Tropical Medicine publications 2007

Garre FG, Zwinderman AH, Geskus RB, Sijpkens YWJ. 2007. A joint latent class changepoint model to improve the prediction of time to graft failure Journal of the Royal Statistical Society: Series A (Statistics in Society), pp. 071029094155005-???. | Citations: 18 (Scopus) | Show Abstract | Read more

The reciprocal of serum creatinine concentration, RC, is often used as a biomarker to monitor renal function. It has been observed that RC trajectories remain relatively stable after transplantation until a certain moment, when an irreversible decrease in the RC levels occurs. This decreasing trend commonly precedes failure of a graft. Two subsets of individuals can be distinguished according to their RC trajectories: a subset of individuals having stable RC levels and a subset of individuals who present an irrevocable decrease in their RC levels. To describe such data, the paper proposes a joint latent class model for longitudinal and survival data with two latent classes. RC trajectories within latent class one are modelled by an intercept-only random-effects model and RC trajectories within latent class two are modelled by a segmented random changepoint model. A Bayesian approach is used to fit this joint model to data from patients who had their first kidney transplantation in the Leiden University Medical Center between 1983 and 2002. The resulting model describes the kidney transplantation data very well and provides better predictions of the time to failure than other joint and survival models. © 2008 Royal Statistical Society.

Gething PW, Noor AM, Goodman CA, Gikandi PW, Hay SI, Sharif SK, Atkinson PM, Snow RW. 2007. Information for decision making from imperfect national data: tracking major changes in health care use in Kenya using geostatistics. BMC Med, 5 (1), pp. 37. | Citations: 18 (Scopus) | Show Abstract | Read more

BACKGROUND: Most Ministries of Health across Africa invest substantial resources in some form of health management information system (HMIS) to coordinate the routine acquisition and compilation of monthly treatment and attendance records from health facilities nationwide. Despite the expense of these systems, poor data coverage means they are rarely, if ever, used to generate reliable evidence for decision makers. One critical weakness across Africa is the current lack of capacity to effectively monitor patterns of service use through time so that the impacts of changes in policy or service delivery can be evaluated. Here, we present a new approach that, for the first time, allows national changes in health service use during a time of major health policy change to be tracked reliably using imperfect data from a national HMIS. METHODS: Monthly attendance records were obtained from the Kenyan HMIS for 1 271 government-run and 402 faith-based outpatient facilities nationwide between 1996 and 2004. A space-time geostatistical model was used to compensate for the large proportion of missing records caused by non-reporting health facilities, allowing robust estimation of monthly and annual use of services by outpatients during this period. RESULTS: We were able to reconstruct robust time series of mean levels of outpatient utilisation of health facilities at the national level and for all six major provinces in Kenya. These plots revealed reliably for the first time a period of steady nationwide decline in the use of health facilities in Kenya between 1996 and 2002, followed by a dramatic increase from 2003. This pattern was consistent across different causes of attendance and was observed independently in each province. CONCLUSION: The methodological approach presented can compensate for missing records in health information systems to provide robust estimates of national patterns of outpatient service use. This represents the first such use of HMIS data and contributes to the resurrection of these hugely expensive but underused systems as national monitoring tools. Applying this approach to Kenya has yielded output with immediate potential to enhance the capacity of decision makers in monitoring nationwide patterns of service use and assessing the impact of changes in health policy and service delivery.

Nosten F, White NJ. 2007. Artemisinin-based combination treatment of falciparum malaria. Am J Trop Med Hyg, 77 (6 Suppl), pp. 181-192. | Citations: 294 (Scopus) | Show Abstract

Artemisinin-based combination treatments (ACTs) are now generally accepted as the best treatments for uncomplicated falciparum malaria. They are rapidly and reliably effective. Efficacy is determined by the drug partnering the artemisinin derivative and, for artesunate-mefloquine, artemether-lumefantrine, and dihydroartemisinin-piperaquine, this usually exceeds 95%. Artesunate-sulfadoxine-pyrimethamine and artesunate-amodiaquine are effective in some areas, but in other areas resistance to the partner precludes their use. There is still uncertainty over the safety of artemisinin derivatives in the first trimester of pregnancy, when they should not be used unless there are no effective alternatives. Otherwise, except for occasional hypersensitivity reactions, the artemisinin derivatives are safe and remarkably well tolerated. The adverse effect profiles of the artemisinin-based combination treatments are determined by the partner drug. Most malaria endemic countries have now adopted artemisinin-based combination treatments as first-line treatment of falciparum malaria, but in most of these only a minority of the patients that need artemisinin-based combination treatments actually receive them.

Chau TT, Campbell JI, Galindo CM, Van Minh Hoang N, Diep TS, Nga TTT, Van Vinh Chau N, Tuan PQ, Page AL, Ochiai RL et al. 2007. Antimicrobial drug resistance of Salmonella enterica serovar typhi in asia and molecular mechanism of reduced susceptibility to the fluoroquinolones. Antimicrob Agents Chemother, 51 (12), pp. 4315-4323. | Citations: 126 (Scopus) | Show Abstract | Read more

This study describes the pattern and extent of drug resistance in 1,774 strains of Salmonella enterica serovar Typhi isolated across Asia between 1993 and 2005 and characterizes the molecular mechanisms underlying the reduced susceptibilities to fluoroquinolones of these strains. For 1,393 serovar Typhi strains collected in southern Vietnam, the proportion of multidrug resistance has remained high since 1993 (50% in 2004) and there was a dramatic increase in nalidixic acid resistance between 1993 (4%) and 2005 (97%). In a cross-sectional sample of 381 serovar Typhi strains from 8 Asian countries, Bangladesh, China, India, Indonesia, Laos, Nepal, Pakistan, and central Vietnam, collected in 2002 to 2004, various rates of multidrug resistance (16 to 37%) and nalidixic acid resistance (5 to 51%) were found. The eight Asian countries involved in this study are home to approximately 80% of the world's typhoid fever cases. These results document the scale of drug resistance across Asia. The Ser83-->Phe substitution in GyrA was the predominant alteration in serovar Typhi strains from Vietnam (117/127 isolates; 92.1%). No mutations in gyrB, parC, or parE were detected in 55 of these strains. In vitro time-kill experiments showed a reduction in the efficacy of ofloxacin against strains harboring a single-amino-acid substitution at codon 83 or 87 of GyrA; this effect was more marked against a strain with a double substitution. The 8-methoxy fluoroquinolone gatifloxacin showed rapid killing of serovar Typhi harboring both the single- and double-amino-acid substitutions.

Day N, Dondorp AM. 2007. The management of patients with severe malaria. Am J Trop Med Hyg, 77 (6 Suppl), pp. 29-35. | Citations: 52 (Scopus) | Show Abstract

Severe malaria is a global problem, claiming at least 1 million lives annually. Few adequately powered clinical studies have been directed at improving the management of severe malaria over the years, but this situation is slowly changing. The antimalarial treatment of severe disease is being transformed by the development and deployment of the water-soluble artemisinin derivative artesunate. Parenteral artesunate is now the treatment of choice in low-transmission areas and in the 2nd and 3rd trimesters of pregnancy, and research is underway into whether it should replace quinine as the treatment of choice in African children. Development of good manufacturing practice (GMP) formulations should make parenteral artesunate more widely available in the near future. The development of artesunate suppositories offers another exciting prospect, the ability to treat patients with severe disease in remote rural settings, delaying the evolution of disease and buying them time to reach a health care facility. No adjunctive therapy has been shown to improve the outcome of severe malaria, but most studies have been underpowered. Future trials of interventions shown to be promising in pilot studies should be large and adequately powered. This will require multi-center designs and necessitate close collaboration between groups, as well as agreement on the research agenda. We suggest a list of candidate interventions for debate.

Breman JG, Alilio MS, White NJ. 2007. Defining and defeating the intolerable burden of malaria III. Progress and perspectives - Objectives and Acknowledgements AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE, 77 (6), pp. I-II. | Citations: 1 (Web of Science Lite)

Breman JG, Alilio MS, White NJ. 2007. Defining and defeating the intolerable burden of malaria III. Progress and perspectives AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE, 77 (6), pp. VI-XI. | Citations: 12 (Web of Science Lite)

Price RN, Tjitra E, Guerra CA, Yeung S, White NJ, Anstey NM. 2007. Vivax malaria: Neglected and not benign AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE, 77 (6), pp. 79-87. | Citations: 492 (Web of Science Lite)

Brooker S, Akhwale W, Pullan R, Estambale B, Clarke SE, Snow RW, Hotez PJ. 2007. Epidemiology of plasmodium-helminth co-infection in Africa: populations at risk, potential impact on anemia, and prospects for combining control. Am J Trop Med Hyg, 77 (6 Suppl), pp. 88-98. | Citations: 181 (Scopus) | Show Abstract

Human co-infection with Plasmodium falciparum and helminths is ubiquitous throughout Africa, although its public health significance remains a topic for which there are many unknowns. In this review, we adopted an empirical approach to studying the geography and epidemiology of co-infection and associations between patterns of co-infection and hemoglobin in different age groups. Analysis highlights the extensive geographic overlap between P. falciparum and the major human helminth infections in Africa, with the population at coincident risk of infection greatest for hookworm. Age infection profiles indicate that school-age children are at the highest risk of co-infection, and re-analysis of existing data suggests that co-infection with P. falciparum and hookworm has an additive impact on hemoglobin, exacerbating anemia-related malarial disease burden. We suggest that both school-age children and pregnant women--groups which have the highest risk of anemia--would benefit from an integrated approach to malaria and helminth control.

Gwer S, Newton CRJC, Berkley JA. 2007. Over-diagnosis and co-morbidity of severe malaria in African children: a guide for clinicians. Am J Trop Med Hyg, 77 (6 Suppl), pp. 6-13. | Citations: 72 (Scopus) | Show Abstract

Severe malaria is clinically similar to other severe febrile illnesses. However, in endemic areas, parasitological confirmation of parasitemia is often unavailable or unreliable. False-positive malaria microscopy is common. The most important consequence of treating only for malaria when no parasitemia exists is failure to address other life-threatening conditions. Invasive bacterial infections are detected in up to one third of children with clinical features of severe malaria but a slide with results negative for malaria. Even among genuinely parasitized children, severe illness is not always due to malaria in endemic areas. We believe that routine use of parenteral antibiotics among children with a slide that indicates malaria and life-threatening disease is warranted because invasive bacterial infections are likely to be under-ascertained and are associated with increased mortality. Published data on co-morbidity with HIV infection and malnutrition are reviewed. A structured approach to assessment and care is essential, and is largely independent of underlying etiology.

Baker S, Holt K, Whitehead S, Goodhead I, Perkins T, Stocker B, Hardy J, Dougan G. 2007. A linear plasmid truncation induces unidirectional flagellar phase change in H:z66 positive Salmonella Typhi. Mol Microbiol, 66 (5), pp. 1207-1218. | Citations: 22 (Web of Science Lite) | Show Abstract | Read more

The process by which bacteria regulate flagellar expression is known as phase variation and in Salmonella enterica this process permits the expression of one of two flagellin genes, fliC or fljB, at any one time. Salmonella Typhi (S. Typhi) is normally not capable of phase variation of flagellar antigen expression as isolates only harbour the fliC gene (H:d) and lacks an equivalent fljB locus. However, some S. Typhi isolates, exclusively from Indonesia, harbour an fljB equivalent encoded on linear plasmid, pBSSB1 that drives the expression of a novel flagellin named H:z66. H:z66+S. Typhi isolates were stimulated to change flagellar phase and genetically analysed for the mechanism of variation. The phase change was demonstrated to be unidirectional, reverting to expression from the resident chromosomal fliC gene. DNA sequencing demonstrated that pBSSB1 linear DNA was still detectable but that these derivatives had undergone deletion and were lacking fljA(z66) (encoding a flagellar repressor) and fljB(z66). The deletion end-point was found to involve one of the plasmid termini and a palindromic repeat sequence within fljB(z66), distinct to that found at the terminus of pBSSB1. These data demonstrate that, like some Streptomyces linear elements, at least one of the terminal inverted repeats of pBSSB1 is non-essential, but that a palindromic repeat sequence may be necessary for replication.

Lubell Y, Reyburn H, Mbakilwa H, Mwangi R, Chonya K, Whitty CJM, Mills A. 2007. The cost-effectiveness of parasitologic diagnosis for malaria-suspected patients in an era of combination therapy. Am J Trop Med Hyg, 77 (6 Suppl), pp. 128-132. | Citations: 60 (Scopus) | Show Abstract

The introduction of artemisinin-based combination therapy in sub-Saharan Africa has prompted calls for increased use of parasitologic diagnosis for malaria. We evaluated the cost-effectiveness of rapid diagnostic tests (RDTs) in comparison to microscopy in guiding treatment of non-severe febrile illness at varying levels of malaria endemicity using data on test accuracy and costs collected as part of a Tanzanian trial. If prescribers complied with current guidelines, microscopy would give rise to lower average costs per patient correctly treated than RDTs in areas of both high and low transmission. RDT introduction would result in an additional 2.3% and 9.4% of patients correctly treated, at an incremental cost of $25 and $7 in the low and high transmission settings, respectively. Cost-effectiveness would be worse if prescribers do not comply with test results. The cost of this additional benefit may be higher than many countries can afford without external assistance or lower RDT prices.

Plugge EH, Yudkin PL, Douglas N. 2007. Predictors of hepatitis B vaccination in women prisoners in two prisons in England. J Public Health (Oxf), 29 (4), pp. 429-433. | Citations: 5 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Hepatitis B is an important public health issue, especially in the female prison population. The high prevalence in this population is largely accounted for by the high rates of injecting drug use and the fact that these women are more likely to exchange sex for drugs or money and practice unprotected sex. There is a national programme in English prisons to vaccinate everyone against Hepatitis B. This study aimed to investigate whether women who had been in prison before were more likely to have been vaccinated against hepatitis B and whether contact with community services was more likely to predict hepatitis B vaccination. METHODS: A questionnaire survey of new entrants into two women's prisons in England. RESULTS: Four hundred and eighty seven out of 613 women approached completed the questionnaire and gave complete data on hepatitis B vaccination status, giving a response rate of 79.4%. One hundred and thirty three women (27.3%) had received at least three vaccinations against hepatitis B. Previous imprisonment and intravenous drug use were independent predictors of vaccination. Six months or more in prison greatly increased an individual's odds of being immunized [odds ratio 12.01 (95% confidence interval (CI) 5.53-26.10)]. Registration with a general practitioner (GP), contact with drug or alcohol services and exchanging money or goods for sex were not independently associated with vaccination status. CONCLUSION: Prisons play an important role in the delivery of hepatitis B vaccination. However, this should not prevent providers of health services making greater efforts to engage this marginalized group and to ensure that they receive an appropriate level of healthcare in the community.

Price RN, Tjitra E, Guerra CA, Yeung S, White NJ, Anstey NM. 2007. Vivax malaria: neglected and not benign. Am J Trop Med Hyg, 77 (6 Suppl), pp. 79-87. | Citations: 529 (Scopus) | Show Abstract

Plasmodium vivax threatens almost 40% of the world's population, resulting in 132-391 million clinical infections each year. Most of these cases originate from Southeast Asia and the Western Pacific, although a significant number also occurs in Africa and South America. Although often regarded as causing a benign and self-limiting infection, there is increasing evidence that the overall burden, economic impact, and severity of disease from P. vivax have been underestimated. Malaria control strategies have had limited success and are confounded by the lack of access to reliable diagnosis, emergence of multidrug resistant isolates, the parasite's ability to transmit early in the course of disease and relapse from dormant liver stages at varying time intervals after the initial infection. Progress in reducing the burden of disease will require improved access to reliable diagnosis and effective treatment of both blood-stage and latent parasites, and more detailed characterization of the epidemiology, morbidity, and economic impact of vivax malaria. Without these, vivax malaria will continue to be neglected by ministries of health, policy makers, researchers, and funding bodies.

Chen X, Stanton B, Pach A, Nyamete A, Ochiai RL, Kaljee L, Dong B, Sur D, Bhattacharya SK, Santoso SS et al. 2007. Adults' perceived prevalence of enteric fever predicts laboratory-validated incidence of typhoid fever in children. J Health Popul Nutr, 25 (4), pp. 469-478. | Citations: 10 (Scopus) | Show Abstract

This study was undertaken to develop a model to predict the incidence of typhoid in children based on adults' perception of prevalence of enteric fever in the wider community. Typhoid cases among children, aged 5-15 years, from epidemic regions in five Asian countries were confirmed with a positive Salmonella Typhi culture of the blood sample. Estimates of the prevalence of enteric fever were obtained from random samples of adults in the same study sites. Regression models were used for establishing the prediction equation. The percentages of enteric fever reported by adults and cases of typhoid incidence per 100,000, detected through blood culture were 4.7 and 24.18 for Viet Nam, 3.8 and 29.20 for China, 26.3 and 180.33 for Indonesia, 66.0 and 454.15 for India, and 52.7 and 407.18 for Pakistan respectively. An established prediction equation was: incidence of typhoid (1/100,000= -2.6946 + 7.2296 x reported prevalence of enteric fever (%) (F=31.7, p<0.01; R2=0.992). Using adults' perception of prevalence of disease as the basis for estimating its incidence in children provides a cost-effective behavioural epidemiologic method to facilitate prevention and control of the disease.

Heiden D, Ford N, Wilson D, Rodriguez WR, Margolis T, Janssens B, Bedelu M, Tun N, Goemaere E, Saranchuk P et al. 2007. Cytomegalovirus retinitis: the neglected disease of the AIDS pandemic. PLoS Med, 4 (12), pp. e334. | Citations: 66 (Scopus) | Read more

Geskus R. 2007. Censoring strategies when using competing risks with time-dependent covariates. J Acquir Immune Defic Syndr, 46 (4), pp. 512. | Read more

Hamers RL, Schuurman R, van Vugt M, Derdelinckx I, Rinke de Wit TF. 2007. [AIDS treatment in Africa: the risk of antiretroviral resistance]. Ned Tijdschr Geneeskd, 151 (48), pp. 2666-2671. | Citations: 1 (Scopus) | Show Abstract

--In recent years, implementation of antiretroviral therapy in developing countries with a high prevalence of HIV-1 has been recognised as a public health priority. Consequently, the availability ofantiretroviral combination therapy for people with HIV is increasing rapidly in sub-Saharan Africa. --HIV treatment programmes are implemented according to the standardised, simplified public health guidelines developed by the World Health Organization (WHO). --However, the implementation of treatment programmes in Africa is hindered by several factors, including the lack of adequate immunological and virological laboratory monitoring, insufficient support for adherence to therapy, vulnerable health care systems and the use of suboptimal drug combinations. --These suboptimal treatment conditions increase the risk that resistant virus strains will emerge that are less susceptible to standard first-line combination therapy, thus threatening the long-term success of the treatment programmes. --The WHO has initiated HIVResNet, an international expert advisory board that has developed a global strategy for surveillance and prevention of antiretroviral drug resistance. --The Dutch initiative known as 'PharmAccess African studies to evaluate resistance' (PASER) is contributing to this strategy by creating a surveillance network in sub-Saharan Africa.

Sanders EJ, Graham SM, Okuku HS, van der Elst EM, Muhaari A, Davies A, Peshu N, Price M, McClelland RS, Smith AD. 2007. HIV-1 infection in high risk men who have sex with men in Mombasa, Kenya. AIDS, 21 (18), pp. 2513-2520. | Citations: 129 (Scopus) | Show Abstract | Read more

BACKGROUND: The role of homosexuality and anal sex practices in the African HIV -1 epidemic is not well described. We aimed to assess the risk factors for prevalent HIV-1 infection among men who have sex with men (MSM) to guide HIV-1 prevention efforts. METHODS: Socio-behavioural characteristics, signs and symptoms of sexually transmitted diseases (STD), and serological evidence of HIV-1 were determined for 285 MSM at enrolment into a vaccine preparedness cohort study. We used multivariate logistic regression to assess risk factors for prevalent HIV-1 infection. RESULTS: HIV-1 prevalence was 43.0% [49/114, 95% confidence interval (CI), 34-52%] for men who reported sex with men exclusively (MSME), and 12.3% (21/171, 95% CI, 7-17%) for men who reported sex with both men and women (MSMW). Eighty-six (75%) MSME and 69 (40%) MSMW reported recent receptive anal sex. Among 174 MSM sexually active in the last week, 44% reported no use of condoms with casual partners. In the previous 3 months, 210 MSM (74%) reported payment for sex, and most clients (93%) were local residents. Prevalent HIV-1 infection was associated with recent receptive anal sex [odds ratio (OR), 6.1; 95% CI, 2.4-16], exclusive sex with men (OR, 6.3; 95% CI, 2.3-17), and increasing age (OR, 1.1 per year; 95% CI, 1.04-1.12). Only four MSM reported injecting drug use. CONCLUSIONS: The high prevalence of HIV-1 in Kenyan MSM is probably attributable to unprotected receptive anal sex. There is an urgent need for HIV-1 prevention programmes to deliver targeted risk-reduction interventions and STD services to MSM in Kenya.

Bejon P, Mwangi T, Lowe B, Peshu N, Hill AVS, Marsh K. 2007. Clearing asymptomatic parasitaemia increases the specificity of the definition of mild febrile malaria. Vaccine, 25 (48), pp. 8198-8202. | Citations: 3 (Web of Science Lite) | Show Abstract | Read more

In clinical trials, the specificity of the disease endpoint is critical to an accurate estimate of vaccine efficacy. We used a logistic regression model to analyse parasite densities among children before and after treatment with antimalarials, in order to estimate the impact that clearing asymptomatic parasitaemia had on the specificity of the endpoint of febrile malaria. The malaria attributable fever fraction was higher after antimalarial treatment (i.e. fever and parasitaemia were more likely to be causally related), implying that drug treatment prior to monitoring decreased the misclassification of febrile malaria. In intervention studies with febrile malaria as an endpoint, clearing asymptomatic parasitaemia increases the study's power more effectively than raising the threshold parasitaemia.

Thiem VD, Canh DG, Anh DD, Deen JL, von Seidlein L, Clemens JD, Holmgren J. 2007. Response to "questionable merits of the field trial of an oral killed whole cell cholera vaccine in Vietnam during 1998-2003" Vaccine 2007;25(8):1353-4. Vaccine, 25 (47), pp. 7981-7983. | Read more

Okiro EA, Hay SI, Gikandi PW, Sharif SK, Noor AM, Peshu N, Marsh K, Snow RW. 2007. The decline in paediatric malaria admissions on the coast of Kenya. Malar J, 6 (1), pp. 151. | Citations: 186 (Scopus) | Show Abstract | Read more

BACKGROUND: There is only limited information on the health impact of expanded coverage of malaria control and preventative strategies in Africa. METHODS: Paediatric admission data were assembled over 8.25 years from three District Hospitals; Kilifi, Msambweni and Malindi, situated along the Kenyan Coast. Trends in monthly malaria admissions between January 1999 and March 2007 were analysed using several time-series models that adjusted for monthly non-malaria admission rates and the seasonality and trends in rainfall. RESULTS: Since January 1999 paediatric malaria admissions have significantly declined at all hospitals. This trend was observed against a background of rising or constant non-malaria admissions and unaffected by long-term rainfall throughout the surveillance period. By March 2007 the estimated proportional decline in malaria cases was 63% in Kilifi, 53% in Kwale and 28% in Malindi. Time-series models strongly suggest that the observed decline in malaria admissions was a result of malaria-specific control efforts in the hospital catchment areas. CONCLUSION: This study provides evidence of a changing disease burden on the Kenyan coast and that the most parsimonious explanation is an expansion in the coverage of interventions such as the use of insecticide-treated nets and the availability of anti-malarial medicines. While specific attribution to intervention coverage cannot be computed what is clear is that this area of Kenya is experiencing a malaria epidemiological transition.

Chantratita N, Wuthiekanun V, Limmathurotsakul D, Thanwisai A, Chantratita W, Day NPJ, Peacock SJ. 2007. Prospective clinical evaluation of the accuracy of 16S rRNA real-time PCR assay for the diagnosis of melioidosis. Am J Trop Med Hyg, 77 (5), pp. 814-817. | Citations: 22 (Scopus) | Show Abstract

The accuracy of a Burkholderia pseudomallei 16s rRNA real-time PCR assay was evaluated against culture for the diagnosis of melioidosis in Thailand. A total of 846 samples were obtained from 383 patients with suspected melioidosis. One or more specimens were PCR positive for 47 of 77 patients with culture-proven melioidosis (sensitivity 61.0%, 95% CI: 49.2-72.0%). PCR was negative for all 306 patients who were culture negative for B. pseudomallei (specificity 100%, 95% CI: 98.8-100%). Diagnostic sensitivity of PCR was 22.7% for patients who were culture positive for blood only, compared with 79.4% for patients who were culture positive for samples other than blood. The median (interquartile range) B. pseudomallei colony count in blood for 44 of 77 patients with positive blood cultures was 2.4 CFU/ml (0.2-13.5 CFU/ml); this may explain the low sensitivity of PCR for this specimen. The PCR assay described here is not sufficiently sensitive to replace culture in our clinical setting.

Wuthiekanun V, Limmathurotsakul D, Wongsuvan G, Chierakul W, Teerawattanasook N, Teparrukkul P, Day NP, Peacock SJ. 2007. Short report: Quantitation of B. pseudomallei in clinical samples AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE, 77 (5), pp. 812-813. | Citations: 19 (Scopus) | Show Abstract

We undertook a prospective study to quantitate Burkholderia pseudomallei in blood, pus, respiratory secretions, and urine obtained from 414 patients with melioidosis. The median was count 1.1, 1.5 × 10 4 , 1.1 × 10 5 , and 1,1 × 10 7 CFU/mL in these sample types, respectively. This provides important insights into the likely feasibility of future studies such as expression microarray analysis using clinical material. Copyright © 2007 by The American Society of Tropical Medicine and Hygiene.

Amornchai P, Chierakul W, Wuthiekanun V, Mahakhunkijcharoen Y, Phetsouvanh R, Currie BJ, Newton PN, van Vinh Chau N, Wongratanacheewin S, Day NPJ, Peacock SJ. 2007. Accuracy of Burkholderia pseudomallei identification using the API 20NE system and a latex agglutination test. J Clin Microbiol, 45 (11), pp. 3774-3776. | Citations: 37 (Scopus) | Show Abstract | Read more

In an evaluation of the API 20NE for the identification of Burkholderia spp., 792/800 (99%) Burkholderia pseudomallei and 17/19 (89%) B. cepacia isolates were correctly identified but 10 B. mallei and 98 B. thailandensis isolates were not correctly identified. A latex agglutination test was positive for 796/800 (99.5%) B. pseudomallei isolates and negative for 120 other oxidase-positive gram-negative bacilli.

Blacksell SD, Bell D, Kelley J, Mammen MP, Gibbons RV, Jarman RG, Vaughn DW, Jenjaroen K, Nisalak A, Thongpaseuth S et al. 2007. Prospective study to determine accuracy of rapid serological assays for diagnosis of acute dengue virus infection in Laos. Clin Vaccine Immunol, 14 (11), pp. 1458-1464. | Citations: 26 (Web of Science Lite) | Show Abstract | Read more

There is an urgent need for accurate and simple dengue virus infection diagnostic assays in limited-resource settings of dengue endemicity, to assist patient management. Using a panel of reference samples (S. D. Blacksell, P. N. Newton, D. Bell, J. Kelley, M. P. Mammen, D. W. Vaughn, V. Wuthiekanun, A. Sungkakum, A. Nisalak, and N. P. Day, Clin. Infect. Dis. 42:1127-1134, 2006), we recently evaluated eihgt commercially available immunochromatographic rapid diagnostic tests (RDTs) designed to detect dengue virus-specific immunoglobulin M (IgM) and/or IgG. We found that 6/8 RDTs had sensitivities of less than 50% (range, 6 to 65%), but specificities were generally high. Here, in conjuction with dengue virus serotyping by reverse transcriptase PCR and in the limited-resource setting of Laos, where dengue virus is endemic, we evaluated the same eight RDTs against a previously validated dengue IgM/IgG enzyme-linked immunosorbent assay for diagnosis of acute dengue virus infection. Paired serum samples were collected from 87 patients, of whom 38 had confirmed dengue virus infections (4 had primary infections, 33 had secondary infections, and 1 had an infection of indeterminate status). RDT sensitivity was low, with 7/8 RDTs having admission sample sensitivities of less than 20% (range, 4 to 26%). The majority (6/8) of the RDTs, demonstrated high specificity (>95%). Kappa statistic values ranged from 6 to 54% for the RDTs, demonstrating poor to moderate variation between three operators. No RDT adequately differentiated between primary and secondary dengue virus infections. The findings of this study suggest that currently available RDTs based on the detection of IgM antibodies for the diagnosis of acute dengue virus infections are unlikely to be useful for patient management.

Keomany S, Mayxay M, Souvannasing P, Vilayhong C, Stuart BL, Srour L, Newton PN. 2007. Toad poisoning in Laos. Am J Trop Med Hyg, 77 (5), pp. 850-853. | Citations: 9 (Scopus) | Show Abstract

We describe two patients who developed severe illness after eating the skin and eggs of a toad, probably Bufo melanostictus Schneider, in southeastern Laos. One boy died, and one developed a digoxin toxicity-like syndrome with bradycardia and heart failure but survived. A telephone survey of 16 Lao provincial hospitals suggested that toad poisoning occurs in at least six provinces. That 93% of villagers in three villages in southeastern Laos were aware that toads are poisonous but that 51% had encountered patients with toad toxicity suggests that the potential gravity is not appreciated. These data indicate that toad poisoning may be underestimated and that education on the seriousness of toad toxins could be a useful public health measure.

Price RN, Hasugian AR, Ratcliff A, Siswantoro H, Purba HLE, Kenangalem E, Lindegardh N, Penttinen P, Laihad F, Ebsworth EP et al. 2007. Clinical and pharmacological determinants of the therapeutic response to dihydroartemisinin-piperaquine for drug-resistant malaria. Antimicrob Agents Chemother, 51 (11), pp. 4090-4097. | Citations: 67 (Scopus) | Show Abstract | Read more

Dihydroartemisinin-piperaquine (DHP) is an important new treatment for drug-resistant malaria, although pharmacokinetic studies on the combination are limited. In Papua, Indonesia, we assessed determinants of the therapeutic efficacy of DHP for uncomplicated malaria. Plasma piperaquine concentrations were measured on day 7 and day 28, and the cumulative risk of parasitological failure at day 42 was calculated using survival analysis. Of the 598 patients in the evaluable population 342 had infections with Plasmodium falciparum, 83 with Plasmodium vivax, and 173 with a mixture of both species. The unadjusted cumulative risks of recurrence were 7.0% (95% confidence interval [CI]: 4.6 to 9.4%) for P. falciparum and 8.9% (95% CI: 6.0 to 12%) for P. vivax. After correcting for reinfections the risk of recrudescence with P. falciparum was 1.1% (95% CI: 0.1 to 2.1%). The major determinant of parasitological failure was the plasma piperaquine concentration. A concentration below 30 ng/ml on day 7 was observed in 38% (21/56) of children less than 15 years old and 22% (31/140) of adults (P = 0.04), even though the overall dose (mg per kg of body weight) in children was 9% higher than that in adults (P < 0.001). Patients with piperaquine levels below 30 ng/ml were more likely to have a recurrence with P. falciparum (hazard ratio [HR] = 6.6 [95% CI: 1.9 to 23]; P = 0.003) or P. vivax (HR = 9.0 [95% CI: 2.3 to 35]; P = 0.001). The plasma concentration of piperaquine on day 7 was the major determinant of the therapeutic response to DHP. Lower plasma piperaquine concentrations and higher failure rates in children suggest that dose revision may be warranted in this age group.

Limmathurotsakul D, Wuthiekanun V, Chantratita N, Wongsuvan G, Thanwisai A, Biaklang M, Tumapa S, Lee S, Day NPJ, Peacock SJ. 2007. Simultaneous infection with more than one strain of Burkholderia pseudomallei is uncommon in human melioidosis. J Clin Microbiol, 45 (11), pp. 3830-3832. | Citations: 14 (Scopus) | Show Abstract | Read more

A prospective study was performed to determine the rate at which patients with melioidosis are infected with more than one strain of Burkholderia pseudomallei. Genotyping of 2,058 bacterial colonies isolated from 215 samples taken from 133 patients demonstrated that mixed infection is uncommon (2/133 cases [1.5%; 95% confidence interval, 0.2 to 5.3%]).

Lindegårdh N, Hanpithakpong W, Wattanagoon Y, Singhasivanon P, White NJ, Day NPJ. 2007. Development and validation of a liquid chromatographic-tandem mass spectrometric method for determination of oseltamivir and its metabolite oseltamivir carboxylate in plasma, saliva and urine. J Chromatogr B Analyt Technol Biomed Life Sci, 859 (1), pp. 74-83. | Citations: 79 (Scopus) | Show Abstract | Read more

A bioanalytical method for the analysis of oseltamivir (OP) and its metabolite oseltamivir carboxylate (OC) in human plasma, saliva and urine using off-line solid-phase extraction and liquid chromatography coupled to positive tandem mass spectroscopy has been developed and validated. OP and OC were analysed on a ZIC-HILIC column (50 mm x 2.1 mm) using a mobile phase gradient containing acetonitrile-ammonium acetate buffer (pH 3.5; 10mM) at a flow rate of 500 microL/min. The method was validated according to published FDA guidelines and showed excellent performance. The lower limit of quantification for OP was determined to be 1, 1 and 5 ng/mL for plasma, saliva and urine, respectively and for OC was 10, 10 and 30 ng/mL for plasma, saliva and urine, respectively. The upper limit of quantification for OP was determined to be 600, 300 and 1500 ng/mL for plasma, saliva and urine, respectively and for OC was 10,000, 10,000 and 30,000 ng/mL for plasma, saliva and urine, respectively. The within-day and between-day precisions expressed as R.S.D., were lower than 5% at all tested concentrations for all matrices and below 12% at the lower limit of quantification. Validation of over-curve samples ensured that it would be possible with dilution if samples went outside the calibration range. Matrix effects were thoroughly evaluated both graphically and quantitatively. No matrix effects were detected for OP or OC in plasma or saliva. Residues from the urine matrix (most likely salts) caused some ion suppression for both OP and its deuterated internal standard but had no effect on OC or its deuterated internal standard. The suppression did not affect the quantification of OP.

Ricci C, Eliasson C, Macleod NA, Newton PN, Matousek P, Kazarian SG. 2007. Characterization of genuine and fake artesunate anti-malarial tablets using Fourier transform infrared imaging and spatially offset Raman spectroscopy through blister packs. Anal Bioanal Chem, 389 (5), pp. 1525-1532. | Citations: 87 (Scopus) | Show Abstract | Read more

In support of the efforts to combat the illegal sale and distribution of counterfeit anti-malarial drugs, we evaluated a new analytical approach for the characterization and fast screening of fake and genuine artesunate tablets using a combination of Raman spectroscopy, Spatially Offset Raman Spectroscopy (SORS) and Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) imaging. Vibrational spectroscopy provided chemically specific information on the composition of the tablets; the complementary nature of Raman scattering and FTIR imaging allowed the characterization of both the overall and surface composition of the tablets. The depth-resolving power of the SORS approach provided chemically specific information on the overall composition of the tablets, non-invasively, through a variety of packaging types. Spatial imaging of the tablet surface (using ATR-FTIR) identified the location of domains of excipients and active ingredients with high sensitivity and enhanced spatial resolution. The advantages provided by a combination of SORS and ATR-FTIR imaging in this context confirm its potential for inclusion in the analytical protocol for forensic investigation of counterfeit medicines.

Paris DH, Imwong M, Faiz AM, Hasan M, Yunus EB, Silamut K, Lee SJ, Day NPJ, Dondorp AM. 2007. Loop-mediated isothermal PCR (LAMP) for the diagnosis of falciparum malaria. Am J Trop Med Hyg, 77 (5), pp. 972-976. | Citations: 77 (Scopus) | Show Abstract

A recently described loop-mediated isothermal polymerase chain reaction (LAMP) for molecular detection of Plasmodium falciparum was compared with microscopy, PfHRP2-based rapid diagnostic test (RDT), and nested polymerase chain reaction (PCR) as the "gold standard" in 115 Bangladeshi in-patients with fever. DNA extraction for LAMP was conducted by conventional methods or simple heating of the sample; test results were either assessed visually or by gel electrophoresis. Conventional DNA extraction followed by gel electrophoresis had the highest agreement with the reference method (81.7%, kappa = 0.64), with a sensitivity (95% CI) of 76.1% (68.3-83.9%), comparable to RDT and microscopy, but a specificity of 89.6% (84.0-95.2%) compared with 100% for RDT and microscopy. DNA extraction by heat treatment deteriorated specificity to unacceptable levels. LAMP enables molecular diagnosis of falciparum malaria in settings with limited technical resources but will need further optimization. The results are in contrast with a higher accuracy reported in an earlier study comparing LAMP with a non-validated PCR method.

Baird JK. 2007. Neglect of Plasmodium vivax malaria. Trends Parasitol, 23 (11), pp. 533-539. | Citations: 169 (Web of Science Lite) | Show Abstract | Read more

Plasmodium vivax infects 130-435 million of the 2.6 billion people living at risk of infection. Recent studies suggest that vivax malaria can become lethal in a similar way to severe falciparum malaria. First-line therapies remain unchanged after 50 years. Despite evidence of failing chloroquine efficacy, little work has assessed the problem or explored alternative therapies. Primaquine treatment, the only therapeutic option against relapse, might also be failing. No licensed primary chemoprophylactic agent protects travelers from relapse. Misdiagnosis of species now affects clinical decisions resulting in inadequate therapy for P. falciparum and P. vivax. All of these factors demonstrate the lack of research on P. vivax.

Barcus MJ, Basri H, Picarima H, Manyakori C, Sekartuti, Elyazar I, Bangs MJ, Maguire JD, Baird JK. 2007. Demographic risk factors for severe and fatal vivax and falciparum malaria among hospital admissions in northeastern Indonesian Papua. Am J Trop Med Hyg, 77 (5), pp. 984-991. | Citations: 132 (Scopus) | Show Abstract

Between January 1998 and December 2000, the Jayapura Provincial Public Hospital in northeastern Indonesian New Guinea (Papua) admitted 5,936 patients with a diagnosis of malaria. The microscopic diagnosis at admission was Plasmodium falciparum (3,976, 67%), Plasmodium vivax (1,135, 19%), Plasmodium malariae (8, < 1%), and mixed species infections (817, 14%). Approximately 9% (367) of patients were classified as having severe malaria (277 P. falciparum, 36 P. vivax, 53 mixed infections, and 1 P. malariae) and 88 died (79 P. falciparum/mixed infections and 9 P. vivax). Risk of fatal outcomes among severe malaria patients was indistinguishable between those with falciparum versus vivax malaria (OR = 0.89; P = 0.771). Compared with non-pregnant women, pregnant women showed no higher risk of severe malaria (P = 0.643) or death caused by severe malaria (P = 0.748). This study compares admissions per population (based on census data), parasitemia, morbidity, and mortality among children versus adults, pregnant versus non-pregnant women, and urban/suburban versus rural residents.

Wuthiekanun V, Limmathurotsakul D, Wongsuvan G, Chierakul W, Teerawattanasook N, Teparrukkul P, Day NP, Peacock SJ. 2007. Quantitation of B. Pseudomallei in clinical samples. Am J Trop Med Hyg, 77 (5), pp. 812-813. | Show Abstract

We undertook a prospective study to quantitate Burkholderia pseudomallei in blood, urine, respiratory secretions, and pus [corrected] obtained from 414 patients with melioidosis. The median was count 1.1, 1.5 x 10(4), 1.1 x 10(5), and 1.1 x 10(7) CFU/mL in these sample types, respectively. This provides important insights into the likely feasibility of future studies such as expression microarray analysis using clinical material.

van Kruijssen AM, Templeton KE, van der Plas RN, van Doorn HR, Claas ECJ, Sukhai RN, Kuijper EJ. 2007. Detection of respiratory pathogens by real-time PCR in children with clinical suspicion of pertussis. Eur J Pediatr, 166 (11), pp. 1189-1191. | Citations: 13 (Scopus) | Show Abstract | Read more

The use of a multiplex respiratory real-time PCR in patients clinically suspected of pertussis increases the number of pathogens detected.

Currie BJ, Thomas AD, Godoy D, Dance DA, Cheng AC, Ward L, Mayo M, Pitt TL, Spratt BG. 2007. Australian and Thai isolates of Burkholderia pseudomallei are distinct by multilocus sequence typing: revision of a case of mistaken identity. J Clin Microbiol, 45 (11), pp. 3828-3829. | Citations: 14 (Scopus) | Show Abstract | Read more

A recent study using multilocus sequence typing (MLST) of Burkholderia pseudomallei isolates found a sequence type (ST60) to be common to both Thailand and Australia, contradicting earlier studies showing complete distinction between isolates from these regions. The ST60 isolates reportedly from Australia had been obtained for MLST from United Kingdom and U.S. collections. We have located and characterized the original Australian isolates; they were collected in 1983, and they are neither ST60 nor B. pseudomallei isolates. The B. pseudomallei MLST database has been corrected, and there is no ST common to isolates verified as obtained from Australia or from Thailand.

von Seidlein L. 2007. Vaccines for cholera control: does herd immunity play a role. PLoS Med, 4 (11), pp. e331. | Citations: 5 (Scopus) | Read more

Choi SY, Jeon Y-S, Lee JH, Choi B, Moon SH, von Seidlein L, Clemens JD, Dougan G, Wain J, Yu J et al. 2007. Multilocus sequence typing analysis of Shigella flexneri isolates collected in Asian countries. J Med Microbiol, 56 (Pt 11), pp. 1460-1466. | Citations: 26 (Scopus) | Show Abstract | Read more

The multilocus sequence typing scheme used previously for phylogenetic analysis of Escherichia coli was applied to 107 clinical isolates of Shigella flexneri. DNA sequencing of 3423 bp throughout seven housekeeping genes identified eight new allele types and ten new sequence types among the isolates. S. flexneri serotypes 1-5, X and Y were clustered together in a group containing many allelic variants while serotype 6 formed a distinct group, as previously established.

Zhou W-Z, Koo H-W, Wang X-Y, Zhang J, Park J-K, Zhu F, Deen J, Acosta CJ, Chen Y, Wang H et al. 2007. Revaccination with locally-produced vi typhoid polysaccharide vaccine among chinese school-aged children: safety and immunogenicity findings. Pediatr Infect Dis J, 26 (11), pp. 1001-1005. | Citations: 9 (Scopus) | Show Abstract | Read more

OBJECTIVE: To evaluate the safety and immunogenicity of revaccination with locally-produced Vi polysaccharide vaccine 3 years after the first dose in Chinese children aged 9 to 14 years. METHODS: A randomized, placebo-controlled trial was conducted in Suzhou, Jiangsu, China. Six hundred and sixty-seven eligible children who had previously received a primary dose of Vi vaccine were randomly assigned to receive 1 dose of 30 mug Vi vaccine or placebo. In addition, 331 eligible children received 1 dose of Vi polysaccharide vaccine as a primary vaccination. Adverse events were followed for 28 days after vaccination. Serum samples were collected from a subgroup of participants on day 0 and day 28, and Vi antibodies were analyzed using a passive hemagglutination method. RESULTS: Revaccination was found to be safe and immunogenic. No severe adverse events were observed. A significant increase in antibody titers after vaccination was observed among children who had and had not been previously vaccinated. Twenty-eight days after injection, the seropositive rate was 79% in both revaccination and primary injection groups; the geometric mean antibody titer was 1:40 in the primary injection group and 1:29 in the revaccination group (P = 0.24). Although the difference of attained geometric mean titers in follow-up sera was not significantly different in these 2 groups, the fold-rise of these titers from baseline was significantly higher in the primary injection group than in the revaccination group (7.7 versus 3.1, P < 0.001). CONCLUSION: We found that revaccination using the locally produced Vi polysaccharide vaccine among Chinese school-aged children was safe and increased antibody titers. Revaccination can be used to extend the duration of protection provided by Vi polysaccharide vaccine.

Rowe JA, Handel IG, Thera MA, Deans A-M, Lyke KE, Koné A, Diallo DA, Raza A, Kai O, Marsh K et al. 2007. Blood group O protects against severe Plasmodium falciparum malaria through the mechanism of reduced rosetting. Proc Natl Acad Sci U S A, 104 (44), pp. 17471-17476. | Citations: 131 (Scopus) | Show Abstract | Read more

Malaria has been a major selective force on the human population, and several erythrocyte polymorphisms have evolved that confer resistance to severe malaria. Plasmodium falciparum rosetting, a parasite virulence phenotype associated with severe malaria, is reduced in blood group O erythrocytes compared with groups A, B, and AB, but the contribution of the ABO blood group system to protection against severe malaria has received little attention. We hypothesized that blood group O may confer resistance to severe falciparum malaria through the mechanism of reduced rosetting. In a matched case-control study of 567 Malian children, we found that group O was present in only 21% of severe malaria cases compared with 44-45% of uncomplicated malaria controls and healthy controls. Group O was associated with a 66% reduction in the odds of developing severe malaria compared with the non-O blood groups (odds ratio 0.34, 95% confidence interval 0.19-0.61, P < 0.0005, severe cases versus uncomplicated malaria controls). In the same sample set, P. falciparum rosetting was reduced in parasite isolates from group O children compared with isolates from the non-O blood groups (P = 0.003, Kruskal-Wallis test). Statistical analysis indicated a significant interaction between host ABO blood group and parasite rosette frequency that supports the hypothesis that the protective effect of group O operates through the mechanism of reduced P. falciparum rosetting. This work provides insights into malaria pathogenesis and suggests that the selective pressure imposed by malaria may contribute to the variable global distribution of ABO blood groups in the human population.

