are warranted to investigate the role of HDAC inhibitors in antimalarial therapy.

. 2011. Hypopituitarism following envenoming by Russell's vipers (Daboia siamensis and D. russelii) resembling Sheehan's syndrome: first case report from Sri Lanka, a review of the literature and recommendations for endocrine management. QJM, 104 (2), pp. 97-108. | Citations: 27 (Scopus) | Show Abstract | Read more

Russell's vipers (Daboia russelii and D. siamensis) inhabit 10 South and South East Asian countries. People envenomed by these snakes suffer coagulopathy, bleeding, shock, neurotoxicity, acute kidney injury and local tissue damage leading to severe morbidity and mortality. An unusual complication of Russell's viper bite envenoming in Burma (D. siamensis) and southern India (D. russelii) is hypopituitarism but until now it has not been reported elsewhere. Here, we describe the first case of hypopituitarism following Russell's viper bite in Sri Lanka, review the literature on this subject and make recommendations for endocrine investigation and management. A 49-year-old man was bitten and seriously envenomed by D. russelii in 2005. He was treated with antivenom but although he recovered from the acute effects he remained feeling unwell. Hypopituitarism, with deficiencies of gonadal, steroid and thyroid axes, was diagnosed 3 years later. He showed marked improvement after replacement of anterior pituitary hormones. We attribute his hypopituitarism to D. russelii envenoming. Russell's viper bite is known to cause acute and chronic hypopituitarism and diabetes insipidus, perhaps through deposition of fibrin microthrombi and haemorrhage in the pituitary gland resulting from the action of venom procoagulant enzymes and haemorrhagins. Forty nine cases of hypopituitarism following Russell's viper bite have been described in the English language literature. Patients with acute hypopituitarism may present with hypoglycaemia and hypotension during the acute phase of envenoming. Those with chronic hypopituitarism seem to have recovered from envenoming but present later with features of hypopituitarism. Over 85% of these patients had suffered acute kidney injury immediately after the bite. Steroid replacement in acute hypopituitarism is life saving. All 11 patients with chronic hypopituitarism in whom the outcome of treatment was reported, showed marked improvement with hormone replacement. Unrecognized acute hypopituitarism is potentially fatal while chronic hypopituitarism can be debilitating. Physicians should therefore be aware of this complication of severe envenoming by Russell's vipers, especially in Burma and South India, so that the diagnosis may be made without delay and replacement started with essential hormones such as hydrocortisone and thyroxine.

. 2011. Susceptibility of community-acquired pathogens to antibiotics in Africa and Asia in neonates--an alarmingly short review. Trop Med Int Health, 16 (2), pp. 145-151. | Citations: 20 (Scopus) | Show Abstract | Read more

OBJECTIVE: To assess the susceptibility of community-acquired pathogens in neonatal sepsis to commonly prescribed antibiotics in sub-Saharan Africa and Asia since 2002. METHODS: Literature review in PubMed and Embase. Susceptibility was estimated for pathogens individually and stratified by region. Isolates were also classified into Gram positive and Gram negative pathogens to estimate their pooled susceptibility. RESULTS AND CONCLUSIONS: Only nine studies met the inclusion criteria. The available data indicated poor susceptibility to almost all commonly used antibiotics in pathogens such as Staphylococcus aureus and Klebsiella spp. Only Streptococcus pneumoniae exhibited good susceptibility to all drugs other than cotrimoxazole. The extreme scarcity of data prevents drawing any firm conclusions beyond the urgent need for more studies to identify the best treatments for neonatal sepsis in the developing world.

