Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

ObjectivesThis study examined individuals with Rickettsia typhi infection in the Lao People's Democratic Republic (Lao PDR) to (a) investigate humoral immune dynamics; (b) determine the differences in reference diagnostic results and recommend appropriate cut-offs; (c) determine differences in immune response after different antibiotic treatments; and (d) determine appropriate diagnostic cut-off parameters for indirect immunofluorescence assay (IFA).MethodsSequential serum samples from 90 non-pregnant, adults were collected at seven time-points (days 0, 7, 14, 28, 90, 180 and 365) as part of a clinical antibiotic treatment trial. Samples were tested using IFA to determine IgM and IgG antibody reciprocal end-point titres against R. typhi and PCR.ResultsFor all 90 individuals, reciprocal R. typhi IgM and IgG antibody titres ranged from <400 to ≥3200. The median half-life of R. typhi IgM was 126 days (interquartile range 36-204 days) and IgG was 177 days (interquartile range 134-355 days). Overall median patient titres for R. typhi IgM and IgG were significantly different (p ConclusionsThis study suggests suitable diagnostic cut-offs for local diagnostic laboratories and other endemic settings and highlights antibody persistence following acute infection. Further studies are required to validate and define cut-offs in other geographically diverse locations.

Original publication

DOI

10.1016/j.cmi.2019.10.022

Type

Journal

Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases

Publication Date

06/2020

Volume

26

Pages

781.e9 - 781.e16

Addresses

Lao-Oxford-Mahosot Hospital-Oxford Tropical Medicine Research Unit, Microbiology Laboratory, Mahosot Hospital, Vientiane, Lao People's Democratic Republic; Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand.

Keywords

Humans, Rickettsia typhi, Typhus, Endemic Flea-Borne, Immunoglobulin G, Immunoglobulin M, Antibodies, Bacterial, Anti-Bacterial Agents, Fluorescent Antibody Technique, Indirect, Bayes Theorem, Sensitivity and Specificity, Longitudinal Studies, Adult, Laos, Immunity, Humoral