Yeo TW, Lampah DA, Gitawati R, Tjitra E, Kenangalem E, McNeil YR, Darcy CJ, Granger DL, Weinberg JB, Lopansri BK et al. 2007. Impaired nitric oxide bioavailability and L-arginine reversible endothelial dysfunction in adults with falciparum malaria. J Exp Med, 204 (11), pp. 2693-2704. | Citations: 185 (Scopus) | Show Abstract | Read more

Severe falciparum malaria (SM) is associated with tissue ischemia related to cytoadherence of parasitized erythrocytes to microvascular endothelium and reduced levels of NO and its precursor, l-arginine. Endothelial function has not been characterized in SM but can be improved by l-arginine in cardiovascular disease. In an observational study in Indonesia, we measured endothelial function using reactive hyperemia-peripheral arterial tonometry (RH-PAT) in 51 adults with SM, 48 patients with moderately severe falciparum malaria (MSM), and 48 controls. The mean RH-PAT index was lower in SM (1.41; 95% confidence interval [CI] = 1.33-1.47) than in MSM (1.82; 95% CI = 1.7-2.02) and controls (1.93; 95% CI = 1.8-2.06; P < 0.0001). Endothelial dysfunction was associated with elevated blood lactate and measures of hemolysis. Exhaled NO was also lower in SM relative to MSM and controls. In an ascending dose study of intravenous l-arginine in 30 more patients with MSM, l-arginine increased the RH-PAT index by 19% (95% CI = 6-34; P = 0.006) and exhaled NO by 55% (95% CI = 32-73; P < 0.0001) without important side effects. Hypoargininemia and hemolysis likely reduce NO bioavailability. Endothelial dysfunction in malaria is nearly universal in severe disease, is reversible with l-arginine, and likely contributes to its pathogenesis. Clinical trials in SM of adjunctive agents to improve endothelial NO bioavailability, including l-arginine, are warranted.

Blessborn D, Römsing S, Annerberg A, Sundquist D, Björkman A, Lindegardh N, Bergqvist Y. 2007. Development and validation of an automated solid-phase extraction and liquid chromatographic method for determination of lumefantrine in capillary blood on sampling paper. J Pharm Biomed Anal, 45 (2), pp. 282-287. | Citations: 56 (Scopus) | Show Abstract | Read more

A bioanalytical method for the determination of lumefantrine in 100 microl blood applied onto sampling paper, by solid-phase extraction and liquid chromatography, has been developed and validated. Whatman 31 ET Chr sampling paper was pre-treated with 0.75 M tartaric acid before sampling capillary blood to enable a high recovery of lumefantrine. Lumefantrine was extracted from the sampling paper, then further purified using solid-phase extraction and finally quantified with HPLC. The between-day variation was below 10% over the range 0.4-25 microM. The lower limit of quantification was 0.25 microM in 100 microl capillary blood. No decrease in lumefantrine concentration in dried blood spot is seen after 4 months storage at 22 degrees C. The method was also evaluated in field samples from patients in Tanzania after treatment with lumefantrine/artemether. Lumefantrine could be estimated accurately enough to assess bioavailability and treatment compliance on day 7 (i.e. 4 days after the last dose) after a standard regimen with the lumefantrine/artemether combination.

Ansaruzzaman M, Bhuiyan NA, Safa A, Sultana M, McUamule A, Mondlane C, Wang X-Y, Deen JL, von Seidlein L, Clemens JD et al. 2007. Genetic diversity of El Tor strains of Vibrio cholerae O1 with hybrid traits isolated from Bangladesh and Mozambique. Int J Med Microbiol, 297 (6), pp. 443-449. | Citations: 16 (Scopus) | Show Abstract | Read more

Vibrio cholerae O1 strains that are hybrids between the classical and El Tor biotypes were isolated during two consecutive years (2004-2005) from diarrheal patients in Mozambique. Similar variants isolated in Bangladesh and recently isolated El Tor strains were analyzed for genetic diversity. Pulsed-field gel electrophoresis (PFGE) analysis using the restriction enzyme NotI, resulted in 18-21 bands showed five closely related PFGE patterns that were distributed similarly in both years (2004-2005) among the 80 strains tested in Mozambique. Overall based on the PFGE patterns the hybrids indicated an El Tor lineage. The restriction patterns of whole-chromosomal DNA grouped the hybrid strains from Mozambique into a separate cluster from Bangladeshi clinical and environmental hybrid strains. A high molecular weight band of 398kb that contain rstR allele of the classical type was detected from all hybrid strains, which was absent in all conventional classical and El Tor strains. This band could be designated as a marker for the hybrid strains. This study suggests that hybrid strains from Mozambique are closely related to each other, different from Bangladeshi hybrid strains that are diverse in nature and all hybrid strains differed markedly from conventional classical and El Tor strains.

Thaipadungpanit J, Wuthiekanun V, Chierakul W, Smythe LD, Petkanchanapong W, Limpaiboon R, Apiwatanaporn A, Slack AT, Suputtamongkol Y, White NJ et al. 2007. A dominant clone of Leptospira interrogans associated with an outbreak of human leptospirosis in Thailand. PLoS Negl Trop Dis, 1 (1), pp. e56. | Citations: 110 (Scopus) | Show Abstract | Read more

BACKGROUND: A sustained outbreak of leptospirosis occurred in northeast Thailand between 1999 and 2003, the basis for which was unknown. METHODS AND FINDINGS: A prospective study was conducted between 2000 and 2005 to identify patients with leptospirosis presenting to Udon Thani Hospital in northeast Thailand, and to isolate the causative organisms from blood. A multilocus sequence typing scheme was developed to genotype these pathogenic Leptospira. Additional typing was performed for Leptospira isolated from human cases in other Thai provinces over the same period, and from rodents captured in the northeast during 2004. Sequence types (STs) were compared with those of Leptospira drawn from a reference collection. Twelve STs were identified among 101 isolates from patients in Udon Thani. One of these (ST34) accounted for 77 (76%) of isolates. ST34 was Leptospira interrogans, serovar Autumnalis. 86% of human Leptospira isolates from Udon Thani corresponded to ST34 in 2000/2001, but this figure fell to 56% by 2005 as the outbreak waned (p = 0.01). ST34 represented 17/24 (71%) of human isolates from other Thai provinces, and 7/8 (88%) rodent isolates. By contrast, 59 STs were found among 76 reference strains, indicating a much more diverse population genetic structure; ST34 was not identified in this collection. CONCLUSIONS: Development of an MLST scheme for Leptospira interrogans revealed that a single ecologically successful pathogenic clone of L. interrogans predominated in the rodent population, and was associated with a sustained outbreak of human leptospirosis in Thailand.

Nuchsongsin F, Chotivanich K, Charunwatthana P, Omodeo-Salè F, Taramelli D, Day NP, White NJ, Dondorp AM. 2007. Effects of malaria heme products on red blood cell deformability. Am J Trop Med Hyg, 77 (4), pp. 617-622. | Citations: 32 (Scopus) | Show Abstract

In falciparum malaria, the deformability of the entire erythrocyte population is reduced in proportion to disease severity, and this compromises microcirculatory blood flow through vessels partially obstructed by cytoadherent parasitized erythrocytes. The cause of rigidity of uninfected erythrocytes in not known but could be mediated by malaria heme products. In this study, we show that red blood cell deformability (RBC-D), measured by laser-assisted optical rotational cell analyzer, decreased in a dose-dependent manner after incubation with hemin and hydrogen peroxide but not with hemoglobin or beta-hematin. Hemin also reduced mean red cell volume. Albumin decreased and N-acetylcysteine (NAC) both prevented and reversed rigidity induced by hemin. Hemin-induced oxidative damage of the membrane seems to be a more important contributor to pathology than cell shrinkage because the antioxidant NAC restored RBC-D but not red blood cell volume. The findings suggest novel approaches to the treatment of potentially lethal malaria.

Newton PN, Mayxay M, Taylor A, White NJ. 2007. Untitled TROPICAL MEDICINE & INTERNATIONAL HEALTH, 12 (10), pp. 1272-1273.

Khor CC, Vannberg FO, Chapman SJ, Walley A, Aucan C, Loke H, White NJ, Peto T, Khor LK, Kwiatkowski D et al. 2007. Positive replication and linkage disequilibrium mapping of the chromosome 21q22.1 malaria susceptibility locus. Genes Immun, 8 (7), pp. 570-576. | Citations: 12 (Web of Science Lite) | Show Abstract | Read more

Four cytokine receptor genes are located on Chr21q22.11, encoding the alpha and beta subunits of the interferon-alpha receptor (IFNAR1 and IFNAR2), the beta subunit of the interleukin 10 receptor (IL10RB) and the second subunit of the interferon-gamma receptor (IFNGR2). We previously reported that two variants in IFNAR1 were associated with susceptibility to malaria in Gambians. We now present an extensive fine-scale mapping of the associated region utilizing 45 additional genetic markers obtained from public databases and by sequencing a 44 kb region in and around the IFNAR1 gene in 24 Gambian children (12 cases/12 controls). Within the IFNAR1 gene, a newly studied C --> G single-nucleotide polymorphism (IFNAR1 272354c-g) at position -576 relative to the transcription start was found to be more strongly associated with susceptibility to severe malaria. Association was observed in three populations: in Gambian (P=0.002), Kenyan (P=0.022) and Vietnamese (P=0.005) case-control studies. When all three studies were combined, using the Mantel-Haenszel test, the presence of IFNAR1 -576G was associated with a substantially elevated risk of severe malaria (N=2444, OR=1.38, 95% CI: 1.17-1.64; P=1.7 x 10(-4)). This study builds on previous work to further highlight the importance of the type-I interferon pathway in malaria susceptibility and illustrates the utility of typing SNPs within regions of high linkage disequilibrium in multiple populations to confirm initial positive associations.

Tanomsing N, Imwong M, Pukrittayakamee S, Chotivanich K, Looareesuwan S, Mayxay M, Dolecek C, Hien TT, do Rosario VE, Arez AP et al. 2007. Genetic analysis of the dihydrofolate reductase-thymidylate synthase gene from geographically diverse isolates of Plasmodium malariae. Antimicrob Agents Chemother, 51 (10), pp. 3523-3530. | Citations: 14 (Web of Science Lite) | Show Abstract | Read more

Plasmodium malariae, the parasite responsible for quartan malaria, is transmitted in most areas of malaria endemicity and is associated with significant morbidity. The sequence of the gene coding for the enzyme dihydrofolate reductase-thymidylate synthase (DHFR-TS) was obtained from field isolates of P. malariae and from the closely related simian parasite Plasmodium brasilianum. The two sequences were nearly 100% homologous, adding weight to the notion that they represent genetically distinct lines of the same species. A survey of polymorphisms of the dhfr sequences in 35 isolates of P. malariae collected from five countries in Asia and Africa revealed a low number of nonsynonymous mutations in five codons. In five of the isolates collected from southeast Asia, a nonsynonymous mutation was found at one of the three positions known to be associated with antifolate resistance in other Plasmodium species. Five isolates with the wild-type DHFR could be assayed for drug susceptibility in vitro and were found to be sensitive to pyrimethamine (mean 50% inhibitory concentration, 2.24 ng/ml [95% confidence interval, 0.4 to 3.1]).

van Belkum A, Emonts M, Wertheim H, de Jongh C, Nouwen J, Bartels H, Cole A, Cole A, Hermans P, Boelens H et al. 2007. The role of human innate immune factors in nasal colonization by Staphylococcus aureus. Microbes Infect, 9 (12-13), pp. 1471-1477. | Citations: 47 (Scopus) | Show Abstract | Read more

Staphylococcus aureus colonization of the human nares predisposes to sometimes severe auto-infection. To investigate whether genetic polymorphism affects the S. aureus carriage status, sequence variation in alpha-defensin and beta-defensin, and mannose-binding lectin (MBL) genes were determined for a group of volunteers (n=109) with known S. aureus nasal carriage status. DEFA1/3 expression was measured in a subset of the volunteers (n=32). None of the single nucleotide polymorphisms studied could clearly distinguish the (non) carriage groups. S. aureus carriers differed from non-carriers in baseline level of HNP1-3 peptide production (median: 218 versus 89mug/ml, P=0.016). No association between HNP1-3 levels and the individual sequence polymorphisms was documented. The combined copy numbers of DEFA1/A3 genes ranged from 5 to 23 per diploid genome. A linear correlation between combined copy numbers and HNP1-3 peptide concentrations in nasal secretions of non-carriers was noted (r(2)=0.8991). DEFA3 gene was absent in 25% of the individuals. MBL haplotype A was overrepresented in persistent S. aureus carriers (87% vs. 67%; P=0.038). In conclusion, defensin gene polymorphism, both in sequence and in gene copy numbers, does not seem to be involved in S. aureus carriage predisposition. However, MBL haplotypes do so significantly. Baseline HNP1-3 production is more the consequence of S. aureus colonization than a reason for the (non) carrier status.

Abdullahi O, Wanjiru E, Musyimi R, Glass N, Scott JAG. 2007. Validation of nasopharyngeal sampling and culture techniques for detection of Streptococcus pneumoniae in children in Kenya. J Clin Microbiol, 45 (10), pp. 3408-3410. | Citations: 11 (Web of Science Lite) | Show Abstract | Read more

We compared nasopharyngeal swabs against nasal wash cultures for detecting colonizing pneumococci and examined the effect of frozen storage in skim milk-tryptone-glucose-glycerin on culture. Among the 55 children with positive nasal wash cultures, swab cultures were positive for 47 (85%). Of the 96 swabs positive on direct plating, 94 (98%) were positive when recultured after freezing.

Antarasena C, Sirimujalin R, Prommuang P, Promkuntod N, Prommuang P, Blacksell SD. 2007. The indirect immunofluorescence assay using cardiac tissue from chickens, quails and ducks for identification of influenza A virus during an outbreak of highly pathogenic avian influenza virus (H5N1): a rapid and simple screening tool for limited resource settings. Res Vet Sci, 83 (2), pp. 279-281. | Citations: 5 (Web of Science Lite) | Show Abstract | Read more

Here we describe the diagnostic utility of the indirect immunofluorescence assay (IFA) during a recent outbreak of highly pathogenic avian influenza (HPAI) subtype H5N1 virus in southern Thailand and demonstrate the usefulness of the cardiac tissue from infected chickens, quail, and ducks for diagnosis. The most reliable sample for IFA diagnosis of influenza A virus was cardiac tissue (83.0%; 44/53) which when divided by species (chicken, quail and duck cardiac tissues) gave respective positivity rates of 88% (22/25), 88.9% (16/18) and 60.0% (6/10). Cardiac tissue also gave the highest IFA intensity for the three species. We believe that the IFA method has wide applicability in developing countries or remote settings where clinically similar avian diseases with high morbidity and mortality such as Newcastle disease and fowl cholera are common and could be rapidly excluded thereby conserving valuable reference laboratory capacity for true HPAI outbreaks.

Pouplin T, Tolon B, Nuhant P, Delpech B, Marazano C. 2007. Synthetic studies towards bridgehead diprenyl-substituted bicyclo[3.3.1]nonane-2,9-diones as models for polyprenylated acylphloroglucinol construction EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, 2007 (30), pp. 5117-5125. | Citations: 18 (Scopus) | Show Abstract | Read more

The synthesis of bridgehead diprenylated bicyclo[3.3.1]-nonane-2,9-dione, based on a reductive rearrangement of an enol lactone, is presented. The same target could be reached by a one-step sequence involving Michael addition of 2,6-diprenylcyclohexanone onto acrolein and intramolecular aldol reaction. The first method could be extended to the formation of a compound with gem-dimethyl substituents adjacent to the bridgehead position, but the construction of a suitably substituted enol lactone, with a view to polyprenylated acylphloroglucinol elaboration, could not be achieved. © Wiley-VCH Verlag GmbH & Co. KGaA, 2007.

Newton O, English M. 2007. Young infant sepsis: aetiology, antibiotic susceptibility and clinical signs. Trans R Soc Trop Med Hyg, 101 (10), pp. 959-966. | Citations: 20 (Web of Science Lite) | Show Abstract | Read more

Globally, young infant mortality comprises 40% of the estimated 10.8 million child deaths annually. Almost all (99%) of these deaths arise in low- and middle-income countries (LMICs). Achievement of the Millennium Development Goal for child survival, however, requires a significant improvement in the management of infections in young infants. We have reviewed current evidence from LMICs on one major cause of young infant mortality, severe infection, and have described the range of pathogens, reported antibiotic susceptibility and value of clinical signs in identifying severe bacterial illness. Evidence from the reviewed studies appears to show that common pathogens in young infant infections change over time and vary within and across settings. However, there are few good, large studies outside major urban settings and many reports describe infections of babies born in hospital when most young infant infections probably occur in the majority born at home. Yet what knowledge there is can aid in instituting prompt and appropriate therapy, and perhaps thus minimize the emergence of multidrug-resistant bacteraemia, a major threat at least in hospital settings. Improved country level data on pattern of microorganisms, resistance and antibiotic use are required to help reduce mortality through development of local, evidence-based clinical guidelines.

Bakker B, Oostdijk W, Geskus RB, Stokvis-Brantsma WH, Vossen JM, Wit JM. 2007. Growth hormone (GH) secretion and response to GH therapy after total body irradiation and haematopoietic stem cell transplantation during childhood. Clin Endocrinol (Oxf), 67 (4), pp. 589-597. | Citations: 9 (Scopus) | Show Abstract | Read more

OBJECTIVE: In January 1997 we introduced a protocol for the treatment with GH of children with impaired growth after unfractionated total body irradiation (TBI). This study is an evaluation of that protocol. PATIENTS AND METHODS: Between January 1997 and July 2005, 66 patients (48 male) treated for haematological malignancies had at least two years of disease-free survival after TBI-based conditioning for stem cell transplantation (SCT). Stimulated and/or spontaneous GH secretion was decreased in 8 of the 29 patients tested because of impaired growth. Treatment with GH (daily dose 1.3 mg/m2 body surface area) was offered to all 29 patients and initiated in 23 of them (17 male). The main outcome measure was the effect of GH therapy on height standard deviation scores (SDS) after onset of GH therapy, estimated by random-effect modelling with corrections for sex, age at time of SCT and puberty (data analysed on intention-to-treat basis). RESULTS: At time of analysis, median duration of therapy was 3.2 years; median follow-up after start of GH therapy was 4.2 years. The estimated effect of GH therapy, modelled as nonlinear (logit) curve, was +1.1 SD after 5 years. Response to GH therapy did not correlate to GH secretion status. CONCLUSION: GH therapy has a positive effect on height SDS after TBI, irrespective of GH secretion status.

Bryant JE, Calvert AE, Mesesan K, Crabtree MB, Volpe KE, Silengo S, Kinney RM, Huang CY-H, Miller BR, Roehrig JT. 2007. Glycosylation of the dengue 2 virus E protein at N67 is critical for virus growth in vitro but not for growth in intrathoracically inoculated Aedes aegypti mosquitoes. Virology, 366 (2), pp. 415-423. | Citations: 39 (Web of Science Lite) | Show Abstract | Read more

To determine the importance of dengue 2 virus (DEN2V) envelope (E) protein glycosylation, virus mutants in one or both of the N-linked glycosylation motifs were prepared. We found that while the E2 mutant virus (N153Q) replicated in mammalian and mosquito cells, the E1 (N67Q) and E1/2 (N67Q and N153Q) mutant viruses were unable to grow in mammalian cells. Infection of C6/36 mosquito cells with either the E1 or E1/2 mutants resulted in the introduction of a compensatory mutation, K64N, restoring glycosylation in the area. All mutants replicated similarly in inoculated Aedes aegypti mosquitoes, with no change in their mutations. These results suggest that N-linked glycosylation of the E protein is not necessary for DEN2V replication in mosquitoes, however N-linked glycosylation at amino acid N67 (or nearby N64) is critical for the survival of the virus in either mammalian or insect cell culture.

Hanson JP, Dondorp AM, Day NPJ. 2007. Malaria treatment in the United States. JAMA, 298 (12), pp. 1396. | Citations: 1 (Web of Science Lite) | Read more

Smith DL, Guerra CA, Snow RW, Hay SI. 2007. Standardizing estimates of the Plasmodium falciparum parasite rate. Malar J, 6 (1), pp. 131. | Citations: 98 (Scopus) | Show Abstract | Read more

BACKGROUND: The Plasmodium falciparum parasite rate (PfPR) is a commonly reported index of malaria transmission intensity. PfPR rises after birth to a plateau before declining in older children and adults. Studies of populations with different age ranges generally report average PfPR, so age is an important source of heterogeneity in reported PfPR data. This confounds simple comparisons of PfPR surveys conducted at different times or places. METHODS: Several algorithms for standardizing PfPR were developed using 21 studies that stratify in detail PfPR by age. An additional 121 studies were found that recorded PfPR from the same population over at least two different age ranges; these paired estimates were used to evaluate these algorithms. The best algorithm was judged to be the one that described most of the variance when converting the PfPR pairs from one age-range to another. RESULTS: The analysis suggests that the relationship between PfPR and age is predictable across the observed range of malaria endemicity. PfPR reaches a peak after about two years and remains fairly constant in older children until age ten before declining throughout adolescence and adulthood. The PfPR pairs were poorly correlated; using one to predict the other would explain only 5% of the total variance. By contrast, the PfPR predicted by the best algorithm explained 72% of the variance. CONCLUSION: The PfPR in older children is useful for standardization because it has good biological, epidemiological and statistical properties. It is also historically consistent with the classical categories of hypoendemic, mesoendemic and hyperendemic malaria. This algorithm provides a reliable method for standardizing PfPR for the purposes of comparing studies and mapping malaria endemicity. The scripts for doing so are freely available to all.

Fegan GW, Noor AM, Akhwale WS, Cousens S, Snow RW. 2007. Effect of expanded insecticide-treated bednet coverage on child survival in rural Kenya: a longitudinal study. Lancet, 370 (9592), pp. 1035-1039. | Citations: 152 (Scopus) | Show Abstract | Read more

BACKGROUND: The potential of insecticide-treated bednets (ITNs) to contribute to child survival has been well documented in randomised controlled trials. ITN coverage has increased rapidly in Kenya from 7% in 2004 to 67% in 2006. We aimed to assess the extent to which this investment has led to improvements in child survival. METHODS: A dynamic cohort of about 3500 children aged 1-59 months were enumerated three times at yearly intervals in 72 rural clusters located in four districts of Kenya. The effect of ITN use on mortality was assessed with Poisson regression to take account of potential effect-modifying and confounding covariates. FINDINGS: 100 children died over 2 years. Overall mortality rates were much the same in the first and second years of the study (14.5 per 1000 person-years in the first year and 15.4 per 1000 person-years in the second). After adjustment for age, time period, and a number of other possible confounding variables, ITN use was associated with a 44% reduction in mortality (mortality rate ratio 0.56, 95% CI 0.33-0.96; p=0.04). This level of protection corresponds to about seven deaths averted for every 1000 ITNs distributed. INTERPRETATION: A combined approach of social marketing followed by mass free distribution of ITNs translated into child survival effects that are comparable with those seen in previous randomised controlled trials.

Lindegårdh N, Dondorp AM, Singhasivanon P, White NJ, Day NPJ. 2007. Validation and application of a liquid chromatographic-mass spectrometric method for determination of artesunate in pharmaceutical samples. J Pharm Biomed Anal, 45 (1), pp. 149-153. | Citations: 26 (Scopus) | Show Abstract | Read more

A simple and rapid liquid chromatographic-mass spectrometric assay for the evaluation of artesunate in vials for injection has been developed and validated. The content of each vial was dissolved in 3.0 mL of methanol using a SGE analytical syringe (1.0 mL). Each sample was diluted to a theoretical concentration of 1000 ng/mL and analysed in triplicate. Three replicates of calibration standards at concentrations 500, 1000 and 1500 ng/mL were used to construct a calibration curve. Artesunate was analysed by liquid chromatography with atmospheric pressure chemical ionisation (APCI) mass spectrometric (MS) detection on a Hypersil Gold column (100 mm x 4.6 mm) using a mobile phase containing methanol-ammonium acetate 10 mM pH 5.3 (70:30, v/v) at a flow rate of 1 mL/min. The assay was implemented for the analysis of artesunate for injection purchased from Guilin Pharmaceutical Company in China.

Geskus RB, Prins M, Hubert J-B, Miedema F, Berkhout B, Rouzioux C, Delfraissy J-F, Meyer L. 2007. The HIV RNA setpoint theory revisited. Retrovirology, 4 (1), pp. 65. | Citations: 25 (Scopus) | Show Abstract | Read more

BACKGROUND: The evolution of plasma viral load after HIV infection has been described as reaching a setpoint, only to start rising again shortly before AIDS diagnosis. In contrast, CD4 T-cell count is considered to show a stable decrease. However, characteristics of marker evolution over time depend on the scale that is used to visualize trends. In reconsidering the setpoint theory for HIV RNA, we analyzed the evolution of CD4 T-cell count and HIV-1 RNA level from HIV seroconversion to AIDS diagnosis. Follow-up data were used from two cohort studies among homosexual men (N = 400), restricting to the period before highly active antiretroviral therapy became widely available (1984 until 1996). Individual trajectories of both markers were fitted and averaged, both from seroconversion onwards and in the four years preceding AIDS diagnosis, using a bivariate random effects model. Both markers were evaluated on a scale that is directly related to AIDS risk. RESULTS: Individuals with faster AIDS progression had higher HIV RNA level six months after seroconversion. For CD4 T-cell count, this ordering was less clearly present. However, HIV RNA level and CD4 T-cell count showed qualitatively similar evolution over time after seroconversion, also when stratified by rate of progression to AIDS. In the four years preceding AIDS diagnosis, a non-significant change in HIV RNA increase was seen, whereas a significant biphasic pattern was present for CD4 T-cell decline. CONCLUSION: HIV RNA level has more setpoint behaviour than CD4 T-cell count as far as the level shortly after seroconversion is concerned. However, with respect to the, clinically more relevant, marker evolution over time after seroconversion, a setpoint theory holds as much for CD4 T-cell count as for HIV RNA level.

Idro R, Crawley J, Marsh K, Newton CRJC, Neville BGR. 2007. Neurological involvement in acute falciparum malaria in Kenyan children - Reply JAMA-JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION, 298 (11), pp. 1274-1274. | Citations: 1 (Web of Science Lite) | Read more

Bejon P, Mwacharo J, Kai O, Todryk S, Keating S, Lowe B, Lang T, Mwangi TW, Gilbert SC, Peshu N et al. 2007. The induction and persistence of T cell IFN-gamma responses after vaccination or natural exposure is suppressed by Plasmodium falciparum. J Immunol, 179 (6), pp. 4193-4201. | Citations: 62 (Web of Science Lite) | Show Abstract | Read more

Epidemiological observations suggest that T cell immunity may be suppressed in malaria-endemic areas. In vitro studies, animal models, and limited data in humans link immunosuppression with malaria, malnutrition, and other parasitic infections. However, there are no data to determine whether malaria-induced immunosuppression is significant in the long-term, or relative data comparing it with other factors in malaria-endemic areas, so as to measure the impact of malaria, other parasitic disease, nutritional status, age. and location on the acquisition and longevity of IFN-gamma responses in children in Kenya. We studied these factors in two cohorts of 1- to 6-year-old children in a malaria-endemic area. T cell responses were induced by vaccination in one cohort, and acquired as a result of natural exposure in a second cohort. Serial ELISPOT assays conducted over a 1-year period measured the induction and kinetics of IFN-gamma production in response to the malaria Ag thrombospondin-related adhesion protein. Induced responses in both cohorts and the longevity of response in the vaccinated cohort were fitted to potential explanatory variables. Parasitemia was prospectively associated with reduced IFN-gamma-producing T cells in both cohorts (by 15-25%), and both parasitemia and episodes of febrile malaria were associated with 19 and 31% greater attrition of T cell responses, respectively. Malaria may reduce the efficacy vaccinations such as bacillus Calmette-Guérin and investigational T cell-inducing vaccines, and may delay the acquisition of immunity following natural exposure to malaria and other pathogens.

Boonma P, Christensen PR, Suwanarusk R, Price RN, Russell B, Lek-Uthai U. 2007. Comparison of three molecular methods for the detection and speciation of Plasmodium vivax and Plasmodium falciparum. Malar J, 6 (1), pp. 124. | Citations: 51 (Scopus) | Show Abstract | Read more

BACKGROUND: Accurate diagnosis of Plasmodium spp. is essential for the rational treatment of malaria. Despite its many disadvantages, microscopic examination of blood smears remains the current "gold standard" for malaria detection and speciation. PCR assays offer an alternative to microscopy which has been shown to have superior sensitivity and specificity. Unfortunately few comparative studies have been done on the various molecular based speciation methods. METHODS: The sensitivity, specificity and cost effectiveness of three molecular techniques were compared for the detection and speciation of Plasmodium falciparum and Plasmodium vivax from dried blood spots collected from 136 patients in western Thailand. The results from the three molecular speciation techniques (nested PCR, multiplex PCR, and real-time PCR) were used to develop a molecular consensus (two or more identical PCR results) as an alternative gold standard. RESULTS: According to the molecular consensus, 9.6% (13/136) of microscopic diagnoses yielded false negative results. Multiplex PCR failed to detect P. vivax in three mixed isolates, and the nested PCR gave a false positive P. falciparum result in one case. Although the real-time PCR melting curve analysis was the most expensive method, it was 100% sensitive and specific and least time consuming of the three molecular techniques investigated. CONCLUSION: Although microscopy remains the most appropriate method for clinical diagnosis in a field setting, its use as a gold standard may result in apparent false positive results by superior techniques. Future studies should consider using more than one established molecular methods as a new gold standard to assess novel malaria diagnostic kits and PCR assays.

Price RN, Dorsey G, Ashley EA, Barnes KI, Baird JK, d'Alessandro U, Guerin PJ, Laufer MK, Naidoo I, Nosten F et al. 2007. World Antimalarial Resistance Network I: clinical efficacy of antimalarial drugs. Malar J, 6 (1), pp. 119. | Citations: 46 (Scopus) | Show Abstract | Read more

The proliferation of antimalarial drug trials in the last ten years provides the opportunity to launch a concerted global surveillance effort to monitor antimalarial drug efficacy. The diversity of clinical study designs and analytical methods undermines the current ability to achieve this. The proposed World Antimalarial Resistance Network (WARN) aims to establish a comprehensive clinical database from which standardised estimates of antimalarial efficacy can be derived and monitored over time from diverse geographical and endemic regions. The emphasis of this initiative is on five key variables which define the therapeutic response. Ensuring that these data are collected at the individual patient level in a consistent format will facilitate better data management and analytical practices, and ensure that clinical data can be readily collated and made amenable for pooled analyses. Such an approach, if widely adopted will permit accurate and timely recognition of trends in drug efficacy. This will guide not only appropriate interventions to deal with established multidrug resistant strains of malaria, but also facilitate prompt action when new strains of drug resistant plasmodia first emerge. A comprehensive global database incorporating the key determinants of the clinical response with in vitro, molecular and pharmacokinetic parameters will bring together relevant data on host, drug and parasite factors that are fundamental contributors to treatment efficacy. This resource will help guide rational drug policies that optimize antimalarial drug use, in the hope that the emergence and spread of resistance to new drugs can be, if not prevented, at least delayed.

Tang CT, Nguyen DT, Hoa NT, Nguyen TMP, Le VT, To SD, Lindsay J, Nguyen TD, Bach VC, Le QT et al. 2007. An outbreak of severe infections with community-acquired MRSA carrying the panton-valentine leukocidin following vaccination PLoS ONE, 2 (9), | Citations: 22 (Scopus) | Show Abstract | Read more

Background. Infections with community-acquired methicillin-resistant Staphyloccus aureus (CA-MRSA) are emerging worldwide. We investigated an outbreak of severe CA-MRSA infections in children following out-patient vaccination. Methods and Findings. We carried out a field investigation after adverse events following immunization (AEFI) were reported. We reviewed the clinical data from all cases. S. aureus recovered from skin infections and from nasal and throat swabs were analyzed by pulse-field gel electrophoresis, multi locus sequence typing, PCR and microarray. In May 2006, nine children presented with AEFI, ranging from fatal toxic shock syndrome, necrotizing soft tissue infection, purulent abscesses, to fever with rash. All had received a vaccination injection in different health centres in one District of Ho Chi Minh City. Eight children had been vaccinated by the same health care worker (HCW). Deficiencies in vaccine quality, storage practices, or preparation and delivery were not found. Infection control practices were insufficient. CA-MRSA was cultured in four children and from nasal and throat swabs from the HCW. Strains from children and HCW were indistinguishable. All carried the Panton-Valentine leukocidine (PVL), the staphylococcal enterotoxin B gene, the gene complex for staphylococcal-cassette-chromosome mectype V, and were sequence type 59. Strain HCM3A is epidemiologically unrelated to a strain of ST59 prevalent in the USA, although they belong to the same lineage. Conclusions. We describe an outbreak of infections with CA-MRSA in children, transmitted by an asymptomatic colonized HCW during immunization injection. Consistent adherence to injection practice guidelines is needed to prevent CA-MRSA transmission in both in- and outpatient settings. © 2007 Chi Thuong et al.

Phimda K, Hoontrakul S, Suttinont C, Chareonwat S, Losuwanaluk K, Chueasuwanchai S, Chierakul W, Suwancharoen D, Silpasakorn S, Saisongkorh W et al. 2007. Doxycycline versus azithromycin for treatment of leptospirosis and scrub typhus. Antimicrob Agents Chemother, 51 (9), pp. 3259-3263. | Citations: 86 (Scopus) | Show Abstract | Read more

Leptospirosis and scrub typhus are important causes of acute fever in Southeast Asia. Options for empirical therapy include doxycycline and azithromycin, but it is unclear whether their efficacies are equivalent. We conducted a multicenter, open, randomized controlled trial with adult patients presenting with acute fever (<15 days), without an obvious focus of infection, at four hospitals in Thailand between July 2003 and January 2005. Patients were randomly allocated to receive either a 7-day course of doxycycline or a 3-day course of azithromycin. The cure rate, fever clearance time, and adverse drug events were compared between the two study groups. A total of 296 patients were enrolled in the study. The cause of acute fever was determined for 151 patients (51%): 69 patients (23.3%) had leptospirosis; 57 patients (19.3%) had scrub typhus; 14 patients (4.7%) had murine typhus; and 11 patients (3.7%) had evidence of both leptospirosis and a rickettsial infection. The efficacy of azithromycin was not inferior to that of doxycycline for the treatment of both leptospirosis and scrub typhus, with comparable fever clearance times in the two treatment arms. Adverse events occurred more frequently in the doxycycline group than in the azithromycin group (27.6% and 10.6%, respectively; P = 0.02). In conclusion, doxycycline is an affordable and effective choice for the treatment of both leptospirosis and scrub typhus. Azithromycin was better tolerated than doxycycline but is more expensive and less readily available.

Mytton OT, Ashley EA, Peto L, Price RN, La Y, Hae R, Singhasivanon P, White NJ, Nosten F. 2007. Electrocardiographic safety evaluation of dihydroartemisinin piperaquine in the treatment of uncomplicated falciparum malaria. Am J Trop Med Hyg, 77 (3), pp. 447-450. | Citations: 26 (Scopus) | Show Abstract

Dihydroartemisinin-piperaquine (DP) could become a leading fixed combination malaria treatment worldwide. Although there is accumulating evidence of efficacy and safety from clinical trials, data on cardiotoxicity are limited. In two randomized controlled trials in Thailand, 56 patients had ECGs performed before treatment, 4 hours after the first dose, and 4 hours after the last dose. The mean (95% CI) changes in QTc interval (Bazett's correction) were 2 (-6 to 9) ms and 14 (7 to 21) ms, respectively. These small changes on the third day of treatment are similar to those observed elsewhere in the convalescent phase following antimalarial treatment with drugs known to have no cardiac effects and are therefore likely to result from recovery from acute malaria and not the treatment given. At therapeutic doses, DP does not have clinically significant effects on the electrocardiogram.

Myint HY, Ashley EA, Day NPJ, Nosten F, White NJ. 2007. Efficacy and safety of dihydroartemisinin-piperaquine. Trans R Soc Trop Med Hyg, 101 (9), pp. 858-866. | Citations: 65 (Web of Science Lite) | Show Abstract | Read more

Dihydroartemisinin-piperaquine, a fixed-dose combination antimalarial, is an inexpensive, safe and highly effective treatment for uncomplicated falciparum or vivax malaria. Efficacy assessed over 28-63 days has consistently exceeded 95% in the treatment of multidrug-resistant falciparum malaria. More than 2600 patients have been treated with this combination in prospective studies, mainly in Southeast Asia. Tolerability was uniformly good, and no serious adverse effects have been identified. The dosing regimen has been simplified from four doses to once daily over 3 days. More information on efficacy in Africa, and more pharmacokinetic and efficacy data in children are needed.

Arreesrisom P, Dondorp AM, Looareesuwan S, Udomsangpetch R. 2007. Suppressive effects of the anti-oxidant N-acetylcysteine on the anti-malarial activity of artesunate. Parasitol Int, 56 (3), pp. 221-226. | Citations: 18 (Scopus) | Show Abstract | Read more

The anti-oxidant drug N-acetylcysteine (NAC) has been proposed as adjunctive treatment in severe falciparum malaria. However, this might inhibit the anti-malarial drug action of the artemisinins, which are thought to exert their parasitocidal action through oxidative damage. We studied the interaction between NAC and artesunate as well as quinine in an in vitro drug sensitivity assay. Combination with NAC reduced the parasitocidal effect of artesunate only within the first 6 h of incubation, whereas no interaction was observed with quinine. Pre-incubation of P. falciparum with NAC resulted in a similar inhibitory effect on the anti-malarial activity of artesunate, whereas no inhibition was observed when NAC was added 2 h after parasite exposure to artesunate. Assessment of parasite maturation inhibition by the standard Giemsa's staining was in accordance with the use of a vital staining. The results herein caution the use of adjunctive treatment for malaria infection. Combination of antagonistic drugs may lead to adverse effects.

Nguansangiam S, Day NPJ, Hien TT, Mai NTH, Chaisri U, Riganti M, Dondorp AM, Lee SJ, Phu NH, Turner GDH et al. 2007. A quantitative ultrastructural study of renal pathology in fatal Plasmodium falciparum malaria. Trop Med Int Health, 12 (9), pp. 1037-1050. | Citations: 59 (Scopus) | Show Abstract | Read more

OBJECTIVE: To use electron microscopy to examine the role of parasitized red blood cell (PRBC) sequestration in the pathogenesis of acute renal failure in severe falciparum malaria. METHODS: Ultrastructural pathological examination of renal tissues from Southeast Asian adults (n = 63) who died from severe falciparum malaria. Qualitative and quantitative determination of the major pathological features of disease, including PRBC and leukocyte sequestration. Clinico-pathological correlation with the pre-mortem clinical picture and peripheral parasite count. RESULTS: There was a high incidence of malaria-associated renal failure in this population (> 40%) and a correlation between this incidence, severe malarial anaemia and shock. Pathological features included PRBC sequestration in glomerular and tubulo-interstitial vessels, acute tubular damage and mild glomerular hypercellularity resulting from the accumulation of host monocytes within glomerular capillaries. No evidence for an immune complex mediated glomerulonephritis was found. There was a correlation between parasite sequestration in the kidney and pre-mortem renal failure, although overall levels of sequestration were relatively low. Levels of sequestration (Knob+ PRBC) were significantly higher in malaria-associated renal failure than in fatal cases without renal failure (P = 0.005). CONCLUSION: Malaria-associated renal failure is a common and serious complication of severe Plasmodium falciparum malaria in this population, associated with acute tubular injury rather than glomerulonephritis, and linked to localization of host monocytes in the kidney as well as sequestration of PRBCs.

Bonnet M, Ramsay A, Gagnidze L, Githui W, Guerin PJ, Varaine F. 2007. Reducing the number of sputum samples examined and thresholds for positivity: an opportunity to optimise smear microscopy. Int J Tuberc Lung Dis, 11 (9), pp. 953-958. | Citations: 26 (Scopus) | Show Abstract

SETTING: Urban health clinic, Nairobi. OBJECTIVE: To evaluate the impact on tuberculosis (TB) case detection and laboratory workload of reducing the number of sputum smears examined and thresholds for diagnosing positive smears and positive cases. DESIGN: In this prospective study, three Ziehl-Neelsen stained sputum smears from consecutive pulmonary TB suspects were examined blind. The standard approach (A), > or = 2 positive smears out of 3, using a cut-off of 10 acid-fast bacilli (AFB)/100 high-power fields (HPF), was compared with approaches B, > or = 2 positive smears (> or = 4 AFB/100 HPF) out of 3, one of which is > or = 10 AFB/100 HPF; C, > or = 2 positive smears (> or = 4 AFB/100 HPF) out of 3; D, > or = 1 positive smear (> or = 10 AFB/100 HPF) out of 2; and E, > or = 1 positive smear (> or = 4 AFB/100 HPF) out of 2. The microscopy gold standard was detection of at least one positive smear (> or = 4 AFB/100 HPF) out of 3. RESULTS: Among 644 TB suspects, the alternative approaches detected from 114 (17.7%) (approach B) to 123 cases (19.1%) (approach E) compared to 105 cases (16.3%) for approach A (P < 0.005). Sensitivity ranged between 82.0% (105/128) for A and 96.1% (123/128) for E. The single positive smear approaches reduced the number of smears by 36% compared to approach A. CONCLUSION: Reducing the number of specimens and the positivity threshold to define a positive case increased the sensitivity of microscopy and reduced laboratory workload.

Ahoua L, Etienne W, Fermon F, Godain G, Brown V, Kadjo K, Bouaffou K, Legros D, Guerin PJ. 2007. Outbreak of beriberi in a prison in Côte d'Ivoire. Food Nutr Bull, 28 (3), pp. 283-290. | Citations: 17 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: A beriberi outbreak occurred in the Maison d'Arrêt et de Correction d'Abidjan (MACA), a detention center in Abidjan, Côte d'Ivoire, between October 2002 and April 2003. OBJECTIVE: A retrospective investigation was conducted to document the outbreak in April 2003. METHODS: A descriptive analysis and a case-control study were performed. A probable case patient was defined as a person detained in the center between October 2002 and April 2003 with at least two of the following symptoms: bilateral leg edema, dyspnea, positive squat test, motor deficiencies, and paresthesia. A definite case patient was defined as a probable case patient who showed clinical improvement under thiamin treatment. RESULTS: Of 712 cases reported, 115 (16%) were probable and 597 (84%) were definite. The overall attack rate was 14.1%, and the case fatality rate was 1.0% (7/712). The highest attack rate was reported in the building housing prisoners with long-term sentences (16.9%). All patients were male, and the mean age was 28 years. During the period studied, the penal ration provided a fifth of the quantity of thiamin recommended by international standards. After adjustment for potential confounders, a history of cholera infection (adjusted odds ratio [OR(a)], 12.9; 95% confidence interval [CI], 2.9 to 54.1) and incarceration in the building for severe penalties (OR(a), 4.8; 95% CI, 1.3 to 18.5) were associated with the disease. CONCLUSIONS: Beriberi has been underreported among prisoners. Further attention should be given to its risk factors, especially a history of acute diarrhea. Systematic food supplementation with vitamins and micronutrients should be discussed when the penal ration does not provide the necessary nutrient intake recommended according to international standards.

van Doorn HR, Wentink-Bonnema E, Rentenaar RJ, van Gool T. 2007. Specific cross-reactivity in sera from cystic echinococcosis patients in an enzyme-linked immunoelectrotransfer blot for cysticercosis diagnostics. Trans R Soc Trop Med Hyg, 101 (9), pp. 948-950. | Citations: 5 (Scopus) | Show Abstract | Read more

A commercially available enzyme-linked immunoelectrotransfer blot originally intended for diagnosis of cysticercosis was evaluated for echinococcosis diagnosis, because a characteristic band pattern--different from the specific cysticercosis pattern--was observed in sera from patients with echinococcosis. This band pattern was observed in 29 (78%) of 37 parasitologically proven cystic echinococcosis patients. Specificity of these bands was 100% for echinococcosis, when tested with 75 control sera.

White LJ, Mandl JN, Gomes MGM, Bodley-Tickell AT, Cane PA, Perez-Brena P, Aguilar JC, Siqueira MM, Portes SA, Straliotto SM et al. 2007. Understanding the transmission dynamics of respiratory syncytial virus using multiple time series and nested models. Math Biosci, 209 (1), pp. 222-239. | Citations: 40 (Scopus) | Show Abstract | Read more

The nature and role of re-infection and partial immunity are likely to be important determinants of the transmission dynamics of human respiratory syncytial virus (hRSV). We propose a single model structure that captures four possible host responses to infection and subsequent reinfection: partial susceptibility, altered infection duration, reduced infectiousness and temporary immunity (which might be partial). The magnitude of these responses is determined by four homotopy parameters, and by setting some of these parameters to extreme values we generate a set of eight nested, deterministic transmission models. In order to investigate hRSV transmission dynamics, we applied these models to incidence data from eight international locations. Seasonality is included as cyclic variation in transmission. Parameters associated with the natural history of the infection were assumed to be independent of geographic location, while others, such as those associated with seasonality, were assumed location specific. Models incorporating either of the two extreme assumptions for immunity (none or solid and lifelong) were unable to reproduce the observed dynamics. Model fits with either waning or partial immunity to disease or both were visually comparable. The best fitting structure was a lifelong partial immunity to both disease and infection. Observed patterns were reproduced by stochastic simulations using the parameter values estimated from the deterministic models.