. 2011. Randomized soil survey of the distribution of Burkholderia pseudomallei in rice fields in Laos. Appl Environ Microbiol, 77 (2), pp. 532-536. | Citations: 23 (Scopus) | Show Abstract | Read more

Melioidosis is a major cause of morbidity and mortality in Southeast Asia, where the causative organism (Burkholderia pseudomallei) is present in the soil. In the Lao People's Democratic Republic (Laos), B. pseudomallei is a significant cause of sepsis around the capital, Vientiane, and has been isolated in soil near the city, adjacent to the Mekong River. We explored whether B. pseudomallei occurs in Lao soil distant from the Mekong River, drawing three axes across northwest, northeast, and southern Laos to create nine sampling areas in six provinces. Within each sampling area, a random rice field site containing a grid of 100 sampling points each 5 m apart was selected. Soil was obtained from a depth of 30 cm and cultured for B. pseudomallei. Four of nine sites (44%) were positive for B. pseudomallei, including all three sites in Saravane Province, southern Laos. The highest isolation frequency was in east Saravane, where 94% of soil samples were B. pseudomallei positive with a geometric mean concentration of 464 CFU/g soil (95% confidence interval, 372 to 579 CFU/g soil; range, 25 to 10,850 CFU/g soil). At one site in northwest Laos (Luangnamtha), only one sample (1%) was positive for B. pseudomallei, at a concentration of 80 CFU/g soil. Therefore, B. pseudomallei occurs in Lao soils beyond the immediate vicinity of the Mekong River, alerting physicians to the likelihood of melioidosis in these areas. Further studies are needed to investigate potential climatic, soil, and biological determinants of this heterogeneity.

. 2011. A prospective evaluation of diagnostic methodologies for the acute diagnosis of dengue virus infection on the Thailand-Myanmar border. Trans R Soc Trop Med Hyg, 105 (1), pp. 32-37. | Citations: 18 (Web of Science Lite) | Show Abstract | Read more

Clinically useful diagnostic tests of dengue virus infection are lacking. We prospectively evaluated the performance of real-time reverse transcriptase (rRT)-PCR, NS-1 antigen and IgM antibody tests to confirm dengue virus infection in acute blood specimens from 162 patients presenting with undifferentiated febrile illness compatible with dengue infection. rRT-PCR was the most sensitive test (89%) and potentially could be used as a single test for confirmation of dengue infection. NS-1 antigen and IgM antibody were not sufficiently sensitive to be used as a single confirmatory test with sensitivities of 54% and 17% respectively. The specificities of rRT-PCR, NS-1 antigen and IgM antibody tests were 96%, 100% and 88% respectively. Combining NS-1 and rRT-PCR or the combination of all three tests resulted in the highest sensitivity (93%) but specificities dropped to 96% and 83% respectively. We conclude that at least the combination of two tests, either agent detection (rRT-PCR) or antigen detection (NS-1) plus IgM antibody detection should be used for laboratory confirmation of dengue infection.

et al. 2011. An in-depth analysis of original antigenic sin in dengue virus infection. J Virol, 85 (1), pp. 410-421. | Citations: 91 (Web of Science Lite) | Show Abstract | Read more

The evolution of dengue viruses has resulted in four antigenically similar yet distinct serotypes. Infection with one serotype likely elicits lifelong immunity to that serotype, but generally not against the other three. Secondary or sequential infections are common, as multiple viral serotypes frequently cocirculate. Dengue infection, although frequently mild, can lead to dengue hemorrhagic fever (DHF) which can be life threatening. DHF is more common in secondary dengue infections, implying a role for the adaptive immune response in the disease. There is currently much effort toward the design and implementation of a dengue vaccine but these efforts are made more difficult by the challenge of inducing durable neutralizing immunity to all four viruses. Domain 3 of the dengue virus envelope protein (ED3) has been suggested as one such candidate because it contains neutralizing epitopes and it was originally thought that relatively few cross-reactive antibodies are directed to this domain. In this study, we performed a detailed analysis of the anti-ED3 response in a cohort of patients suffering either primary or secondary dengue infections. The results show dramatic evidence of original antigenic sin in secondary infections both in terms of binding and enhancement activity. This has important implications for dengue vaccine design because heterologous boosting is likely to maintain the immunological footprint of the first vaccination. On the basis of these findings, we propose a simple in vitro enzyme-linked immunosorbent assay (ELISA) to diagnose the original dengue infection in secondary dengue cases.