Malacrida S, Katsuyama Y, Droma Y, Basnyat B, Angelini C, Ota M, Danieli GA. 2007. Association between human polymorphic DNA markers and hypoxia adaptation in Sherpa detected by a preliminary genome scan. Ann Hum Genet, 71 (Pt 5), pp. 630-638. | Citations: 7 (Scopus) | Show Abstract | Read more

Genetic determinants of resistance to hypobaric hypoxia in the Sherpa are still unknown. Since adaptive gene variants must still be subjected to positive selection, linkage disequilibrium between such variants and specific alleles of flanking DNA markers is expected. Following this line of reasoning, we performed a human genome scan using 998 polymorphic DNA markers in 7 unrelated Sherpa porters living in the Solu-Khumbu area. This minimalist approach succeeded in detecting 8 DNA markers showing homozygosity for the same shared allele. Analysis of additional DNA samples from 2 more Sherpa porters focused our attention on three polymorphic DNA markers (D6S1697, D14S274, D17S1795) showing homozygosity for the same shared allele in 8 out 9 tested individuals. Analysis of DNA samples from Sherpa and non-Sherpa populations of Nepal proved HW equilibrium in both populations for markers D14S274 and D17S1795, while an excess of heterozygotes was observed in the Sherpa population for marker D6S1697. A significant difference in allele frequencies for D14S274 and D17S1795 between the two populations was observed. These findings exclude the possibility that homozygosity for 3 specific loci in 8 unrelated individuals might be ascribed to inbreeding or recent genetic drift. We therefore conclude that the chromosomal segments detected by such DNA markers may include genes involved in adaptation to hypobaric hypoxia.

Chierakul W, Anunnatsiri S, Chaowagul W, Peacock SJ, Chetchotisakd P, Day NP. 2007. Addition of trimethoprim-sulfamethoxazole to ceftazidime during parenteral treatment of melioidosis is not associated with a long-term outcome benefit CLINICAL INFECTIOUS DISEASES, 45 (4), pp. 521-523. | Citations: 10 (Scopus) | Read more

Bejon P, Ogada E, Mwangi T, Milligan P, Lang T, Fegan G, Gilbert SC, Peshu N, Marsh K, Hill AVS. 2007. Extended follow-up following a phase 2b randomized trial of the candidate malaria vaccines FP9 ME-TRAP and MVA ME-TRAP among children in Kenya. PLoS One, 2 (8), pp. e707. | Citations: 51 (Scopus) | Show Abstract | Read more

BACKGROUND: "FFM ME-TRAP" is sequential immunisation with two attenuated poxvirus vectors (FP9 and modified vaccinia virus Ankara) delivering the pre-erythrocytic malaria antigen ME-TRAP. Over nine months follow-up in our original study, there was no evidence that FFM ME-TRAP provided protection against malaria. The incidence of malaria was slightly higher in children who received FFM ME-TRAP, but this was not statistically significant (hazard ratio 1.5, 95% CI 1.0-2.3). Although the study was unblinded, another nine months follow-up was planned to monitor the incidence of malaria and other serious adverse events. METHODS AND FINDINGS: 405 children aged 1-6 yrs were initially randomized to vaccination with either FFM ME-TRAP or control (rabies vaccine). 380 children were still available for follow-up after the first nine months. Children were seen weekly and whenever they were unwell for nine months monitoring. The axillary temperature was measured, and blood films taken when febrile. The primary analysis was time to parasitaemia >2,500/microl. During the second nine months monitoring, 49 events met the primary endpoint (febrile malaria with parasites >2,500/microl) in the Intention To Treat (ITT) group. 23 events occurred among the 189 children in the FFM ME-TRAP group, and 26 among the 194 children in the control group. In the full 18 months of monitoring, there were 63 events in the FFM ME-TRAP group and 60 in the control group (HR = 1.2, CI 0.84-1.73, p = 0.35). There was no evidence that the HR changed over the 18 months (test for interaction between time and vaccination p = 0.11). CONCLUSIONS: Vaccination with FFM ME-TRAP was not protective against malaria in this study. Malaria incidence during 18 months of surveillance was similar in both vaccine groups. TRIAL REGISTRATION: ISRCTN88335123.

Anstey NM, Pain MCF, Price RN, Maguire GP. 2007. Tumor necrosis factor and increase in alveolar capillary barrier in malaria - Reply to Eisenhut JOURNAL OF INFECTIOUS DISEASES, 196 (4), pp. 647-648. | Read more

Micol R, Lortholary O, Sar B, Laureillard D, Ngeth C, Dousset J-P, Chanroeun H, Ferradini L, Guerin PJ, Dromer F, Fontanet A. 2007. Prevalence, determinants of positivity, and clinical utility of cryptococcal antigenemia in Cambodian HIV-infected patients. J Acquir Immune Defic Syndr, 45 (5), pp. 555-559. | Citations: 83 (Scopus) | Show Abstract | Read more

OBJECTIVES: To determine the prevalence, determinants ofpositivity, and clinical utility of serum cryptococcal polysaccharide (CPS) antigen testing among HIV-infected patients in 2004 in Cambodia, an area highly endemic for cryptococcosis. METHODS: All HIV-infected patients with a CD4+ count <200 cells/mm3 attending 1 of 2 Phnom Penh hospitals for the first time were systematically screened for serum CPS. Patients with positive test results were further investigated to identify those with cryptococcal meningitis (CM), pulmonary cryptococcosis, or isolated positive cryptococcal antigenemia (IPCA). RESULTS: The median (interquartile range [IQR]) CD4+ count of 327 enrolled patients was 24 (IQR: 8 to 65) cells/mm3. The prevalence of cryptococcal infection was 59 (18.0%) of 327 cases, of which 41 were CM and 10 were IPCA. In the absence of serum CPS detection, 17 (28.8%) of 59 cryptococcal infections would have been missed on the day of consultation. In patients with no specific symptoms of meningoencephalitis, the prevalence of positive serum CPS detection was 32 (10.8%) of 295 cases. Countryside residence (adjusted odds ratio [AOR] = 3.6), headache (AOR = 3.2), body mass index <15.4 kg/m2 (AOR = 3.4), CD4+ count <50 cells/mm3 (AOR = 4.0), and male gender (marginally, AOR = 2.1) were all independently associated with a positive test results. CONCLUSION: Serum CPS screening among AIDS patients with a CD4+ count <100 cells/mm3 is useful in areas highly endemic for cryptococcosis, allowing early diagnosis and treatment of this opportunistic infection.

Chierakul W, Anunnatsiri S, Chaowagul W, Peacock SJ, Chetchotisakd P, Day NP. 2007. Addition of trimethoprim-sulfamethoxazole to ceftazidime during parenteral treatment of melioidosis is not associated with a long-term outcome benefit. Clin Infect Dis, 45 (4), pp. 521-523. | Read more

Cumberland P, Shulman CE, Maple PAC, Bulmer JN, Dorman EK, Kawuondo K, Marsh K, Cutts FT. 2007. Maternal HIV infection and placental malaria reduce transplacental antibody transfer and tetanus antibody levels in newborns in Kenya. J Infect Dis, 196 (4), pp. 550-557. | Citations: 62 (Scopus) | Show Abstract | Read more

BACKGROUND: In clinical trials, maternal tetanus toxoid (TT) vaccination is effective in protecting newborns against tetanus infection, but inadequate placental transfer of tetanus antibodies may contribute to lower-than-expected rates of protection in routine practice. We studied the effect of placental malaria and maternal human immunodeficiency virus (HIV) infection on placental transfer of antibodies to tetanus. METHODS: A total of 704 maternal-cord paired serum samples were tested by ELISA for antibodies to tetanus. The HIV status of all women was determined by an immunoglobulin G antibody-capture particle-adherence test, and placental malaria was determined by placental biopsy. Maternal history of TT vaccination was recorded. RESULTS: Tetanus antibody levels were reduced by 52% (95% confidence interval [CI], 30%-67%) in newborns of HIV-infected women and by 48% (95% CI, 26%-62%) in newborns whose mothers had active-chronic or past placental malaria. Thirty-seven mothers (5.3%) and 55 newborns (7.8%) had tetanus antibody levels <0.1 IU/mL (i.e., were seronegative). Mothers' self-reported history of lack of tetanus immunization was the strongest predictor of seronegativity and of tetanus antibody levels in maternal and cord serum. CONCLUSION: Malarial and HIV infections may hinder efforts to eliminate maternal and neonatal tetanus, making implementation of the current policy for mass vaccination of women of childbearing age an urgent priority.

Willemze AJ, Geskus RB, Noordijk EM, Kal HB, Egeler RM, Vossen JM. 2007. HLA-identical haematopoietic stem cell transplantation for acute leukaemia in children: less relapse with higher biologically effective dose of TBI. Bone Marrow Transplant, 40 (4), pp. 319-327. | Citations: 10 (Scopus) | Show Abstract | Read more

To examine relapse, survival and transplant-related complications in relationship to disease- and pre-treatment-related characteristics, we evaluated 132 children, who consecutively received an allogeneic HLA-identical SCT for acute leukaemia in our centre: ALL in first remission (n=24), ALL in second remission (n=53) and AML in first remission (n=55). The source of the stem cells was bone marrow in all but three cases. Most patients (89%) were pre-treated with cyclophosphamide and an age-related dose of TBI. Initially, GVHD prophylaxis consisted of long-course MTX only (n=24), later short-course MTX and CsA (n=102) was given. All patients were nursed in strictly protective isolation and received total gut decontamination to suppress their potentially pathogenic enteric microflora. The 5-year probability of overall survival was 63, 53 and 74% for ALL1, ALL2 and AML1, respectively (median follow-up: 10.6 years). The overall transplant-related mortality was 6%. The incidence of acute GVHD was 17%; 6% was grades II-IV. A higher total biologically effective TBI dose (BED) resulted in a decreased relapse frequency (P=0.034) and increased overall survival. AML patients with acute GVHD got no relapse (P=0.02); this was not the case in ALL patients. Fractionated TBI regimens with higher BED should be evaluated in prospective studies.

Wiersinga WJ, Wieland CW, van der Windt GJW, de Boer A, Florquin S, Dondorp A, Day NP, Peacock SJ, van der Poll T. 2007. Endogenous interleukin-18 improves the early antimicrobial host response in severe melioidosis. Infect Immun, 75 (8), pp. 3739-3746. | Citations: 31 (Scopus) | Show Abstract | Read more

Melioidosis is caused by the soil saprophyte Burkholderia pseudomallei and is endemic in Southeast Asia. The pathogenesis of melioidosis is still largely unknown, although gamma interferon (IFN-gamma) seems to play an obligatory role in host defense. Previously, we have shown that IFN-gamma production in melioidosis is controlled in part by interleukin-18 (IL-18). The aim of the present study was to determine the role of IL-18 in the immune response to B. pseudomallei. For this the following investigations were performed. (i) Plasma IL-18 and blood monocyte IL-18 mRNA levels were elevated in 34 patients with culture-proven melioidosis compared to the levels in 32 local healthy controls; in addition, IL-18 binding protein levels were markedly elevated in patients, strongly correlating with mortality. (ii) IL-18 gene-deficient (IL-18 knockout [KO]) mice showed accelerated mortality after intranasal infection with a lethal dose of B. pseudomallei, which was accompanied by enhanced bacterial growth in their lungs, livers, spleens, kidneys, and blood at 24 and 48 h postinfection, compared to wild-type mice. In addition, IL-18 KO mice displayed evidence of enhanced hepatocellular injury and renal insufficiency. Together, these data indicate that the enhanced production of IL-18 in melioidosis is an essential part of a protective immune response to this severe infection.

Cheng AC, Limmathurotsakul D, Chierakul W, Getchalarat N, Wuthiekanun V, Stephens DP, Day NPJ, White NJ, Chaowagul W, Currie BJ, Peacock SJ. 2007. A randomized controlled trial of granulocyte colony-stimulating factor for the treatment of severe sepsis due to melioidosis in Thailand. Clin Infect Dis, 45 (3), pp. 308-314. | Citations: 60 (Scopus) | Show Abstract | Read more

BACKGROUND: Melioidosis is a tropical infectious disease associated with significant mortality. Most deaths occur early and are caused by fulminant sepsis. METHODS: In this randomized, placebo-controlled trial, we assessed the efficacy of lenograstim (granulocyte colony-stimulating factor [G-CSF], 263 mu g per day administered intravenously) in ceftazidime-treated patients with severe sepsis caused by suspected melioidosis in Thailand. RESULTS: Over a 27-month period, 60 patients were enrolled to receive either G-CSF (30 patients, 18 of whom had culture-confirmed melioidosis) or placebo (30 patients, 23 of whom had culture-confirmed melioidosis). Mortality rates were similar in both groups (G-CSF group, 70%; placebo group, 87%; risk ratio, 0.81; 95% confidence interval, 0.61-1.06; P=.2), including among patients with confirmed melioidosis (83% vs. 96%; P=.3). The duration of survival was longer for patients who received G-CSF than for patients who received placebo (33 h vs. 18.6 h; hazard ratio, 0.56; 95% confidence interval, 0.31-1.00; P=.05). CONCLUSIONS: Receipt of G-CSF is associated with a longer duration of survival but is not associated with a mortality benefit in patients with severe sepsis who are suspected of having melioidosis in Thailand. We hypothesize that G-CSF may "buy time" for severely septic patients, but survival is more likely to be improved by management of associated metabolic abnormalities and organ dysfunction associated with severe sepsis.

Dunstan SJ, Nguyen TH, Rockett K, Forton J, Morris AP, Diakite M, Mai NL, Le TP, House D, Parry CM et al. 2007. A TNF region haplotype offers protection from typhoid fever in Vietnamese patients. Hum Genet, 122 (1), pp. 51-61. | Citations: 18 (Scopus) | Show Abstract | Read more

The genomic region surrounding the TNF locus on human chromosome 6 has previously been associated with typhoid fever in Vietnam (Dunstan et al. in J Infect Dis 183:261-268, 2001). We used a haplotypic approach to understand this association further. Eighty single nucleotide polymorphisms (SNPs) spanning a 150 kb region were genotyped in 95 Vietnamese individuals (typhoid case/mother/father trios). A subset of data from 33 SNPs with a minor allele frequency of >4.3% was used to construct haplotypes. Fifteen SNPs, which tagged the 42 constructed haplotypes were selected. The haplotype tagging SNPs (T1-T15) were genotyped in 380 confirmed typhoid cases and 380 Vietnamese ethnically matched controls. Allelic frequencies of seven SNPs (T1, T2, T3, T5, T6, T7, T8) were significantly different between typhoid cases and controls. Logistic regression results support the hypothesis that there is just one signal associated with disease at this locus. Haplotype-based analysis of the tag SNPs provided positive evidence of association with typhoid (posterior probability 0.821). The analysis highlighted a low-risk cluster of haplotypes that each carry the minor allele of T1 or T7, but not both, and otherwise carry the combination of alleles *12122*1111 at T1-T11, further supporting the one associated signal hypothesis. Finally, individuals that carry the typhoid fever protective haplotype *12122*1111 also produce a relatively low TNF-alpha response to LPS.

Simmons CP, Chau TNB, Thuy TT, Tuan NM, Hoang DM, Thien NT, Lien LB, Quy NT, Hieu NT, Hien TT et al. 2007. Maternal antibody and viral factors in the pathogenesis of dengue virus in infants. J Infect Dis, 196 (3), pp. 416-424. | Citations: 93 (Scopus) | Show Abstract | Read more

The pathogenesis of dengue in infants is poorly understood. We postulated that dengue severity in infants would be positively associated with markers of viral burden and that maternally derived, neutralizing anti-dengue antibody would have decayed before the age at which infants with dengue presented to the hospital. In 75 Vietnamese infants with primary dengue, we found significant heterogeneity in viremia and NS1 antigenemia at hospital presentation, and these factors were independent of disease grade or continuous measures of disease severity. Neutralizing antibody titers, predicted in each infant at the time of their illness, suggested that the majority of infants (65%) experienced dengue hemorrhagic fever when the maternally derived neutralizing antibody titer had declined to <1 : 20. Collectively, these data have important implications for dengue vaccine research because they suggest that viral burden may not solely explain severe dengue in infants and that neutralizing antibody is a reasonable but not absolute marker of protective immunity in infants.

Dondorp AM, Silamut K, Charunwatthana P, Chuasuwanchai S, Ruangveerayut R, Krintratun S, White NJ, Ho M, Day NPJ. 2007. Levamisole inhibits sequestration of infected red blood cells in patients with falciparum malaria. J Infect Dis, 196 (3), pp. 460-466. | Citations: 35 (Scopus) | Show Abstract | Read more

BACKGROUND: Sequestration of infected red blood cells (iRBCs) in the microcirculation is central to the pathophysiology of falciparum malaria. It is caused by cytoadhesion of iRBCs to vascular endothelium, mediated through the binding of Plasmodium falciparum erythrocyte membrane protein-1 to several endothelial receptors. Binding to CD36, the major vascular receptor, is stabilized through dephosphorylation of CD36 by an alkaline phosphatase. This is inhibited by the alkaline phosphatase-inhibitor levamisole, resulting in decreased cytoadhesion. METHODS: Patients with uncomplicated falciparum malaria were randomized to receive either quinine treatment alone or treatment with a single 150-mg dose of levamisole as an adjunct to quinine. Peripheral blood parasitemia and parasite stage distribution were monitored closely over time. RESULTS: Compared with those in control subjects, peripheral blood parasitemias of mature P. falciparum parasites increased during the 24 h after levamisole administration (n=21; P=.006). The sequestration ratio (between observed and expected peripheral blood parasitemia) of early trophozoite and midtrophozoite parasites increased after levamisole treatment, with near complete prevention of early trophozoite sequestration and >65% prevention of midtrophozoite sequestration. CONCLUSION: These findings strongly suggest that levamisole decreases iRBC sequestration in falciparum malaria in vivo and should be considered as a potential adjunctive treatment for severe falciparum malaria. TRIAL REGISTRATION: Current Controlled Trials identifier: 15314870.

White NJ. 2007. Cardiotoxicity of antimalarial drugs. Lancet Infect Dis, 7 (8), pp. 549-558. | Citations: 133 (Scopus) | Show Abstract | Read more

There are consistent differences in cardiovascular state between acute illness in malaria and recovery that prolong the electrocardiographic QT interval and have been misinterpreted as resulting from antimalarial cardiotoxicity. Of the different classes of antimalarial drugs, only the quinolines, and structurally related antimalarial drugs, have clinically significant cardiovascular effects. Drugs in this class can exacerbate malaria-associated orthostatic hypotension and several have been shown to delay ventricular depolarisation slightly (class 1c effect), resulting in widening of the QRS complex, but only quinidine and halofantrine have clinically significant effects on ventricular repolarisation (class 3 effect). Both drugs cause potentially dangerous QT prolongation, and halofantrine has been associated with sudden death. The parenteral quinoline formulations (chloroquine, quinine, and quinidine) are predictably hypotensive when injected rapidly, and cardiovascular collapse can occur with self-poisoning. Transiently hypotensive plasma concentrations of chloroquine can occur when doses of 5 mg base/kg or more are given by intramuscular or subcutaneous injection. At currently recommended doses, other antimalarial drugs do not have clinically significant cardiac effects. More information on amodiaquine, primaquine, and the newer structurally related compounds is needed.

Bejon P, Berkley JA, Mwangi T, Ogada E, Mwangi I, Maitland K, Williams T, Scott JAG, English M, Lowe BS et al. 2007. Defining childhood severe falciparum malaria for intervention studies. PLoS Med, 4 (8), pp. e251. | Citations: 72 (Scopus) | Show Abstract | Read more

BACKGROUND: Clinical trials of interventions designed to prevent severe falciparum malaria in children require a clear endpoint. The internationally accepted definition of severe malaria is sensitive, and appropriate for clinical purposes. However, this definition includes individuals with severe nonmalarial disease and coincident parasitaemia, so may lack specificity in vaccine trials. Although there is no "gold standard" individual test for severe malaria, malaria-attributable fractions (MAFs) can be estimated among groups of children using a logistic model, which we use to test the suitability of various case definitions as trial endpoints. METHODS AND FINDINGS: A total of 4,583 blood samples were taken from well children in cross-sectional surveys and from 1,361 children admitted to a Kenyan District hospital with severe disease. Among children under 2 y old with severe disease and over 2,500 parasites per microliter of blood, the MAFs were above 85% in moderate- and low-transmission areas, but only 61% in a high-transmission area. HIV and malnutrition were not associated with reduced MAFs, but gastroenteritis with severe dehydration (defined by reduced skin turgor), lower respiratory tract infection (clinician's final diagnosis), meningitis (on cerebrospinal fluid [CSF] examination), and bacteraemia were associated with reduced MAFs. The overall MAF was 85% (95% confidence interval [CI] 83.8%-86.1%) without excluding these conditions, 89% (95% CI 88.4%-90.2%) after exclusions, and 95% (95% CI 94.0%-95.5%) when a threshold of 2,500 parasites/mul was also applied. Applying a threshold and exclusion criteria reduced sensitivity to 80% (95% CI 77%-83%). CONCLUSIONS: The specificity of a case definition for severe malaria is improved by applying a parasite density threshold and by excluding children with meningitis, lower respiratory tract infection (clinician's diagnosis), bacteraemia, and gastroenteritis with severe dehydration, but not by excluding children with HIV or malnutrition.

Tsai I-H, Tsai H-Y, Wang Y-M, Tun-Pe, Warrell DA. 2007. Venom phospholipases of Russell's vipers from Myanmar and eastern India--cloning, characterization and phylogeographic analysis. Biochim Biophys Acta, 1774 (8), pp. 1020-1028. | Citations: 19 (Web of Science Lite) | Show Abstract | Read more

Venoms of Russell's vipers (genus Daboia) are known for their deadly coagulopathic and other effects. We herein studied various isoforms of venom phospholipases A(2) (PLAs) from two Daboia species at their geographic boundary. From Myanmar Daboia siamensis venom (designated as DsM), four PLAs (designated DsM-aI, aI', aII' and bI') were purified, and the cDNAs encoding two acidic (DsM-aI and aII) and two basic PLAs (DsM-bI and S1) were also cloned from its venom-glands. DsM-S1 is identical to the major venom PLA of southern India Daboia russelii, but the protein is absent from the venom. Additionally, four PLAs (designated DrK-aI, aII, bI and bII) were cloned from cDNA obtained from venom glands of a Kolkata D. russelii, and the PLAs were purified from the pooled venom (designated as DrK). The acidic DrK-aI is the most neurotoxic and lethal among these PLAs; DsM-aI which differs from DrK-aI by only the Phe2 substitution shows greatly reduced enzymatic activity and lethality. Both acidic PLAs do not form dimeric complex with basic PLAs in the same venoms. DsM-bI' is neurotoxic and lethal but its orthologous DrK-bI (97% identical to DsM-bI') is a much weaker toxin. Given the fact that most of the orthologous PLAs of DrK and DsM share 97-100% sequence identity, Daboia vipers of Myanmar and Kolkata must be closely related. Molecular phylogenetic analyses on 30 venom PLAs of Eurasian vipers' revealed co-evolution of five subtypes of venom PLAs in both Daboia and Vipera genera. Our results shed light on the intra- and inter-species variations and structure-function relationships of viperid venom PLAs.

Anstey NM, Price RN. 2007. Improving case definitions for severe malaria. PLoS Med, 4 (8), pp. e267. | Citations: 23 (Web of Science Lite) | Read more

Tsegaye A, Ran L, Wolday D, Petros B, Dorigo W, Piriou E, Messele T, Sanders E, Tilahun T, Eshetu D et al. 2007. HIV-1 Subtype C gag-specific T-cell responses in relation to human leukocyte antigens in a diverse population of HIV-infected Ethiopians. J Acquir Immune Defic Syndr, 45 (4), pp. 389-400. | Citations: 2 (Web of Science Lite) | Show Abstract | Read more

Knowledge of the most dominant T-cell epitopes in the context of the local human leukocyte antigen (HLA) background is a prerequisite for the development of an effective HIV vaccine. In 100 Ethiopian subjects, 16 different HLA-A, 23 HLA-B, and 12 HLA-C specificities were observed. Ninety-four percent of the population carried at least 1 of the 5 most common HLA-A and/or HLA-B specificities. HIV-specific T-cell responses were measured in 48 HIV-infected Ethiopian subjects representing a wide range of ethnicities in Ethiopia using the interferon (IFN)-gamma enzyme-linked immunospot (Elispot) assay and 49 clade C-specific synthetic Gag peptides. Fifty-eight percent of the HIV-positive study subjects showed T-cell responses directed to 1 or more HIV Gag peptides. Most Gag-specific responses were directed against the subset of peptides spanning Gag p24. The breadth of response ranged from 1 to 9 peptides, with most (78%) individuals showing detectable responses to <3 Gag peptides. The magnitude of HIV-specific T-cell responses was not associated with HIV viral load but correlated positively with CD4 T-cell counts. The most frequently targeted Gag peptides overlapped with those previously described for HIV-1 subtype C-infected southern Africans, and therefore can be used in a multiethnic vaccine.

Noor AM, Amin AA, Akhwale WS, Snow RW. 2007. Increasing coverage and decreasing inequity in insecticide-treated bed net use among rural Kenyan children. PLoS Med, 4 (8), pp. e255. | Citations: 179 (Scopus) | Show Abstract | Read more

BACKGROUND: Inexpensive and efficacious interventions that avert childhood deaths in sub-Saharan Africa have failed to reach effective coverage, especially among the poorest rural sectors. One particular example is insecticide-treated bed nets (ITNs). In this study, we present repeat observations of ITN coverage among rural Kenyan homesteads exposed at different times to a range of delivery models, and assess changes in coverage across socioeconomic groups. METHODS AND FINDINGS: We undertook a study of annual changes in ITN coverage among a cohort of 3,700 children aged 0-4 y in four districts of Kenya (Bondo, Greater Kisii, Kwale, and Makueni) annually between 2004 and 2006. Cross-sectional surveys of ITN coverage were undertaken coincidentally with the incremental availability of commercial sector nets (2004), the introduction of heavily subsidized nets through clinics (2005), and the introduction of free mass distributed ITNs (2006). The changing prevalence of ITN coverage was examined with special reference to the degree of equity in each delivery approach. ITN coverage was only 7.1% in 2004 when the predominant source of nets was the commercial retail sector. By the end of 2005, following the expansion of heavily subsidized clinic distribution system, ITN coverage rose to 23.5%. In 2006 a large-scale mass distribution of ITNs was mounted providing nets free of charge to children, resulting in a dramatic increase in ITN coverage to 67.3%. With each subsequent survey socioeconomic inequity in net coverage sequentially decreased: 2004 (most poor [2.9%] versus least poor [15.6%]; concentration index 0.281); 2005 (most poor [17.5%] versus least poor [37.9%]; concentration index 0.131), and 2006 with near-perfect equality (most poor [66.3%] versus least poor [66.6%]; concentration index 0.000). The free mass distribution method achieved highest coverage among the poorest children, the highly subsidised clinic nets programme was marginally in favour of the least poor, and the commercial social marketing favoured the least poor. CONCLUSIONS: Rapid scaling up of ITN coverage among Africa's poorest rural children can be achieved through mass distribution campaigns. These efforts must form an important adjunct to regular, routine access to ITNs through clinics, and each complimentary approach should aim to make this intervention free to clients to ensure equitable access among those least able to afford even the cost of a heavily subsidized net.

Osier FHA, Polley SD, Mwangi T, Lowe B, Conway DJ, Marsh K. 2007. Naturally acquired antibodies to polymorphic and conserved epitopes of Plasmodium falciparum merozoite surface protein 3. Parasite Immunol, 29 (8), pp. 387-394. | Citations: 38 (Scopus) | Show Abstract | Read more

Many studies on the role of merozoite surface protein 3 (MSP3) in immunity against malaria have focused on a conserved section of MSP3. New evidence suggests that polymorphic sequences within MSP3 are under immune selection. We report a detailed analysis of naturally-acquired antibodies to allele-specific and conserved parts of MSP3 in a Kenyan cohort. Indirect and competition ELISA to heterologous recombinant MSP3 proteins were used for antibody assays, and parasites were genotyped for msp3 alleles. Antibody reactivity to allele-specific and conserved epitopes of MSP3 was heterogeneous between individuals. Overall, the prevalence of allele-specific antibody reactivity was significantly higher (3D7-specific 54%, K1-specific 41%) than that to a recombinant protein representing a conserved portion of C-terminal MSP3 (24%, P < 0.01). The most abundant IgG subclass was IgG3, followed by IgG1. Allele-specific reactivity to the K1-type of MSP3 was associated with a lower risk of clinical malaria episodes during a 6-month follow-up in individuals who were parasitized at the start of the malaria transmission season (Relative risk 0.41 with 95% confidence interval 0.20-0.81, P = 0.011). The potential importance of allele-specific immunity to MSP3 should be considered in addition to immunity to conserved epitopes, in the development of an MSP3 malaria vaccine.

Jansen GFA, Krins A, Basnyat B, Odoom JA, Ince C. 2007. Role of the altitude level on cerebral autoregulation in residents at high altitude. J Appl Physiol (1985), 103 (2), pp. 518-523. | Citations: 24 (Scopus) | Show Abstract | Read more

Cerebral autoregulation is impaired in Himalayan high-altitude residents who live above 4,200 m. This study was undertaken to determine the altitude at which this impairment of autoregulation occurs. A second aim of the study was to test the hypothesis that administration of oxygen can reverse this impairment in autoregulation at high altitudes. In four groups of 10 Himalayan high-altitude dwellers residing at 1,330, 2,650, 3,440, and 4,243 m, arterial oxygen saturation (Sa(O(2))), blood pressure, and middle cerebral artery blood velocity were monitored during infusion of phenylephrine to determine static cerebral autoregulation. On the basis of these measurements, the cerebral autoregulation index (AI) was calculated. Normally, AI is between zero and 1. AI of 0 implies absent autoregulation, and AI of 1 implies intact autoregulation. At 1,330 m (Sa(O(2)) = 97%), 2,650 m (Sa(O(2)) = 96%), and 3,440 m (Sa(O(2)) = 93%), AI values (mean +/- SD) were, respectively, 0.63 +/- 0.27, 0.57 +/- 0.22, and 0.57 +/- 0.15. At 4,243 m (Sa(O(2)) = 88%), AI was 0.22 +/- 0.18 (P < 0.0005, compared with AI at the lower altitudes) and increased to 0.49 +/- 0.23 (P = 0.008, paired t-test) when oxygen was administered (Sa(O(2)) = 98%). In conclusion, high-altitude residents living at 4,243 m have almost total loss of cerebral autoregulation, which improved during oxygen administration. Those people living at 3,440 m and lower have still functioning cerebral autoregulation. This study showed that the altitude region between 3,440 and 4,243 m, marked by Sa(O(2)) in the high-altitude dwellers of 93% and 88%, is a transitional zone, above which cerebral autoregulation becomes critically impaired.

Chapman SJ, Khor CC, Vannberg FO, Frodsham A, Walley A, Maskell NA, Davies CWH, Segal S, Moore CE, Gillespie SH et al. 2007. IkappaB genetic polymorphisms and invasive pneumococcal disease. Am J Respir Crit Care Med, 176 (2), pp. 181-187. | Citations: 62 (Scopus) | Show Abstract | Read more

RATIONALE: Increasing evidence supports a key role for the transcription factor nuclear factor (NF)-kappaB in the host response to pneumococcal infection. Control of NF-kappaB activity is achieved through interactions with the IkappaB family of inhibitors, encoded by the genes NFKBIA, NFKBIB, and NFKBIE. Rare NFKBIA mutations cause immunodeficiency with severe bacterial infection, raising the possibility that common IkappaB gene polymorphisms confer susceptibility to common bacterial disease. OBJECTIVES: To determine whether polymorphisms in NFKBIA, NFKBIB, and NFKBIE associate with susceptibility to invasive pneumococcal disease (IPD) and thoracic empyema. METHODS: We studied the frequencies of 62 single-nucleotide polymorphisms (SNPs) across NFKBIA, NFKBIB, and NFKBIE in individuals with IPD and control subjects (n=1,060). Significantly associated SNPs were then studied in a group of individuals with thoracic empyema and a second control group (n=632). MEASUREMENTS AND MAIN RESULTS: Two SNPs in the NFKBIA promoter region were associated with protection from IPD in both the initial study group and the pneumococcal empyema subgroup. Significant protection from IPD was observed for carriage of mutant alleles at these two loci on combining the groups (SNP rs3138053: Mantel-Haenszel 2x2 chi2=13.030, p=0.0003; odds ratio [OR], 0.60; 95% confidence interval [CI], 0.45-0.79; rs2233406: Mantel-Haenszel 2x2 chi2=18.927, p=0.00001; OR, 0.55; 95% CI, 0.42-0.72). An NFKBIE SNP associated with susceptibility to IPD but not pneumococcal empyema. None of the NFKBIB SNPs associated with IPD susceptibility. CONCLUSIONS: NFKBIA polymorphisms associate with susceptibility to IPD. Genetic variation in an inhibitor of NF-kappaB therefore not only causes a very rare immunodeficiency state but may also influence the development of common infectious disease.

Baker S, Dougan G. 2007. The genome of Salmonella enterica serovar Typhi. Clin Infect Dis, 45 Suppl 1 (Supplement_1), pp. S29-S33. | Citations: 45 (Web of Science Lite) | Show Abstract | Read more

The generation of complete genome sequences provides a blueprint that facilitates the genetic characterization of pathogens and their hosts. The genome of Salmonella enterica serovar Typhi (S. Typhi) harbors ~5 million base pairs encoding some 4000 genes, of which >200 are functionally inactive. Comparison of S. Typhi isolates from around the world indicates that they are highly related (clonal) and that they emerged from a single point of origin ~30,000-50,000 years ago. Evidence suggests that, as well as undergoing gene degradation, S. Typhi has also recently acquired genes, such as those encoding the Vi antigen, by horizontal transfer events.

Jenkins N, Wu Y, Chakravorty S, Kai O, Marsh K, Craig A. 2007. Plasmodium falciparum intercellular adhesion molecule-1-based cytoadherence-related signaling in human endothelial cells. J Infect Dis, 196 (2), pp. 321-327. | Citations: 26 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Cytoadherence of Plasmodium falciparum-infected erythrocytes to host endothelium has been associated with pathology in severe malaria, but, despite extensive information on the primary processes involved in the adhesive interactions, the mechanisms underlying disease are poorly understood. METHODS: We compared parasite lines varying in their binding properties to human endothelial cells for their ability to stimulate signaling activity. RESULTS: In human umbilical vein endothelial cells (HUVECs), which rely on adhesion to intercellular adhesion molecule (ICAM)-1 for binding, signaling is related to the avidity of the parasite line for ICAM-1 and can be blocked either through the use of anti-ICAM-1 monoclonal antibodies or HUVECs with altered ICAM-1 binding properties (i.e., ICAM-1(Kilifi)). Human dermal microvascular endothelial cells (HDMECs), which can bind infected erythrocytes via ICAM-1 and CD36, have a more complex pattern of signaling behavior, but this is also dependent on adhesive interactions rather than merely contact between cells. CONCLUSIONS: Signaling via apposition of P. falciparum-infected erythrocytes with host endothelium is dependent, at least in part, on the cytoadherence characteristics of the invading isolate. An understanding of the postadhesive processes produced by cytoadherence may help us to understand the variable pathologies seen in malaria disease.

Ochiai RL, Acosta CJ, Agtini M, Bhattacharya SK, Bhutta ZA, Do CG, Dong B, Chen X, Stanton B, Kaljee L et al. 2007. The use of typhoid vaccines in Asia: the DOMI experience. Clin Infect Dis, 45 Suppl 1 (Supplement_1), pp. S34-S38. | Citations: 28 (Scopus) | Show Abstract | Read more

BACKGROUND: Two currently licensed typhoid vaccines have been evaluated in Asia, yet few Asian countries have considered including typhoid vaccines in their vaccination programs. The Diseases of the Most Impoverished (DOMI) Program was initiated to provide evidence to decide on the introduction of typhoid vaccines in Asian countries. METHODS: The centerpiece of the program is a multidisciplinary demonstration project with Vi vaccine in 5 Asian countries. The project includes epidemiologic, economic, sociobehavioral, and policy studies. RESULTS: Policy makers want evidence on which to base their vaccine-related decisions. The DOMI Program has provided updated information on the typhoid fever burden at several Asian sites. Cost-of-illness studies found high costs to governments and individuals. Sociobehavioral studies indicated a positive attitude toward typhoid vaccines. The results of the demonstration projects indicate that mass-immunization campaigns are feasible and acceptable. CONCLUSIONS: The DOMI Program has begun to provide momentum for the evidence-based, rational introduction of typhoid vaccines into the public health programs of several Asian countries.

Ota M, Droma Y, Basnyat B, Katsuyama Y, Asamura H, Sakai H, Fukuhsima H. 2007. Allele frequencies for 15 STR loci in Tibetan populations from Nepal. Forensic Sci Int, 169 (2-3), pp. 234-238. | Citations: 15 (Scopus) | Show Abstract | Read more

Samples from 105 unrelated healthy Sherpa in Namche Bazaar and 111 unrelated non-Sherpa in Kathmandu valley from Nepal were used to obtain allele frequency data for 15 short tandem repeat (STR) loci (CSF1PO, D2S1338, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D19S433, D21S11, FGA, TH01, TPOX and vWA) included in the AmpFLSTR Identifiler kit. No deviations from Hardy-Weinberg equilibrium were observed, but only after applying a Bonferroni correction in the case of D5S818 in the Sherpa population and D7S820 in the Kathmandu population. Genetic parameters of forensic interest were calculated and genetic differentiation between the two populations tested.

Bull PC, Kyes S, Buckee CO, Montgomery J, Kortok MM, Newbold CI, Marsh K. 2007. An approach to classifying sequence tags sampled from Plasmodium falciparum var genes. Mol Biochem Parasitol, 154 (1), pp. 98-102. | Citations: 33 (Web of Science Lite) | Read more

Wiersinga WJ, Wieland CW, Dessing MC, Chantratita N, Cheng AC, Limmathurotsakul D, Chierakul W, Leendertse M, Florquin S, de Vos AF et al. 2007. Toll-like receptor 2 impairs host defense in gram-negative sepsis caused by Burkholderia pseudomallei (Melioidosis). PLoS Med, 4 (7), pp. e248. | Citations: 99 (Scopus) | Show Abstract | Read more

BACKGROUND: Toll-like receptors (TLRs) are essential in host defense against pathogens by virtue of their capacity to detect microbes and initiate the immune response. TLR2 is seen as the most important receptor for gram-positive bacteria, while TLR4 is regarded as the gram-negative TLR. Melioidosis is a severe infection caused by the gram-negative bacterium, Burkholderia pseudomallei, that is endemic in Southeast Asia. We aimed to characterize the expression and function of TLRs in septic melioidosis. METHODS AND FINDINGS: Patient studies: 34 patients with melioidosis demonstrated increased expression of CD14, TLR1, TLR2, and TLR4 on the cell surfaces of monocytes and granulocytes, and increased CD14, TLR1, TLR2, TLR4, LY96 (also known as MD-2), TLR5, and TLR10 mRNA levels in purified monocytes and granulocytes when compared with healthy controls. In vitro experiments: Whole-blood and alveolar macrophages obtained from TLR2 and TLR4 knockout (KO) mice were less responsive to B. pseudomallei in vitro, whereas in the reverse experiment, transfection of HEK293 cells with either TLR2 or TLR4 rendered these cells responsive to this bacterium. In addition, the lipopolysaccharide (LPS) of B. pseudomallei signals through TLR2 and not through TLR4. Mouse studies: Surprisingly, TLR4 KO mice were indistinguishable from wild-type mice with respect to bacterial outgrowth and survival in experimentally induced melioidosis. In contrast, TLR2 KO mice displayed a markedly improved host defenses as reflected by a strong survival advantage together with decreased bacterial loads, reduced lung inflammation, and less distant-organ injury. CONCLUSIONS: Patients with melioidosis displayed an up-regulation of multiple TLRs in peripheral blood monocytes and granulocytes. Although both TLR2 and TLR4 contribute to cellular responsiveness to B. pseudomallei in vitro, TLR2 detects the LPS of B. pseudomallei, and only TLR2 impacts on the immune response of the intact host in vivo. Inhibition of TLR2 may be a novel treatment strategy in melioidosis.

Limmathurotsakul D, Chaowagul W, Wongsrikaew P, Narmwong A, Day NP, Peacock SJ. 2007. Variable presentation of neurological melioidosis in Northeast Thailand. Am J Trop Med Hyg, 77 (1), pp. 118-120. | Citations: 22 (Scopus) | Show Abstract

We describe three instructive cases of neurologic melioidosis that demonstrate the variable nature of clinical manifestations and disease pathology. The appropriate duration and choice of parenteral and oral antimicrobial therapy for neurologic melioidosis are also discussed.

Mayxay M, Nair S, Sudimack D, Imwong M, Tanomsing N, Pongvongsa T, Phompida S, Phetsouvanh R, White NJ, Anderson TJC, Newton PN. 2007. Combined molecular and clinical assessment of Plasmodium falciparum antimalarial drug resistance in the Lao People's Democratic Republic (Laos). Am J Trop Med Hyg, 77 (1), pp. 36-43. | Citations: 12 (Scopus) | Show Abstract

Molecular markers provide a rapid and relatively inexpensive approach for assessing antimalarial drug susceptibility. We collected 884 Plasmodium falciparum-infected blood samples from 17 Lao provinces. Each sample was genotyped for 11 codons in the chloroquine resistance transporter (pfcrt), dihydrofolate reductase (pfdhfr), and dihydropteroate synthase (pfdhps) genes. The samples included 227 collected from patients recruited to clinical trials. The pfcrt K76T mutation was an excellent predictor of treatment failure for both chloroquine and chloroquine plus sulfadoxine-pyrimethamine, and mutations in both pfdhfr and pfdhps were predictive of sulfadoxine-pyrimethamine treatment failure. In multivariate analysis, the presence of the pfdhfr triple mutation (51 + 59 + 108) was strongly and independently correlated with sulfadoxine-pyrimethamine failure (odds ratio = 9.1, 95% confidence interval = 1.4-60.2, P = 0.017). Considerable geographic heterogeneity in allele frequencies occurred at all three loci with lower frequencies of mutant alleles in southern than in northern Laos. These findings suggest that chloroquine and sulfadoxine-pyrimethamine are no longer viable therapy in this country.

Blacksell SD, Sharma NP, Phumratanaprapin W, Jenjaroen K, Peacock SJ, White NJ, Pukrittayakamee S, Day NPJ. 2007. Serological and blood culture investigations of Nepalese fever patients. Trans R Soc Trop Med Hyg, 101 (7), pp. 686-690. | Citations: 24 (Web of Science Lite) | Show Abstract | Read more

Serological testing of paired (i.e. admission and convalescent) sera from 103 fever patients in Kathmandu, Nepal, was performed to estimate the prevalence rates of scrub typhus, murine typhus, Leptospira and dengue virus antibodies and to determine their role in the cause of active infections. Blood cultures from 15 patients grew Salmonella enterica serovar Typhi, 8 grew S. Paratyphi A and 6 grew other bacteria. Diagnostic antibody levels were detected against murine typhus (27/103; 26%), scrub typhus (23/103; 22%), Leptospira (10/103; 10%) and dengue virus (8/103; 8%). Nineteen patients (18%) had diagnostically raised antibodies to more than one infectious agent. Seven S. Typhi (7/15; 47%) and two S. Paratyphi A (2/8; 25%) patients had significant scrub typhus, murine typhus, Leptospira or dengue virus IgM antibody titres. This study confirms the presence of leptospiral, rickettsial and dengue infections in Kathmandu as well as evidence for mixed infections with S. Typhi and Orientia tsutsugamushi or Rickettsia typhi. These infections should be kept in mind when considering the differential diagnoses of fever and empirical treatment options in Nepal. Many patients demonstrated static IgM antibody results between paired serum collections, suggesting recent rather than acutely active infections.

Imwong M, Nair S, Pukrittayakamee S, Sudimack D, Williams JT, Mayxay M, Newton PN, Kim JR, Nandy A, Osorio L et al. 2007. Contrasting genetic structure in Plasmodium vivax populations from Asia and South America. Int J Parasitol, 37 (8-9), pp. 1013-1022. | Citations: 106 (Web of Science Lite) | Show Abstract | Read more

Populations of Plasmodium falciparum show striking differences in linkage disequilibrium, population differentiation and diversity, but only fragmentary data exists on the genetic structure of Plasmodium vivax. We genotyped nine tandem repeat loci bearing 2-8 bp motifs from 345 P. vivax infections collected from three Asian countries and from five locations in Colombia. We observed 9-37 alleles per locus and high diversity (He=0.72-0.79, mean=0.75) in all countries. Numbers of multiple clone infections varied considerably: these were rare in Colombia and India, but > 60% of isolates carried multiple alleles in at least one locus in Thailand and Laos. However, only one or two of the nine loci show >1 allele in many samples, suggesting that mutation within infections may result in overestimation of true multiple carriage rates. Identical nine-locus genotypes were frequently found in Colombian populations, contributing to strong linkage disequilibrium. These identical genotypes were strongly clustered in time, consistent with epidemic transmission of clones and subsequent breakdown of allelic associations, suggesting high rates of inbreeding and low effective recombination rates in this country. In contrast, identical genotypes were rare and loci were randomly associated in all three Asian populations, consistent with higher rates of outcrossing and recombination. We observed low but significant differentiation between different Asian countries (standardized FST = 0.13-0.45). In comparison, we see greater differentiation between collection locations within Colombia (standardized FST = 0.4-0.7), and strong differentiation between continents (standardized FST = 0.48-0.79). The observed heterogeneity in multiple clone carriage rates, linkage disequilibrium and population differentiation are similar in some, but not all, respects to those observed in P. falciparum, and have important implications for the design of association mapping studies, and interpretation of P. vivax epidemiology.

Kelly S, Reed J, Kramer S, Ellis L, Webb H, Sunter J, Salje J, Marinsek N, Gull K, Wickstead B, Carrington M. 2007. Functional genomics in Trypanosoma brucei: a collection of vectors for the expression of tagged proteins from endogenous and ectopic gene loci. Mol Biochem Parasitol, 154 (1), pp. 103-109. | Citations: 98 (Web of Science Lite) | Read more

Dondorp AM, Day NPJ. 2007. The treatment of severe malaria. Trans R Soc Trop Med Hyg, 101 (7), pp. 633-634. | Citations: 22 (Scopus) | Show Abstract | Read more

In the SEAQUAMAT trial, parenteral artesunate was shown to be associated with a considerably lower mortality than quinine, and is now the recommended treatment for severe malaria in low-transmission areas and in the second and third trimesters of pregnancy. A trial is underway to establish its role in African children. The development of artesunate suppositories may provide the means to treat patients with severe disease in remote rural settings, potentially buying the time needed to reach a health care facility. The increasing availability of basic intensive care facilities in developing countries also has the potential to further reduce mortality.

Thuong NTT, Hawn TR, Thwaites GE, Chau TTH, Lan NTN, Quy HT, Hieu NT, Aderem A, Hien TT, Farrar JJ, Dunstan SJ. 2007. A polymorphism in human TLR2 is associated with increased susceptibility to tuberculous meningitis. Genes Immun, 8 (5), pp. 422-428. | Citations: 127 (Scopus) | Show Abstract | Read more

Tuberculous meningitis (TBM) results from the haematogenous dissemination of Mycobacterium tuberculosis from the lung to the brain. Dissemination is believed to occur early during infection, before the development of adaptive immunity. Toll-like receptor 2 (TLR2) mediates recognition of M. tuberculosis and initiates the innate immune response to infection. We hypothesized that polymorphisms in the TLR2 gene influence bacterial dissemination and the development of TBM. A case-control study was designed to test the hypothesis. Cases of bacteriologically confirmed pulmonary tuberculosis (TB) (n=183) and TBM (n=175), and cord blood controls (n=389) were enrolled in Vietnam. TLR2 genotype 597CC was associated with susceptibility to TB (odds ratio (OR)=2.22, 95% confidence interval (CI): 1.23-3.99). The association was found with meningeal rather than pulmonary TB (TBM vs control, OR=3.26, 95% CI: 1.72-6.18), and was strongest when miliary TB was found on chest radiography (controls vs TBM with miliary TB, OR=5.28, 95% CI: 2.20-12.65). Furthermore, the association increased with the severity of neurologic symptoms (grade I TBM, OR=1.93, 95% CI: 0.54-6.92; grade II, OR=3.32, 95% CI: 0.84-13.2; and grade III, OR=5.70, 95% CI: 1.81-18.0). These results demonstrate a strong association of TLR2 SNP T597C with the development of TBM and miliary TB and indicate that TLR2 influences the dissemination of M. tuberculosis.

Akumu AO, English M, Scott JAG, Griffiths UK. 2007. Economic evaluation of delivering Haemophilus influenzae type b vaccine in routine immunization services in Kenya. Bull World Health Organ, 85 (7), pp. 511-518. | Citations: 42 (Scopus) | Show Abstract | Read more

OBJECTIVE: Haemophilus influenzae type b (Hib) vaccine was introduced into routine immunization services in Kenya in 2001. We aimed to estimate the cost-effectiveness of Hib vaccine delivery. METHODS: A model was developed to follow the Kenyan 2004 birth cohort until death, with and without Hib vaccine. Incidence of invasive Hib disease was estimated at Kilifi District Hospital and in the surrounding demographic surveillance system in coastal Kenya. National Hib disease incidence was estimated by adjusting incidence observed by passive hospital surveillance using assumptions about access to care. Case fatality rates were also assumed dependent on access to care. A price of US$ 3.65 per dose of pentavalent diphtheria-tetanus-pertussis-hep B-Hib vaccine was used. Multivariate Monte Carlo simulations were performed in order to assess the impact on the cost-effectiveness ratios of uncertainty in parameter values. FINDINGS: The introduction of Hib vaccine reduced the estimated incidence of Hib meningitis per 100,000 children aged < 5 years from 71 to 8; of Hib non-meningitic invasive disease from 61 to 7; and of non-bacteraemic Hib pneumonia from 296 to 34. The costs per discounted disability adjusted life year (DALY) and per discounted death averted were US$ 38 (95% confidence interval, CI: 26-63) and US$ 1197 (95% CI: 814-2021) respectively. Most of the uncertainty in the results was due to uncertain access to care parameters. The break-even pentavalent vaccine price--where incremental Hib vaccination costs equal treatment costs averted from Hib disease--was US$ 1.82 per dose. CONCLUSION: Hib vaccine is a highly cost-effective intervention in Kenya. It would be cost-saving if the vaccine price was below half of its present level.

Beeson JG, Ndungu F, Persson KEM, Chesson JM, Kelly GL, Uyoga S, Hallamore SL, Williams TN, Reeder JC, Brown GV, Marsh K. 2007. Antibodies among men and children to placental-binding Plasmodium falciparum-infected erythrocytes that express var2csa. Am J Trop Med Hyg, 77 (1), pp. 22-28. | Citations: 27 (Web of Science Lite) | Show Abstract

During pregnancy, specific variants of Plasmodium falciparum-infected erythrocytes (IEs) can accumulate in the placenta through adhesion to chondroitin sulfate A (CSA) mediated by expression of PfEMP1 encoded by var2csa-type genes. Antibodies against these variants are associated with protection from maternal malaria. We evaluated antibodies among Kenyan, Papua New Guinean, and Malawian men and Kenyan children against two different CSA-binding P. falciparum isolates expressing var2csa variants. Specific IgG was present at significant levels among some men and children from each population, suggesting exposure to these variants is not exclusive to pregnancy. However, the level and prevalence of antibodies was substantially lower overall than exposed multigravidas. IgG-binding was specific and did not represent antibodies to subpopulations of non-CSA-binding IEs, and some sera inhibited IE adhesion to CSA. These findings have significant implications for understanding malaria pathogenesis and immunity and may be significant for understanding the acquisition of immunity to maternal malaria.

Van der Bij AK, Geskus RB, Fennema HSA, Adams K, Coutinho RA, Dukers NHTM. 2007. No evidence for a sustained increase in sexually transmitted diseases among heterosexuals in Amsterdam, the Netherlands: a 12-year trend analysis at the sexually transmitted disease outpatient clinic, Amsterdam. Sex Transm Dis, 34 (7), pp. 461-467. | Citations: 7 (Scopus) | Show Abstract | Read more

OBJECTIVES: Sexually transmitted diseases (STDs) are on the rise, mainly among men having sex with men (MSM). GOAL: The goal of this study was to evaluate whether STD increases as seen in MSM are also visible among heterosexuals. STUDY DESIGN: Attendees of the STD clinic in Amsterdam, The Netherlands, are routinely tested for chlamydia, gonorrhea, and syphilis. Additionally, all women are tested for trichomoniasis. STD time trends of heterosexual attendees between 1994 and 2005 were analyzed by logistic regression and generalized linear models with a negative binomial distribution. RESULTS: The number of consultations doubled since 1994. However, no long-term increase was seen in the number of syphilis and gonorrhea infections. Additionally, the trichomonas prevalence declined. However, the number of chlamydia infections increased over time. CONCLUSIONS: Although the number of attendees increased, no evidence for increasing STD incidence was found among heterosexuals. The increase in chlamydia infections can probably be explained by increased screening resulting from increased numbers of attendees.

Pandit A, Arjyal A, Day JN, Paudyal B, Dangol S, Zimmerman MD, Yadav B, Stepniewska K, Campbell JI, Dolecek C et al. 2007. An Open Randomized Comparison of Gatifloxacin versus Cefixime for the Treatment of Uncomplicated Enteric Fever PLOS ONE, 2 (6), | Citations: 18 (Web of Science Lite) | Read more

Geibel S, van der Elst EM, King'ola N, Luchters S, Davies A, Getambu EM, Peshu N, Graham SM, McClelland RS, Sanders EJ. 2007. 'Are you on the market?': a capture-recapture enumeration of men who sell sex to men in and around Mombasa, Kenya. AIDS, 21 (10), pp. 1349-1354. | Citations: 46 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Men who have sex with men (MSM) are highly vulnerable to HIV infection, but this population can be particularly difficult to reach in sub-Saharan Africa. We aimed to estimate the number of MSM who sell sex in and around Mombasa, Kenya, in order to plan HIV prevention research. METHODS: We identified 77 potential MSM contact locations, including public streets and parks, brothels, bars and nightclubs, in and around Mombasa and trained 37 MSM peer leader enumerators to extend a recruitment leaflet to MSM who were identified as 'on the market', that is, a man who admitted to selling sex to men. We captured men on two consecutive Saturdays, 1 week apart. A record was kept of when, where and by whom the invitation was extended and received, and of refusals. The total estimate of MSM who sell sex was derived from capture-recapture calculation. RESULTS: Capture 1 included 284 men (following removal of 15 duplicates); 89 men refused to participate. Capture 2 included 484 men (following removal of 35 duplicates); 75 men refused to participate. Of the 484 men in capture 2, 186 were recaptures from capture 1, resulting in a total estimate of 739 (95% confidence interval, 690-798) MSM who sell sex in the study area. CONCLUSIONS: We estimated that 739 MSM sell sex in and around Mombasa. Of these, 484 were contacted through trained peer enumerators in a single day. MSM who sell sex in and around Mombasa represent a sizeable population who urgently need to be targeted by HIV prevention strategies.

Wangroongsarb P, Chanket T, Gunlabun K, Long DH, Satheanmethakul P, Jetanadee S, Thaipadungpanit J, Wuthiekanun V, Peacock SJ, Blacksell SD et al. 2007. Molecular typing of Leptospira spp. based on putative O-antigen polymerase gene (wzy), the benefit over 16S rRNA gene sequence. FEMS Microbiol Lett, 271 (2), pp. 170-179. | Citations: 9 (Scopus) | Show Abstract | Read more

Molecular typing of leptospiral strains based on variation within putative O-antigen polymerase gene (wzy) was determined among reference strains and those isolated from patients. Using the PCR primers designed from the flanking gene of wzy derived from Leptospira interrogans serovar Copenhageni, all L. interrogans serovars as well as human and rodent leptospiral isolates from Thailand could be amplified. The size of PCR product ranged from 1 to 1.5 kb. The limitation of these primer pairs was the inability to amplify those strains whose sequences differ in the region of the primers, these included Leptospira biflexa (serovar Patoc), Leptospira borgpetersenii (serovar Tarassovi) and Leptospira kirschneri (serovar Bim, Bulgarica, Butembo). Notably, amplification was not limited to L. interrogans as demonstrated by the amplification of some strains from L. kirschneri, Leptospira meyeri, Leptospira noguchii, Leptospira santarosai, L. borgpetersenii and Leptospira weilii. The phylogenetic tree of wzy sequence, inferred by posterior probability of the Bayesian, enabled the categorization of leptospiral serovars into seven genetically related group, of which its differentiation power was better than that of the more highly conserved 16S rRNA gene, which is used extensively for genotyping.

Wiersinga WJ, Dessing MC, Kager PA, Cheng AC, Limmathurotsakul D, Day NP, Dondorp AM, van der Poll T, Peacock SJ. 2007. High-throughput mRNA profiling characterizes the expression of inflammatory molecules in sepsis caused by Burkholderia pseudomallei. Infect Immun, 75 (6), pp. 3074-3079. | Citations: 36 (Scopus) | Show Abstract | Read more

Sepsis is characterized by an uncontrolled inflammatory response to invading microorganisms. We describe the inflammatory mRNA profiles in whole-blood leukocytes, monocytes, and granulocytes using a multigene system for 35 inflammatory markers that included pro- and anti-inflammatory cytokines, chemokines, and signal transduction molecules in a case-control study with 34 patients with sepsis caused by the gram-negative bacterium Burkholderia pseudomallei (the pathogen causing melioidosis) and 32 healthy volunteers. Relative to healthy controls, patients with sepsis showed increased transcription of a whole array of inflammatory genes in peripheral blood leukocytes, granulocytes, and monocytes. Specific monocyte and granulocyte mRNA profiles were identified. Strong correlations were found between inflammatory mRNA expression levels in monocytes and clinical outcome. These data underline the notion that circulating leukocytes are an important source for inflammatory mediators in patients with gram-negative sepsis. Gene profiling such as was done here provides an excellent tool to obtain insight into the extent of inflammation activation in patients with severe infection.

Farrar J, Focks D, Gubler D, Barrera R, Guzman MG, Simmons C, Kalayanarooj S, Lum L, McCall PJ, Lloyd L et al. 2007. Editorial: Towards a global dengue research agenda TROPICAL MEDICINE & INTERNATIONAL HEALTH, 12 (6), pp. 695-699. | Citations: 113 (Scopus) | Read more

Baird JK, Snow RW. 2007. Acquired immunity in a holoendemic setting of Plasmodium falciparum and p. Vivax malaria. Am J Trop Med Hyg, 76 (6), pp. 995-996. | Citations: 7 (Scopus)

Weill F-X, Tran HH, Roumagnac P, Fabre L, Minh NB, Stavnes TL, Lassen J, Bjune G, Grimont PAD, Guerin PJ. 2007. Clonal reconquest of antibiotic-susceptible Salmonella enterica serotype Typhi in Son La Province, Vietnam. Am J Trop Med Hyg, 76 (6), pp. 1174-1181. | Citations: 6 (Web of Science Lite) | Show Abstract

In the last three decades, high rates of resistance to common first-line antimicrobial agents have been reported in Salmonella enterica serotype Typhi (Typhi), the causative organism of typhoid fever (TF), in many regions of the world, especially in South East Asia. Analysis of Typhi strains isolated from outbreaks and sporadic cases of TF in Son La province, northwest Vietnam, in 2002 revealed that 94.5% (85/90) of the isolates were fully susceptible to amoxicillin, chloramphenicol, cotrimoxazole, tetracycline, and nalidixic acid. There was a clear decline in the occurrence of multi-drug resistant (MDR) Typhi isolates collected in this province in 2002 (4.4%) compared with the period 1995-1999 in the same province (30.8-100%). By using molecular (IS200 profiling, PstI-ribotyping, XbaI-pulsed-field gel electrophoresis, and haplotyping) and phage-typing methods, we showed that the Typhi isolates from Son La province in 2002 were genetically related; however, they were unrelated to the previous MDR clones established in Vietnam.

Nathan N, Rose AMC, Legros D, Tiendrebeogo SRM, Bachy C, Bjørløw E, Firmenich P, Guerin PJ, Caugant DA. 2007. Meningitis serogroup W135 outbreak, Burkina Faso, 2002. Emerg Infect Dis, 13 (6), pp. 920-923. | Citations: 39 (Scopus) | Show Abstract | Read more

In 2002, the largest epidemic of Neisseria meningitidis serogroup W135 occurred in Burkina Faso. The highest attack rate was in children <5 years of age. We describe cases from 1 district and evaluate the performance of the Pastorex test, which had good sensitivity (84%) and specificity (89%) compared with culture or PCR.

Horby P. 2007. Determining risk factors for infection with influenza A (H5N1) - Response EMERGING INFECTIOUS DISEASES, 13 (6), pp. 956-956.

Deans A-M, Nery S, Conway DJ, Kai O, Marsh K, Rowe JA. 2007. Invasion pathways and malaria severity in Kenyan Plasmodium falciparum clinical isolates. Infect Immun, 75 (6), pp. 3014-3020. | Citations: 31 (Web of Science Lite) | Show Abstract | Read more

The invasion of erythrocytes by Plasmodium falciparum occurs through multiple pathways that can be studied in vitro by examining the invasion of erythrocytes treated with enzymes such as neuraminidase, trypsin, and chymotrypsin. We have studied the invasion pathways used by 31 Kenyan P. falciparum isolates from children with uncomplicated or severe malaria. Six distinct invasion profiles were detected, out of eight possible profiles. The majority of isolates (23 of 31) showed neuraminidase-resistant, trypsin-sensitive invasion, characteristic of the pathway mediated by an unknown parasite ligand and erythrocyte receptor "X." The neuraminidase-sensitive, trypsin-sensitive phenotype consistent with invasion mediated by the binding of parasite ligand erythrocyte binding antigen 175 to glycophorin A, the most common invasion profile in a previous study of Gambian field isolates, was seen in only 3 of 31 Kenyan isolates. No particular invasion profile was associated with severe P. falciparum malaria, and there was no significant difference in the levels of inhibition by the various enzyme treatments between isolates from children with severe malaria and those from children with uncomplicated malaria (P, >0.1 for all enzymes; Mann-Whitney U test). These results do not support the hypothesis that differences in invasion phenotypes play an important role in malaria virulence and indicate that considerable gaps remain in our knowledge of the molecular basis of invasion pathways in natural P. falciparum infections.

White RG, Ben SC, Kedhar A, Orroth KK, Biraro S, Baggaley RF, Whitworth J, Korenromp EL, Ghani A, Boily M-C, Hayes RJ. 2007. Quantifying HIV-1 transmission due to contaminated injections. Proc Natl Acad Sci U S A, 104 (23), pp. 9794-9799. | Citations: 19 (Scopus) | Show Abstract | Read more

Assessments of the importance of different routes of HIV-1 (HIV) transmission are vital for prioritization of control efforts. Lack of consistent direct data and large uncertainty in the risk of HIV transmission from HIV-contaminated injections has made quantifying the proportion of transmission caused by contaminated injections in sub-Saharan Africa difficult and unavoidably subjective. Depending on the risk assumed, estimates have ranged from 2.5% to 30% or more. We present a method based on an age-structured transmission model that allows the relative contribution of HIV-contaminated injections, and other routes of HIV transmission, to be robustly estimated, both fully quantifying and substantially reducing the associated uncertainty. To do this, we adopt a Bayesian perspective, and show how prior beliefs regarding the safety of injections and the proportion of HIV incidence due to contaminated injections should, in many cases, be substantially modified in light of age-stratified incidence and injection data, resulting in improved (posterior) estimates. Applying the method to data from rural southwest Uganda, we show that the highest estimates of the proportion of incidence due to injections are reduced from 15.5% (95% credible interval) (0.7%, 44.9%) to 5.2% (0.5%, 17.0%) if random mixing is assumed, and from 14.6% (0.7%, 42.5%) to 11.8% (1.2%, 32.5%) under assortative mixing. Lower, and more widely accepted, estimates remain largely unchanged, between 1% and 3% (0.1-6.3%). Although important uncertainty remains, our analysis shows that in rural Uganda, contaminated injections are unlikely to account for a large proportion of HIV incidence. This result is likely to be generalizable to many other populations in sub-Saharan Africa.

Jay A, Dhanda J, Chiodini PL, Woodrow CJ, Farthing PM, Evans J, Jager HR. 2007. Oral cysticercosis British Journal of Oral and Maxillofacial Surgery, 45 (4), pp. 331-334. | Read more

Amin AA, Zurovac D, Kangwana BB, Greenfield J, Otieno DN, Akhwale WS, Snow RW. 2007. The challenges of changing national malaria drug policy to artemisinin-based combinations in Kenya. Malar J, 6 (1), pp. 72. | Citations: 100 (Scopus) | Show Abstract | Read more

BACKGROUND: Sulphadoxine/sulphalene-pyrimethamine (SP) was adopted in Kenya as first line therapeutic for uncomplicated malaria in 1998. By the second half of 2003, there was convincing evidence that SP was failing and had to be replaced. Despite several descriptive investigations of policy change and implementation when countries moved from chloroquine to SP, the different constraints of moving to artemisinin-based combination therapy (ACT) in Africa are less well documented. METHODS: A narrative description of the process of anti-malarial drug policy change, financing and implementation in Kenya is assembled from discussions with stakeholders, reports, newspaper articles, minutes of meetings and email correspondence between actors in the policy change process. The narrative has been structured to capture the timing of events, the difficulties and hurdles faced and the resolutions reached to the final implementation of a new treatment policy. RESULTS: Following a recognition that SP was failing there was a rapid technical appraisal of available data and replacement options resulting in a decision to adopt artemether-lumefantrine (AL) as the recommended first-line therapy in Kenya, announced in April 2004. Funding requirements were approved by the Global Fund to Fight AIDS, Tuberculosis and Malaria (GFATM) and over 60 million US$ were agreed in principle in July 2004 to procure AL and implement the policy change. AL arrived in Kenya in May 2006, distribution to health facilities began in July 2006 coincidental with cascade in-service training in the revised national guidelines. Both training and drug distribution were almost complete by the end of 2006. The article examines why it took over 32 months from announcing a drug policy change to completing early implementation. Reasons included: lack of clarity on sustainable financing of an expensive therapeutic for a common disease, a delay in release of funding, a lack of comparative efficacy data between AL and amodiaquine-based alternatives, a poor dialogue with pharmaceutical companies with a national interest in antimalarial drug supply versus the single sourcing of AL and complex drug ordering, tendering and procurement procedures. CONCLUSION: Decisions to abandon failing monotherapy in favour of ACT for the treatment of malaria can be achieved relatively quickly. Future policy changes in Africa should be carefully prepared for a myriad of financial, political and legislative issues that might limit the rapid translation of drug policy change into action.

Hamer DH, Ndhlovu M, Zurovac D, Fox M, Yeboah-Antwi K, Chanda P, Sipilinyambe N, Simon JL, Snow RW. 2007. Improved diagnostic testing and malaria treatment practices in Zambia. JAMA, 297 (20), pp. 2227-2231. | Citations: 179 (Scopus) | Show Abstract | Read more

CONTEXT: Improving the accuracy of malaria diagnosis with rapid antigen-detection diagnostic tests (RDTs) has been proposed as an approach for reducing overtreatment of malaria in the current era of widespread implementation of artemisinin-based combination therapy in sub-Saharan Africa. OBJECTIVE: To assess the association between use of microscopy and RDT and the prescription of antimalarials. DESIGN, SETTING, AND PARTICIPANTS: Cross-sectional, cluster sample survey, carried out between March and May 2006, of all outpatients treated during 1 working day at government and mission health facilities in 4 sentinel districts in Zambia. MAIN OUTCOME MEASURE: Proportions of patients undergoing malaria diagnostic procedures and receiving antimalarial treatment. RESULTS: Seventeen percent of the 104 health facilities surveyed had functional microscopy, 63% had RDTs available, and 73% had 1 or more diagnostics available. Of patients with fever (suspected malaria), 27.8% (95% confidence interval [CI], 13.1%-42.5%) treated in health facilities with malaria diagnostics were tested and 44.6% had positive test results. Of patients with negative blood smear results, 58.4% (95% CI, 36.7%-80.2%) were prescribed an antimalaria drug, as were 35.5% (95% CI, 16.0%-55.0%) of those with a negative RDT result. Of patients with fever who did not have diagnostic tests done, 65.9% were also prescribed antimalarials. In facilities with artemether-lumefantrine in stock, this antimalarial was prescribed to a large proportion of febrile patients with a positive diagnostic test result (blood smear, 75.0% [95% CI, 51.7%-98.3%]; RDT, 70.4% [95% CI, 39.3%-100.0%]), but also to some of those with a negative diagnostic test result (blood smear, 30.4% [95% CI, 8.0%-52. 9%]; RDT, 26.7% [95% CI, 5.7%-47.7%]). CONCLUSIONS: Despite efforts to expand the provision of malaria diagnostics in Zambia, they continue to be underused and patients with negative test results frequently receive antimalarials. Provision of new tools to reduce inappropriate use of new expensive antimalarial treatments must be accompanied by a major change in clinical treatment of patients presenting with fever but lacking evidence of malaria infection.

Idro R, Ndiritu M, Ogutu B, Mithwani S, Maitland K, Berkley J, Crawley J, Fegan G, Bauni E, Peshu N et al. 2007. Burden, features, and outcome of neurological involvement in acute falciparum malaria in Kenyan children. JAMA, 297 (20), pp. 2232-2240. | Citations: 88 (Scopus) | Show Abstract | Read more

CONTEXT: Plasmodium falciparum appears to have a particular propensity to involve the brain but the burden, risk factors, and full extent of neurological involvement have not been systematically described. OBJECTIVES: To determine the incidence and describe the clinical phenotypes and outcomes of neurological involvement in African children with acute falciparum malaria. DESIGN, SETTING, AND PATIENTS: A review of records of all children younger than 14 years admitted to a Kenyan district hospital with malaria from January 1992 through December 2004. Neurological involvement was defined as convulsive seizures, agitation, prostration, or impaired consciousness or coma. MAIN OUTCOME MEASURES: The incidence, pattern, and outcome of neurological involvement. RESULTS: Of 58,239 children admitted, 19,560 (33.6%) had malaria as the primary clinical diagnosis. Neurological involvement was observed in 9313 children (47.6%) and manifested as seizures (6563/17,517 [37.5%]), agitation (316/11,193 [2.8%]), prostration (3223/15,643 [20.6%]), and impaired consciousness or coma (2129/16,080 [13.2%]). In children younger than 5 years, the mean annual incidence of admissions with malaria was 2694 per 100,000 persons and the incidence of malaria with neurological involvement was 1156 per 100,000 persons. However, readmissions may have led to a 10% overestimate in incidence. Children with neurological involvement were older (median, 26 [interquartile range {IQR}, 15-41] vs 21 [IQR, 10-40] months; P<.001), had a shorter duration of illness (median, 2 [IQR, 1-3] vs 3 [IQR, 2-3] days; P<.001), and a higher geometric mean parasite density (42.0 [95% confidence interval {CI}, 40.0-44.1] vs 30.4 [95% CI, 29.0-31.8] x 10(3)/microL; P<.001). Factors independently associated with neurological involvement included past history of seizures (adjusted odds ratio [AOR], 3.50; 95% CI, 2.78-4.42), fever lasting 2 days or less (AOR, 2.02; 95% CI, 1.64-2.49), delayed capillary refill time (AOR, 3.66; 95% CI, 2.40-5.56), metabolic acidosis (AOR, 1.55; 95% CI, 1.29-1.87), and hypoglycemia (AOR, 2.11; 95% CI, 1.31-3.37). Mortality was higher in patients with neurological involvement (4.4% [95% CI, 4.2%-5.1%] vs 1.3% [95% CI, 1.1%-1.5%]; P<.001). At discharge, 159 (2.2%) of 7281 patients had neurological deficits. CONCLUSIONS: Neurological involvement is common in children in Kenya with acute falciparum malaria, and is associated with metabolic derangements, impaired perfusion, parasitemia, and increased mortality and neurological sequelae. This study suggests that falciparum malaria exposes many African children to brain insults.

Putter H, Fiocco M, Geskus RB. 2007. Tutorial in biostatistics: competing risks and multi-state models. Stat Med, 26 (11), pp. 2389-2430. | Show Abstract | Read more

Standard survival data measure the time span from some time origin until the occurrence of one type of event. If several types of events occur, a model describing progression to each of these competing risks is needed. Multi-state models generalize competing risks models by also describing transitions to intermediate events. Methods to analyze such models have been developed over the last two decades. Fortunately, most of the analyzes can be performed within the standard statistical packages, but may require some extra effort with respect to data preparation and programming. This tutorial aims to review statistical methods for the analysis of competing risks and multi-state models. Although some conceptual issues are covered, the emphasis is on practical issues like data preparation, estimation of the effect of covariates, and estimation of cumulative incidence functions and state and transition probabilities. Examples of analysis with standard software are shown.

Bryant JE, Holmes EC, Barrett ADT. 2007. Out of Africa: a molecular perspective on the introduction of yellow fever virus into the Americas. PLoS Pathog, 3 (5), pp. e75. | Citations: 104 (Web of Science Lite) | Show Abstract | Read more

Yellow fever virus (YFV) remains the cause of severe morbidity and mortality in South America and Africa. To determine the evolutionary history of this important reemerging pathogen, we performed a phylogenetic analysis of the largest YFV data set compiled to date, representing the prM/E gene region from 133 viral isolates sampled from 22 countries over a period of 76 years. We estimate that the currently circulating strains of YFV arose in Africa within the last 1,500 years and emerged in the Americas following the slave trade approximately 300-400 years ago. These viruses then spread westwards across the continent and persist there to this day in the jungles of South America. We therefore illustrate how gene sequence data can be used to test hypotheses of viral dispersal and demographics, and document the role of human migration in the spread of infectious disease.

Lühn K, Simmons CP, Moran E, Dung NTP, Chau TNB, Quyen NTH, Thao LTT, Van Ngoc T, Dung NM, Wills B et al. 2007. Increased frequencies of CD4+ CD25(high) regulatory T cells in acute dengue infection. J Exp Med, 204 (5), pp. 979-985. | Citations: 80 (Scopus) | Show Abstract | Read more

Dengue virus infection is an increasingly important tropical disease, causing 100 million cases each year. Symptoms range from mild febrile illness to severe hemorrhagic fever. The pathogenesis is incompletely understood, but immunopathology is thought to play a part, with antibody-dependent enhancement and massive immune activation of T cells and monocytes/macrophages leading to a disproportionate production of proinflammatory cytokines. We sought to investigate whether a defective population of regulatory T cells (T reg cells) could be contributing to immunopathology in severe dengue disease. CD4(+)CD25(high)FoxP3(+) T reg cells of patients with acute dengue infection of different severities showed a conventional phenotype. Unexpectedly, their capacity to suppress T cell proliferation and to secrete interleukin-10 was not altered. Moreover, T reg cells suppressed the production of vasoactive cytokines after dengue-specific stimulation. Furthermore, T reg cell frequencies and also T reg cell/effector T cell ratios were increased in patients with acute infection. A strong indication that a relative rise of T reg cell/effector T cell ratios is beneficial for disease outcome comes from patients with mild disease in which this ratio is significantly increased (P < 0.0001) in contrast to severe cases (P = 0.2145). We conclude that although T reg cells expand and function normally in acute dengue infection, their relative frequencies are insufficient to control the immunopathology of severe disease.

Baker S, Hardy J, Sanderson KE, Quail M, Goodhead I, Kingsley RA, Parkhill J, Stocker B, Dougan G. 2007. A novel linear plasmid mediates flagellar variation in Salmonella Typhi. PLoS Pathog, 3 (5), pp. e59. | Citations: 36 (Web of Science Lite) | Show Abstract | Read more

Unlike the majority of Salmonella enterica serovars, Salmonella Typhi (S. Typhi), the etiological agent of human typhoid, is monophasic. S. Typhi normally harbours only the phase 1 flagellin gene (fliC), which encodes the H:d antigen. However, some S. Typhi strains found in Indonesia express an additional flagellin antigen termed H:z66. Molecular analysis of H:z66+ S. Typhi revealed that the H:z66 flagellin structural gene (fljB(z66)) is encoded on a linear plasmid that we have named pBSSB1. The DNA sequence of pBSSB1 was determined to be just over 27 kbp, and was predicted to encode 33 coding sequences. To our knowledge, pBSSB1 is the first non-bacteriophage-related linear plasmid to be described in the Enterobacteriaceae.

Abuya TO, Mutemi W, Karisa B, Ochola SA, Fegan G, Marsh V. 2007. Use of over-the-counter malaria medicines in children and adults in three districts in Kenya: implications for private medicine retailer interventions. Malar J, 6 (1), pp. 57. | Citations: 47 (Scopus) | Show Abstract | Read more

BACKGROUND: Global malaria control strategies highlight the need to increase early uptake of effective antimalarials for childhood fevers in endemic settings, based on a presumptive diagnosis of malaria in this age group. Many control programmes identify private medicine sellers as important targets to promote effective early treatment, based on reported widespread inadequate childhood fever treatment practices involving the retail sector. Data on adult use of over-the-counter (OTC) medicines is limited. This study aimed to assess childhood and adult patterns of OTC medicine use to inform national medicine retailer programmes in Kenya and other similar settings. METHODS: Large-scale cluster randomized surveys of treatment seeking practices and malaria parasite prevalence were conducted for recent fevers in children under five years and recent acute illnesses in adults in three districts in Kenya with differing malaria endemicity. RESULTS: A total of 12, 445 households were visited and data collected on recent illnesses in 11, 505 children and 19, 914 adults. OTC medicines were the most popular first response to fever in children with fever (47.0%; 95% CI 45.5, 48.5) and adults with acute illnesses (56.8%; 95% CI 55.2, 58.3). 36.9% (95% CI 34.7, 39.2) adults and 22.7% (95% CI 20.9, 24.6) children using OTC medicines purchased antimalarials, with similar proportions in low and high endemicity districts. 1.9% (95% CI 0.8, 4.2) adults and 12.1% (95% CI 16.3,34.2) children used multidose antimalarials appropriately. Although the majority of children and adults sought no further treatment, self-referral to a health facility within 72 hours of illness onset was the commonest pattern amongst those seeking further help. CONCLUSION: In these surveys, OTC medicines were popular first treatments for fever in children or acute illnesses in adults. The proportions using OTC antimalarials were similar in areas of high and low malaria endemicity. In all districts, adults were more likely to self-treat with OTC antimalarial medicines than febrile children were to receive them, and less likely to use them in recommended ways. Government health centres were the most common second resort for treatment and were often used within 72 hours. In view of these practices, more research is needed to assess the impact on the popularity of private medicine sellers of strengthened public sector policies on access to malaria treatment and insecticide-treated bed nets. Improved targeting of OTC antimalarials to high risk groups, better communication strategies regarding adult as well as children's dosages, and facilitating more rapid referral to trained health workers where needed are important challenges to private medicine seller programmes.

Lindegardh N, Davies GR, Hien TT, Farrar J, Singhasivanon P, Day NPJ, White NJ. 2007. Importance of collection tube during clinical studies of oseltamivir. Antimicrob Agents Chemother, 51 (5), pp. 1835-1836. | Citations: 23 (Scopus) | Show Abstract | Read more

Ex vivo conversion of the anti-influenza drug oseltamivir to its active metabolite can be inhibited by the esterase inhibitor dichlorvos or by using commercial fluoride-oxalate tubes. Oseltamivir and its active metabolite remain intact in plasma samples during a proposed virus heat inactivation step: incubation at 60 degrees C for 45 min.

Chapman SJ, Vannberg FO, Khor CC, Segal S, Moore CE, Knox K, Day NP, Davies RJO, Crook DW, Hill AVS. 2007. Functional polymorphisms in the FCN2 gene are not associated with invasive pneumococcal disease. Mol Immunol, 44 (12), pp. 3267-3270. | Citations: 34 (Web of Science Lite) | Show Abstract | Read more

L-ficolin is a pattern-recognition molecule which binds lipoteichoic acid and Gram-positive bacteria and activates the lectin pathway of complement. Five common functional polymorphisms have recently been identified in the FCN2 gene which encodes L-ficolin: three promoter polymorphisms (at positions -986, -602 and -4) which affect serum L-ficolin concentration, and two non-synonymous polymorphisms (Thr236Met and Ala258Ser) which influence carbohydrate binding. We studied the frequencies of these polymorphisms in individuals with invasive pneumococcal disease (IPD) and a control group. Although the five FCN2 polymorphisms were each present in the UK Caucasian population studied, no significant associations were observed between the FCN2 polymorphisms and susceptibility to IPD. This is in contrast to mannose-binding lectin deficiency, which we have previously shown to be associated with increased susceptibility to IPD. Although we are unable to exclude small effects of FCN2 genetic variation on susceptibility to IPD, the result suggests that L-ficolin may not be critical for host defence against pneumococcal infection.

Paris DH, Jenjaroen K, Blacksell SD, Rattanaphone P, Newton PN, Turner GD, Day NP. 2007. Differential patterns of endothelial activation in 'typhus-like' illness TROPICAL MEDICINE & INTERNATIONAL HEALTH, 12 pp. 189-189.

Mytton OT, McGready R, Lee SJ, Roberts CH, Ashley EA, Carrara VI, Thwai KL, Jay MP, Wiangambun T, Singhasivanon P, Nosten F. 2007. Safety of benzyl benzoate lotion and permethrin in pregnancy: a retrospective matched cohort study. BJOG, 114 (5), pp. 582-587. | Citations: 28 (Scopus) | Show Abstract | Read more

OBJECTIVE: To assess the safety of benzyl benzoate lotion (BBL) and permethrin, topical treatments for scabies, during pregnancy. DESIGN: A retrospective controlled cohort study. POPULATION: Refugee and migrant women attending antenatal clinics (ANC) on the Thai-Burmese border between August 1993 and April 2006. METHODS: Women treated with either BBL (25%) or permethrin (4%) were identified from a manual search of antenatal records. Each case of scabies was matched with four scabies-free controls for gravidity, age, smoking status, malaria, period of treatment and gestational age at treatment. Conditional Poisson regression was used to estimate risk ratios for outcomes of pregnancy (proportion of abortions, congenital abnormalities, neonatal deaths, stillbirths and premature babies), mean birthweight and estimated median gestational age, for scabies and scabies-free women, independently for BBL and permethrin. RESULTS: There were no statistically significant differences in pregnancy outcomes between women who were treated with either BBL (n = 444) compared with their matched controls (n = 1,776) or permethrin (n = 196) treated women and their matched controls (n = 784). Overall, only 10.9% (n = 66) of treatments were in the first trimester. Retreatment rates were higher with BBL 16.4%, than permethrin 9.7%, P = 0.038. Scabies was more common during cooler periods. CONCLUSION: We found no evidence of adverse effects on pregnancy outcome due to topical 25% BBL or 4% permethrin.

Rijken M, Boel M, Barends M, Lindegardh N, McGready R, Nosten F. 2007. Dihydroartemisinin - piperaquine rescue treatment of multidrug-resistant Plasmodium falciparum malaria in pregnancy: a preliminary report TROPICAL MEDICINE & INTERNATIONAL HEALTH, 12 pp. 34-34.

Barends M, Jaidee A, Brockman A, Sriprawat K, Anderson T, Singhasivanon P, Nosten F. 2007. Twelve year surveillance of Plasmodium falciparum in vitro drug susceptibility on the Thai-Burmese border TROPICAL MEDICINE & INTERNATIONAL HEALTH, 12 pp. 70-70.

Schünemann HJ, Hill SR, Kakad M, Vist GE, Bellamy R, Stockman L, Wisløff TF, Del Mar C, Hayden F, Uyeki TM et al. 2007. Transparent development of the WHO rapid advice guidelines. PLoS Med, 4 (5), pp. e119. | Citations: 84 (Scopus) | Show Abstract | Read more

Emerging health problems require rapid advice. We describe the development and pilot testing of a systematic, transparent approach used by the World Health Organization (WHO) to develop rapid advice guidelines in response to requests from member states confronted with uncertainty about the pharmacological management of avian influenza A (H5N1) virus infection. We first searched for systematic reviews of randomized trials of treatment and prevention of seasonal influenza and for non-trial evidence on H5N1 infection, including case reports and animal and in vitro studies. A panel of clinical experts, clinicians with experience in treating patients with H5N1, influenza researchers, and methodologists was convened for a two-day meeting. Panel members reviewed the evidence prior to the meeting and agreed on the process. It took one month to put together a team to prepare the evidence profiles (i.e., summaries of the evidence on important clinical and policy questions), and it took the team only five weeks to prepare and revise the evidence profiles and to prepare draft guidelines prior to the panel meeting. A draft manuscript for publication was prepared within 10 days following the panel meeting. Strengths of the process include its transparency and the short amount of time used to prepare these WHO guidelines. The process could be improved by shortening the time required to commission evidence profiles. Further development is needed to facilitate stakeholder involvement, and evaluate and ensure the guideline's usefulness.

Dondorp AM. 2007. The treatment of severe malaria TROPICAL MEDICINE & INTERNATIONAL HEALTH, 12 pp. 21-21.

Warrell DA. 2007. Advances in clinical toxinology TROPICAL MEDICINE & INTERNATIONAL HEALTH, 12 pp. 24-24.

Paris D, Imwong M, Faiz M, Hasan M, Bin Yunus E, Silamut K, Lee S, Day N, Dondorp A. 2007. Loop-mediated isothermal PCR (LAMP) for the diagnosis of falciparum malaria TROPICAL MEDICINE & INTERNATIONAL HEALTH, 12 pp. 129-129.

Mahavanakul W, Limmathurotsakul D, Teerawattanasuk N, Peacock SJ. 2007. Invasive Erysipelothrix rhusiopathiae infection in northeast Thailand. Southeast Asian J Trop Med Public Health, 38 (3), pp. 478-481. | Citations: 3 (Scopus) | Show Abstract

Three cases of invasive Erysipelothrix rhusipathiae infection, which is considered rare, presented to a hospital in Ubon Ratchathani, northeast Thailand during 2006. Patients presented with variable clinical manifestations including diffused cutaneous lesions, bacteremia and endocarditis. Erysipelothrix infection may be an emerging infection in immunocompromized individuals in Thailand.

Stone SP, Cooper BS, Kibbler CC, Cookson BD, Roberts JA, Medley GF, Duckworth G, Lai R, Ebrahim S, Brown EM et al. 2007. The ORION statement: guidelines for transparent reporting of outbreak reports and intervention studies of nosocomial infection. J Antimicrob Chemother, 59 (5), pp. 833-840. | Citations: 69 (Scopus) | Show Abstract | Read more

The quality of research in hospital epidemiology (infection control) must be improved to be robust enough to influence policy and practice. In order to raise the standards of research and publication, a CONSORT equivalent for these largely quasi-experimental studies has been prepared by the authors of two relevant systematic reviews, following consultation with learned societies, editors of journals and researchers. It consists of a 22 item checklist, and a summary table. The emphasis is on transparency to improve the quality of reporting and on the use of appropriate statistical techniques. The statement has been endorsed by a number of professional special interest groups and societies. Like CONSORT, ORION should be considered a 'work in progress', which requires ongoing dialogue for successful promotion and dissemination. The statement is therefore offered for further public discussion. Journals and research councils are strongly recommended to incorporate it into their submission and reviewing processes. Feedback to the authors is encouraged and the statement will be revised in 2 years.

Ayieko P, English M. 2007. Case management of childhood pneumonia in developing countries. Pediatr Infect Dis J, 26 (5), pp. 432-440. | Citations: 56 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Pneumonia is a leading cause of morbidity and mortality in children worldwide. Appropriate management depends on accurate assessment of disease severity, and for the majority of children in developing countries the assessment is based on clinical signs alone. This article reviews recent evidence on clinical assessment and severity classification of pneumonia and reported results on the effectiveness of currently recommended treatments. METHODS: Potential studies for inclusion were identified by Medline (1990-2006) search. The Oxford Center for Evidence Based Medicine criteria were used to describe the methodologic quality of selected studies. RESULTS: In the included studies the sensitivity of current definitions of tachypnea for diagnosing radiologic pneumonia ranged from 72% to 94% with specificities between 38% and 99%; chest indrawing had reported sensitivities of between 46% and 78%. Data provide some support for the value of current clinical criteria for classifying pneumonia severity, with those meeting severe or very severe criteria being at considerably increased risk of death, hypoxemia or bacteremia. Results of randomized controlled trials report clinically defined improvement at 48 hours in at least 80% of children treated using recommended antibiotics. However, a limitation of these data may include inappropriate definitions of treatment failure. CONCLUSION: Particularly with regard to severe pneumonia, issues that specifically need to be addressed are the adequacy of penicillin monotherapy, or oral amoxicillin or alternative antibiotics; the timing of introduction of high-dose trimethoprim-sulfamethoxazole in children at risk for or known to be infected by HIV and the value of pulse oximetry.

Basnyat B. 2007. Reducing the incidence of high-altitude pulmonary edema. Ann Intern Med, 146 (8), pp. 613. | Read more

Simmons CP, Popper S, Dolocek C, Chau TNB, Griffiths M, Dung NTP, Long TH, Hoang DM, Chau NV, Thao LTT et al. 2007. Patterns of host genome-wide gene transcript abundance in the peripheral blood of patients with acute dengue hemorrhagic fever. J Infect Dis, 195 (8), pp. 1097-1107. | Citations: 117 (Scopus) | Show Abstract | Read more

Responses by peripheral blood leukocytes may contribute to the pathogenesis of dengue hemorrhagic fever (DHF). We used DNA microarrays to reveal transcriptional patterns in the blood of 14 adults with DHF. Acute DHF was defined by an abundance of transcripts from cell cycle- and endoplasmic reticulum (ER)-related genes, suggesting a proliferative response accompanied by ER stress. Transcript-abundance levels for immunoresponse-associated genes, including cell surface markers, immunoglobulin, and innate response elements, were also elevated. Twenty-four genes were identified for which transcript abundance distinguished patients with dengue shock syndrome (DSS) from those without DSS. All the gene transcripts associated with DSS, many of which are induced by type I interferons, were less abundant in patients with DSS than in those without DSS. To our knowledge, these data provide the first snapshot of gene-expression patterns in peripheral blood during acute dengue and suggest that DSS is associated with attenuation of selected aspects of the innate host response.