. 2011. Common filaggrin null alleles are not associated with hymenoptera venom allergy in Europeans. Int Arch Allergy Immunol, 154 (4), pp. 353-355. | Citations: 5 (Scopus) | Show Abstract | Read more

The association of filaggrin mutations with atopic eczema (atopic dermatitis, AD) is well established and it is thought that filaggrin dysfunction impairs the skin's barrier function allowing allergen penetration and subsequent cutaneous sensitisation and inflammation. However, as most forms of barrier dysfunction are not associated with allergic sensitisation to common allergens, the possibility that filaggrin itself is involved in Th1/Th2 polarisation remains. We tested the hypothesis that allergen delivered to the skin independently of the stratum corneum is not associated with filaggrin mutations. Wasp stings bypass the stratum corneum and deliver antigen to the dermis. We found that European individuals with AD (n = 32) have an increased frequency of the 2 commonest filaggrin null mutations (R501X and 2282del4) compared to those with vespid allergy (n = 56) and healthy controls (n = 30). Thus, filaggrin does not appear to have a downstream effect on the development of allergic disease, and it is indeed filaggrin's role in the epithelial function that is likely to determine the link between filaggrin mutations and allergic sensitisation.

et al. 2011. Predictive diagnostic value of the tourniquet test for the diagnosis of dengue infection in adults. Trop Med Int Health, 16 (1), pp. 127-133. | Citations: 25 (Scopus) | Show Abstract | Read more

OBJECTIVE: To examine the accuracy of the admission tourniquet test in the diagnosis of dengue infection among Lao adults. METHODS: Prospective assessment of the predictive diagnostic value of the tourniquet test for the diagnosis of dengue infection, as defined by IgM, IgG and NS1 ELISAs (Panbio Ltd, Australia), among Lao adult inpatients with clinically suspected dengue infection. RESULTS: Of 234 patients with clinically suspected dengue infection on admission, 73% were serologically confirmed to have dengue, while 64 patients with negative dengue serology were diagnosed as having scrub typhus (39%), murine typhus (11%), undetermined typhus (12%), Japanese encephalitis virus (5%), undetermined flavivirus (5%) and typhoid fever (3%); 25% had no identifiable aetiology. The tourniquet test was positive in 29.1% (95% CI = 23.2-34.9%) of all patients and in 34.1% (95% CI = 27.0-41.2%) of dengue-seropositive patients, in 32.7% (95% CI = 23.5-41.8) of those with dengue fever and in 36.4% (95% CI = 24.7-48.0) of those with dengue haemorrhagic fever. Interobserver agreement for the tourniquet test was 90.2% (95% CI = 86.4-94.0) (Kappa = 0.76). Using ELISAs as the diagnostic gold standard, the sensitivity of the tourniquet test was 33.5-34%; its specificity was 84-91%. The positive and negative predictive values were 85-90% and 32.5-34%, respectively. CONCLUSIONS: The admission tourniquet test has low sensitivity and adds relatively little value to the diagnosis of dengue among Lao adult inpatients with suspected dengue. Although a positive tourniquet test suggests dengue and that treatment of alternative diagnoses may not be needed, a negative test result does not exclude dengue.

et al. 2011. In vivo and in vitro efficacy of chloroquine against Plasmodium malariae and P. ovale in Papua, Indonesia. Antimicrob Agents Chemother, 55 (1), pp. 197-202. | Citations: 14 (Scopus) | Show Abstract | Read more

Reports of potential drug-resistant strains of Plasmodium malariae in western Indonesia raise concerns that chloroquine resistance may be emerging in P. malariae and P. ovale. In order to assess this, in vivo and in vitro efficacy studies were conducted in patients with monoinfection in Papua, Indonesia. Consecutive patients with uncomplicated malaria due to P. ovale or P. malariae were enrolled in a prospective clinical trial, provided with supervised chloroquine treatment, and followed for 28 days. Blood from patients with P. malariae or P. ovale parasitemia greater than 1,000 per microliter underwent in vitro antimalarial drug susceptibility testing using a modified schizont maturation assay. Of the 57 evaluable patients in the clinical study (P. malariae, n = 46; P. ovale, n = 11), none had recurrence with the same species during follow-up. The mean parasite reduction ratio at 48 h was 86 (95% confidence interval [CI], 57 to 114) for P. malariae and 150 (95% CI, 54 to 245) for P. ovale (P = 0.18). One patient infected with P. malariae, with 93% of parasites at the trophozoite stage, was still parasitemic on day 4. In vitro drug susceptibility assays were carried out successfully for 40 isolates (34 infected with P. malariae and 6 with P. ovale). The P. malariae infections at trophozoite stages had significantly higher chloroquine 50% effective concentrations (EC(50)s) (median, 127.9 nM [range, 7.9 to 2,980]) than those initially exposed at the ring stage (median, 14.0 nM [range, 3.5 to 27.0]; P = 0.01). The EC(50) for chloroquine in P. ovale was also higher in an isolate initially at the trophozoite stage (23.2 nM) than in the three isolates predominantly at ring stage (7.8 nM). Chloroquine retains adequate efficacy against P. ovale and P. malariae, but its marked stage specificity of action may account for reports of delayed parasite clearance times.