Hasugian AR, Purba HLE, Kenangalem E, Wuwung RM, Ebsworth EP, Maristela R, Penttinen PMP, Laihad F, Anstey NM, Tjitra E, Price RN. 2007. Dihydroartemisinin-piperaquine versus artesunate-amodiaquine: superior efficacy and posttreatment prophylaxis against multidrug-resistant Plasmodium falciparum and Plasmodium vivax malaria. Clin Infect Dis, 44 (8), pp. 1067-1074. | Citations: 108 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Antimalarial drug resistance is now well established in both Plasmodium falciparum and Plasmodium vivax. In southern Papua, Indonesia, where both strains of plasmodia coexist, we have been conducting a series of studies to optimize treatment strategies. METHODS: We conducted a randomized trial that compared the efficacy and safety of dihydroartemisinin-piperaquine (DHP) with artesunate-amodiaquine (AAQ). The primary end point was the overall cumulative parasitological failure rate at day 42. RESULTS: Of the 334 patients in the evaluable patient population, 185 were infected with P. falciparum, 80 were infected with P. vivax, and 69 were infected with both species. The overall parasitological failure rate at day 42 was 45% (95% confidence interval [CI], 36%-53%) for AAQ and 13% (95% CI, 7.2%-19%) for DHP (hazard ratio [HR], 4.3; 95% CI, 2.5-7.2; P<.001). Rates of both recrudescence of P. falciparum infection and recurrence of P. vivax infection were significantly higher after receipt of AAQ than after receipt of DHP (HR, 3.4 [95% CI, 1.2-9.4] and 4.3 [95% CI, 2.2-8.2], respectively; P<.001). By the end of the study, AAQ recipients were 2.95-fold (95% CI, 1.2- to 4.9-fold) more likely to be anemic and 14.5-fold (95% CI, 3.4- to 61-fold) more likely to have carried P. vivax gametocytes. CONCLUSIONS: DHP was more effective and better tolerated than AAQ against multidrug-resistant P. falciparum and P. vivax infections. The prolonged therapeutic effect of piperaquine delayed the time to P. falciparum reinfection, decreased the rate of recurrence of P. vivax infection, and reduced the risk of P. vivax gametocyte carriage and anemia.

Molyneux M. 2007. UK doctors are already put off by changes in training. BMJ, 334 (7596), pp. 709-710. | Citations: 2 (Web of Science Lite) | Read more

Imwong M, Snounou G, Pukrittayakamee S, Tanomsing N, Kim JR, Nandy A, Guthmann J-P, Nosten F, Carlton J, Looareesuwan S et al. 2007. Relapses of Plasmodium vivax infection usually result from activation of heterologous hypnozoites. J Infect Dis, 195 (7), pp. 927-933. | Citations: 173 (Scopus) | Show Abstract | Read more

BACKGROUND: Relapses originating from hypnozoites are characteristic of Plasmodium vivax infections. Thus, reappearance of parasitemia after treatment can result from relapse, recrudescence, or reinfection. It has been assumed that parasites causing relapse would be a subset of the parasites that caused the primary infection. METHODS: Paired samples were collected before initiation of antimalarial treatment and at recurrence of parasitemia from 149 patients with vivax malaria in Thailand (n=36), where reinfection could be excluded, and during field studies in Myanmar (n=75) and India (n=38). RESULTS: Combined genetic data from 2 genotyping approaches showed that novel P. vivax populations were present in the majority of patients with recurrent infection (107 [72%] of 149 patients overall [78% of patients in Thailand, 75% of patients in Myanmar {Burma}, and 63% of patients in India]). In 61% of the Thai and Burmese patients and in 55% of the Indian patients, the recurrent infections contained none of the parasite genotypes that caused the acute infection. CONCLUSIONS: The P. vivax populations emerging from hypnozoites commonly differ from the populations that caused the acute episode. Activation of heterologous hypnozoite populations is the most common cause of first relapse in patients with vivax malaria.

Khor CC, Chapman SJ, Vannberg FO, Dunne A, Murphy C, Ling EY, Frodsham AJ, Walley AJ, Kyrieleis O, Khan A et al. 2007. A Mal functional variant is associated with protection against invasive pneumococcal disease, bacteremia, malaria and tuberculosis. Nat Genet, 39 (4), pp. 523-528. | Citations: 305 (Scopus) | Show Abstract | Read more

Toll-like receptors (TLRs) and members of their signaling pathway are important in the initiation of the innate immune response to a wide variety of pathogens. The adaptor protein Mal (also known as TIRAP), encoded by TIRAP (MIM 606252), mediates downstream signaling of TLR2 and TLR4 (refs. 4-6). We report a case-control study of 6,106 individuals from the UK, Vietnam and several African countries with invasive pneumococcal disease, bacteremia, malaria and tuberculosis. We genotyped 33 SNPs, including rs8177374, which encodes a leucine substitution at Ser180 of Mal. We found that heterozygous carriage of this variant associated independently with all four infectious diseases in the different study populations. Combining the study groups, we found substantial support for a protective effect of S180L heterozygosity against these infectious diseases (N = 6,106; overall P = 9.6 x 10(-8)). We found that the Mal S180L variant attenuated TLR2 signal transduction.

Wuthiekanun V, Chierakul W, Limmathurotsakul D, Smythe LD, Symonds ML, Dohnt MF, Slack AT, Limpaiboon R, Suputtamongkol Y, White NJ et al. 2007. Optimization of culture of Leptospira from humans with leptospirosis. J Clin Microbiol, 45 (4), pp. 1363-1365. | Citations: 31 (Web of Science Lite) | Show Abstract | Read more

A prospective study of 989 patients with acute febrile illness was performed in northeast Thailand to define the yield of Leptospira from four different types of blood sample. Based on a comparison of the yields from whole blood, surface plasma, deposit from spun plasma, and clotted blood samples from 80 patients with culture-proven leptospirosis, we suggest a sampling strategy in which culture is performed using whole blood and deposit from spun plasma.

Medana IM, Day NP, Hien TT, Mai NTH, Bethell D, Phu NH, Turner GD, Farrar J, White NJ, Esiri MM. 2007. Cerebral calpain in fatal falciparum malaria. Neuropathol Appl Neurobiol, 33 (2), pp. 179-192. | Citations: 10 (Scopus) | Show Abstract | Read more

Disruption of axonal transport may represent a final common pathway leading to neurological dysfunction in cerebral malaria (CM). Calpains are calcium (Ca2+)-activated cysteine proteases which have been implicated in axonal injury in neurological diseases of various aetiologies. In this study we examined the association between mu- and m-calpain, the specific inhibitor calpastatin, and axonal injury in post mortem brain tissue from patients who died from severe malaria. Calpains were associated with axons labelled for the beta-amyloid precursor protein that detects impaired axonal transport. Elevated levels of calpastatin were rarely observed in injured axons. There were increased numbers of neurones with mu-calpain in the nuclear compartment in severe malaria cases compared with non-neurological controls, and increased numbers of glia with nuclear mu-calpain in CM patients compared with non-CM malaria cases and non-neurological controls. There was marked redistribution of calpastatin in the sequestered Plasmodium falciparum-infected erythrocytes. Responses specific to malaria infection were ascertained following analysis of brain samples from fatal cases with acute axonal injury, HIV encephalitis, and progressive multifocal leucoencephalopathy. Our findings implicate a role for calpains in the modulation of disease progression in CM.

Mayxay M, Pongvongsa T, Phompida S, Phetsouvanh R, White NJ, Newton PN. 2007. Diagnosis and management of malaria by rural community health providers in the Lao People's Democratic Republic (Laos). Trop Med Int Health, 12 (4), pp. 540-546. | Citations: 13 (Web of Science Lite) | Show Abstract | Read more

We assessed the knowledge of malaria diagnosis and management by community health providers in rural Vientiane and Savannakhet Provinces, Lao PDR. Sixty health providers (17 pharmacy owners/drug sellers and 43 village health volunteers) were interviewed. All diagnosed malaria using symptoms and signs only; 14% were aware of >2 criteria for the diagnosis of severe malaria. Although chloroquine and quinine, the then recommended Lao national policy for uncomplicated malaria treatment, were the most common antimalarials prescribed - 65% gave incorrect doses and 70% did not know the side effects. Although not recommended by the then national policy, 27% of the health providers used combinations of antimalarials as they considered monotherapy ineffective. This study strongly suggests that further training of Lao rural health providers in malaria diagnosis and management is needed to improve the quality of health services in areas remote from district hospitals.

Flohr C, Tuyen LN, Lewis S, Minh TT, Campbell J, Britton J, Williams H, Hien TT, Farrar J, Quinnell RJ. 2007. Low efficacy of mebendazole against hookworm in Vietnam: two randomized controlled trials. Am J Trop Med Hyg, 76 (4), pp. 732-736. | Citations: 60 (Scopus) | Show Abstract

Vietnam is participating in a global de-worming effort that aims to treat 650 million school children regularly by 2010. The treatment used in Vietnam is single dose oral mebendazole (Phardazone) 500 mg. We tested the efficacy of single dose mebendazole 500 mg in the therapy of hookworm infection in a randomized double-blind placebo-controlled trial among 271 Vietnamese schoolchildren. The treatment efficacy of single dose mebendazole in children did not differ significantly from placebo, with a reduction in mean eggs per gram of feces relative to placebo of 31% (95% CI -9 to 56%, P = 0.1). In light of these findings we then carried out a similar randomized trial comparing triple dose mebendazole, single dose albendazole, and triple dose albendazole against placebo in 209 adults in the same area. The estimated reduction in mean post-treatment eggs per gram of feces relative to placebo was 63% (95% CI 30-81%) for triple mebendazole, 75% (47-88%) for single albendazole, and 88% (58-97%) for triple albendazole. Our results suggest that single dose oral mebendazole has low efficacy against hookworm infection in Vietnam, and that it should be replaced by albendazole. These findings are of major public health relevance given the opportunity costs of treating entire populations with ineffective therapies. We recommend that efficacy of anti-helminth therapies is pilot tested before implementation of national gut worm control programs.

De Fost M, Chierakul W, Limpaiboon R, Dondorp A, White NJ, van Der Poll T. 2007. Release of granzymes and chemokines in Thai patients with leptospirosis. Clin Microbiol Infect, 13 (4), pp. 433-436. | Citations: 15 (Web of Science Lite) | Show Abstract | Read more

The plasma concentrations of granzymes are considered to reflect the involvement of cytotoxic T-cells and natural killer cells in various disease states. Interferon (IFN)-gamma-inducible protein-10 (IP-10) and monokine induced by IFN-gamma (Mig) are members of the non-ELR CXC chemokine family that act on T-cells and natural killer cells. This study revealed that the plasma concentrations of granzyme B (but not granzyme A), IP-10 and Mig were higher in 44 Thai patients with definite or possible leptospirosis than in healthy blood donors. These data suggest that activation of cell-mediated immunity is part of the early host response to leptospirosis.

Cox J, Hay SI, Abeku TA, Checchi F, Snow RW. 2007. The uncertain burden of Plasmodium falciparum epidemics in Africa. Trends Parasitol, 23 (4), pp. 142-148. | Citations: 30 (Web of Science Lite) | Show Abstract | Read more

Although the control of malaria epidemics has been a priority for the World Health Organization and other agencies for many years, surprisingly little is known about the public health burden of these epidemics. Here, we evaluate the available evidence of the morbidity and mortality impacts of individual epidemics in Africa and examine the problems associated with using these data to estimate the average annual burden of epidemics at national and continental scales. We argue that conventional approaches that are used to assess the burden of epidemics are inadequate, and outline the future steps that are required to produce estimates that are more accurate.

Ratcliff A, Siswantoro H, Kenangalem E, Wuwung M, Brockman A, Edstein MD, Laihad F, Ebsworth EP, Anstey NM, Tjitra E, Price RN. 2007. Therapeutic response of multidrug-resistant Plasmodium falciparum and P. vivax to chloroquine and sulfadoxine-pyrimethamine in southern Papua, Indonesia. Trans R Soc Trop Med Hyg, 101 (4), pp. 351-359. | Citations: 98 (Web of Science Lite) | Show Abstract | Read more

To determine the level of antimalarial drug resistance in southern Papua, Indonesia, we assessed the therapeutic efficacy of chloroquine plus sulfadoxine-pyrimethamine (CQ+SP) for Plasmodium falciparum infections as well as CQ monotherapy for P. vivax infections. Patients with P. falciparum failing therapy were re-treated with unsupervised quinine+/-doxycycline therapy and those with P. vivax with either unsupervised quinine+/-doxycycline or amodiaquine. In total, 143 patients were enrolled in the study (103 treated with CQ+SP and 40 with CQ). Early treatment failures occurred in four patients (4%) with P. falciparum and six patients (15%) with P. vivax. The failure rate by Day 28 for P. vivax was 65% (95% CI 49-81). After PCR correction for re-infections, the Day 42 recrudescence rate for P. falciparum infections was 48% (95% CI 31-65). Re-treatment with unsupervised quinine+/-doxycycline resulted in further recurrence of malaria in 48% (95% CI 31-65) of P. falciparum infections and 70% (95% CI 37-100) of P. vivax infections. Eleven patients with recurrent P. vivax were re-treated with amodiaquine; there were no early or late treatment failures. In southern Papua, a high prevalence of drug resistance of P. falciparum and P. vivax exists both to first- and second-line therapies. Preliminary data indicate that amodiaquine retains superior efficacy compared with CQ for CQ-resistant P. vivax.

Tuan PA, Horby P, Dinh PN, Mai LTQ, Zambon M, Shah J, Huy VQ, Bloom S, Gopal R, Comer J et al. 2007. SARS transmission in Vietnam outside of the health-care setting. Epidemiol Infect, 135 (3), pp. 392-401. | Citations: 2 (Web of Science Lite) | Show Abstract | Read more

To evaluate the risk of transmission of SARS coronavirus outside of the health-care setting, close household and community contacts of laboratory-confirmed SARS cases were identified and followed up for clinical and laboratory evidence of SARS infection. Individual- and household-level risk factors for transmission were investigated. Nine persons with serological evidence of SARS infection were identified amongst 212 close contacts of 45 laboratory-confirmed SARS cases (secondary attack rate 4.2%, 95% CI 1.5-7). In this cohort, the average number of secondary infections caused by a single infectious case was 0.2. Two community contacts with laboratory evidence of SARS coronavirus infection had mild or sub-clinical infection, representing 3% (2/65) of Vietnamese SARS cases. There was no evidence of transmission of infection before symptom onset. Physically caring for a symptomatic laboratory-confirmed SARS case was the only independent risk factor for SARS transmission (OR 5.78, 95% CI 1.23-24.24).

Kyriacou HM, Steen KE, Raza A, Arman M, Warimwe G, Bull PC, Havlik I, Rowe JA. 2007. In vitro inhibition of Plasmodium falciparum rosette formation by Curdlan sulfate. Antimicrob Agents Chemother, 51 (4), pp. 1321-1326. | Citations: 25 (Web of Science Lite) | Show Abstract | Read more

Spontaneous binding of infected erythrocytes to uninfected erythrocytes to form rosettes is a property of some strains of Plasmodium falciparum that is linked to severe complications of malaria. Curdlan sulfate (CRDS) is a sulfated glycoconjugate compound that is chemically similar to known rosette-inhibiting drugs such as heparin. CRDS has previously been shown to have antimalarial activity in vitro and is safe for clinical use. Here we show that CRDS at therapeutic levels (10 to 100 microg/ml) significantly reduces rosette formation in vitro in seven P. falciparum laboratory strains and in a group of 18 African clinical isolates. The strong ability to inhibit rosetting suggests that CRDS has the potential to reduce the severe complications and mortality rates from P. falciparum malaria among African children. Our data support further clinical trials of CRDS.

van Doorn HR, Hofwegen H, Koelewijn R, Gilis H, Wentink-Bonnema E, Pinelli E, van Genderen PJJ, Schipper HG, van Gool T. 2007. Reliable serodiagnosis of imported cystic echinococcosis with a commercial indirect hemagglutination assay. Diagn Microbiol Infect Dis, 57 (4), pp. 409-412. | Citations: 8 (Scopus) | Show Abstract | Read more

A commercially available indirect hemagglutination assay (IHA) (Echinococcosis Fumouze; Laboratoires Fumouze, Levallois-Perret, France) was evaluated using sera from 52 patients with proven cystic echinococcosis. The specificity was assessed using 247 sera from patients with various parasitic, bacterial, viral, and fungal infectious diseases; sera containing autoimmune antibodies; and sera from healthy blood donors. With a cutoff value for a positive result of 320 (as recommended by the manufacturer), the sensitivity and specificity were 88% and 98.4%; with a cutoff of 160, the sensitivity and specificity were 94% and 95.1%, respectively. The IHA is rapid, easy to perform, and is a very sensitive serodiagnostic test for cystic echinococcosis.

Stone SP, Cooper BS, Kibbler CC, Cookson BD, Roberts JA, Medley GF, Duckworth G, Lai R, Ebrahim S, Brown EM et al. 2007. The ORION statement: guidelines for transparent reporting of outbreak reports and intervention studies of nosocomial infection. Lancet Infect Dis, 7 (4), pp. 282-288. | Citations: 143 (Scopus) | Show Abstract | Read more

The quality of research in hospital epidemiology (infection control) must be improved to be robust enough to influence policy and practice. In order to raise the standards of research and publication, a CONSORT equivalent for these largely quasi-experimental studies has been prepared by the authors of two relevant systematic reviews, following consultation with learned societies, editors of journals, and researchers. The ORION (Outbreak Reports and Intervention Studies Of Nosocomial infection) statement consists of a 22 item checklist, and a summary table. The emphasis is on transparency to improve the quality of reporting and on the use of appropriate statistical techniques. The statement has been endorsed by a number of professional special interest groups and societies. Like CONSORT, ORION should be considered a "work in progress", which requires ongoing dialogue for successful promotion and dissemination. The statement is therefore offered for further public discussion. Journals and research councils are strongly recommended to incorporate it into their submission and reviewing processes. Feedback to the authors is encouraged and the statement will be revised in 2 years.

Basnyat B. 2007. The treatment of enteric fever. J R Soc Med, 100 (4), pp. 161-162. | Citations: 6 (Scopus) | Read more

Lucas MES, Jeuland M, Deen J, Lazaro N, MacMahon M, Nyamete A, Barreto A, von Seidlein L, Cumbane A, Songane FF, Whittington D. 2007. Private demand for cholera vaccines in Beira, Mozambique. Vaccine, 25 (14), pp. 2599-2609. | Citations: 38 (Scopus) | Show Abstract | Read more

In the summer of 2005, we interviewed 996 randomly selected respondents in Beira, Mozambique concerning their willingness and ability to pay for cholera vaccine for themselves and for other household members. Respondents were told that two doses of the vaccine would be required 2 weeks apart, and that the cholera vaccine would offer excellent protection against infection for the first year following vaccination, and some protection during the second and third year after a person is vaccinated. This research was carried out in order to learn more about private demand for vaccines in a cholera-endemic area. We asked two types of valuation questions: (1) a discrete-price offer for a vaccine that could be purchased for household members and (2) a payment card designed to assess uncertainty in the respondent's demand for a vaccine for self-protection. We estimate average household willingness to pay (WTP) for cholera vaccines in Beira to be 2005 US$ 8.45. This estimate of household WTP represents the perceived private economic benefits to a household--six persons on average--of giving all members free cholera vaccines.

Zurovac D, Ndhlovu M, Sipilanyambe N, Chanda P, Hamer DH, Simon JL, Snow RW. 2007. Paediatric malaria case-management with artemether-lumefantrine in Zambia: a repeat cross-sectional study. Malar J, 6 (1), pp. 31. | Citations: 65 (Scopus) | Show Abstract | Read more

BACKGROUND: Zambia was the first African country to change national antimalarial treatment policy to artemisinin-based combination therapy--artemether-lumefantrine. An evaluation during the early implementation phase revealed low readiness of health facilities and health workers to deliver artemether-lumefantrine, and worryingly suboptimal treatment practices. Improvements in the case-management of uncomplicated malaria two years after the initial evaluation and three years after the change of policy in Zambia are reported. METHODS: Data collected during the health facility surveys undertaken in 2004 and 2006 at all outpatient departments of government and mission facilities in four Zambian districts were analysed. The surveys were cross-sectional, using a range of quality of care assessment methods. The main outcome measures were changes in health facility and health worker readiness to deliver artemether-lumefantrine, and changes in case-management practices for children below five years of age presenting with uncomplicated malaria as defined by national guidelines. RESULTS: In 2004, 94 health facilities, 103 health workers and 944 consultations for children with uncomplicated malaria were evaluated. In 2006, 104 facilities, 135 health workers and 1125 consultations were evaluated using the same criteria of selection. Health facility and health worker readiness improved from 2004 to 2006: availability of artemether-lumefantrine from 51% (48/94) to 60% (62/104), presence of artemether-lumefantrine dosage wall charts from 20% (19/94) to 75% (78/104), possession of guidelines from 58% (60/103) to 92% (124/135), and provision of in-service training from 25% (26/103) to 41% (55/135). The proportions of children with uncomplicated malaria treated with artemether-lumefantrine also increased from 2004 to 2006: from 1% (6/527) to 27% (149/552) in children weighing 5 to 9 kg, and from 11% (42/394) to 42% (231/547) in children weighing 10 kg or more. In both weight groups and both years, 22% (441/2020) of children with uncomplicated malaria were not prescribed any antimalarial drug. CONCLUSION: Although significant improvements in malaria case-management have occurred over two years in Zambia, the quality of treatment provided at the point of care is not yet optimal. Strengthening weak health systems and improving the delivery of effective interventions should remain high priority in all countries implementing new treatment policies for malaria.

Cordery DV, Kishore U, Kyes S, Shafi MJ, Watkins KR, Williams TN, Marsh K, Urban BC. 2007. Characterization of a Plasmodium falciparum macrophage-migration inhibitory factor homologue. J Infect Dis, 195 (6), pp. 905-912. | Citations: 37 (Scopus) | Show Abstract | Read more

BACKGROUND: Macrophage-migration inhibitory factor (MIF), one of the first cytokines described, has a broad range of proinflammatory properties. The genome sequencing project of Plasmodium falciparum identified a parasite homologue of MIF. The protein is expressed during the asexual blood stages of the parasite life cycle that cause malarial disease. The identification of a parasite homologue of MIF raised the question of whether it affects monocyte function in a manner similar to its human counterpart. METHODS: Recombinant P. falciparum MIF (PfMIF) was generated and used in vitro to assess its influence on monocyte function. Antibodies generated against PfMIF were used to determine the expression profile and localization of the protein in blood-stage parasites. Antibody responses to PfMIF were determined in Kenyan children with acute malaria and in control subjects. RESULTS: PfMIF protein was expressed in asexual blood-stage parasites, localized to the Maurer's cleft. In vitro treatment of monocytes with PfMIF inhibited random migration and reduced the surface expression of Toll-like receptor (TLR) 2, TLR4, and CD86. CONCLUSIONS: These results indicate that PfMIF is released during blood-stage malaria and potentially modulates the function of monocytes during acute P. falciparum infection.

Tiyawisutsri R, Holden MTG, Tumapa S, Rengpipat S, Clarke SR, Foster SJ, Nierman WC, Day NPJ, Peacock SJ. 2007. Burkholderia Hep_Hag autotransporter (BuHA) proteins elicit a strong antibody response during experimental glanders but not human melioidosis. BMC Microbiol, 7 (1), pp. 19. | Citations: 32 (Scopus) | Show Abstract | Read more

BACKGROUND: The bacterial biothreat agents Burkholderia mallei and Burkholderia pseudomallei are the cause of glanders and melioidosis, respectively. Genomic and epidemiological studies have shown that B. mallei is a recently emerged, host restricted clone of B. pseudomallei. RESULTS: Using bacteriophage-mediated immunoscreening we identified genes expressed in vivo during experimental equine glanders infection. A family of immunodominant antigens were identified that share protein domain architectures with hemagglutinins and invasins. These have been designated Burkholderia Hep_Hag autotransporter (BuHA) proteins. A total of 110/207 positive clones (53%) of a B. mallei expression library screened with sera from two infected horses belonged to this family. This contrasted with 6/189 positive clones (3%) of a B. pseudomallei expression library screened with serum from 21 patients with culture-proven melioidosis. CONCLUSION: Members of the BuHA proteins are found in other Gram-negative bacteria and have been shown to have important roles related to virulence. Compared with other bacterial species, the genomes of both B. mallei and B. pseudomallei contain a relative abundance of this family of proteins. The domain structures of these proteins suggest that they function as multimeric surface proteins that modulate interactions of the cell with the host and environment. Their effect on the cellular immune response to B. mallei and their potential as diagnostics for glanders requires further study.

Atkinson SH, Mwangi TW, Uyoga SM, Ogada E, Macharia AW, Marsh K, Prentice AM, Williams TN. 2007. The haptoglobin 2-2 genotype is associated with a reduced incidence of Plasmodium falciparum malaria in children on the coast of Kenya. Clin Infect Dis, 44 (6), pp. 802-809. | Citations: 29 (Scopus) | Show Abstract | Read more

BACKGROUND: Haptoglobin (Hp) genotype determines the efficiency of hemoglobin clearance after malaria-induced hemolysis and alters antioxidant and immune functions. The Hp2 allele is thought to have spread under strong selection pressure, but it is unclear whether this is due to protection from malaria or other diseases. METHODS: We monitored the incidence of febrile malaria and other childhood illnesses with regard to Hp genotype in a prospective cohort of 312 Kenyan children during 558.3 child-years of follow-up. We also conducted 7 cross-sectional surveys to determine the prevalence of Plasmodium falciparum parasitemia. RESULTS: The Hp2/2 genotype was associated with a 30% reduction in clinical malarial episodes (adjusted incidence rate ratio, 0.67; P=.008 for Hp2/2 vs. Hp1/1 and Hp2/1 combined). Protection increased with age; there was no protection in the first 2 years of life, 30% protection at > or = 2 years of age, and 50% protection from 4-10 years of age. Children with the Hp1/1 genotype had a significantly lower rate of nonmalarial fever (P=.001). CONCLUSIONS: Balancing selection pressures may have influenced the spread of the Hp gene. Our observations suggest that the Hp2 allele may have spread as a result of protection from malaria, and the Hp1 allele may be sustained by protection from other infections.

Ratcliff A, Siswantoro H, Kenangalem E, Maristela R, Wuwung RM, Laihad F, Ebsworth EP, Anstey NM, Tjitra E, Price RN. 2007. Two fixed-dose artemisinin combinations for drug-resistant falciparum and vivax malaria in Papua, Indonesia: an open-label randomised comparison. Lancet, 369 (9563), pp. 757-765. | Citations: 178 (Scopus) | Show Abstract | Read more

BACKGROUND: The burden of Plasmodium vivax infections has been underappreciated, especially in southeast Asia where chloroquine resistant strains have emerged. Our aim was to compare the safety and efficacy of dihydroartemisinin-piperaquine with that of artemether-lumefantrine in patients with uncomplicated malaria caused by multidrug-resistant P falciparum and P vivax. METHODS: 774 patients in southern Papua, Indonesia, with slide-confirmed malaria were randomly assigned to receive either artemether-lumefantrine or dihydroartemisinin-piperaquine and followed up for at least 42 days. The primary endpoint was the overall cumulative risk of parasitological failure at day 42 with a modified intention-to-treat analysis. This trial is registered with, trial number 00157833. FINDINGS: Of the 754 evaluable patients enrolled, 466 had infections with P falciparum, 175 with P vivax, and 113 with a mixture of both species. The overall risk of failure at day 42 was 43% (95% CI 38-48) for artemether-lumefantrine and 19% (14-23) for dihydroartemisinin-piperaquine (hazard ratio=3.0, 95% CI 2.2-4.1, p<0.0001). After correcting for reinfections, the risk of recrudescence of P falciparum was 4.4% (2.6-6.2) with no difference between regimens. Recurrence of vivax occurred in 38% (33-44) of patients given artemether-lumefantrine compared with 10% (6.9-14.0) given dihydroartemisinin-piperaquine (p<0.0001). At the end of the study, patients receiving dihydroartemisinin-piperaquine were 2.0 times (1.2-3.6) less likely to be anaemic and 6.6 times (2.8-16) less likely to carry vivax gametocytes than were those given artemether-lumefantrine. INTERPRETATION: Both dihydroartemisinin-piperaquine and artemether-lumefantrine were safe and effective for the treatment of multidrug-resistant uncomplicated malaria. However, dihydroartemisinin-piperaquine provided greater post-treatment prophylaxis than did artemether-lumefantrine, reducing P falciparum reinfections and P vivax recurrences, the clinical public-health importance of which should not be ignored.

Newton PN, Green MD, Fernandez F. 2007. Counterfeit artemisinin derivatives and Africa: update from authors. PLoS Med, 4 (3), pp. e139. | Citations: 5 (Web of Science Lite) | Read more

Blacksell SD, Myint KSA, Khounsy S, Phruaravanh M, Mammen MP, Day NPJ, Newton PN. 2007. Prevalence of hepatitis E virus antibodies in pigs: implications for human infections in village-based subsistence pig farming in the Lao PDR. Trans R Soc Trop Med Hyg, 101 (3), pp. 305-307. | Citations: 17 (Web of Science Lite) | Show Abstract | Read more

We report a high seroprevalence of hepatitis E virus (HEV) in pigs in the Lao PDR. HEV seroprevalence was 51.2% (300/586) amongst abattoir pigs and 15.3% (46/301) amongst village pigs. The age distribution suggested previous in-village HEV pig infections. These findings suggest a zoonotic risk associated with village-based smallholder pig farming.

Mayxay M, Taylor AM, Khanthavong M, Keola S, Pongvongsa T, Phompida S, Phetsouvanh R, White NJ, Newton PN. 2007. Thiamin deficiency and uncomplicated falciparum malaria in Laos. Trop Med Int Health, 12 (3), pp. 363-369. | Citations: 15 (Scopus) | Show Abstract | Read more

OBJECTIVE: Thiamin deficiency complicates severe Plasmodium falciparum malaria in Thailand and may contribute to acidosis. We therefore estimated the frequency of biochemical thiamin deficiency in patients presenting with uncomplicated falciparum malaria in southern Laos. METHODS: Red cell transketolase activation coefficients (alpha) were measured in 310 patients presenting with uncomplicated falciparum malaria and 42 days after starting treatment. RESULTS: Twelve per cent of patients had biochemical evidence of severe deficiency (alpha values >1.31) at presentation, declining to 3% 42 days later. CONCLUSION: Thiamin deficiency was common in Lao patients admitted with uncomplicated P. falciparum infection and was reduced following treatment of malaria and multivitamin supplementation. The role of this preventable and treatable disorder in malaria and other acute infections, and the incidence of beriberi in rural Laos, needs further investigation.

Nyadong L, Green MD, De Jesus VR, Newton PN, Fernández FM. 2007. Reactive desorption electrospray ionization linear ion trap mass spectrometry of latest-generation counterfeit antimalarials via noncovalent complex formation. Anal Chem, 79 (5), pp. 2150-2157. | Citations: 121 (Scopus) | Show Abstract | Read more

Desorption electrospray ionization mass spectrometry (DESI MS) is rapidly becoming accepted as a powerful surface characterization tool for a wide variety of samples in the open air. Besides its well-established high-throughput capabilities, a unique feature of DESI is that chemical reactions between the charged spray microdroplets and surface molecules can be exploited to enhance ionization. Here, we present a rapid screening assay for artesunate antimalarials based on reactive DESI. Artesunate is a vital therapy for Plasmodium falciparum malaria, but artesunate tablets have been counterfeited on a very large scale in SE Asia, and more recently in Africa. For this reason, faster and more sensitive screening tests are urgently needed. The proposed DESI assay is based on the formation of stable noncovalent complexes between linear alkylamines dissolved in the DESI spray solution and artesunate molecules exposed on the tablet surface. We found that, depending on amine type and concentration, a sensitivity gain of up to 170x can be obtained, in comparison to reagent-less DESI. Hexylamine (Hex), dodecylamine (DDA), and octadecylamine (ODA) produced proton-bound noncovalent complexes with gas-phase stabilities, increasing in the order [M + Hex + H]+ < [M + DDA + H]+ < [M + ODA + H]+. Tandem MS experiments revealed that complex formation occurred by hydrogen bonding between the amine nitrogen and the ether-like moieties within the artesunate lactone ring. After the reactive DESI assay was fully characterized, it was applied to a set of recently collected suspicious artesunate tablets purchased in shops and pharmacies in SE Asia. Not only did we find that these samples were counterfeits, but we also detected the presence of several wrong active ingredients. Of particular concern was the positive detection of artesunate traces in the surface of one of the samples, which we quantified with standard chromatographic techniques.

Thwaites GE, Macmullen-Price J, Tran THC, Pham PM, Nguyen TD, Simmons CP, White NJ, Tran TH, Summers D, Farrar JJ. 2007. Serial MRI to determine the effect of dexamethasone on the cerebral pathology of tuberculous meningitis: an observational study. Lancet Neurol, 6 (3), pp. 230-236. | Citations: 102 (Scopus) | Show Abstract | Read more

BACKGROUND: Adjunctive dexamethasone increases survival from tuberculous meningitis, but the underlying mechanism is unclear. We aimed to determine the effect of dexamethasone on cerebral MRI changes and their association with intracerebral inflammatory responses and clinical outcome in adults treated for tuberculous meningitis. METHODS: Cerebral MRI was undertaken, when possible, at diagnosis and after 60 days and 270 days of treatment in adults with tuberculous meningitis admitted to two hospitals in Vietnam. Patients were randomly assigned either dexamethasone (n=24) or placebo (n=19) and received 9 months of treatment with standard first-line antituberculosis drugs. We assessed associations between MRI findings, treatment allocation, and resolution of fever, coma, cerebrospinal fluid inflammation, and neurological outcome. FINDINGS: 83 scans were done for 43 patients: 19 given placebo, 24 given dexamethasone. Basal meningeal enhancement (82%) and hydrocephalus (77%) were the most common presenting findings. Fewer patients had hydrocephalus after 60 days of treatment with dexamethasone than after placebo treatment (p=0.217). Tuberculomas developed in 74% of patients during treatment and in equal proportions in the treatment groups; they were associated with long-term fever, but not relapse or poor clinical outcome. The basal ganglia were the most common site of infarction; the proportion with infarction after 60 days was halved in the dexamethasone group (27%vs 58%, p=0.130). INTERPRETATION: Dexamethasone may affect outcome from tuberculous meningitis by reducing hydrocephalus and preventing infarction. The effect may have been under-estimated because the most severe patients could not be scanned.

Smith DL, McKenzie FE, Snow RW, Hay SI. 2007. Revisiting the basic reproductive number for malaria and its implications for malaria control. PLoS Biol, 5 (3), pp. e42. | Citations: 223 (Web of Science Lite) | Show Abstract | Read more

The prospects for the success of malaria control depend, in part, on the basic reproductive number for malaria, R0. Here, we estimate R0 in a novel way for 121 African populations, and thereby increase the number of R0 estimates for malaria by an order of magnitude. The estimates range from around one to more than 3,000. We also consider malaria transmission and control in finite human populations, of size H. We show that classic formulas approximate the expected number of mosquitoes that could trace infection back to one mosquito after one parasite generation, Z0(H), but they overestimate the expected number of infected humans per infected human, R0(H). Heterogeneous biting increases R0 and, as we show, Z0(H), but we also show that it sometimes reduces R0(H); those who are bitten most both infect many vectors and absorb infectious bites. The large range of R0 estimates strongly supports the long-held notion that malaria control presents variable challenges across its transmission spectrum. In populations where R0 is highest, malaria control will require multiple, integrated methods that target those who are bitten most. Therefore, strategic planning for malaria control should consider R0, the spatial scale of transmission, human population density, and heterogeneous biting.

Imoukhuede EB, Andrews L, Milligan P, Berthoud T, Bojang K, Nwakanma D, Ismaili J, Buckee C, Njie F, Keita S et al. 2007. Low-level malaria infections detected by a sensitive polymerase chain reaction assay and use of this technique in the evaluation of malaria vaccines in an endemic area. Am J Trop Med Hyg, 76 (3), pp. 486-493. | Citations: 18 (Web of Science Lite) | Show Abstract

The feasibility of using a sensitive polymerase chain reaction (PCR) to evaluate malaria vaccines in small group sizes was tested in 102 adult Gambian volunteers who received either the malaria vaccine regimen FP9 ME-TRAP/MVA ME-TRAP or rabies vaccine. All volunteers received the antimalarial drugs primaquine and Lapdap plus artesunate to eliminate malaria parasites. Volunteers in a further group received an additional single treatment with sulfadoxine-pyrimethamine (SP) to prevent new infections. There was substantially lower T-cell immunogenicity than in previous trials with this vaccine regimen and no protection against infection in the malaria vaccine group. Using the primary endpoint of 20 parasites per mL, no difference was found in the prevalence of low-level infections in volunteers who received SP compared with those who did not, indicating that SP did not reduce the incidence of very low-density infection. However, SP markedly reduced the incidence of higher density infections. These findings support the feasibility and potential of this approach to screen pre-erythrocytic vaccines for efficacy against infection in small numbers of vaccinees in endemic areas.

Amin AA, Walley T, Kokwaro GO, Winstanley PA, Snow RW. 2007. Reconciling national treatment policies and drug regulation in Kenya. Health Policy Plan, 22 (2), pp. 111-112. | Citations: 8 (Web of Science Lite) | Read more

Brouwer AE, van Kan HJM, Johnson E, Rajanuwong A, Teparrukkul P, Wuthiekanun V, Chierakul W, Day N, Harrison TS. 2007. Oral versus intravenous flucytosine in patients with human immunodeficiency virus-associated cryptococcal meningitis. Antimicrob Agents Chemother, 51 (3), pp. 1038-1042. | Citations: 29 (Scopus) | Show Abstract | Read more

In a randomized controlled trial of amphotericin B-based therapy for human immunodeficiency virus (HIV)-associated cryptococcal meningitis in Thailand, we also compared the mycological efficacy, toxicity, and pharmacokinetics of oral versus intravenous flucytosine at 100 mg/kg of body weight/day for the initial 2 weeks. Half of 32 patients assigned to the two arms containing flucytosine were randomized to oral and half to intravenous flucytosine. Early fungicidal activity was determined from serial quantitative cultures of cerebrospinal fluid (CSF), and toxicity was assessed by clinical and laboratory monitoring. Flucytosine and fluorouracil concentrations in plasma and CSF were measured by high-performance liquid chromatography. No significant bone marrow or hepatotoxicity was seen, there was no detectable difference in bone marrow toxicity between patients on intravenous and those on oral formulation, and no patients discontinued treatment. In patients receiving intravenous flucytosine, the median 24-h area under the concentration-time curve was significantly higher than in the oral group. Despite this difference, there was no difference in early fungicidal activity between patients on intravenous compared with patients on oral flucytosine. The results suggest that either formulation can be used safely at this dosage in a developing country setting, without drug concentration monitoring. The bioavailability of the oral formulation may be reduced in late-stage HIV-infected patients in Thailand. Concentrations of flucytosine with intravenous formulation at 100 mg/kg/day may be in excess of those required for maximal fungicidal activity.

van den Berg CHSB, Smit C, Bakker M, Geskus RB, Berkhout B, Jurriaans S, Coutinho RA, Wolthers KC, Prins M. 2007. Major decline of hepatitis C virus incidence rate over two decades in a cohort of drug users. Eur J Epidemiol, 22 (3), pp. 183-193. | Citations: 82 (Scopus) | Show Abstract | Read more

Injecting drug users (DU) are at high risk for hepatitis C virus (HCV) and HIV infections. To examine the prevalence and incidence of these infections over a 20-year period (1985-2005), the authors evaluated 1276 DU from the Amsterdam Cohort Studies who had been tested prospectively for HIV infection and retrospectively for HCV infection. To compare HCV and HIV incidences, a smooth trend was assumed for both curves over calendar time. Risk factors for HCV seroconversion were determined using Poisson regression. Among ever-injecting DU, the prevalence of HCV antibodies was 84.5% at study entry, and 30.9% were co-infected with HIV. Their yearly HCV incidence dropped from 27.5/100 person years (PY) in the 1980s to 2/100 PY in recent years. In multivariate analyses, ever-injecting DU who currently injected and borrowed needles were at increased risk of HCV seroconversion (incidence rate ratio 29.9, 95% CI 12.6, 70.9) compared to ever-injecting DU who did not currently inject. The risk of HCV seroconversion decreased over calendar time. The HCV incidence in ever-injecting DU was on average 4.4 times the HIV incidence, a pattern seen over the entire study period. The simultaneous decline of both HCV and HIV incidence probably results from reduced risk behavior at the population level.

Humphreys GS, Merinopoulos I, Ahmed J, Whitty CJM, Mutabingwa TK, Sutherland CJ, Hallett RL. 2007. Amodiaquine and Artemether-Lumefantrine Select Distinct Alleles of the Plasmodium falciparum mdr1 Gene in Tanzanian Children Treated for Uncomplicated Malaria Antimicrobial Agents and Chemotherapy, 51 (3), pp. 991-997. | Read more

Warrell DA. 2007. Bent Einer Juel-Jensen - Obituary BRITISH MEDICAL JOURNAL, 334 (7589), pp. 373-373. | Read more

Guerra CA, Hay SI, Lucioparedes LS, Gikandi PW, Tatem AJ, Noor AM, Snow RW. 2007. Assembling a global database of malaria parasite prevalence for the Malaria Atlas Project MALARIA JOURNAL, 6 | Citations: 89 (Scopus) | Show Abstract | Read more

Background. Open access to databases of information generated by the research community can synergize individual efforts and are epitomized by the genome mapping projects. Open source models for outputs of scientific research funded by tax-payers and charities are becoming the norm. This has yet to be extended to malaria epidemiology and control. Methods. The exhaustive searches and assembly process for a global database of malaria parasite prevalence as part of the Malaria Atlas Project (MAP) are described. The different data sources visited and how productive these were in terms of availability of parasite rate (PR) data are presented, followed by a description of the methods used to assemble a relational database and an associated geographic information system. The challenges facing spatial data assembly from varied sources are described in an effort to help inform similar future applications. Results. At the time of writing, the MAP database held 3,351 spatially independent PR estimates from community surveys conducted since 1985. These include 3,036 Plasmodium falciparum and 1,347 Plasmodium vivax estimates in 74 countries derived from 671 primary sources. More than half of these data represent malaria prevalence after the year 2000. Conclusion. This database will help refine maps of the global spatial limits of malaria and be the foundation for the development of global malaria endemicity models as part of MAP. A widespread application of these maps is envisaged. The data compiled and the products generated by MAP are planned to be released in June 2009 to facilitate a more informed approach to global malaria control. © 2007 Guerra et al; licensee BioMed Central Ltd.

Anstey NM, Handojo T, Pain MCF, Kenangalem E, Tjitra E, Price RN, Maguire GP. 2007. Lung injury in vivax malaria: pathophysiological evidence for pulmonary vascular sequestration and posttreatment alveolar-capillary inflammation. J Infect Dis, 195 (4), pp. 589-596. | Citations: 123 (Scopus) | Show Abstract | Read more

BACKGROUND: The mechanisms underlying lung injury in vivax malaria are not well understood. Inflammatory responses to Plasmodium falciparum and P. vivax, to our knowledge, have not previously been compared at an organ level. METHODS: Respiratory symptoms and physiological aspects were measured longitudinally in Indonesian adults with uncomplicated vivax (n=50) and falciparum (n=50) malaria. Normal values were derived from 109 control subjects. Gas transfer was partitioned into its alveolar-capillary membrane (D(M)) and pulmonary capillary vascular (V(C)) components, to characterize the site and timing of impaired gas transfer. RESULTS: Mean baseline V(C) volume was significantly reduced in vivax and falciparum malaria, improving with treatment in each species. Baseline D(M) function was not impaired in either species. The progressive deterioration in D(M) function after treatment was statistically significant in vivax malaria but not in uncomplicated falciparum malaria. Oxygen saturation deteriorated after treatment in vivax but improved in falciparum malaria. CONCLUSIONS: The baseline reduction in V(C) volume but not in D(M) function suggests encroachment on V(C) volume by parasitized erythrocytes and suggests that P. vivax-infected erythrocytes may sequester within the pulmonary microvasculature. Progressive alveolar-capillary dysfunction after treatment of vivax malaria is consistent with a greater inflammatory response to a given parasite burden in P. vivax relative to that in P. falciparum.

Nguyen-Pouplin J, Tran H, Tran H, Phan TA, Dolecek C, Farrar J, Tran TH, Caron P, Bodo B, Grellier P. 2007. Antimalarial and cytotoxic activities of ethnopharmacologically selected medicinal plants from South Vietnam. J Ethnopharmacol, 109 (3), pp. 417-427. | Citations: 53 (Scopus) | Show Abstract | Read more

Malaria is a major global public health problem and the alarming spread of drug resistance and limited number of effective drugs now available underline how important it is to discover new antimalarial compounds. An ethnopharmacological investigation was undertaken of medicinal plants traditionally used to treat malaria in the South Vietnam. Forty-nine plants were identified, 228 extracts were prepared and tested for their in vitro activity against Plasmodium falciparum, and assessed for any cytotoxicity against the human cancer cell line HeLa and the embryonic lung MRC5 cell line. In a first screening at a concentration of 10 microg/ml, 92 extracts from 46 plants showed antiplasmodial activity (parasite growth inhibition >30%). The IC(50) values of the most active extracts were determined as well as their selectivity towards Plasmodium falciparum in comparison to their cytotoxic effects against the human cell lines. Six plants showed interesting antiplasmodial activity (IC(50) ranging from 0.4 to 8.6 microg/ml) with a good selectivity: two Menispermaceae, Arcangelisia flava (L.) Merr. and Fibraurea tinctoria Lour., and also Harrisonia perforata (Blanco) Merr. (Simaroubaceae), Irvingia malayana Oliv. ex Benn. (Irvingiaceae), Elaeocarpus kontumensis Gagn. (Elaeocarpaceae) and Anneslea fragrans Wall. (Theaceae).

Ashley EA, Stepniewska K, Lindegårdh N, McGready R, Annerberg A, Hutagalung R, Singtoroj T, Hla G, Brockman A, Proux S et al. 2007. Pharmacokinetic study of artemether-lumefantrine given once daily for the treatment of uncomplicated multidrug-resistant falciparum malaria. Trop Med Int Health, 12 (2), pp. 201-208. | Citations: 59 (Scopus) | Show Abstract | Read more

BACKGROUND: Adherence to antimalarial drug regimens is improved by simple dosing. If the fixed antimalarial drug combination artemether-lumefantrine (AL) could be given once daily, this should improve adherence and thus effectiveness and lower the risk of selecting for resistance. METHODS: In an open randomized study, 43 patients with uncomplicated falciparum malaria were given equivalent doses of AL with 200 ml flavoured milk either as the conventional twice-daily regimen or as a single daily dose for 3 days. The primary end point was a comparison of the areas under the plasma lumefantrine concentration-time curves (AUC). Secondary end points were the day 42 polymerase chain reaction (PCR)-adjusted cure rates and the tolerability profiles. RESULTS: Lumefantrine pharmacokinetic profiles were obtained for 36 patients. The AUC((0-->infinity)) of the once-daily regimen was 30% lower than that in the conventional regimen (P = 0.011) with a median (range) value of 306 (114-5781) microg/ml h, compared with 432 (308-992) microg/ml h. There was no significant difference in the peak plasma concentrations reached. PCR-adjusted cure rate estimates at day 42 of follow-up were 94% (95% CI: 84-100) in the six-dose arm and 85% (70-100) in the three-dose arm (P = 0.3). CONCLUSION: Artemether-lumefantrine efficacy is reduced by once-daily dosing, because absorption of lumefantrine is dose limited. At currently recommended doses, this antimalarial should be given twice daily in a 3-day regimen, with food containing fat.

de Veij M, Vandenabeele P, Hall KA, Fernandez FM, Green MD, White NJ, Dondorp AM, Newton PN, Moens L. 2007. Fast detection and identification of counterfeit antimalarial tablets by Raman spectroscopy JOURNAL OF RAMAN SPECTROSCOPY, 38 (2), pp. 181-187. | Citations: 58 (Scopus) | Show Abstract | Read more

During the last decade there has been an apparent increase in the prevalence of counterfeit medicines in developing as well as developed countries. The pivotal antimalarial artesunate has been counterfeited on a large scale in SE Asia. In this work, the possibilities of Raman spectroscopy are explored as a fast and reliable screening method for the detection of counterfeit artesunate tablets. In this study, 50 'artesunate tablets', purchased in SE Asia, were examined. This spectroscopic method was able to distinguish between genuine and counterfeit artesunate and to identify the composition of the counterfeit tablets. These contained no detectable levels of artesunate, but consisted mostly of starch, calcite (CaCO 3 ), and paracetamol (4-acetamidophenol). In one particular case an admixture of rutile (TiO 2 ) and artesunate was detected. The results of the investigation by Raman spectroscopy were in agreement with those of colorimetric tests and of liquid chromatography-mass spectrometry on the artesunate. Moreover, principal components analysis (PCA) was combined with hierarchical cluster analysis to establish an automated approach for the discrimination between different groups of counterfeits and genuine artesunate tablets. These results demonstrate that Raman spectroscopy combined with multivariate analysis is a promising and reliable methodology for the fast characterization of genuine and counterfeit artesunate antimalarial tablets. Copyright © 2006 John Wiley & Sons, Ltd.

Chantratita N, Wuthiekanun V, Boonbumrung K, Tiyawisutsri R, Vesaratchavest M, Limmathurotsakul D, Chierakul W, Wongratanacheewin S, Pukritiyakamee S, White NJ et al. 2007. Biological relevance of colony morphology and phenotypic switching by Burkholderia pseudomallei. J Bacteriol, 189 (3), pp. 807-817. | Citations: 82 (Scopus) | Show Abstract | Read more

Melioidosis is a notoriously protracted illness and is difficult to cure. We hypothesize that the causative organism, Burkholderia pseudomallei, undergoes a process of adaptation involving altered expression of surface determinants which facilitates persistence in vivo and that this is reflected by changes in colony morphology. A colony morphotyping scheme and typing algorithm were developed using clinical B. pseudomallei isolates. Morphotypes were divided into seven types (denoted I to VII). Type I gave rise to other morphotypes (most commonly type II or III) by a process of switching in response to environmental stress, including starvation, iron limitation, and growth at 42 degrees C. Switching was associated with complex shifts in phenotype, one of which (type I to type II) was associated with a marked increase in production of factors putatively associated with in vivo concealment. Isogenic types II and III, derived from type I, were examined using several experimental models. Switching between isogenic morphotypes occurred in a mouse model, where type II appeared to become adapted for persistence in a low-virulence state. Isogenic type II demonstrated a significant increase in intracellular replication fitness compared with parental type I after uptake by epithelial cells in vitro. Isogenic type III demonstrated a higher replication fitness following uptake by macrophages in vitro, which was associated with a switch to type II. Mixed B. pseudomallei morphologies were common in individual clinical specimens and were significantly more frequent in samples of blood, pus, and respiratory secretions than in urine and surface swabs. These findings have major implications for therapeutics and vaccine development.

McGready R, Kaveri SV, Lacroix-Desmazes S, Krudsood S, Newton PN. 2007. Acquired haemophilia A in early pregnancy associated with Plasmodium vivax malaria and hyperthyroidism. Aust N Z J Obstet Gynaecol, 47 (1), pp. 76-77. | Citations: 2 (Web of Science Lite) | Read more

Ashley EA, Stepniewska K, Lindegårdh N, Annerberg A, Kham A, Brockman A, Singhasivanon P, White NJ, Nosten F. 2007. How much fat is necessary to optimize lumefantrine oral bioavailability? Trop Med Int Health, 12 (2), pp. 195-200. | Citations: 91 (Scopus) | Show Abstract | Read more

BACKGROUND: Artemether-lumefantrine (AL) is the only fixed, artemisinin-based combination antimalarial drug which is registered internationally and deployed on a large scale. Absorption of the hydrophobic lipophilic lumefantrine component varies widely between individuals and is greatly increased by fat coadministration; but patients with acute malaria are frequently nauseated and anorexic, making dietary advice difficult to comply with. The aim of this study was to describe the dose-response relationship between coadministration of fat and relative lumefantrine bioavailability, in order to determine the minimum amount of fat necessary to optimize absorption. METHOD: We conducted a multiple crossover pharmacokinetic study in 12 healthy volunteers. This compared the area under the plasma concentration-time curve (AUC) for lumefantrine after administration of a single dose of AL in the fasting state given with 0, 10, 40, 150 and 500 ml of soya milk corresponding to 0, 0.32, 1.28, 4.8 and 16 g of fat. All volumes of milk supplements were tested in all subjects with a 3- to 4-week washout period in-between. RESULTS: A dose-response relationship was demonstrated between the volume of soya milk administered and lumefantrine bioavailability. AL administration with soya milk increased the lumefantrine AUC more than five fold. The population mean estimated volume of soya milk required to obtain 90% of maximum effect (in terms of lumefantrine AUC) was 36 ml (corresponding to 1.2 g of fat). CONCLUSIONS: Coadministration of artemether-lumefantrine with a relatively small amount of fat (as soya milk) was required to ensure maximum absorption of lumefantrine in healthy adult volunteers.

Desai M, ter Kuile FO, Nosten F, McGready R, Asamoa K, Brabin B, Newman RD. 2007. Epidemiology and burden of malaria in pregnancy. Lancet Infect Dis, 7 (2), pp. 93-104. | Citations: 606 (Scopus) | Show Abstract | Read more

We reviewed evidence of the clinical implications and burden of malaria in pregnancy. Most studies come from sub-Saharan Africa, where approximately 25 million pregnant women are at risk of Plasmodium falciparum infection every year, and one in four women have evidence of placental infection at the time of delivery. P falciparum infections during pregnancy in Africa rarely result in fever and therefore remain undetected and untreated. Meta-analyses of intervention trials suggest that successful prevention of these infections reduces the risk of severe maternal anaemia by 38%, low birthweight by 43%, and perinatal mortality by 27% among paucigravidae. Low birthweight associated with malaria in pregnancy is estimated to result in 100,000 infant deaths in Africa each year. Although paucigravidae are most affected by malaria, the consequences for infants born to multigravid women in Africa may be greater than previously appreciated. This is because HIV increases the risk of malaria and its adverse effects, particularly in multigravidae, and recent observational studies show that placental infection almost doubles the risk of malaria infection and morbidity in infants born to multigravidae. Outside Africa, malaria infection rates in pregnant women are much lower but are more likely to cause severe disease, preterm births, and fetal loss. Plasmodium vivax is common in Asia and the Americas and, unlike P falciparum, does not cytoadhere in the placenta, yet, is associated with maternal anaemia and low birthweight. The effect of infection in the first trimester, and the longer term effects of malaria beyond infancy, are largely unknown and may be substantial. Better estimates are also needed of the effects of malaria in pregnancy outside Africa, and on maternal morbidity and mortality in Africa. Global risk maps will allow better estimation of potential impact of successful control of malaria in pregnancy.

Mayxay M, Barends M, Brockman A, Jaidee A, Nair S, Sudimack D, Pongvongsa T, Phompida S, Phetsouvanh R, Anderson T et al. 2007. In vitro antimalarial drug susceptibility and pfcrt mutation among fresh Plasmodium falciparum isolates from the Lao PDR (Laos). Am J Trop Med Hyg, 76 (2), pp. 245-250. | Citations: 14 (Scopus) | Show Abstract

Recent drug trials in Laos have shown high levels of Plasmodium falciparum resistance to chloroquine, but there are no published data on in vitro antimalarial drug susceptibility. We used the double-site enzyme-linked pLDH immunodetection (DELI) assay to estimate the in vitro antimalarial drug susceptibility of 108 fresh P. falciparum isolates from southern Laos. The geometric mean (95% confidence interval) 50% inhibitory concentration values (nmol/L) were 152.4 (123.8-187.6) for chloroquine, 679.8 (533.8-863.0) for quinine, 45.9 (37.9-55.7) for mefloquine, 5.0 (4.4-6.4) for artesunate, 6.3 (4.5-8.9) for dihydroartemisinin, and 59.1 (46.4-75.3) for lumefantrine. The proportion of isolates defined as resistant were 65%, 40%, and 8% for chloroquine, quinine, and mefloquine, respectively. Of 53 isolates genotyped for the pfcrt T76K chloroquine-resistance mutation, 48 (91%) were mutants. P. falciparum in Laos is multi-drug resistant; antimalarial immunity resulting from the use of ineffective chloroquine before 2005 probably contributes significantly to the therapeutic responses in clinical trials.

Nair S, Nash D, Sudimack D, Jaidee A, Barends M, Uhlemann A-C, Krishna S, Nosten F, Anderson TJC. 2007. Recurrent gene amplification and soft selective sweeps during evolution of multidrug resistance in malaria parasites. Mol Biol Evol, 24 (2), pp. 562-573. | Citations: 103 (Scopus) | Show Abstract | Read more

When selection is strong and beneficial alleles have a single origin, local reductions in genetic diversity are expected. However, when beneficial alleles have multiple origins or were segregating in the population prior to a change in selection regime, the impact on genetic diversity may be less clear. We describe an example of such a "soft" selective sweep in the malaria parasite Plasmodium falciparum that involves adaptive genome rearrangements. Amplification in copy number of genome regions containing the pfmdr1 gene on chromosome 5 confer resistance to mefloquine and spread rapidly in the 1990s. Using flanking microsatellite data and real-time polymerase chain reaction determination of copy number, we show that 5-15 independent amplification events have occurred in parasites on the Thailand/Burma border. The amplified genome regions (amplicons) range in size from 14.7 to 49 kb and contain 2-11 genes, with 2-4 copies arranged in tandem. To examine the impact of drug selection on flanking variation, we genotyped 48 microsatellites on chromosome 5 in 326 parasites from a single Thai location. Diversity was reduced in a 170- to 250-kb (10-15 cM) region of chromosomes containing multiple copies of pfmdr1, consistent with hitchhiking resulting from the rapid recent spread of selected chromosomes. However, diversity immediately flanking pfmdr1 is reduced by only 42% on chromosomes bearing multiple amplicons relative to chromosomes carrying a single copy. We highlight 2 features of these results: 1) All amplicon break points occur in monomeric A/T tracts (9-45 bp). Given the abundance of these tracts in P. falciparum, we expect that duplications will occur frequently at multiple genomic locations and have been underestimated as drivers of phenotypic evolution in this pathogen. 2) The signature left by the spread of amplified genome segments is broad, but results in only limited reduction in diversity. If such "soft" sweeps are common in nature, statistical methods based on diversity reduction may be inefficient at detecting evidence for selection in genome-wide marker screens. This may be particularly likely when mutation rate is high, as appears to be the case for gene duplications, and in pathogen populations where effective population sizes are typically very large.

Ward SA, Sevene EJP, Hastings IM, Nosten F, McGready R. 2007. Antimalarial drugs and pregnancy: safety, pharmacokinetics, and pharmacovigilance. Lancet Infect Dis, 7 (2), pp. 136-144. | Citations: 113 (Scopus) | Show Abstract | Read more

Before a recommendation for antimalarial drug use in pregnancy is made, it is essential that we understand the potential risks involved and have mechanisms in place to monitor risk during treatment. This requires data on drug disposition during pregnancy and potential toxicological liabilities to the developing fetus and mother. In most cases this information is not available. We review the reproductive toxicology of the main antimalarial drug classes in use or under development. Preclinical data are presented if appropriate, but as human experience overrides such data, in instances in which preclinical studies do not correlate with the human experience the data are reviewed only briefly. Additionally, we highlight the lack of appropriate drug disposition data in pregnancy and suggest mechanisms that can be used to capture data on risk after drug treatment in pregnancy.

Nosten F, McGready R, Mutabingwa T. 2007. Case management of malaria in pregnancy. Lancet Infect Dis, 7 (2), pp. 118-125. | Citations: 58 (Scopus) | Show Abstract | Read more

In all malarious areas, infection by any of the main human plasmodial species during pregnancy is detrimental to the mother and the fetus. These potentially fatal infections must be prevented, but when they develop they require prompt diagnosis and treatment. Current tools to detect malaria parasites in pregnant women are often not used and remain too insensitive to detect a low parasitaemia. The kinetics, safety, and efficacy of available antimalarial drugs are poorly documented because pregnant women are systematically excluded from clinical trials. A considerable effort, involving clinical trials, is urgently required to improve the diagnosis and case management of malaria during pregnancy if the morbidity and mortality of maternal malaria is to be reduced.

Villegas L, McGready R, Htway M, Paw MK, Pimanpanarak M, Arunjerdja R, Viladpai-Nguen SJ, Greenwood B, White NJ, Nosten F. 2007. Chloroquine prophylaxis against vivax malaria in pregnancy: a randomized, double-blind, placebo-controlled trial. Trop Med Int Health, 12 (2), pp. 209-218. | Citations: 42 (Scopus) | Show Abstract | Read more

OBJECTIVE: To assess the safety of chloroquine (CQ) as prophylaxis against Plasmodium vivax infection during pregnancy. METHOD: One thousand pregnant Karen women were enrolled in a randomized, double-blind, placebo-controlled trial of chemoprophylaxis with chloroquine (500 mg phosphate (or 300 mg base) weekly). Women received a median (range) chloroquine phosphate total dose of 9500 (1500-17 500) mg. The mothers were actively followed from inclusion to delivery and their infants until 12 months of age. RESULTS: Chloroquine prophylaxis completely prevented P. vivax episodes; 10.1% (95%CI: 7.3-14.5) of women in the placebo group experienced at least one episode of vivax malaria but no episode occurred in women in the CQ group. By contrast, the numbers of P. falciparum episodes were similar in each group: 7.4% (95%CI: 3.7-11.1) and 5.6% (95%CI: 3.3-7.9) in the placebo and CQ groups respectively (P = 0.56). Chloroquine prophylaxis was well tolerated and there was no difference in the proportions of reported side effects between CQ treated and placebo groups except for the duration of palpitations and sleeping disorders which were more frequent in those who had received CQ. Chloroquine prophylaxis had no impact on maternal anaemia, birth weight, gestational age, development of newborns or on growth, neurological development or visual acuity in infants at 1 year of age. CONCLUSION: Chloroquine is safe and effective as prophylaxis against P. vivax during pregnancy in this population.

Caws M, Thwaites GE, Duy PM, Tho DQ, Lan NTN, Hoa DV, Chau TTH, Huyen MNT, Anh PTH, Chau NVV et al. 2007. Molecular analysis of Mycobacterium tuberculosis causing multidrug-resistant tuberculosis meningitis. Int J Tuberc Lung Dis, 11 (2), pp. 202-208. | Citations: 13 (Scopus) | Show Abstract

SETTING: Tertiary referral hospitals in southern Vietnam. OBJECTIVE: Molecular characterisation of multidrug-resistant (MDR) tuberculous meningitis (TBM). DESIGN: Mycobacterium tuberculosis isolates from the cerebrospinal fluid (CSF) of 198 Vietnamese adults were compared with 237 isolates from patients with pulmonary tuberculosis (PTB) matched for age, sex and residential district. Isolates resistant to isoniazid or rifampicin (RMP) were sequenced in the rpoB and katG genes, inhA promoter and oxyR-ahpC intergenic regions. RESULTS: While drug resistance rates were lower in the CSF (2.5% MDR) than pulmonary isolates (5.9% MDR), the difference was not significant. The most commonly mutated codons were 531, 526 and 516 in rpoB and 315 in katG. Four novel triple mutants in rpoB were identified. CONCLUSION: RMP resistance is a good surrogate marker for MDR-TBM in this setting. However, probes directed against these three codons would have a maximum sensitivity of only 65%. A rapid phenotypic detection test may be more applicable for the diagnosis of MDR-TBM.

Blacksell SD, Bryant NJ, Paris DH, Doust JA, Sakoda Y, Day NPJ. 2007. Scrub typhus serologic testing with the indirect immunofluorescence method as a diagnostic gold standard: a lack of consensus leads to a lot of confusion. Clin Infect Dis, 44 (3), pp. 391-401. | Citations: 96 (Scopus) | Show Abstract | Read more

A review was performed to determine the evidence base for scrub typhus indirect immunofluorescence assay (IFA) methodologies and the criteria for positive results. This review included a total of 109 publications, which comprised 123 eligible studies for analysis (14 publications included 2 substudies). There was considerable underreporting of the IFA methodology and seropositivity criteria used, with most studies using a defined cutoff titer rather than an increase in the titer in paired samples. The choice of positivity cutoff titer varied by country and purpose of the IFA test. This variation limits the comparability of seroprevalence rates between studies and, more seriously, raises questions about the appropriateness of the cutoffs for positive IFA results chosen for diagnosis of acute scrub typhus infection. We suggest that the diagnosis of scrub typhus using IFA should be based on a > or =4-fold increase in the titer in paired serum samples and should only be based on a single sample titer when there is an adequate local evidence base.

Lalloo DG, Shingadia D, Pasvol G, Chiodini PL, Whitty CJ, Beeching NJ, Hill DR, Warrell DA, Bannister BA, HPA Advisory Committee on Malaria Prevention in UK Travellers. 2007. UK malaria treatment guidelines. J Infect, 54 (2), pp. 111-121. | Citations: 179 (Scopus) | Show Abstract | Read more

Malaria is the tropical disease most commonly imported into the UK, with 1500-2000 cases reported each year, and 10-20 deaths. Approximately three-quarters of reported malaria cases in the UK are caused by Plasmodium falciparum, which is capable of invading a high proportion of red blood cells and rapidly leading to severe or life-threatening multi-organ disease. Most non-falciparum malaria cases are caused by Plasmodium vivax; a few cases are caused by the other two species of Plasmodium: Plasmodium ovale or Plasmodium malariae. Mixed infections with more than 1 species of parasite can occur; they commonly involve P. falciparum with the attendant risks of severe malaria. Management of malaria depends on awareness of the diagnosis and on performing the correct diagnostic tests: the diagnosis cannot be excluded until 3 blood specimens have been examined by an experienced microscopist. There are no typical clinical features of malaria, even fever is not invariably present. The optimum diagnostic procedure is examination of thick and thin blood films by an expert to detect and speciate the malarial parasites; P. falciparum malaria can be diagnosed almost as accurately using rapid diagnostic tests (RDTs) which detect plasmodial antigens or enzymes, although RDTs for other Plasmodium species are not as reliable. The treatment of choice for non-falciparum malaria is a 3-day course of oral chloroquine, to which only a limited proportion of P. vivax strains have gained resistance. Dormant parasites (hypnozoites) persist in the liver after treatment of P. vivax or P. ovale infection: the only currently effective drug for eradication of hypnozoites is primaquine. This must be avoided or given with caution under expert supervision in patients with glucose-6-phosphate dehydrogenase deficiency (G6PD), in whom it may cause severe haemolysis. Uncomplicated P. falciparum malaria can be treated orally with quinine, atovaquone plus proguanil (Malarone) or co-artemether (Riamet); quinine is highly effective but poorly tolerated in prolonged dosage and is always supplemented by additional treatment, usually with oral doxycycline. ALL patients treated for P. falciparum malaria should be admitted to hospital for at least 24 h, since patients can deteriorate suddenly, especially early in the course of treatment. Severe falciparum malaria, or infections complicated by a relatively high parasite count (more than 2% of red blood cells parasitized), should be treated with intravenous therapy until the patient is well enough to continue with oral treatment. In the UK, the treatment of choice for severe or complicated malaria is currently an infusion of intravenous quinine. This may exacerbate hypoglycaemia that can occur in malaria; patients treated with intravenous quinine therefore require careful monitoring. Intravenous artesunate reduces high parasite loads more rapidly than quinine and is more effective in treating severe malaria in selected situations. It can also be used in patients with contra-indications to quinine. Intravenous artesunate is unlicensed in the EU. Assistance in obtaining artesunate may be sought from specialist tropical medicine centres, on consultation, for named patients. Patients with severe or complicated malaria should be managed in a high dependency or intensive care environment. They may require haemodynamic support and management of acute respiratory distress syndrome, disseminated intravascular coagulation, renal impairment/failure, seizures, and severe intercurrent infections including gram-negative bacteraemia/septicaemia. Falciparum malaria in pregnancy is more likely to be severe and complicated: the placenta contains high levels of parasites. Stillbirth or early delivery may occur and diagnosis can be difficult if parasites are concentrated in the placenta and scanty in the blood. The treatment of choice for falciparum malaria in pregnancy is quinine; doxycycline is contraindicated in pregnancy but clindamycin can be substituted for it, and is equally effective. Primaquine (for eradication of P. vivax or P. ovale hypnozoites) is contraindicated in pregnancy; after treatment for these infections a pregnant woman should take weekly chloroquine prophylaxis until after delivery when hypnozoite eradication can be considered. Children are over-represented in the incidence of malaria in the UK, probably because completely susceptible UK-born children accompany their overseas-born parents on visits to family and friends in endemic areas. Malaria in children (and sometimes in adults) may present with misleading symptoms such as gastrointestinal features, sore throat or lower respiratory complaints; the diagnosis must always be sought in a feverish or very sick child who has visited malaria-endemic areas. Children can be treated with most of the antimalarial regimens which are effective in adults, with appropriate dosage adjustment. Doxycycline plus quinine should not be given to children under 12 years as doxycycline is contraindicated in this age group, but clindamycin can be substituted for doxycycline, and pyrimethamine-sulfadoxine (Fansidar) may also be an effective substitute. An acute attack of malaria does not confer protection from future attacks: individuals who have had malaria should take effective anti-mosquito precautions and chemoprophylaxis during future visits to endemic areas.

Vanlerberghe V, Diap G, Guerin PJ, Meheus F, Gerstl S, Van der Stuyft P, Boelaert M. 2007. Drug policy for visceral leishmaniasis: a cost-effectiveness analysis. Trop Med Int Health, 12 (2), pp. 274-283. | Citations: 39 (Scopus) | Show Abstract | Read more

OBJECTIVE: To facilitate the choice of the best visceral leishmaniasis (VL) treatment strategy for first-line health services in (VL)-endemic areas, we compared in a formal decision analysis the cost and the cost-effectiveness of the different available options. METHODS: We selected four drug regimens for VL on the basis of frequency of use, feasibility and reported efficacy studies. The point estimates and the range of plausible values of effectiveness and cost were retrieved from a literature review. A decision tree was constructed and the strategy minimizing the cost per death averted was selected. RESULTS: Treatment with amphotericin B deoxycholate was the most effective approach in the baseline analysis and averted 87.2% of all deaths attributable to VL. The least expensive and the most cost-effective treatment was the miltefosine regimen, and the most expensive and the least cost-effective was AmBisome treatment. The cost of drug and medical care are the main determinants of the cost-effectiveness ranking of the alternative schemes. Sensitivity analysis showed that antimonial was competitive with miltefosine in the low-resistance regions. CONCLUSION: In areas with >94% response rates to antimonials, generic sodium stibogluconate remains the most cost-effective option for VL treatment, mainly due to low drug cost. In other regions, miltefosine is the most cost-effective option of treatment, but its use as a first-line drug is limited by its teratogenicity and rapid resistance development. AmBisome in mono- or combination therapy is too expensive to compete in cost-effectiveness with the other regimens.

Karita E, Price M, Hunter E, Chomba E, Allen S, Fei L, Kamali A, Sanders EJ, Anzala O, Katende M et al. 2007. Investigating the utility of the HIV-1 BED capture enzyme immunoassay using cross-sectional and longitudinal seroconverter specimens from Africa. AIDS, 21 (4), pp. 403-408. | Citations: 92 (Scopus) | Show Abstract | Read more

BACKGROUND: The identification of populations at risk of HIV infection is a priority for trials of preventive technologies, including HIV vaccines. To quantify incidence traditionally requires laborious and expensive prospective studies. METHODS: The BED IgG-Capture enzyme immunoassay (EIA) was developed to estimate HIV-1 incidence using cross-sectional data by measuring increasing levels of HIV-specific IgG as a proportion of total IgG. To evaluate this assay, we tested 189 seroconversion samples taken at 3-monthly intervals from 15 Rwandan and 26 Zambian volunteers with known time of infection and cross-sectional specimens from 617 Kenyan and Ugandan volunteers with prevalent infection. RESULTS: The BED-EIA-estimated incidence in Uganda was unexpectedly high, at 6.1%/year [95% confidence interval (CI) 4.2-8.0] in Masaka and 6.0%/year (95% CI 4.3-7.7) in Kakira. Prospective incidence data in Masaka from the same population was 1.7%/year before and 1.4%/year after the study. Kenyan estimates were 3.5%/year in Kilifi (95% CI 2.1-4.9) and 3.4%/year in Nairobi (95% CI 1.5-5.3). From the Rwandan and Zambian data, the sensitivity of the assay was 81.2% and the specificity was 67.8%. After approximately one year, subjects misclassified as recently infected tended to have lower plasma viral loads compared with those not misclassified as recent (median copies/ml 14 773 versus 93 560; P = 0.02). Clinical presentation, sex and HIV subtype were not significantly associated with BED-EIA misclassification in seroconverter samples. CONCLUSION: These data suggest that this assay does not perform reliably in all populations. Further research is warranted before using this assay to estimate incidence from prevalent HIV samples.

Fryauff DJ, Owusu-Agyei S, Utz G, Baird JK, Koram KA, Binka F, Nkrumah F, Hoffman SL. 2007. Mefloquine treatment for uncomplicated falciparum malaria in young children 6-24 months of age in northern Ghana. Am J Trop Med Hyg, 76 (2), pp. 224-231. | Citations: 2 (Web of Science Lite) | Show Abstract

Mefloquine (MQ) single dose 20 mg/kg treatment of falciparum malaria was evaluated in 186 children of 6-24 months of age in northern Ghana. There were 15 RII/RIII-type parasitologic failures, all with Day 2 MQ blood levels significantly lower than children whose parasitemias cleared before Day 7 and remained clear through 28 days. Predictors of RII/RIII parasitologic response were vomiting after MQ dosing, Day 2 MQ levels < 500 ng/mL, and undetectable Day 2 levels of the carboxymefloquine metabolite. There were 50 cases of delayed RI parasitologic failure, but 71% of these cases had undetectable Day 28 blood levels of MQ and drug levels in the remaining 29% ranged below the 620 ng/mL level that suppresses MQ sensitive strains of P. falciparum. Drug levels among infants that tolerated MQ well were not associated with age, weight, hemoglobin, parasitemia, and pre-existing symptoms of vomiting or diarrhea. An observed recurrent parasitemia of 34,400 trophozoites/microL against a MQ blood concentration of 550 ng/mL was taken as indication of tolerance to suppressive levels of the drug at this location.

Baird JK. 2007. A rare glimpse at the efficacy of primaquine. Am J Trop Med Hyg, 76 (2), pp. 201-202. | Citations: 6 (Web of Science Lite)

van Doorn HR, Koelewijn R, Hofwegen H, Gilis H, Wetsteyn JCFM, Wismans PJ, Sarfati C, Vervoort T, van Gool T. 2007. Use of enzyme-linked immunosorbent assay and dipstick assay for detection of Strongyloides stercoralis infection in humans. J Clin Microbiol, 45 (2), pp. 438-442. | Citations: 77 (Scopus) | Show Abstract | Read more

A homemade enzyme-linked immunosorbent assay (ELISA) (Academic Medical Center ELISA [AMC-ELISA]) and a dipstick assay for the detection of anti-Strongyloides stercoralis antibodies in serum were developed and evaluated together with two commercially available ELISAs (IVD-ELISA [IVD Research, Inc.] and Bordier-ELISA [Bordier Affinity Products SA]) for their use in the serodiagnosis of imported strongyloidiasis. Both commercially available ELISAs have not been evaluated previously. The sensitivities of the assays were evaluated using sera from 90 patients with parasitologically proven intestinal strongyloidiasis and from 9 patients with clinical larva currens. The sensitivities of the AMC-ELISA, dipstick assay, IVD-ELISA, and Bordier-ELISA were 93, 91, 89, and 83%, respectively, for intestinal strongyloidiasis. In all tests, eight of nine sera from patients with larva currens were positive. The specificity was assessed using a large serum bank of 220 sera from patients with various parasitic, bacterial, viral, and fungal infectious diseases; sera containing autoimmune antibodies; and sera from healthy blood donors. The specificities of AMC-ELISA, dipstick assay, IVD-ELISA, and Bordier-ELISA were 95.0, 97.7, 97.2, and 97.2%, respectively. Our data suggest that all four assays are sensitive and specific tests for the diagnosis of both intestinal and cutaneous strongyloidiasis.

Brent AJ, Matthews PC, Dance DA, Pitt TL, Handy R. 2007. Misdiagnosing melioidosis. Emerg Infect Dis, 13 (2), pp. 349-351. | Citations: 12 (Scopus) | Read more

Pitt TL, Trakulsomboon S, Dance DAB. 2007. Recurrent melioidosis: possible role of infection with multiple strains of Burkholderia pseudomallei. J Clin Microbiol, 45 (2), pp. 680-681. | Citations: 11 (Scopus) | Read more

Dukers NHTM, Fennema HSA, van der Snoek EM, Krol A, Geskus RB, Pospiech M, Jurriaans S, van der Meijden WI, Coutinho RA, Prins M. 2007. HIV incidence and HIV testing behavior in men who have sex with men: using three incidence sources, The Netherlands, 1984-2005. AIDS, 21 (4), pp. 491-499. | Citations: 40 (Scopus) | Show Abstract | Read more

BACKGROUND: In The Netherlands, the western part, including Rotterdam and Amsterdam harbors the majority of the known HIV-infected population, of whom men who have sex with men (MSM) comprise the largest transmission category. Given a general rise in sexually transmitted infections (STI) and risky sexual behavior, we examine the HIV incidence among MSM in the Netherlands with data from three different sources. METHODS: To describe the HIV epidemic among MSM we use: a prospective cohort study in Rotterdam (ROHOCO: 1998-2003, n = 265) and another in Amsterdam (ACS: 1984-2005, n = 1498]) plus an anonymous HIV surveillance study (Amsterdam STI clinic: 1991-2004, n = 3733) in which HIV-positive MSM were tested with a less-sensitive HIV assay. We evaluated calendar trends in HIV incidence, also focusing on age effects. RESULTS: Since the start of the HIV epidemic in the early 1980s, incidence has declined strongly in the ACS. In recent years, an increase was noted among older MSM attending the Amsterdam STI clinic (P = 0.0334). In both cohort studies, HIV incidence was lower and recent time-trends were not statistically significant. Among recently infected men at the STI clinic, only 40% accepted named HIV testing at their STI consultation. CONCLUSIONS: Data suggest that among MSM in the Netherlands, the HIV incidence is between one and four infections per 100 person-years. The epidemic expands among older STI clinic attendees. Prevention should be developed specifically for older men, along with a more efficient HIV testing approach such as routine HIV testing of MSM when they are screened for STI.

Anh DD, Canh DG, Lopez AL, Thiem VD, Long PT, Son NH, Deen J, von Seidlein L, Carbis R, Han SH et al. 2007. Safety and immunogenicity of a reformulated Vietnamese bivalent killed, whole-cell, oral cholera vaccine in adults. Vaccine, 25 (6), pp. 1149-1155. | Citations: 71 (Scopus) | Show Abstract | Read more

Vietnam currently produces an orally administered, bivalent (O1 and O139) killed whole-cell vaccine and is the only country in the world with endemic cholera to use an oral cholera vaccine in public health practice. In order to allow international use, the vaccine had to be reformulated to meet World Health Organization (WHO) requirements. We performed a randomized, placebo controlled, safety and immunogenicity studies of this reformulated vaccine among Vietnamese adults. One hundred and forty-four subjects received the two-dose regimen and 143 had two blood samples obtained for analysis. We found that this reformulated oral killed whole-cell cholera vaccine was safe, well tolerated and highly immunogenic.

Nuhant P, David M, Pouplin T, Delpech B, Marazano C. 2007. Alpha,alpha'-annulation of 2,6-prenyl-substituted cyclohexanone derivatives with malonyl chloride: application to a short synthesis of (+/-)-clusianone. Formation and rearrangement of a biogenetic-like intermediate. Org Lett, 9 (2), pp. 287-289. | Citations: 58 (Scopus) | Show Abstract | Read more

Conditions were found for the successful Effenberger alpha,alpha'-annulation of 3,3-dimethyl-2,4,6-triprenyl cyclohexanone silyl enol ethers with malonyl chloride to give the corresponding bicyclo[3.3.1]nonane-trione in 35% yield, this result allowing a short synthesis of (+/-)-clusianone. An isomeric rearranged bicyclo[3.3.1]nonane-trione was also isolated in 25% yield, and changing the Lewis acid resulted in formation of a lavandulyl-substituted phloroglucinol derivative in 38% yield. The mechanism of formation of these two last products mimics the biogenetic pathway to PPAPs. [reaction: see text].

Stepniewska K, Chotivanich K, Brockman A, Day NPJ, White NJ. 2007. Overestimating resistance in field testing of malaria parasites: simple methods for estimating high EC50 values using a Bayesian approach. Malar J, 6 pp. 4. | Citations: 7 (Scopus) | Show Abstract | Read more

Conventional methods of assessing in-vitro antimalarial drug-concentration effect relationships in field testing of fresh isolates assess each parasite isolate individually. This leads to systematic overestimation of EC50 values for the most resistant isolates, and thus overestimation of the degree of resistance. In antimalarial drug-susceptibility studies conducted on the north-western border of Thailand the overestimation of EC50 for the most resistant isolate ranged from 15% for artesunate to 43% for mefloquine. If isolates cannot be stored for re-testing, more accurate estimations of the degree of resistance can be obtained using a Bayesian approach to data analysis which is described here.

Warsame M, Kimbute O, Machinda Z, Ruddy P, Melkisedick M, Peto T, Ribeiro I, Kitua A, Tomson G, Gomes M. 2007. Recognition, Perceptions and Treatment Practices for Severe Malaria in Rural Tanzania: Implications for Accessing Rectal Artesunate as a Pre-Referral PLoS ONE, 2 (1), pp. e149-e149. | Read more

Wang X-Y, Xu Z-Y, Ma J-C, von Seidlein L, Zhang Y, Hao Z-Y, Han OP, Zhang Y-L, Tian M-Y, Ouyang P-Y et al. 2007. Long-term immunogenicity after single and booster dose of a live attenuated hepatitis A vaccine: results from 8-year follow-up. Vaccine, 25 (3), pp. 446-449. | Citations: 30 (Scopus) | Show Abstract | Read more

Live, attenuated hepatitis A vaccines are used widely in China but there is uncertainty regarding the persistence of vaccine-induced anti-HAV antibodies after single dose and booster dose administrated at month 12. A large scale clinical trial to evaluate the live, attenuated hepatitis A vaccine was conducted in Hebei province between 1996 and 1999. Five years after the trials, children in single dose and booster dose groups were bled and followed. Seventy two percent (61/85) of children who received a single trial dose had detectable anti-HAV antibodies for 96 months (GMC at 96 months: 89.0 mIU/mL). In the booster group 98% (48/49) children remained anti-HAV positive with GMC of 262.8 mIU/mL at month 96. The reinjection with live attenuated HAV vaccine can elicit a booster effect. Results from single dose group seems not to support the need for booster doses of live attenuated hepatitis A vaccine in immunocompetent individuals regarding the persisting anti-HAV and anamnestic response of a single dose vaccine. Continued monitoring of anti-HAV antibodies is needed for a rational hepatitis A immunization strategy in China.

Green MD, Nettey H, Villalva Rojas O, Pamanivong C, Khounsaknalath L, Grande Ortiz M, Newton PN, Fernández FM, Vongsack L, Manolin O. 2007. Use of refractometry and colorimetry as field methods to rapidly assess antimalarial drug quality. J Pharm Biomed Anal, 43 (1), pp. 105-110. | Citations: 37 (Scopus) | Show Abstract | Read more

The proliferation of counterfeit and poor-quality drugs is a major public health problem; especially in developing countries lacking adequate resources to effectively monitor their prevalence. Simple and affordable field methods provide a practical means of rapidly monitoring drug quality in circumstances where more advanced techniques are not available. Therefore, we have evaluated refractometry, colorimetry and a technique combining both processes as simple and accurate field assays to rapidly test the quality of the commonly available antimalarial drugs; artesunate, chloroquine, quinine, and sulfadoxine. Method bias, sensitivity, specificity and accuracy relative to high-performance liquid chromatographic (HPLC) analysis of drugs collected in the Lao PDR were assessed for each technique. The HPLC method for each drug was evaluated in terms of assay variability and accuracy. The accuracy of the combined method ranged from 0.96 to 1.00 for artesunate tablets, chloroquine injectables, quinine capsules, and sulfadoxine tablets while the accuracy was 0.78 for enterically coated chloroquine tablets. These techniques provide a generally accurate, yet simple and affordable means to assess drug quality in resource-poor settings.

Golfetto I, McGready R, Ghebremeskel K, Min Y, Dubowitz L, Nosten F, Drury P, Simpson JA, Arunjerdja R, Crawford MA. 2007. Fatty acid composition of milk of refugee Karen and urban Korean mothers. Is the level of DHA in breast milk of Western women compromised by high intake of saturated fat and linoleic acid? Nutr Health, 18 (4), pp. 319-332. | Citations: 4 (Scopus) | Show Abstract | Read more

BACKGROUND: Lower proportions of docosahexaenoic acid (DHA) and total n-3 metabolites have been reported in breast milk of European, Australian and North American women compared with milk of mothers from non-Western countries. This difference is not always explained by intakes of marine products. OBJECTIVE: We investigated the possibility that the relative composition of DHA and total n-3 metabolites in breast milk of non-Western mothers with low fat intakes is higher than the levels commonly reported in their Western counterparts. SUBJECTS: Mature milk of refugee Karen women from two different camps in Thailand (n=26 and n=53), and transition milk from urban Korean mothers (n=12) in Seoul was collected. In common with their respective community, the mothers have low fat intake, which is predominately of plant origin. RESULTS: The percentage levels of DHA and n-3 metabolites in the milk of the Karen mothers were 0.52 +/- 0.14 and 0.85 +/- 0.24 (camp 1) and 0.54 +/- 0.22 and 0.92 +/- 0.42 (camp 2). In the Korean milk, DHA was 0.96 +/- 0.21 and total n-3 metabolites 1.51 +/- 0.3. CONCLUSION: We postulate that the levels of DHA and total n-3 metabolites may be compromised in breast milk of mothers on the Western high fat diet. This calls into question the use of DHA composition of such milk as a reference for the formulation of milk designed, for infant feed or, to test the function of DHA in neuro-visual development.

Uhlemann A-C, McGready R, Ashley EA, Brockman A, Singhasivanon P, Krishna S, White NJ, Nosten F, Price RN. 2007. Intrahost selection of Plasmodium falciparum pfmdr1 alleles after antimalarial treatment on the northwestern border of Thailand. J Infect Dis, 195 (1), pp. 134-141. | Citations: 37 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Increased pfmdr1 copy number is associated with reduced susceptibility to structurally unrelated antimalarial drugs. We assessed how administration of different antimalarial drugs altered pfmdr1 polymorphism in parasites from patients who experienced treatment failure. METHODS: In studies conducted on the northwestern border of Thailand, amplifications and single-nucleotide polymorphisms in pfmdr1 were compared before and after antimalarial drug treatment. RESULTS: Intrahost changes in pfmdr1 copy number were observed in 20% (26/132) of patients with recurrent infections. Among infections that recrudesced after mefloquine-containing regimens, increases in pfmdr1 copy number occurred in 68% (95% confidence interval [CI], 46%-85%), and decreases occurred in 2% (95% CI, 0.4%-11%) of isolates; corresponding proportions after artemether-lumefantrine were 25% (2/8) and 11% (2/19); after quinine, 50% (1/2) and 40% (4/10); and after artemisinins alone, 0% (0/10) and 19% (3/16) of isolates (overall P<.001). CONCLUSIONS: Intrahost selection based on pfmdr1 copy number occurs frequently in parasite populations within individual patients. Amplification confers multidrug resistance but probably imposes a significant fitness cost to the parasites.

Barends M, Jaidee A, Khaohirun N, Singhasivanon P, Nosten F. 2007. In vitro activity of ferroquine (SSR 97193) against Plasmodium falciparum isolates from the Thai-Burmese border. Malar J, 6 (1), pp. 81. | Citations: 43 (Scopus) | Show Abstract | Read more

BACKGROUND: On the borders of Thailand, Plasmodium falciparum has become resistant to nearly all available drugs, and there is an urgent need to find new antimalarial drugs or drug combinations. Ferroquine (SSR97193) is a new 4-aminoquinoline antimalarial active against chloroquine resistant and sensitive P. falciparum strains in vivo and in vitro. This antimalarial organic iron complex (a ferrocenyl group has been associated with chloroquine) is meant to use the affinity of Plasmodium for iron to increase the probability for encountering the anti-malarial molecule.The aim of the present study was to investigate the activity of ferroquine against P. falciparum isolates from an area with a known high multi-drug resistance rate. METHODS: Parasite isolates were obtained from patients with acute falciparum malaria attending the clinics of SMRU. In vitro cultures of these isolates were set-up in the SMRU-laboratory on pre-dosed drug plates, and grown in culture for 42 hours. Parasite growth was assessed by the double-site enzyme-linked pLDH immunodetection (DELI) assay. RESULTS: Sixty-five P. falciparum isolates were successfully grown in culture. The ferroquine mean IC50 (95% CI) was 9.3 nM (95% C.I.: 8.7 - 10.0). The mean IC50 value for the principal metabolite of ferroquin, SR97213A, was 37.0 nM (95% C.I.: 34.3 - 39.9), which is four times less active than ferroquine. The isolates in this study were highly multi-drug resistant but ferroquine was more active than chloroquine, quinine, mefloquine and piperaquine. Only artesunate was more active than ferroquine. Weak but significant correlations were found between ferroquine and its principal metabolite (r2 = 0.4288), chloroquine (r2 = 0.1107) and lumefantrine (r2 = 0.2364). CONCLUSION: The results presented in this study demonstrate that the new ferroquine compound SSR97193 has high anti-malarial activity in vitro against multi-drug resistant P. falciparum.

Suwanarusk R, Russell B, Chavchich M, Chalfein F, Kenangalem E, Kosaisavee V, Prasetyorini B, Piera KA, Barends M, Brockman A et al. 2007. Chloroquine resistant Plasmodium vivax: in vitro characterisation and association with molecular polymorphisms. PLoS One, 2 (10), pp. e1089. | Citations: 113 (Scopus) | Show Abstract | Read more

BACKGROUND: Treatment failure of chloroquine for P. vivax infections has reached high levels in the eastern provinces of Indonesia, however, in vitro characterization of chloroquine resistance and its associated molecular profile have yet to be determined. METHODS: Using a modified schizont maturation assay we investigated the in vitro chloroquine susceptibility profile and molecular polymorphisms of P. vivax isolates collected from Papua, Indonesia, where high levels of clinical chloroquine treatment failure have been reported, and from Thailand, where chloroquine treatment is generally effective. RESULTS: The geometric mean chloroquine IC(50) for P. vivax isolates from Papua (n = 145) was 312 nM [95%CI: 237-411 nM] compared to 46.8 nM [95%CI: 34.7-63.1 nM] from Thailand (n = 81); p<0.001. Correlating with the known clinical efficacy of the area, a cut off for chloroquine resistance was defined as 220 nM, a level exceeded in 13.6% (11/81) of Thai isolates and 65% (94/145) of Papuan isolates; p<0.001. Several sequence polymorphisms in pvcrt-o and pvmdr1, and difference in pvmdr1 copy number were identified. A Y976F mutation in pvmdr1 was present in 96% (123/128) of Papuan isolates and 25% (17/69) of Thai isolates; p<0.001. Overall, the geometric mean chloroquine IC(50) in isolates with the Y976F mutation was 283 nM [95%CI: 211-379], compared to 44.5 nM [95%CI: 31.3-63.4] in isolates with the wild type; p< 0.001. Pvmdr1 amplification occurred in 23% (15/66) of Thai isolates compared to none (0/104) of Indonesian isolates (p<0.001), but was not associated with increased chloroquine resistance after controlling for geographical location. CONCLUSIONS: In vitro susceptibility testing of P. vivax discriminates between populations with differing levels of clinical efficacy of chloroquine. The pvmdr1 polymorphism at Y976F may provide a useful tool to highlight areas of emerging chloroquine resistance, although further studies defining its clinical correlates are needed.