et al. 2011. Virological and molecular epidemiological investigations into the role of wild birds in the epidemiology of influenza A/H5N1 in central Thailand. Vet Microbiol, 148 (2-4), pp. 213-218. | Citations: 5 (Web of Science Lite) | Show Abstract | Read more

A serological and virological surveillance program to investigate the HPAI H5N1 virus in wild bird populations was undertaken from February 2007 to October 2008. The purpose of the survey was to investigate the infection status in free ranging wild birds in Banglane district, Nakhon Pathom province, central Thailand. Samples from wild birds were collected every two months. Choanal and cloacal swabs, serum and tissue samples were collected from 421 birds comprising 44 species. Sero-prevalence of the virus tested by H5N1 serum neutralization test (using a H5N1 virus clade 1; A/chicken/Thailand/vsmu-3-BKK/2004) was 2.1% (8 out of 385 samples; 95% CI 0.7, 3.5). Species that were antibody positive included rock pigeons (Columba livia), Asian pied starling (Gracupica contra), spotted dove (Streptopelia chinensis), oriental magpie robin (Copsychus saularis), blue-tailed bee-eater (Merops philippinus), myna (Acridotheres spp.), and pond heron (Ardeola spp.). Prevalence by H5N1 virus isolation was 0.5% (2 out of 421 samples; 95% CI 0.0, 1.1); the two H5N1 virus-positive samples were from Asian pied starling (Gracupica contra) and white vented myna (Acridotheres grandis). Positive virological samples were collected in June 2007 while all positive serology samples were collected between May and August except for one sample collected in December 2007. No positive samples were collected in 2008. Molecular studies revealed that the wild bird H5N1 viruses were closely related to poultry viruses isolated in other parts of Thailand. However, there was no poultry H5N1 prevalence study performed in the study site during the time of this wild bird survey. Interpretation of source of virus isolates would include spill-over of H5N1 viruses from contaminated sources due to movement of domestic poultry and/or fomites from other areas; or infection of wild birds within the outbreak locations and then translocation by wild bird movement and interaction with wild birds inhabiting distant locations.

. 2011. Community and facility-level engagement in planning and budgeting for the government health sector--a district perspective from Kenya. Health Policy, 99 (3), pp. 234-243. | Citations: 15 (Web of Science Lite) | Show Abstract | Read more

Health systems reform processes have increasingly recognized the essential contribution of communities to the success of health programs and development activities in general. Here we examine the experience from Kilifi district in Kenya of implementing annual health sector planning guidelines that included community participation in problem identification, priority setting, and planning. We describe challenges in the implementation of national planning guidelines, how these were met, and how they influenced final plans and budgets. The broad-based community engagement envisaged in the guidelines did not take place due to the delay in roll out of the Ministry of Health-trained community health workers. Instead, community engagement was conducted through facility management committees, though in a minority of facilities, even such committees were not involved. Some overlap was found in the priorities highlighted by facility staff, committee members and national indicators, but there were also many additional issues raised by committee members and not by other groups. The engagement of the community through committees influenced target and priority setting, but the emphasis on national health indicators left many local priorities unaddressed by the final work plans. Moreover, it appears that the final impact on budgets allocated at district and facility level was limited. The experience in Kilifi highlights the feasibility of engaging the community in the health planning process, and the challenges of ensuring that this engagement feeds into consolidated plans and future implementation.