Larsen RA, Bauer M, Brouwer AE, Sanchez A, Thomas AM, Rajanuwong A, Chierakul W, Peacock SJ, Day N, White NJ et al. 2007. In vitro-clinical correlations for amphotericin B susceptibility in AIDS-associated cryptococcal meningitis. Antimicrob Agents Chemother, 51 (1), pp. 343-345. | Citations: 8 (Scopus) | Show Abstract | Read more

Reliable measures of antifungal drug susceptibility are needed. We tested the susceptibility of Cryptococcus neoformans from patients treated with amphotericin B. In vitro susceptibility employed a modified broth macrodilution method. We demonstrate a strong correlation between the quantitative measures of in vitro amphotericin B susceptibility and the quantitative response observed in patients.

Ricci C, Nyadong L, Fernandez FM, Newton PN, Kazarian SG. 2007. Combined Fourier-transform infrared imaging and desorption electrospray-ionization linear ion-trap mass spectrometry for analysis of counterfeit antimalarial tablets. Anal Bioanal Chem, 387 (2), pp. 551-559. | Citations: 82 (Scopus) | Show Abstract | Read more

This paper reports use of a combination of Fourier-transform infrared (FTIR) spectroscopic imaging and desorption electrospray ionization linear ion-trap mass spectrometry (DESI MS) for characterization of counterfeit pharmaceutical tablets. The counterfeit artesunate antimalarial tablets were analyzed by both techniques. The results obtained revealed the ability of FTIR imaging in non-destructive micro-attenuated total reflection (ATR) mode to detect the distribution of all components in the tablet, the identities of which were confirmed by DESI MS. Chemical images of the tablets were obtained with high spatial resolution. The FTIR spectroscopic imaging method affords inherent chemical specificity with rapid acquisition of data. DESI MS enables high-sensitivity detection of trace organic compounds. Combination of these two orthogonal surface-characterization methods has great potential for detection and analysis of counterfeit tablets in the open air and without sample preparation.

Kamya MR, Yeka A, Bukirwa H, Lugemwa M, Rwakimari JB, Staedke SG, Talisuna AO, Greenhouse B, Nosten F, Rosenthal PJ et al. 2007. Artemether-lumefantrine versus dihydroartemisinin-piperaquine for treatment of malaria: a randomized trial. PLoS Clin Trials, 2 (5), pp. e20. | Citations: 96 (Scopus) | Show Abstract | Read more

OBJECTIVES: To compare the efficacy and safety of artemether-lumefantrine (AL) and dihydroartemisinin-piperaquine (DP) for treating uncomplicated falciparum malaria in Uganda. DESIGN: Randomized single-blinded clinical trial. SETTING: Apac, Uganda, an area of very high malaria transmission intensity. PARTICIPANTS: Children aged 6 mo to 10 y with uncomplicated falciparum malaria. INTERVENTION: Treatment of malaria with AL or DP, each following standard 3-d dosing regimens. OUTCOME MEASURES: Risks of recurrent parasitemia at 28 and 42 d, unadjusted and adjusted by genotyping to distinguish recrudescences and new infections. RESULTS: Of 421 enrolled participants, 417 (99%) completed follow-up. The unadjusted risk of recurrent falciparum parasitemia was significantly lower for participants treated with DP than for those treated with AL after 28 d (11% versus 29%; risk difference [RD] 18%, 95% confidence interval [CI] 11%-26%) and 42 d (43% versus 53%; RD 9.6%, 95% CI 0%-19%) of follow-up. Similarly, the risk of recurrent parasitemia due to possible recrudescence (adjusted by genotyping) was significantly lower for participants treated with DP than for those treated with AL after 28 d (1.9% versus 8.9%; RD 7.0%, 95% CI 2.5%-12%) and 42 d (6.9% versus 16%; RD 9.5%, 95% CI 2.8%-16%). Patients treated with DP had a lower risk of recurrent parasitemia due to non-falciparum species, development of gametocytemia, and higher mean increase in hemoglobin compared to patients treated with AL. Both drugs were well tolerated; serious adverse events were uncommon and unrelated to study drugs. CONCLUSION: DP was superior to AL for reducing the risk of recurrent parasitemia and gametocytemia, and provided improved hemoglobin recovery. DP thus appears to be a good alternative to AL as first-line treatment of uncomplicated malaria in Uganda. To maximize the benefit of artemisinin-based combination therapy in Africa, treatment should be integrated with aggressive strategies to reduce malaria transmission intensity.

Wuthiekanun V, Sirisukkarn N, Daengsupa P, Sakaraserane P, Sangkakam A, Chierakul W, Smythe LD, Symonds ML, Dohnt MF, Slack AT et al. 2007. Clinical diagnosis and geographic distribution of leptospirosis, Thailand. Emerg Infect Dis, 13 (1), pp. 124-126. | Citations: 38 (Scopus) | Show Abstract | Read more

We defined the positive predictive accuracy of a hospital-based clinical diagnosis of leptospirosis in 9 provinces across Thailand. Of 700 suspected cases, 143 (20%) were confirmed by laboratory testing. Accuracy of clinical diagnosis varied from 0% to 50% between the provinces and was highest during the rainy season. Most confirmed cases occurred in the north and northeast regions of the country.

Barnes KI, Lindegardh N, Ogundahunsi O, Olliaro P, Plowe CV, Randrianarivelojosia M, Gbotosho GO, Watkins WM, Sibley CH, White NJ. 2007. World Antimalarial Resistance Network (WARN) IV: clinical pharmacology. Malar J, 6 (1), pp. 122. | Citations: 37 (Scopus) | Show Abstract | Read more

A World Antimalarial Resistance Network (WARN) database has the potential to improve the treatment of malaria, through informing current drug selection and use and providing a prompt warning of when treatment policies need changing. This manuscript outlines the contribution and structure of the clinical pharmacology component of this database. The determinants of treatment response are multi-factorial, but clearly providing adequate blood concentrations is pivotal to curing malaria. The ability of available antimalarial pharmacokinetic data to inform optimal dosing is constrained by the small number of patients studied, with even fewer (if any) studies conducted in the most vulnerable populations. There are even less data relating blood concentration data to the therapeutic response (pharmacodynamics). By pooling all available pharmacokinetic data, while paying careful attention to the analytical methodologies used, the limitations of small (and thus underpowered) individual studies may be overcome and factors that contribute to inter-individual variability in pharmacokinetic parameters defined. Key variables for pharmacokinetic studies are defined in terms of patient (or study subject) characteristics, the formulation and route of administration of the antimalarial studied, the sampling and assay methodology, and the approach taken to data analysis. Better defining these information needs and criteria of acceptability of pharmacokinetic-pharmacodynamic (PK-PD) studies should contribute to improving the quantity, relevance and quality of these studies. A better understanding of the pharmacokinetic properties of antimalarials and a more clear definition of what constitutes "therapeutic drug levels" would allow more precise use of the term "antimalarial resistance", as it would indicate when treatment failure is not caused by intrinsic parasite resistance but is instead the result of inadequate drug levels. The clinical pharmacology component of the WARN database can play a pivotal role in monitoring accurately for true antimalarial drug resistance and promptly correcting sub-optimal dosage regimens to prevent these contributing to the emergence and spread of antimalarial resistance.

Chantratita N, Wuthiekanun V, Thanwisai A, Limmathurotsakul D, Cheng AC, Chierakul W, Day NPJ, Peacock SJ. 2007. Accuracy of enzyme-linked immunosorbent assay using crude and purified antigens for serodiagnosis of melioidosis. Clin Vaccine Immunol, 14 (1), pp. 110-113. | Citations: 31 (Scopus) | Show Abstract | Read more

Five enzyme-linked immunosorbent assays developed to detect antibodies to different Burkholderia pseudomallei antigen preparations were evaluated as diagnostic tests for melioidosis in northeast Thailand. The highest diagnostic indices were observed for an affinity-purified antigen (sensitivity, 82%; specificity, 72%) and crude B. pseudomallei antigen (sensitivity, 81%; specificity, 70%), an improvement over the indirect hemagglutination assay (sensitivity, 73%; specificity, 64%).

Makani J, Williams TN, Marsh K. 2007. Sickle cell disease in Africa: burden and research priorities. Ann Trop Med Parasitol, 101 (1), pp. 3-14. | Citations: 63 (Scopus) | Show Abstract | Read more

Sickle cell disease (SCD) has recently been recognised as a problem of major public-health significance by the World Health Organization. Despite the fact that >70% of sufferers live in Africa, expenditure on the related care and research in the continent is negligible, and most advances in the understanding and management of this condition have been based on research conducted in the North. In order to target limited resources, African countries need to focus research and interventions on areas that will lead to the maximum impact. This review details the epidemiological and clinical background of SCD, with an emphasis on Africa, before identifying the research priorities that will provide the necessary evidence base for improving the management of African patients. Malaria, bacterial and viral infections and cerebrovascular accidents are areas in which further research may lead to a significant improvement in SCD-related morbidity and mortality. As patients with high concentrations of foetal haemoglobin (HbF) appear to be protected from all but mild SCD, the various factors and pharmacological agents that might increase HbF levels need to be assessed in Africa, as options for interventions that would improve quality of life and reduce mortality.

Guerra CA, Hay SI, Lucioparedes LS, Gikandi PW, Tatem AJ, Noor AM, Snow RW. 2007. Assembling a global database of malaria parasite prevalence for the Malaria Atlas Project. Malar J, 6 pp. 17. | Show Abstract | Read more

BACKGROUND: Open access to databases of information generated by the research community can synergize individual efforts and are epitomized by the genome mapping projects. Open source models for outputs of scientific research funded by tax-payers and charities are becoming the norm. This has yet to be extended to malaria epidemiology and control. METHODS: The exhaustive searches and assembly process for a global database of malaria parasite prevalence as part of the Malaria Atlas Project (MAP) are described. The different data sources visited and how productive these were in terms of availability of parasite rate (PR) data are presented, followed by a description of the methods used to assemble a relational database and an associated geographic information system. The challenges facing spatial data assembly from varied sources are described in an effort to help inform similar future applications. RESULTS: At the time of writing, the MAP database held 3,351 spatially independent PR estimates from community surveys conducted since 1985. These include 3,036 Plasmodium falciparum and 1,347 Plasmodium vivax estimates in 74 countries derived from 671 primary sources. More than half of these data represent malaria prevalence after the year 2000. CONCLUSION: This database will help refine maps of the global spatial limits of malaria and be the foundation for the development of global malaria endemicity models as part of MAP. A widespread application of these maps is envisaged. The data compiled and the products generated by MAP are planned to be released in June 2009 to facilitate a more informed approach to global malaria control.

Caws M, Dang TMH, Torok E, Campbell J, Do DAT, Tran THC, Nguyen VVC, Nguyen TC, Farrar J. 2007. Evaluation of the MODS culture technique for the diagnosis of tuberculous meningitis. PLoS One, 2 (11), pp. e1173. | Citations: 41 (Scopus) | Show Abstract | Read more

BACKGROUND: Tuberculous meningitis (TBM) is a devastating condition. The rapid instigation of appropraite chemotherapy is vital to reduce morbidity and mortality. However rapid diagnosis remains elusive; smear microscopy has extremely low sensitivity on cerebrospinal fluid (CSF) in most laboratories and PCR requires expertise with advanced infrastructure and has sensitivity of only around 60% under optimal conditions. Neither technique allows for the microbiological isolation of M. tuberculosis and subsequent drug susceptibility testing. We evaluated the recently developed microscopic observation drug susceptibility (MODS) assay format for speed and accuracy in diagnosing TBM. METHODOLOGY/PRINCIPAL FINDINGS: Two hundred and thirty consecutive CSF samples collected from 156 patients clinically suspected of TBM on presentation at a tertiary referal hospital in Vietnam were enrolled into the study over a five month period and tested by Ziehl-Neelsen (ZN) smear, MODS, Mycobacterial growth Indicator tube (MGIT) and Lowenstein-Jensen (LJ) culture. Sixty-one samples were from patients already on TB therapy for >1day and 19 samples were excluded due to untraceable patient records. One hundred and fifty samples from 137 newly presenting patients remained. Forty-two percent (n = 57/137) of patients were deemed to have TBM by clinical diagnostic and microbiological criteria (excluding MODS). Sensitivity by patient against clinical gold standard for ZN smear, MODS MGIT and LJ were 52.6%, 64.9%, 70.2% and 70.2%, respectively. Specificity of all microbiological techniques was 100%. Positive and negative predictive values for MODS were 100% and 78.7%, respectively for HIV infected patients and 100% and 82.1% for HIV negative patients. The median time to positive was 6 days (interquartile range 5-7), significantly faster than MGIT at 15.5 days (interquartile range 12-24), and LJ at 24 days (interquartile range 18-35 days) (P<0.01). CONCLUSIONS: We have shown MODS to be a sensitive, rapid technique for the diagnosis of TBM with high sensitivity, ease of performance and low cost (0.53 USD/sample).

Heiny AT, Miotto O, Srinivasan KN, Khan AM, Zhang GL, Brusic V, Tan TW, August JT. 2007. Evolutionarily conserved protein sequences of influenza a viruses, avian and human, as vaccine targets. PLoS One, 2 (11), pp. e1190. | Citations: 116 (Scopus) | Show Abstract | Read more

BACKGROUND: Influenza A viruses generate an extreme genetic diversity through point mutation and gene segment exchange, resulting in many new strains that emerge from the animal reservoirs, among which was the recent highly pathogenic H5N1 virus. This genetic diversity also endows these viruses with a dynamic adaptability to their habitats, one result being the rapid selection of genomic variants that resist the immune responses of infected hosts. With the possibility of an influenza A pandemic, a critical need is a vaccine that will recognize and protect against any influenza A pathogen. One feasible approach is a vaccine containing conserved immunogenic protein sequences that represent the genotypic diversity of all current and future avian and human influenza viruses as an alternative to current vaccines that address only the known circulating virus strains. METHODOLOGY/PRINCIPAL FINDINGS: Methodologies for large-scale analysis of the evolutionary variability of the influenza A virus proteins recorded in public databases were developed and used to elucidate the amino acid sequence diversity and conservation of 36,343 sequences of the 11 viral proteins of the recorded virus isolates of the past 30 years. Technologies were also applied to identify the conserved amino acid sequences from isolates of the past decade, and to evaluate the predicted human lymphocyte antigen (HLA) supertype-restricted class I and II T-cell epitopes of the conserved sequences. Fifty-five (55) sequences of 9 or more amino acids of the polymerases (PB2, PB1, and PA), nucleoprotein (NP), and matrix 1 (M1) proteins were completely conserved in at least 80%, many in 95 to 100%, of the avian and human influenza A virus isolates despite the marked evolutionary variability of the viruses. Almost all (50) of these conserved sequences contained putative supertype HLA class I or class II epitopes as predicted by 4 peptide-HLA binding algorithms. Additionally, data of the Immune Epitope Database (IEDB) include 29 experimentally identified HLA class I and II T-cell epitopes present in 14 of the conserved sequences. CONCLUSIONS/SIGNIFICANCE: This study of all reported influenza A virus protein sequences, avian and human, has identified 55 highly conserved sequences, most of which are predicted to have immune relevance as T-cell epitopes. This is a necessary first step in the design and analysis of a polyepitope, pan-influenza A vaccine. In addition to the application described herein, these technologies can be applied to other pathogens and to other therapeutic modalities designed to attack DNA, RNA, or protein sequences critical to pathogen function.

Dong T, Moran E, Vinh Chau N, Simmons C, Luhn K, Peng Y, Wills B, Phuong Dung N, Thi Thu Thao L, Hien TT et al. 2007. High pro-inflammatory cytokine secretion and loss of high avidity cross-reactive cytotoxic T-cells during the course of secondary dengue virus infection. PLoS One, 2 (12), pp. e1192. | Citations: 54 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Dengue is one of the most important human diseases transmitted by an arthropod vector and the incidence of dengue virus infection has been increasing - over half the world's population now live in areas at risk of infection. Most infections are asymptomatic, but a subset of patients experience a potentially fatal shock syndrome characterised by plasma leakage. Severe forms of dengue are epidemiologically associated with repeated infection by more than one of the four dengue virus serotypes. Generally attributed to the phenomenon of antibody-dependent enhancement, recent observations indicate that T-cells may also influence disease phenotype. METHODS AND FINDINGS: Virus-specific cytotoxic T lymphocytes (CTL) showing high level cross reactivity between dengue serotypes could be expanded from blood samples taken during the acute phase of secondary dengue infection. These could not be detected in convalescence when only CTL populations demonstrating significant serotype specificity were identified. Dengue cross-reactive CTL clones derived from these patients were of higher avidity than serotype-specific clones and produced much higher levels of both type 1 and certain type 2 cytokines, many previously implicated in dengue pathogenesis. CONCLUSION: Dengue serotype cross-reactive CTL clones showing high avidity for antigen produce higher levels of inflammatory cytokines than serotype-specific clones. That such cells cannot be expanded from convalescent samples suggests that they may be depleted, perhaps as a consequence of activation-induced cell death. Such high avidity cross-reactive memory CTL may produce inflammatory cytokines during the course of secondary infection, contributing to the pathogenesis of vascular leak. These cells appear to be subsequently deleted leaving a more serotype-specific memory CTL pool. Further studies are needed to relate these cellular observations to disease phenotype in a large group of patients. If confirmed they have significant implications for understanding the role of virus-specific CTL in pathogenesis of dengue disease.

Schünemann HJ, Hill SR, Kakad M, Bellamy R, Uyeki TM, Hayden FG, Yazdanpanah Y, Beigel J, Chotpitayasunondh T, Del Mar C et al. 2007. WHO Rapid Advice Guidelines for pharmacological management of sporadic human infection with avian influenza A (H5N1) virus. Lancet Infect Dis, 7 (1), pp. 21-31. | Citations: 141 (Scopus) | Show Abstract | Read more

Recent spread of avian influenza A (H5N1) virus to poultry and wild birds has increased the threat of human infections with H5N1 virus worldwide. Despite international agreement to stockpile antivirals, evidence-based guidelines for their use do not exist. WHO assembled an international multidisciplinary panel to develop rapid advice for the pharmacological management of human H5N1 virus infection in the current pandemic alert period. A transparent methodological guideline process on the basis of the Grading Recommendations, Assessment, Development and Evaluation (GRADE) approach was used to develop evidence-based guidelines. Our development of specific recommendations for treatment and chemoprophylaxis of sporadic H5N1 infection resulted from the benefits, harms, burden, and cost of interventions in several patient and exposure groups. Overall, the quality of the underlying evidence for all recommendations was rated as very low because it was based on small case series of H5N1 patients, on extrapolation from preclinical studies, and high quality studies of seasonal influenza. A strong recommendation to treat H5N1 patients with oseltamivir was made in part because of the severity of the disease. Similarly, strong recommendations were made to use neuraminidase inhibitors as chemoprophylaxis in high-risk exposure populations. Emergence of other novel influenza A viral subtypes with pandemic potential, or changes in the pathogenicity of H5N1 virus strains, will require an update of these guidelines and WHO will be monitoring this closely.

Molyneux S, Gikonyo C, Marsh V, Bejon P. 2007. Incorporating a quiz into informed consent processes: qualitative study of participants' reactions. Malar J, 6 (1), pp. 145. | Citations: 16 (Scopus) | Show Abstract | Read more

BACKGROUND: Formal checks of participant understanding are now widely recommended to improve informed consent processes. However, the views of the participants these assessments are designed to protect are rarely considered. In this paper the findings of a qualitative study aimed at documenting community reactions to a semi-structured questionnaire ('quiz') are reported. The quiz was administered to 189 mothers after consenting for their children to participate in a malaria vaccine trial on the Kenyan Coast. METHODS: Once the malaria vaccine trial was underway, focus group discussions were held with some of these mothers (nine groups; 103 mothers), and with community-based field staff attached to the malaria vaccine trial (two groups of five workers). Individual interviews with other trial staff were also held. RESULTS: The quiz prompted community members to voice concerns about blood sampling and vaccine side-effects, thereby encouraging additional discussions and interactions between the research team and potential study participants. However, it also caused significant upset and concern. Some of the quiz questions, or the way in which they were asked, appeared to fuel misconceptions and fears, with potentially negative consequences for both the study and community members. CONCLUSION: Formal approaches to checking study understanding should be employed with sensitivity and caution. They are influenced by and impact upon complex social relationships between and among researchers and community members. Adequate consideration of these contexts in assessments of understanding, and in responding to the issues raised, requires strong social science capacity.

Bejon P, Ogada E, Mwangi T, Milligan P, Lang T, Fegan G, Gilbert SC, Peshu N, Marsh K, Hill AVS. 2007. Extended Follow-Up Following a Phase 2b Randomized Trial of the Candidate Malaria Vaccines FP9 ME-TRAP and MVA ME-TRAP among Children in Kenya PLOS ONE, 2 (8), | Citations: 17 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: "FFM ME-TRAP" is sequential immunisation with two attenuated poxvirus vectors (FP9 and modified vaccinia virus Ankara) delivering the pre-erythrocytic malaria antigen ME-TRAP. Over nine months follow-up in our original study, there was no evidence that FFM ME-TRAP provided protection against malaria. The incidence of malaria was slightly higher in children who received FFM ME-TRAP, but this was not statistically significant (hazard ratio 1.5, 95% CI 1.0-2.3). Although the study was unblinded, another nine months follow-up was planned to monitor the incidence of malaria and other serious adverse events. METHODS AND FINDINGS: 405 children aged 1-6 yrs were initially randomized to vaccination with either FFM ME-TRAP or control (rabies vaccine). 380 children were still available for follow-up after the first nine months. Children were seen weekly and whenever they were unwell for nine months monitoring. The axillary temperature was measured, and blood films taken when febrile. The primary analysis was time to parasitaemia >2,500/microl. During the second nine months monitoring, 49 events met the primary endpoint (febrile malaria with parasites >2,500/microl) in the Intention To Treat (ITT) group. 23 events occurred among the 189 children in the FFM ME-TRAP group, and 26 among the 194 children in the control group. In the full 18 months of monitoring, there were 63 events in the FFM ME-TRAP group and 60 in the control group (HR = 1.2, CI 0.84-1.73, p = 0.35). There was no evidence that the HR changed over the 18 months (test for interaction between time and vaccination p = 0.11). CONCLUSIONS: Vaccination with FFM ME-TRAP was not protective against malaria in this study. Malaria incidence during 18 months of surveillance was similar in both vaccine groups. TRIAL REGISTRATION: ISRCTN88335123.

Joseph JK, Simpson ID, Menon NCS, Jose MP, Kulkarni KJ, Raghavendra GB, Warrell DA. 2007. First authenticated cases of life-threatening envenoming by the hump-nosed pit viper (Hypnale hypnale) in India. Trans R Soc Trop Med Hyg, 101 (1), pp. 85-90. | Citations: 52 (Scopus) | Show Abstract | Read more

In Kerala, south-western India, five patients developed systemic envenoming after bites by hump-nosed pit vipers (Hypnale hypnale), proved by identification of the snakes responsible. Two of the dead snakes had been misidentified as saw-scaled vipers (Echis carinatus), while three had remained unidentified. Symptoms of local envenoming were pain, swelling, haemorrhagic blistering, bruising and regional lymphadenopathy. Systemic symptoms included headache, nausea, vomiting and abdominal and chest pain. There was evidence of haemostatic dysfunction (coagulopathy, fibrinolysis, thrombocytopenia or spontaneous systemic haemorrhage) in all cases and of microangiopathic haemolysis in two. Two patients were haemodialysed for acute renal failure, one of whom developed pulmonary oedema requiring mechanical ventilation. In India, H. hypnale has not previously been regarded as a cause of frequent or potentially dangerous envenoming. Its medical importance has been overlooked throughout its geographical range, probably because of confusion with other small species. No specific antivenom exists, yet most patients are treated with non-specific antivenoms, risking reactions without hope of benefit. An effective antivenom is urgently needed in south India and in Sri Lanka, where this species is also a common cause of bites.

Eddleston M, Haggalla S, Reginald K, Sudarshan K, Senthilkumaran M, Karalliedde L, Ariaratnam A, Sheriff MHR, Warrell DA, Buckley NA. 2007. The hazards of gastric lavage for intentional self-poisoning in a resource poor location. Clin Toxicol (Phila), 45 (2), pp. 136-143. | Citations: 33 (Scopus) | Show Abstract | Read more

OBJECTIVE: The 10-20% case fatality found with self-poisoning in the developing world differs markedly from the 0.5% found in the West. This may explain in part why the recent movement away from the use of gastric lavage in the West has not been followed in the developing world. After noting probable harm from gastric lavage in Sri Lanka, we performed an observational study to determine how lavage is routinely performed and the frequency of complications. CASE SERIES: Fourteen consecutive gastric lavages were observed in four hospitals. Lavage was given to patients unable or unwilling to undergo forced emesis, regardless of whether they gave consent or the time elapsed since ingestion. It was also given to patients who had taken non-lethal ingestions. The airway was rarely protected in patients with reduced consciousness, large volumes of fluid were given for each cycle (200 to more than 1000 ml), and monitoring was not used. Serious complications likely to be due to the lavage were observed, including cardiac arrest and probable aspiration of fluid. Health care workers perceived lavage as being highly effective and often life-saving; there was peer and relative pressure to perform lavage in self-poisoned patients. CONCLUSIONS: Gastric lavage as performed for highly toxic poisons in a resource-poor location is hazardous. In the absence of evidence for patient benefit from lavage, (and in agreement with some local guidelines), we believe that lavage should be considered for few patients - in those who have recently taken a potentially fatal dose of a poison, and who either give their verbal consent for the procedure or are sedated and intubated. Ideally, a randomized controlled trial should be performed to determine the balance of risks and benefits of safely performed gastric lavage in this patient population.

Eddleston M, Juszczak E, Buckley NA, Senarathna L, Mohammed F, Allen S, Dissanayake W, Hittarage A, Azher S, Jeganathan K et al. 2007. Study protocol: a randomised controlled trial of multiple and single dose activated charcoal for acute self-poisoning. BMC Emerg Med, 7 (1), pp. 2. | Citations: 2 (Scopus) | Show Abstract | Read more

BACKGROUND: The case fatality for intentional self-poisoning in rural Asia is 10-30 times higher than in the West, mostly due to the use of highly toxic poisons. Activated charcoal is a widely available intervention that may - if given early - bind to poisons in the stomach and prevent their absorption. Current guidelines recommend giving a single dose of charcoal (SDAC) if patients arrive within an hour of ingestion. Multiple doses (MDAC) may increase poison elimination at a later time by interrupting any enterohepatic or enterovascular circulations. The effectiveness of SDAC or MDAC is unknown. Since most patients present to hospital after one hour, we considered MDAC to have a higher likelihood of clinical benefit and set up a study to compare MDAC with no charcoal. A third arm of SDAC was added to help determine whether any benefit noted from MDAC resulted from the first dose or all doses. METHODS/DESIGN: We set up a randomised controlled trial assessing the effectiveness of superactivated charcoal in unselected adult self-poisoning patients admitted to the adult medical wards of three Sri Lankan secondary hospitals. Patients were randomised to standard treatment or standard treatment plus either a single 50 g dose of superactivated charcoal dissolved in 300 ml of water or six doses every four hours. All patients with a history of poison ingestion were approached concerning the study and written informed consent taken from each patient, or their relative (for unconscious patients or those <16 yrs), recruited to the study. The exclusion criteria were: age under 14 yrs; prior treatment with activated charcoal during this poisoning episode; pregnancy; ingestion of a corrosive or hydrocarbon; requirement for oral medication; inability of the medical staff to intubate the patient with a Glasgow Coma Score <13; presentation >72 hrs post-ingestion, and previous recruitment. The primary outcome was in-hospital mortality; secondary outcomes included the occurrence of serious complications (need for intubation, time requiring assisted ventilation, fits, cardiac dysrhythmias). Analysis will be on an intention-to-treat basis; the effects of reported time to treatment after poisoning and status on admission will also be assessed. DISCUSSION: This trial will provide important information on the effectiveness of both single and multiple dose activated charcoal in the forms of poisoning commonly seen in rural Asia. If charcoal is found to be effective, it should be possible to make it widely available across rural Asia in an affordable formulation. TRIAL REGISTRATION: Current Controlled Trials ISRCTN02920054.

Guerin PJ, Grais RF, Rottingen JA, Valleron AJ, Shigella Study Group. 2007. Using European travellers as an early alert to detect emerging pathogens in countries with limited laboratory resources. BMC Public Health, 7 (1), pp. 8. | Citations: 7 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: The volume, extent and speed of travel have dramatically increased in the past decades, providing the potential for an infectious disease to spread through the transportation network. By collecting information on the suspected place of infection, existing surveillance systems in industrialized countries may provide timely information for areas of the world without adequate surveillance currently in place. We present the results of a case study using reported cases of Shigella dysenteriae serotype 1 (Sd1) in European travellers to detect "events" of Sd1, related to either epidemic cases or endemic cases in developing countries. METHODS: We identified papers from a Medline search for reported events of Sd1 from 1940 to 2002. We requested data on shigella infections reported to the responsible surveillance entities in 17 European countries. Reports of Sd1 from the published literature were then compared with Sd1 notified cases among European travellers from 1990 to 2002. RESULTS: Prior to a large epidemic in 1999-2000, no cases of Sd1 had been identified in West Africa. However, if travellers had been used as an early warning, Sd1 could have been identified in this region as earlier as 1992. CONCLUSION: This project demonstrates that tracking diseases in European travellers could be used to detect emerging disease in developing countries. This approach should be further tested with a view to the continuous improvement of national health surveillance systems and existing European networks, and may play a significant role in aiding the international public health community to improve infectious disease control.

Horby P. 2007. The global war on terrorism. Clin Infect Dis, 44 (1), pp. 151. | Read more

Pandit A, Arjyal A, Day JN, Paudyal B, Dangol S, Zimmerman MD, Yadav B, Stepniewska K, Campbell JI, Dolecek C et al. 2007. An open randomized comparison of gatifloxacin versus cefixime for the treatment of uncomplicated enteric fever. PLoS One, 2 (6), pp. e542. | Citations: 49 (Scopus) | Show Abstract | Read more

OBJECTIVE: To assess the efficacy of gatifloxacin versus cefixime in the treatment of uncomplicated culture positive enteric fever. DESIGN: A randomized, open-label, active control trial with two parallel arms. SETTING: Emergency Room and Outpatient Clinics in Patan Hospital, Lagankhel, Lalitpur, Nepal. PARTICIPANTS: Patients with clinically diagnosed uncomplicated enteric fever meeting the inclusion criteria. INTERVENTIONS: Patients were allocated to receive one of two drugs, Gatifloxacin or Cefixime. The dosages used were Gatifloxacin 10 mg/kg, given once daily for 7 days, or Cefixime 20 mg/kg/day given in two divided doses for 7 days. OUTCOME MEASURES: The primary outcome measure was fever clearance time. The secondary outcome measure was overall treatment failure (acute treatment failure and relapse). RESULTS: Randomization was carried out in 390 patients before enrollment was suspended on the advice of the independent data safety monitoring board due to significant differences in both primary and secondary outcome measures in the two arms and the attainment of a priori defined endpoints. Median (95% confidence interval) fever clearance times were 92 hours (84-114 hours) for gatifloxacin recipients and 138 hours (105-164 hours) for cefixime-treated patients (Hazard Ratio[95%CI] = 2.171 [1.545-3.051], p<0.0001). 19 out of 70 (27%) patients who completed the 7 day trial had acute clinical failure in the cefixime group as compared to 1 out of 88 patients (1%) in gatifloxacin group(Odds Ratio [95%CI] = 0.031 [0.004 - 0.237], p<0.001). Overall treatment failure patients (relapsed patients plus acute treatment failure patients plus death) numbered 29. They were determined to be (95% confidence interval) 37.6 % (27.14%-50.2%) in the cefixime group and 3.5% (2.2%-11.5%) in the gatifloxacin group (HR[95%CI] = 0.084 [0.025-0.280], p<0.0001). There was one death in the cefixime group. CONCLUSIONS: Based on this study, gatifloxacin is a better treatment for uncomplicated enteric fever as compared to cefixime. TRIAL REGISTRATION: Current Controlled Trials ISRCTN75784880.

Chotivanich K, Silamut K, Day NPJ. 2007. Laboratory diagnosis of malaria infection - A short review of methods New Zealand Journal of Medical Laboratory Science, 61 (1), pp. 4-7. | Citations: 10 (Scopus) | Show Abstract

Malaria is one of the most important tropical infectious diseases. The incidence of malaria worldwide is estimated to be 300-500 million clinical cases each year with a mortality of between one and three million people worldwide annually. The accurate and timely diagnosis of malaria infection is essential if severe complications and mortality are to be reduced by early specific antimalarial treatment. This review details the methods for the laboratory diagnosis of malaria infection.

Verra F, Simpore J, Warimwe GM, Tetteh KK, Howard T, Osier FHA, Bancone G, Avellino P, Blot I, Fegan G et al. 2007. Haemoglobin C and S role in acquired immunity against Plasmodium falciparum malaria. PLoS One, 2 (10), pp. e978. | Citations: 47 (Scopus) | Show Abstract | Read more

A recently proposed mechanism of protection for haemoglobin C (HbC; beta6Glu-->Lys) links an abnormal display of PfEMP1, an antigen involved in malaria pathogenesis, on the surface of HbC infected erythrocytes together with the observation of reduced cytoadhesion of parasitized erythrocytes and impaired rosetting in vitro. We investigated the impact of this hypothesis on the development of acquired immunity against Plasmodium falciparum variant surface antigens (VSA) encoding PfEMP1 in HbC in comparison with HbA and HbS carriers of Burkina Faso. We measured: i) total IgG against a single VSA, A4U, and against a panel of VSA from severe malaria cases in human sera from urban and rural areas of Burkina Faso of different haemoglobin genotypes (CC, AC, AS, SC, SS); ii) total IgG against recombinant proteins of P. falciparum asexual sporozoite, blood stage antigens, and parasite schizont extract; iii) total IgG against tetanus toxoid. Results showed that the reported abnormal cell-surface display of PfEMP1 on HbC infected erythrocytes observed in vitro is not associated to lower anti- PfEMP1 response in vivo. Higher immune response against the VSA panel and malaria antigens were observed in all adaptive genotypes containing at least one allelic variant HbC or HbS in the low transmission urban area whereas no differences were detected in the high transmission rural area. In both contexts the response against tetanus toxoid was not influenced by the beta-globin genotype. These findings suggest that both HbC and HbS affect the early development of naturally acquired immunity against malaria. The enhanced immune reactivity in both HbC and HbS carriers supports the hypothesis that the protection against malaria of these adaptive genotypes might be at least partially mediated by acquired immunity against malaria.

Baird JK, Schwartz E, Hoffman SL. 2007. Prevention and treatment of vivax malaria. Curr Infect Dis Rep, 9 (1), pp. 39-46. | Show Abstract | Read more

Plasmodium vivax is a significant public health threat throughout most of the tropics and to travelers to these regions. The infection causes a debilitating febrile syndrome that often recurs and in rare cases ends in death. The complex life cycle of the parasite compounds the difficulty of prevention and treatment, principally due to the phenomenon of relapse. Most commonly used drugs for preventing malaria fail to prevent late relapses by this parasite. Treatment requires dealing with both blood and liver stages. Since 1950, primaquine has been the only drug available for treatment of liver stages, and important clinical questions surround its appropriate use (ie, dosing, efficacy, safety, and tolerability). Likewise, chloroquine has been first-line therapy for vivax malaria since 1946, and the emergence of resistance to the drug further complicates therapeutic management decisions.

Schultsz C, Vien LM, Campbell JI, Chau NVV, Diep TS, Hoang NVM, Nga TTT, Savelkoul P, Stepnieuwska K, Parry C et al. 2007. Changes in the nasal carriage of drug-resistant Streptococcus pneumoniae in urban and rural Vietnamese schoolchildren. Trans R Soc Trop Med Hyg, 101 (5), pp. 484-492. | Citations: 12 (Scopus) | Show Abstract | Read more

Studying the antimicrobial drug resistance of nasopharyngeal or nasal carriage isolates of Streptococcus pneumoniae in children is likely to have predictive potential for invasive isolates. Streptococcus pneumoniae nasal carriage was studied in 1422 Vietnamese children. Forty-six percent of 536 isolates showed reduced susceptibility to penicillin and 7% showed intermediate susceptibility to ceftriaxone; and 50% of 518 isolates showed resistance to erythromycin. All isolates were sensitive to levofloxacin and gatifloxacin. Urban and suburban children were significantly more likely to carry drug-resistant isolates than rural children. Rates of non-susceptibility to penicillin and erythromycin increased significantly in the rural province Khanh Hoa in 2003/2004 compared with rates obtained in 1997. An emerging clone of penicillin non-susceptible S. pneumoniae of serogroup 15 was identified, which was widely distributed in addition to the pandemic clones Spain(23F)-1 and Taiwan(19F)-14. Although resistance to fluoroquinolones was not observed, 6 (18%) of 34 isolates had a Lys137Asn mutation in the parC gene. This study shows that drug resistance is increasing in carriage isolates of S. pneumoniae in rural areas in Vietnam owing to spread of pandemic and emerging resistant clones.

Simmons CP, Bernasconi NL, Suguitan AL, Mills K, Ward JM, Chau NVV, Hien TT, Sallusto F, Ha DQ, Farrar J et al. 2007. Prophylactic and therapeutic efficacy of human monoclonal antibodies against H5N1 influenza. PLoS Med, 4 (5), pp. e178. | Citations: 159 (Scopus) | Show Abstract | Read more

BACKGROUND: New prophylactic and therapeutic strategies to combat human infections with highly pathogenic avian influenza (HPAI) H5N1 viruses are needed. We generated neutralizing anti-H5N1 human monoclonal antibodies (mAbs) and tested their efficacy for prophylaxis and therapy in a murine model of infection. METHODS AND FINDINGS: Using Epstein-Barr virus we immortalized memory B cells from Vietnamese adults who had recovered from infections with HPAI H5N1 viruses. Supernatants from B cell lines were screened in a virus neutralization assay. B cell lines secreting neutralizing antibodies were cloned and the mAbs purified. The cross-reactivity of these antibodies for different strains of H5N1 was tested in vitro by neutralization assays, and their prophylactic and therapeutic efficacy in vivo was tested in mice. In vitro, mAbs FLA3.14 and FLD20.19 neutralized both Clade I and Clade II H5N1 viruses, whilst FLA5.10 and FLD21.140 neutralized Clade I viruses only. In vivo, FLA3.14 and FLA5.10 conferred protection from lethality in mice challenged with A/Vietnam/1203/04 (H5N1) in a dose-dependent manner. mAb prophylaxis provided a statistically significant reduction in pulmonary virus titer, reduced associated inflammation in the lungs, and restricted extrapulmonary dissemination of the virus. Therapeutic doses of FLA3.14, FLA5.10, FLD20.19, and FLD21.140 provided robust protection from lethality at least up to 72 h postinfection with A/Vietnam/1203/04 (H5N1). mAbs FLA3.14, FLD21.140 and FLD20.19, but not FLA5.10, were also therapeutically active in vivo against the Clade II virus A/Indonesia/5/2005 (H5N1). CONCLUSIONS: These studies provide proof of concept that fully human mAbs with neutralizing activity can be rapidly generated from the peripheral blood of convalescent patients and that these mAbs are effective for the prevention and treatment of H5N1 infection in a mouse model. A panel of neutralizing, cross-reactive mAbs might be useful for prophylaxis or adjunctive treatment of human cases of H5N1 influenza.

Parry CM, Ho VA, Phuong LT, Bay PVB, Lanh MN, Tung LT, Tham NTH, Wain J, Hien TT, Farrar JJ. 2007. Randomized controlled comparison of ofloxacin, azithromycin, and an ofloxacin-azithromycin combination for treatment of multidrug-resistant and nalidixic acid-resistant typhoid fever. Antimicrob Agents Chemother, 51 (3), pp. 819-825. | Citations: 92 (Scopus) | Show Abstract | Read more

Isolates of Salmonella enterica serovar Typhi that are multidrug resistant (MDR, resistant to chloramphenicol, ampicillin, and trimethoprim-sulfamethoxazole) and have reduced susceptibility to fluoroquinolones (nalidixic acid resistant, Na(r)) are common in Asia. The optimum treatment for infections caused by such isolates is not established. This study compared different antimicrobial regimens for the treatment of MDR/Na(r) typhoid fever. Vietnamese children and adults with uncomplicated typhoid fever were entered into an open randomized controlled trial. Ofloxacin (20 mg/kg of body weight/day for 7 days), azithromycin (10 mg/kg/day for 7 days), and ofloxacin (15 mg/kg/day for 7 days) combined with azithromycin (10 mg/kg/day for the first 3 days) were compared. Of the 241 enrolled patients, 187 were eligible for analysis (186 S. enterica serovar Typhi, 1 Salmonella enterica serovar Paratyphi A). Eighty-seven percent (163/187) of the patients were children; of the S. enterica serovar Typhi isolates, 88% (165/187) were MDR and 93% (173/187) were Na(r). The clinical cure rate was 64% (40/63) with ofloxacin, 76% (47/62) with ofloxacin-azithromycin, and 82% (51/62) with azithromycin (P = 0.053). The mean (95% confidence interval [CI]) fever clearance time for patients treated with azithromycin (5.8 days [5.1 to 6.5 days]) was shorter than that for patients treated with ofloxacin-azithromycin (7.1 days [6.2 to 8.1 days]) and ofloxacin (8.2 days [7.2 to 9.2 days]) (P < 0.001). Positive fecal carriage immediately posttreatment was detected in 19.4% (12/62) of patients treated with ofloxacin, 6.5% (4/62) of those treated with the combination, and 1.6% (1/62) of those treated with azithromycin (P = 0.006). Both antibiotics were well tolerated. Uncomplicated typhoid fever due to isolates of MDR S. enterica serovar Typhi with reduced susceptibility to fluoroquinolones (Na(r)) can be successfully treated with a 7-day course of azithromycin.

Thwaites GE, Hien TT, Farrar JJ. 2007. Reply to "Dr D Dhasmana and Dr R Davidson: Multi-drug resistant tuberculous meningitis" JOURNAL OF INFECTION, 54 (2), pp. 206-206. | Read more

Nguyen THM, Tran THC, Thwaites G, Ly VC, Dinh XS, Ho Dang TN, Dang QT, Nguyen DP, Nguyen HP, To SD et al. 2007. Dexamethasone in Vietnamese adolescents and adults with bacterial meningitis. N Engl J Med, 357 (24), pp. 2431-2440. | Citations: 139 (Scopus) | Show Abstract | Read more

BACKGROUND: It is uncertain whether all adults with bacterial meningitis benefit from treatment with adjunctive dexamethasone. METHODS: We conducted a randomized, double-blind, placebo-controlled trial of dexamethasone in 435 patients over the age of 14 years who had suspected bacterial meningitis. The goal was to determine whether dexamethasone reduced the risk of death at 1 month and the risk of death or disability at 6 months. RESULTS: A total of 217 patients were assigned to the dexamethasone group, and 218 to the placebo group. Bacterial meningitis was confirmed in 300 patients (69.0%), probable meningitis was diagnosed in 123 patients (28.3%), and an alternative diagnosis was made in 12 patients (2.8%). An intention-to-treat analysis of all the patients showed that dexamethasone was not associated with a significant reduction in the risk of death at 1 month (relative risk, 0.79; 95% confidence interval [CI], 0.45 to 1.39) or the risk of death or disability at 6 months (odds ratio, 0.74; 95% CI, 0.47 to 1.17). In patients with confirmed bacterial meningitis, however, there was a significant reduction in the risk of death at 1 month (relative risk, 0.43; 95% CI, 0.20 to 0.94) and in the risk of death or disability at 6 months (odds ratio, 0.56; 95% CI, 0.32 to 0.98). These effects were not found in patients with probable bacterial meningitis. Results of multivariate analysis indicated that dexamethasone treatment for patients with probable bacterial meningitis was significantly associated with an increased risk of death at 1 month, an observation that may be explained by cases of tuberculous meningitis in the treatment group. CONCLUSIONS: Dexamethasone does not improve the outcome in all adolescents and adults with suspected bacterial meningitis; a beneficial effect appears to be confined to patients with microbiologically proven disease, including those who have received prior treatment with antibiotics. (Current Controlled Trials number, ISRCTN42986828 [] .).

Dong T, Moran E, Vinh Chau N, Simmons C, Luhn K, Peng Y, Wills B, Phuong Dung N, Thi Thu Thao L, Hien TT et al. 2007. High pro-inflammatory cytokine secretion and loss of high avidity cross-reactive cytotoxic T-cells during the course of secondary dengue virus infection PLoS ONE, 2 (12), | Citations: 56 (Scopus) | Show Abstract | Read more

Background: Dengue is one of the most important human diseases transmitted by an arthropod vector and the incidence of dengue virus infection has been increasing - over half the world's population now live in areas at risk of infection. Most infections are asymptomatic, but a subset of patients experience a potentially fatal shock syndrome characterised by plasma leakage. Severe forms of dengue are epidemiologically associated with repeated infection by more than one of the four dengue virus serotypes. Generally attributed to the phenomenon of antibody-dependent enhancement, recent observations indicate that T-cells may also influence disease phenotype. Methods and Findings: Virus-specific cytotoxic T lymphocytes (CTL) showing high level cross reactivity between dengue serotypes could be expanded from blood samples taken during the acute phase of secondary dengue infection. These could not be detected in convalescence when only CTL populations demonstrating significant serotype specificity were identified. Dengue cross-reactive CTL clones derived from these patients were of higher avidity than serotype-specific clones and produced much higher levels of both type 1 and certain type 2 cytokines, many previously implicated in dengue pathogenesis. Conclusion: Dengue serotype cross-reactive CTL clones showing high avidity for antigen produce higher levels of inflammatory cytokines than serotype-specific clones. That such cells cannot be expanded from convalescent samples suggests that they maybe depleted, perhaps as a consequence of activation-induced cell death. Such high avidity cross-reactive memory CTL may produce inflammatory cytokines during the course of secondary infection, contributing to the pathogenesis of vascular leak. These cells appear to be subsequently deleted leaving a more serotype-specific memory CTL pool. Further studies are needed to relate these cellular observations to disease phenotype in a large group of patients. If confirmed they have significant implications for understanding the role of virus-specific CTL in pathogenesis of dengue disease. © 2007 Dong et al.

Tang CT, Nguyen DT, Ngo TH, Nguyen TMP, Le VT, To SD, Lindsay J, Nguyen TD, Bach VC, Le QT et al. 2007. An outbreak of severe infections with community-acquired MRSA carrying the Panton-Valentine leukocidin following vaccination. PLoS One, 2 (9), pp. e822. | Citations: 22 (Web of Science Lite) | Show Abstract | Read more

BACKGROUND: Infections with community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) are emerging worldwide. We investigated an outbreak of severe CA-MRSA infections in children following out-patient vaccination. METHODS AND FINDINGS: We carried out a field investigation after adverse events following immunization (AEFI) were reported. We reviewed the clinical data from all cases. S. aureus recovered from skin infections and from nasal and throat swabs were analyzed by pulse-field gel electrophoresis, multi locus sequence typing, PCR and microarray. In May 2006, nine children presented with AEFI, ranging from fatal toxic shock syndrome, necrotizing soft tissue infection, purulent abscesses, to fever with rash. All had received a vaccination injection in different health centres in one District of Ho Chi Minh City. Eight children had been vaccinated by the same health care worker (HCW). Deficiencies in vaccine quality, storage practices, or preparation and delivery were not found. Infection control practices were insufficient. CA-MRSA was cultured in four children and from nasal and throat swabs from the HCW. Strains from children and HCW were indistinguishable. All carried the Panton-Valentine leukocidine (PVL), the staphylococcal enterotoxin B gene, the gene complex for staphylococcal-cassette-chromosome mec type V, and were sequence type 59. Strain HCM3A is epidemiologically unrelated to a strain of ST59 prevalent in the USA, although they belong to the same lineage. CONCLUSIONS: We describe an outbreak of infections with CA-MRSA in children, transmitted by an asymptomatic colonized HCW during immunization injection. Consistent adherence to injection practice guidelines is needed to prevent CA-MRSA transmission in both in- and outpatient settings.

Török ME, Nghia HDT, Chau TTH, Mai NTH, Thwaites GE, Stepniewska K, Farrar JJ. 2007. Validation of a diagnostic algorithm for adult tuberculous meningitis. Am J Trop Med Hyg, 77 (3), pp. 555-559. | Citations: 32 (Scopus) | Show Abstract

Tuberculous meningitis (TBM) remains difficult to diagnose. We prospectively evaluated a diagnostic algorithm for TBM in 205 HIV-negative patients with meningitis and a low CSF glucose. Patients were classified as having TBM or bacterial meningitis (BM) by two diagnostic methods: logistic regression method (LRM) and classification and regression tree (CART). We performed analyses of TBM versus BM and TBM versus non-TBM in all patients and in patients with microbiologically confirmed diagnoses. Diagnostic sensitivities for TBM were 99% (LRM) and 87% (CART). For BM, diagnostic sensitivities were 81.5% (LRM) and 86.5% (CART) in the primary analysis and 86.5% (LRM) and 74% (CART) in the secondary analysis. In microbiologically confirmed cases, similar rates were achieved. These figures are superior to microbiological confirmation rates in routine laboratories and support the use of this algorithm in high-prevalence TB settings with limited diagnostic facilities. Validation in an HIV-endemic setting is required.

Hawn TR, Misch EA, Dunstan SJ, Thwaites GE, Lan NTN, Quy HT, Chau TTH, Rodrigues S, Nachman A, Janer M et al. 2007. A common human TLR1 polymorphism regulates the innate immune response to lipopeptides. Eur J Immunol, 37 (8), pp. 2280-2289. | Citations: 136 (Scopus) | Show Abstract | Read more

Toll-like receptors (TLR) are critical mediators of the immune response to pathogens and human polymorphisms in this gene family regulate inflammatory pathways and are associated with susceptibility to infection. Lipopeptides are present in a wide variety of microbes and stimulate immune responses through TLR1/2 or TLR2/6 heterodimers. It is not currently known whether polymorphisms in TLR1 regulate the innate immune response. We stimulated human whole blood with triacylated lipopeptide, a ligand for TLR1/2 heterodimers, and found substantial inter-individual variation in the immune response. We sequenced the coding region of TLR1 and found a non-synonymous polymorphism, I602S (base pair T1805G), that regulated signalling. In comparison to TLR1_602S, the 602I variant mediated substantially greater basal and lipopeptide-induced NF-kappaB signalling in transfected HEK293 cells. These signalling differences among TLR1 variants were also found with stimulation by extracts of Mycobacterium tuberculosis. Furthermore, individuals with the 602II genotype produced substantially more IL-6 than those with the 602SS variant in a lipopeptide-stimulated whole-blood cytokine assay. Together, these observations demonstrate that variation in the inflammatory response to bacterial lipopeptides is regulated by a common TLR1 transmembrane domain polymorphism that could potentially impact the innate immune response and clinical susceptibility to a wide spectrum of pathogens.

Grais RF, Dubray C, Gerstl S, Guthmann JP, Djibo A, Nargaye KD, Coker J, Alberti KP, Cochet A, Ihekweazu C et al. 2007. Unacceptably high mortality related to measles epidemics in Niger, Nigeria, and Chad PLoS Medicine, 4 (1), pp. 0122-0129. | Citations: 79 (Scopus) | Show Abstract | Read more

Background: Despite the comprehensive World Health Organization (WHO)/United Nations Children's Fund (UNICEF) measles mortality-reduction strategy and the Measles Initiative, a partnership of international organizations supporting measles mortality reduction in Africa, certain high-burden countries continue to face recurrent epidemics. To our knowledge, few recent studies have documented measles mortality in sub-Saharan Africa. The objective of our study was to investigate measles mortality in three recent epidemics in Niamey (Niger), N'Djamena (Chad), and Adamawa State (Nigeria). Methods and Findings: We conducted three exhaustive household retrospective mortality surveys in one neighbourhood of each of the three affected areas: Boukoki, Niamey, Niger (April 2004, n = 26,795); Moursal, N'Djamena, Chad (June 2005, n = 21,812); and Dong D istrict, Adamawa State, Nigeria (April 2005, n = 16,249), where n is the total surveyed population in each of the respective areas. Study populations included all persons resident for at least 2 wk prior to the study, a duration encompassing the measles incubation period. Heads of households provided information on measles cases, clinical outcomes up to 30 d after rash onset, and health-seeking behaviour during the epidemic. Measles cases and deaths were ascertained using standard WHO surveillance-case definitions. Our main outcome measures were measles attack rates (ARs) and case fatality ratios (CFRs) by age group, and descriptions of measles complications and health-seeking behaviour. Measles ARs were the highest in children under 5 y old (under 5 y): 17.1% in Boukoki, 17.2% in Moursal, and 24.3% in Dong District. CFRs in under 5-y-olds were 4.6%, 4.0%, and 10.8% in Boukoki, Moursal, and Dong District, respectively. In all sites, more than half of measles cases in children aged under 5 y experienced acute respiratory infection and/or diarrhoea in the 30 d following rash onset. Of measles cases, it was reported that 85.7% (979/1,142) of patients visited a health-care facility within 30 d after rash onset in Boukoki, 73.5% (519/706) in Moursal, and 52.8% (603/1,142) in Dong District. Conclusions: Children in these countries still face unacceptably high mortality from a completely preventable disease. While the successes of measles mortality-reduction strategies and progress observed in measles control in other countries of the region are laudable and evident, they should not overshadow the need for intensive efforts in countries that have just begun implementation of the WHO/UNICEF comprehensive strategy. © 2007 Grais et al.

Green MD, Nettey H, Rojas OV, Pamanivong C, Khounsaknalath L, Ortiz MG, Newton PN, Fernández FM, Vongsack L, Manolin O. 2007. Corrigendum to “Use of refractometry and colorimetry as field methods to rapidly assess antimalarial drug quality” [J. Pharm. Biomed. Anal. 43 (2007) 105–110] Journal of Pharmaceutical and Biomedical Analysis, 43 (5), pp. 1890-1890. | Citations: 1 (Scopus) | Read more

Slesak G, Phanthavong P, Rasphone O, Luangxay K, Anoulakkham P, Pahatsalang V, Soumphonphakdy B, White JA, Newton PN. 2007. Obstructive biliary ascariasis with cholangitis and hepatic abscesses in Laos: a case report with gall bladder ultrasound video. J Infect, 54 (4), pp. e233-e235. | Citations: 7 (Scopus) | Show Abstract | Read more

A 12-year-old Lao boy with obstructive biliary Ascaris infection is described and video of the gallbladder ultrasound presented. The patient developed severe complications of obstructive cholangitis, a large right pleural effusion and hepatic abscesses requiring prolonged antibiotic therapy. The differential diagnosis of worms in the gall-bladder is discussed.

Mayxay M, Khomthilat T, Souvannasing P, Phounesavath K, Vorasane B, Keomany S, Douangdala P, Philavong K, Srour L, Newton PN. 2007. Factors associated with a measles outbreak in children admitted at Mahosot Hospital, Vientiane, Laos. BMC Public Health, 7 (1), pp. 193. | Citations: 3 (Scopus) | Show Abstract | Read more

BACKGROUND: In 2002 and 2003 there were large outbreaks of measles in many provinces of Laos, including in Vientiane. We therefore conducted a study to determine risk factors associated with measles amongst children admitted at Mahosot Hospital, Vientiane. METHODS: A retrospective case-control study was conducted in 50 children with clinical measles who were matched by age and sex with 50 healthy children (who had never had a febrile rash) living in the same villages as the cases. RESULTS: The proportion of children with complete immunizations was significantly lower in the group with clinical measles compared to the controls [13/50 (26%) vs 34/50 (68%), P < 0.001). The percentage of children who had received measles vaccine at 9-23 months of age was significantly lower in the group with clinical measles compared to the healthy controls [12/50 (24%) vs 24/50 (48%), P = 0.01). The family educational and socio-economic status did not differ significantly (P > 0.05) between cases and controls. CONCLUSION: These results emphasize the importance of intensification of measles immunization coverage in Laos. The strengthening of campaigns with large, widespread high second dose coverage is likely to be a key measure to prevent further measles outbreaks in Laos (192 words).

Horby P. 2007. In response [11] Emerging Infectious Diseases, 13 (6), pp. 956.

Luksameetanasan R, Blacksell SD, Kalambaheti T, Wuthiekanun V, Chierakul W, Chueasuwanchai S, Apiwattanaporn A, Stenos J, Graves S, Peacock SJ, Day NPJ. 2007. Patient and sample-related factors that effect the success of in vitro isolation of Orientia tsutsugamushi. Southeast Asian J Trop Med Public Health, 38 (1), pp. 91-96. | Citations: 31 (Scopus) | Show Abstract

Orientia tsutsugamushi is the causative agent of scrub typhus infection, a major cause of human disease in rural areas of Southeast Asia. Twenty-six blood samples collected from patients with serologically proven scrub typhus during a six month period were sent to Bangkok (535 km from the clinical site) by road at ambient temperature (average daily temperature range: 27.1-29.1 degrees C) for attempted in vitro isolation in Vero cells. O. tsutsugamushi was isolated from 12 samples (sensitivity 46.7%) with the time to isolation ranging from 16 to 37 days [median 27 days, inter-quartile range (IQR) 22.5-33.5 days]. Patient factors such as days of fever and O. tsutsugamushi IgM antibody titer, transport factors such as transit time, and isolate genotype (Karp and Gilliam/Kawasaki) were assessed to determine their influence on the outcome of in vitro isolation. None of the factors significantly influenced the isolation outcome. This study demonstrates that O. tsutsugamushi can often be isolated in vitro from the blood of scrub typhus patients when transported at ambient tropical temperatures for many days.

Khounsy S, Gleeson LJ, Van Aken D, Westbury HA, Blacksell SD. 2007. Diagnosis of classical swine fever virus in a limited resource setting: the influence of pig breed on methodology and sample selection. Trop Anim Health Prod, 39 (1), pp. 21-25. | Read more

Smith DL, McKenzie FE, Snow RW, Hay SI. 2007. Revisiting the basic reproductive number for malaria and its implications for malaria control PLoS Biology, 5 (3), pp. 0531-0542. | Citations: 182 (Scopus) | Show Abstract | Read more

The prospects for the success of malaria control depend, in part, on the basic reproductive number for malaria, R 0 . Here, we estimate R 0 in a novel way for 121 African populations, and thereby increase the number of R 0 estimates for malaria by an order of magnitude. The estimates range from around one to more than 3,000. We also consider malaria transmission and control in finite human populations, of size H. We show that classic formulas approximate the expected number of mosquitoes that could trace infection back to one mosquito after one parasite generation, Z 0 (H), but they overestimate the expected number of infected humans per infected human, R 0 (H). Heterogeneous biting increases R 0 and, as we show, Z 0 (H), but we also show that it sometimes reduces R 0 (H); those who are bitten most both infect many vectors and absorb infectious bites. The large range of R 0 estimates strongly supports the long-held notion that malaria control presents variable challenges across its transmission spectrum. In populations where R 0 is highest, malaria control will require multiple, integrated methods that target those who are bitten most. Therefore, strategic planning for malaria control should consider R 0 , the spatial scale of transmission, human population density, and heterogeneous biting.

White NJ, Day NPJ, Dondorp A, Anstey N. 2007. UK recommendations for severe malaria are worrying. BMJ, 334 (7592), pp. 490. | Citations: 1 (Web of Science Lite) | Read more

Hoa NT, Zheng L. 2007. Functional characterization of the NF-kappa B transcription factor gene REL2 from Anopheles gambiae INSECT SCIENCE, 14 (3), pp. 175-184. | Citations: 5 (Web of Science Lite) | Show Abstract | Read more

The REL2 gene plays an important role in innate immunity against both Gram (+) and Gram (-) bacteria and malaria parasites in Anopheles gambiae, the main vector of malaria in Africa. Through alternative splicing, REL2 produces two protein products, REL2F (with a Rel-homology domain as well as an inhibitory ankyrin repeat region) and REL2S (without the ankyrin repeats). In the immune-competent cell line Sua1B from An. gambiae, REL2 has been shown to be a key regulator for cecropin A (or CEC1). The high level expression of CEC1 in Sua1B was postulated to be the result of constitutive activation of REL2F. Here we showed that REL2F is indeed processed, albeit at a low level, in the Sua1B cell line. The primary cleavage requires residue 678 (an aspartic acid). Proteolytic cleavage of REL2Fcan be enhanced by challenge with bacteria Escherichia coli and Bacillus subtilis, but not with fungus Deauveria bassiana. The inducible cleavage can be substantially reduced by RNA interference against PGRP-LC and CASPL1. Over-expression of REL2S or a constitutively active form of REL2F (REL2F380C or REL2F678) in An. gambiae cell line can further increase expression of CECI and other antimicrobial peptide genes. Over-expression of these constitutive active proteins in an immune naive cell line, MSQ43, from Anopheles stephensi, results in even more dramatic increased expression of antimicrobial peptides. © Institute of Zoology, Chinese Academy of Sciences.

Lee SWH, Cheah PY, Liong ML, Yuen KH, Schaeffer AJ, Propert K, Krieger JN, Northern Malaysia Prostatitis Study Group, Chronic Prostatitis Collaborative Research Network Group. 2007. Demographic and clinical characteristics of chronic prostatitis: prospective comparison of the University of Sciences Malaysia Cohort with the United States National Institutes of Health Cohort. J Urol, 177 (1), pp. 153-157. | Citations: 14 (Scopus) | Show Abstract | Read more

PURPOSE: We compared demographic and clinical characteristics of the University of Sciences Malaysia Chronic Prostatitis Cohort to the United States National Institutes of Health Chronic Prostatitis Cohort. MATERIALS AND METHODS: Participants met the same definition of chronic prostatitis/chronic pelvic pain syndrome. Each participant had extensive demographic, medical history, previous treatment, clinical and laboratory evaluations. RESULTS: The University of Sciences Malaysia and National Institutes of Health cohorts proved similar in most respects. National Institutes of Health-Chronic Prostatitis Symptom Index total scores, pain and urinary subscores were similar for the 332 University of Sciences Malaysia Chronic Prostatitis Cohort and 488 National Institutes of Health Chronic Prostatitis Cohort participants. Differences included worse quality of life subscore for the University of Sciences Malaysia Chronic Prostatitis Cohort, differences in the location, number of sites, and types of pain/discomfort between the 2 populations, and that the University of Sciences Malaysia participants had received less previous treatment. CONCLUSIONS: The demographic characteristics and clinical presentation of chronic prostatitis/chronic pelvic pain syndrome proved remarkably similar in these diverse populations. Both cohorts experienced major reduction in their quality of life from chronic pelvic pain and urinary symptoms. Comparison of diverse populations using standard clinical, laboratory and assessment instruments is feasible, and may provide important insights into chronic prostatitis/chronic pelvic pain syndrome and the factors that determine clinical outcome.

Kinyanjui SM, Conway DJ, Lanar DE, Marsh K. 2007. IgG antibody responses to Plasmodium falciparum merozoite antigens in Kenyan children have a short half-life. Malar J, 6 (1), pp. 82. | Citations: 101 (Scopus) | Show Abstract | Read more

BACKGROUND: Data suggest that antibody responses to malaria parasites merozoite antigens are generally short-lived and this has implications for serological studies and malaria vaccine designs. However, precise data on the kinetics of these responses is lacking. METHODS: IgG1 and IgG3 responses to five recombinant Plasmodium falciparum merozoite antigens (MSP-119, MSP-2 type A and B, AMA-1 ectodomain and EBA-175 region II) among Kenyan children were monitored using ELISA for 12 weeks after an acute episode of malaria and their half-lives estimated using an exponential decay model. RESULTS: The responses peaked mainly at week 1 and then decayed rapidly to very low levels within 6 weeks. Estimation of the half-lives of 40 IgG1 responses yielded a mean half-life of 9.8 days (95% CI: 7.6-12.0) while for 16 IgG3 responses it was 6.1 days (95% CI: 3.7-8.4), periods that are shorter than those normally described for the catabolic half-life of these antibody subclasses. CONCLUSION: This study indicates antibodies against merozoite antigens have very short half-lives and this has to be taken into account when designing serological studies and vaccines based on the antigens.

Ostrowski SR, Shulman CE, Peshu N, Staalsøe T, Høyer-Hansen G, Pedersen BK, Marsh K, Ullum H. 2007. Elevated plasma urokinase receptor predicts low birth weight in maternal malaria. Parasite Immunol, 29 (1), pp. 37-46. | Citations: 15 (Web of Science Lite) | Show Abstract | Read more

The blood level of soluble urokinase receptor (suPAR) is increased and associated with a poor clinical or fatal outcome in children with acute malaria. This study hypothesized that the suPAR level would be associated with foetal outcome in maternal malaria. suPAR was measured by ELISA in maternal and cord plasma samples taken during delivery in 253 pregnant Kenyan women stratified according to placental histology: no malaria infection (non-infected), active or active-chronic infection (actively infected) or past-chronic infection (past-infected). Maternal-suPAR was higher in actively infected women (median 3.93 (IQR 2.92-5.29) ng/mL) compared with non-infected (median 2.78 (IQR 1.86-3.87) ng/mL, P = 0.001) and past-infected (median 2.67 (IQR 1.94-3.7) ng/mL, P = 0.012) women. Cord-suPAR was comparable across the groups (median 2.98 (IQR 2.38-3.77) ng/mL). In actively infected women, maternal-suPAR and gestational age were the only independent predictors of birth weight in multivariate linear regression adjusted for maternal-suPAR, HIV-1 infection, age, BMI, haemoglobin, peripheral parasitaemia, parity and gestational age; 1 ng/mL higher maternal-suPAR predicted -56 g (95% CI -100 to -12, P = 0.016) reduced birth weight. Cord-suPAR could not predict birth weight after adjusting for gestational age. Future studies are warranted to investigate whether the maternal suPAR level is increased earlier in pregnancy in women with active placental malaria infection and whether early maternal suPAR measurements can predict birth weight. If so, measurements of maternal suPAR early in pregnancy might then potentially identify women with increased needs for antenatal care and intervention.

Idro R, Crawley J, Marsh K, Newton CRJC, Neville BGR. 2007. In reply [2] Journal of the American Medical Association, 298 (11), pp. 1274.

Molyneux M, Marsh K, White N, Farrar J, French N, Day N, Rowland-Jones S. 2007. UK doctors are already put off by changes in training [3] British Medical Journal, 334 (7596), pp. 709-710. | Citations: 1 (Scopus)

Carrique-Mas JJ, Bedford S, Davies RH. 2007. Organic acid and formaldehyde treatment of animal feeds to control Salmonella: efficacy and masking during culture. J Appl Microbiol, 103 (1), pp. 88-96. | Citations: 24 (Scopus) | Show Abstract | Read more

AIMS: To investigate whether treatment of animals feeds with organic acids/formaldehyde may mask the presence of Salmonella, when assessed by standard cultural methods. METHODS AND RESULTS: Four commercial treatments were applied at the manufacturers' recommended rates on feeds artificially inoculated with Salmonella. The recovery of Salmonella from these treated feeds was assessed after specific antagonists were added to the treatments during culture. A control group of treated feed received no antagonist. Masking of Salmonella was demonstrated when the addition of antagonists resulted in recovery of Salmonella from the treated feed, compared with a negative recovery when no antagonists were added. There were large variations in the efficacy of treatments, and masking was demonstrated with all four tested treatments. One formaldehyde-based product showed greater efficacy and less masking. Masking was greater when high levels of Salmonella were present in the feed. CONCLUSIONS: Some organic acid or formaldehyde-based feed treatments may mask the presence of Salmonella. SIGNIFICANCE AND IMPACT OF THE STUDY: Feeds may be deemed safe despite being contaminated with Salmonella. The use of antagonists during culture may help assess the level of Salmonella contamination when organic acid or formaldehyde treatments have been applied to feed ingredients.

Snow LC, Davies RH, Christiansen KH, Carrique-Mas JJ, Wales AD, O'Connor JL, Cook AJC, Evans SJ. 2007. Survey of the prevalence of Salmonella species on commercial laying farms in the United Kingdom. Vet Rec, 161 (14), pp. 471-476. | Citations: 48 (Scopus) | Show Abstract | Read more

A survey of salmonella infection on 454 commercial layer flock holdings in the uk was carried out between October 2004 and September 2005. Fifty-four (11.7 per cent, 95 per cent confidence interval 9.3 to 14.0 per cent) were salmonella positive. The most common serovar identified was Salmonella Enteritidis at a prevalence of 5.8 per cent, and 70 per cent of these isolates were phage types 4, 6, 7 and 35. Salmonella Typhimurium was the second most prevalent serovar, found in 1.8 per cent of the farms. Of the three other serovars given top priority by the eu because of their public health significance, Salmonella Virchow and Salmonella Infantis were each isolated from one holding, but Salmonella Hadar was not isolated from any of the holdings. Analysis of antimicrobial resistance patterns revealed that over 76 per cent of the isolates were sensitive to all of the 16 drugs tested, and all the isolates were sensitive to ciprofloxacin, gentamicin, ceftazidime, apramycin, amikacin, amoxicillin/clavulanic acid, neomycin and cefotaxime.

Tang CT, Nguyen DT, Ngo TH, Nguyen TM, Le VT, To SD, Lindsay J, Nguyen TD, Bach VC, Le QT et al. 2007. An outbreak of severe infections with community-acquired MRSA carrying the Panton-Valentine leukocidin following vaccination. PloS one, 2 (9), | Citations: 16 (Scopus) | Show Abstract

BACKGROUND: Infections with community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) are emerging worldwide. We investigated an outbreak of severe CA-MRSA infections in children following out-patient vaccination. METHODS AND FINDINGS: We carried out a field investigation after adverse events following immunization (AEFI) were reported. We reviewed the clinical data from all cases. S. aureus recovered from skin infections and from nasal and throat swabs were analyzed by pulse-field gel electrophoresis, multi locus sequence typing, PCR and microarray. In May 2006, nine children presented with AEFI, ranging from fatal toxic shock syndrome, necrotizing soft tissue infection, purulent abscesses, to fever with rash. All had received a vaccination injection in different health centres in one District of Ho Chi Minh City. Eight children had been vaccinated by the same health care worker (HCW). Deficiencies in vaccine quality, storage practices, or preparation and delivery were not found. Infection control practices were insufficient. CA-MRSA was cultured in four children and from nasal and throat swabs from the HCW. Strains from children and HCW were indistinguishable. All carried the Panton-Valentine leukocidine (PVL), the staphylococcal enterotoxin B gene, the gene complex for staphylococcal-cassette-chromosome mec type V, and were sequence type 59. Strain HCM3A is epidemiologically unrelated to a strain of ST59 prevalent in the USA, although they belong to the same lineage. CONCLUSIONS: We describe an outbreak of infections with CA-MRSA in children, transmitted by an asymptomatic colonized HCW during immunization injection. Consistent adherence to injection practice guidelines is needed to prevent CA-MRSA transmission in both in- and outpatient settings.

Plowe CV, Roper C, Barnwell JW, Happi CT, Joshi HH, Mbacham W, Meshnick SR, Mugittu K, Naidoo I, Price RN et al. 2007. World Antimalarial Resistance Network (WARN) III: molecular markers for drug resistant malaria. Malar J, 6 (1), pp. 121. | Citations: 79 (Scopus) | Show Abstract | Read more

Molecular markers for drug resistant malaria represent public health tools of great but mostly unrealized potential value. A key reason for the failure of molecular resistance markers to live up to their potential is that data on the their prevalence is scattered in disparate databases with no linkage to the clinical, in vitro and pharmacokinetic data that are needed to relate the genetic data to relevant phenotypes. The ongoing replacement of older monotherapies for malaria by new, more effective combination therapies presents an opportunity to create an open access database that brings together standardized data on molecular markers of drug resistant malaria from around the world. This paper presents a rationale for creating a global database of molecular markers for drug resistant malaria and for linking it to similar databases containing results from clinical trials of drug efficacy, in vitro studies of drug susceptibility, and pharmacokinetic studies of antimalarial drugs, in a World Antimalarial Resistance Network (WARN). This database will be a global resource, guiding the selection of first line drugs for treating uncomplicated malaria, for preventing malaria in travelers and for intermittent preventive treatment of malaria in pregnant women, infants and other vulnerable groups. Perhaps most important, a global database for molecular markers of drug resistant malaria will accelerate the identification and validation of markers for resistance to artemisinin-based combination therapies and, thereby, potentially prolong the useful therapeutic lives of these important new drugs.

Anstey NM, Pain MCF, Price RN, Maguire GP. 2007. Reply to Eisenhut The Journal of Infectious Diseases, 196 (4), pp. 647-648. | Read more

McBryde ES, Pettitt AN, Cooper BS, McElwain DLS. 2007. Characterizing an outbreak of vancomycin-resistant enterococci using hidden Markov models. J R Soc Interface, 4 (15), pp. 745-754. | Citations: 24 (Scopus) | Show Abstract | Read more

BACKGROUND: Antibiotic-resistant nosocomial pathogens can arise in epidemic clusters or sporadically. Genotyping is commonly used to distinguish epidemic from sporadic vancomycin-resistant enterococci (VRE). We compare this to a statistical method to determine the transmission characteristics of VRE. METHODS AND FINDINGS: A structured continuous-time hidden Markov model (HMM) was developed. The hidden states were the number of VRE-colonized patients (both detected and undetected). The input for this study was weekly point-prevalence data; 157 weeks of VRE prevalence. We estimated two parameters: one to quantify the cross-transmission of VRE and the other to quantify the level of VRE colonization from sporadic sources. We compared the results to those obtained by concomitant genotyping and phenotyping. We estimated that 89% of transmissions were due to ward cross-transmission while 11% were sporadic. Genotyping found that 90% had identical glycopeptide resistance genes and 84% were identical or nearly identical on pulsed-field gel electrophoresis (PFGE). There was some evidence, based on model selection criteria, that the cross-transmission parameter changed throughout the study period. The model that allowed for a change in transmission just prior to the outbreak and again at the peak of the outbreak was superior to other models. This model estimated that cross-transmission increased at week 120 and declined after week 135, coinciding with environmental decontamination. SIGNIFICANCE: We found that HMMs can be applied to serial prevalence data to estimate the characteristics of acquisition of nosocomial pathogens and distinguish between epidemic and sporadic acquisition. This model was able to estimate transmission parameters despite imperfect detection of the organism. The results of this model were validated against PFGE and glycopeptide resistance genotype data and produced very similar results. Additionally, HMMs can provide information about unobserved events such as undetected colonization.

Stone S, Slade R, Fuller C, McAteer J, Cookson B, Teare L, Jeanes A, Cooper B, Roberts J, Duckworth G et al. 2007. Cleanyourhands Campaign: a critique of the critique. J Hosp Infect, 66 (3), pp. 288-289. | Citations: 5 (Scopus) | Read more

McAteer J, Stone S, Roberts J, Michie S, FIT study team, Fuller C, Slade R, Charlett A, Cookson B, Cooper B et al. 2007. Use of performance feedback to increase healthcare worker hand-hygiene behaviour. J Hosp Infect, 66 (3), pp. 291-292. | Citations: 6 (Scopus) | Read more

Stone S, Slade R, Fuller C, Charlett A, Cookson B, Teare L, Jeanes A, Cooper B, Roberts J, Duckworth G et al. 2007. Early communication: does a national campaign to improve hand hygiene in the NHS work? Initial English and Welsh experience from the NOSEC study (National Observational Study to Evaluate the CleanYourHandsCampaign). J Hosp Infect, 66 (3), pp. 293-296. | Citations: 20 (Scopus) | Read more

Cooper BS, Cookson BD, Davey PG, Stone SP. 2007. Introducing the ORION Statement, a CONSORT equivalent for infection control studies. J Hosp Infect, 65 Suppl 2 (SUPPL. 2), pp. 85-87. | Citations: 15 (Scopus) | Read more

Cooper BS. 2007. Confronting models with data. J Hosp Infect, 65 Suppl 2 pp. 88-92. | Show Abstract | Read more

Until now, most of the mathematical modelling work on nosocomial infections has used simple models that have permitted qualitative, but not reliable quantitative predictions about the likely effect of different interventions. Increasingly, researchers would like to use models to provide reliable quantitative answers to both scientific and policy questions. This requires confronting models with data. Here, we discuss the importance of this confrontation with data with reference to previous modelling work, and outline the standard methods for doing this. We then describe a powerful new set of tools that promises to allow us to provide better answers to such questions, making far greater use than current methods of the information content of highly detailed hospital infection datasets. These tools should allow us to address questions that would have been impossible to answer using previous analytical techniques.

Fowler S, Webber A, Cooper BS, Phimister A, Price K, Carter Y, Kibbler CC, Simpson AJH, Stone SP. 2007. Successful use of feedback to improve antibiotic prescribing and reduce Clostridium difficile infection: a controlled interrupted time series. J Antimicrob Chemother, 59 (5), pp. 990-995. | Citations: 111 (Scopus) | Show Abstract | Read more

OBJECTIVES: To investigate the effect of reinforcing a narrow-spectrum antibiotic policy on antibiotic prescription and Clostridium difficile infection (CDI) rates by feedback of antibiotic use to doctors, as part of a departmental audit and feedback programme. DESIGN: A prospective controlled interrupted time-series (ITS) study, with pre-defined pre- and post-intervention periods, each of 21 months. SETTING: Three acute medical wards for elderly people in a teaching hospital. PARTICIPANTS: Six thousand one hundred and twenty-nine consecutive unselected acute medical admissions aged >or=80 years. INTERVENTIONS: A 'narrow-spectrum' antibiotic policy (reinforced by an established programme of audit and feedback of antibiotic usage and CDI rates) was introduced, following an unplanned rise in amoxicillin/clavulanate (Augmentin) use. It targeted broad-spectrum antibiotics for reduction (cephalosporins and amoxicillin/clavulanate) and narrow-spectrum antibiotics for increase (benzyl penicillin, amoxicillin and trimethoprim). Changes in the use of targeted antibiotics (intervention group) were compared with those of untargeted antibiotics (control group) using segmented regression analysis. Changes in CDI rates were examined by the Poisson regression model. Methicillin-resistant Staphylococcus aureus (MRSA) acquisition rates acted as an additional control. RESULTS: There was a reduction in the use of all targeted broad-spectrum antibiotics and an increase in all targeted narrow-spectrum antibiotics, statistically significant for sudden change and/or linear trend. All other antibiotic use remained unchanged. CDI rates fell with incidence rate ratios of 0.35 (0.17, 0.73) (P=0.009). MRSA incidence did not change [0.79 (0.49, 1.28); P=0.32]. CONCLUSIONS: This is the first controlled prospective ITS study to use feedback to reinforce antibiotic policy and reduce CDI. Multicentre ITS or cluster randomized trials of this and other methods need to be undertaken to establish the most effective means of optimizing antibiotic use and reducing CDI.

Miotto O, Heiny AT, Tan TW, August JT, Brusic V. 2007. Identification of human-to-human transmissibility factors in PB2 proteins of influenza A by large-scale mutual information analysis Asia Pacific Bioinformatics Network (APBioNet) 6th International Conference on Bioinformatics, InCoB 2007 - Proceedings, 9 (SUPPL. 1), | Citations: 3 (Scopus) | Show Abstract | Read more

Background: The identification of mutations that confer unique properties to a pathogen, such as host range, is of fundamental importance in the fight against disease. This paper describes a novel method for identifying amino acid sites that distinguish specific sets of protein sequences, by comparative analysis of matched alignments. The use of mutual information to identify distinctive residues responsible for functional variants makes this approach highly suitable for analyzing large sets of sequences. To support mutual information analysis, we developed the AVANA software, which utilizes sequence annotations to select sets for comparison, according to user-specified criteria. The method presented was applied to an analysis of influenza A PB2 protein sequences, with the objective of identifying the components of adaptation to human-to-human transmission, and reconstructing the mutation history of these components. Results: We compared over 3,000 PB2 protein sequences of human-transmissible and avian isolates, to produce a catalogue of sites involved in adaptation to human-to-human transmission. This analysis identified 17 characteristic sites, five of which have been present in human-transmissible strains since the 1918 Spanish flu pandemic. Sixteen of these sites are located in functional domains, suggesting they may play functional roles in host-range specificity. The catalogue of characteristic sites was used to derive sequence signatures from historical isolates. These signatures, arranged in chronological order, reveal an evolutionary timeline for the adaptation of the PB2 protein to human hosts. Conclusion: By providing the most complete elucidation to date of the functional components participating in PB2 protein adaptation to humans, this study demonstrates that mutual information is a powerful too l for comparative characterization of sequence sets. In addition to confirming previously reported findings, several novel characteristic sites within PB2 are reported. Sequence signatures generated using the characteristic sites catalogue characterize concisely the adaptation characteristics of individual isolates. Evolutionary timelines derived from signatures of early human influenza isolates suggest that characteristic variants emerged rapidly, and remained remarkably stable through subsequent pandemics. In addition, the signatures of human-infecting H5N1 isolates suggest that this avian subtype has low pandemic potential at present, although it presents more human adaptation components than most avian subtypes. © 2006 Brahmachary et al; licensee BioMed Central Ltd.

Miotto O, Tan TW, Brusic V. 2007. Rule-based knowledge aggregation for large-scale protein sequence analysis of influenza A viruses Asia Pacific Bioinformatics Network (APBioNet) 6th International Conference on Bioinformatics, InCoB 2007 - Proceedings, 9 (SUPPL. 1), | Citations: 1 (Scopus) | Show Abstract | Read more

Background: The explosive growth of biological data provides opportunities for new statistical and comparative analyses of large information sets, such as alignments comprising tens of thousands of sequences. In such studies, sequence annotations frequently play an essential role, and reliable results depend on metadata quality. However, the semantic heterogeneity and annotation inconsistencies in biological databases greatly increase the complexity of aggregating and cleaning metadata. Manual curation of datasets, traditionally favoured by life scientists, is impractical for studies involving thousands of records. In this study, we investigate quality issues that affect major public databases, and quantify the effectiveness of an automated metadata extraction approach that combines structural and semantic rules. We applied this approach to more than 90,000 influenza A records, to annotate sequences with protein name, virus subtype, isolate, host, geographic origin, and year of isolation. Results: Over 40,000 annotated Influenza A protein sequences were collected by combining information from more than 90,000 documents from NCBI public databases. Metadata values were automatically extracted, aggregated and reconciled from several document fields by applying user-defined structural rules. For each property, values were recovered from ≥88.8% of records, with accuracy exceeding 96% in most cases. Because of semantic heterogeneity, each property required up to six different structural rules to be combined. Significant quality differences between databases were found: GenBank documents yield values more reliably than documents extracted from GenPept. Using a simple set of semantic rules and a reasoner, we reconstructed relationships between sequences from the same isolate, thus identifying 7640 isolates. Validation of isolate metadata against a simple ontology highlighted more than 400 inconsistencies, leading to over 3,000 property value corrections. Conclusion: To overcome the quality issues inherent in public databases, automated knowledge aggregation with embedded intelligence is needed for large-scale analyses. Our results show that user-controlled intuitive approaches, based on combination of simple rules, can reliably automate various curation tasks, reducing the need for manual corrections to approximately 5% of the records. Emerging semantic technologies possess desirable features to support today's knowledge aggregation tasks, with a potential to bring immediate benefits to this field. © 2006 Brahmachary et al; licensee BioMed Central Ltd.

LIN HUI, ZHANG LINGMIN, LUNA CORALIA, HOA NGOT, ZHENG LIANGBIAO. 2007. A splice variant of PGRP-LC required for expression of antimicrobial peptides in Anopheles gambiae Insect Science, 14 (3), pp. 185-192. | Citations: 6 (Scopus) | Show Abstract | Read more

Members of the peptidoglycan recognition protein (PGRP) family play essential roles in different manifestations of immune responses in insects. PGRP-LC, one of seven members of this family in the malaria vector Anopheles gambiae produced several spliced variants. Here we show that PGRP-LC, and not other members of the PGRP family nor the six members of the Gram-negative binding protein families, is required for the expression of antimicrobial peptide genes (such as CEC1 and GAMI) under the control of the Imd-Rel2 pathway in an A. gambiae cell line, 4a3A. PGRP-LC produces many splice variants that can be classified into three sub-groups (LC1, LC2 and LC3), based on the carboxyl terminal sequences. RNA interference against one LC1 sub-group resulted in dramatic reduction of CEC1 and GAM1. Over-expression of LC1a and to a lesser extent LC3a (a member of the LC1 and LC3 sub-group, respectively) in the 4a3A cell line enhances the expression of CEC1 and GAM1. These results demonstrate that the LC1-subgroup splice variants are essential for the expression of CEC1 and GAM1 in A. gambiae cell line. © Institute of Zoology, Chinese Academy of Sciences.

Breman JG, Alilio MS, White NJ. 2007. Defining and defeating the intolerable burden of Malaria III. Progress and perspectives American Journal of Tropical Medicine and Hygiene, 77 (SUPPL. 6), | Citations: 10 (Scopus)

Breman JG, Alilio MS, White NJ. 2007. Defining and defeating the intolerable burden of malaria III. Progress and perspectives American Journal of Tropical Medicine and Hygiene, 77 (SUPPL. 6), | Citations: 13 (Scopus)

SonLa Study Group. 2007. Using a fingerprint recognition system in a vaccine trial to avoid misclassification. Bull World Health Organ, 85 (1), pp. 64-67. | Citations: 7 (Scopus) | Show Abstract | Read more

PROBLEM: The potential for misidentification of trial participants, leading to misclassification, is a threat to the integrity of randomized controlled trials. The correct identification of study subjects in large trials over prolonged periods is of vital importance to those conducting clinical trials. Currently used means of identifying study participants, such as identity cards and records of name, address, name of household head and demographic characteristics, require large numbers of well-trained personnel, and still leave room for uncertainty. APPROACH: We used fingerprint recognition technology for the identification of trial participants. This technology is already widely used in security and commercial contexts but not so far in clinical trials. LOCAL SETTING: A phase 2 cholera vaccine trial in SonLa, Viet Nam. RELEVANT CHANGES: An optical sensor was used to scan fingerprints. The fingerprint template of each participant was used to verify his or her identity during each of eight follow-up visits. LESSONS LEARNED: A system consisting of a laptop computer and sensor is small in size, requires minimal training and on average six seconds for scanning and recognition. All participants' identities were verified in the trial. Fingerprint recognition should become the standard technology for identification of participants in field trials. Fears exist, however, regarding the potential for invasion of privacy. It will therefore be necessary to convince not only trial participants but also investigators that templates of fingerprints stored in databases are less likely to be subject to abuse than currently used information databases.

Agtini MD, Soeharno R, Lesmana M, Punjabi NH, Simanjuntak C, Wangsasaputra F, Nurdin D, Pulungsih SP, Rofiq A, Santoso H et al. 2007. Erratum To: The burden of diarrhoea, shigellosis, and cholera in North Jakarta, Indonesia: findings from 24 months surveillance BMC Infectious Diseases, 7 (1), | Citations: 1 (Scopus) | Read more

Sur D, Ali M, von Seidlein L, Manna B, Deen JL, Acosta CJ, Clemens JD, Bhattacharya SK. 2007. Comparisons of predictors for typhoid and paratyphoid fever in Kolkata, India. BMC Public Health, 7 (1), pp. 289. | Citations: 34 (Scopus) | Show Abstract | Read more

BACKGROUND: Exposure of the individual to contaminated food or water correlates closely with the risk for enteric fever. Since public health interventions such as water improvement or vaccination campaigns are implemented for groups of individuals we were interested whether risk factors not only for the individual but for households, neighbourhoods and larger areas can be recognised? METHODS: We conducted a large enteric fever surveillance study and analyzed factors which correlate with enteric fever on an individual level and factors associated with high and low risk areas with enteric fever incidence. Individual level data were linked to a population based geographic information systems. Individual and household level variables were fitted in Generalized Estimating Equations (GEE) with the logit link function to take into account the likelihood that household factors correlated within household members. RESULTS: Over a 12-month period 80 typhoid fever cases and 47 paratyphoid fever cases were detected among 56,946 residents in two bustees (slums) of Kolkata, India. The incidence of paratyphoid fever was lower (0.8/1000/year), and the mean age of paratyphoid patients was older (17.1 years) than for typhoid fever (incidence 1.4/1000/year, mean age 14.7 years). Residents in areas with a high risk for typhoid fever had lower literacy rates and economic status, bigger household size, and resided closer to waterbodies and study treatment centers than residents in low risk areas. CONCLUSION: There was a close correlation between the characteristics detected based on individual cases and characteristics associated with high incidence areas. Because the comparison of risk factors of populations living in high versus low risk areas is statistically very powerful this methodology holds promise to detect risk factors associated with diseases using geographic information systems.

Graham SP, Honda Y, Pellé R, Mwangi DM, Glew EJ, de Villiers EP, Shah T, Bishop R, van der Bruggen P, Nene V, Taracha ELN. 2007. A novel strategy for the identification of antigens that are recognised by bovine MHC class I restricted cytotoxic T cells in a protozoan infection using reverse vaccinology. Immunome Res, 3 (1), pp. 2. | Citations: 26 (Scopus) | Show Abstract | Read more

BACKGROUND: Immunity against the bovine protozoan parasite Theileria parva has previously been shown to be mediated through lysis of parasite-infected cells by MHC class I restricted CD8+ cytotoxic T lymphocytes. It is hypothesized that identification of CTL target schizont antigens will aid the development of a sub-unit vaccine. We exploited the availability of the complete genome sequence data and bioinformatics tools to identify genes encoding secreted or membrane anchored proteins that may be processed and presented by the MHC class I molecules of infected cells to CTL. RESULTS: Of the 986 predicted open reading frames (ORFs) encoded by chromosome 1 of the T. parva genome, 55 were selected based on the presence of a signal peptide and/or a transmembrane helix domain. Thirty six selected ORFs were successfully cloned into a eukaryotic expression vector, transiently transfected into immortalized bovine skin fibroblasts and screened in vitro using T. parva-specific CTL. Recognition of gene products by CTL was assessed using an IFN-gamma ELISpot assay. A 525 base pair ORF encoding a 174 amino acid protein, designated Tp2, was identified by T. parva-specific CTL from 4 animals. These CTL recognized and lysed Tp2 transfected skin fibroblasts and recognized 4 distinct epitopes. Significantly, Tp2 specific CD8+ T cell responses were observed during the protective immune response against sporozoite challenge. CONCLUSION: The identification of an antigen containing multiple CTL epitopes and its apparent immunodominance during a protective anti-parasite response makes Tp2 an attractive candidate for evaluation of its vaccine potential.

Woodrow CJ, Eziefula AC, Agranoff D, Scott GM, Watson J, Chiodini PL, Lockwood DNJ, Grant AD. 2007. Early risk assessment for viral haemorrhagic fever: Experience at the Hospital for tropical diseases, London, UK Journal of Infection, 54 (1), pp. 6-11. | Read more

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