Estimating the Burden of Leptospirosis among Febrile Subjects Aged below 20 Years in Kampong Cham Communities, Cambodia, 2007-2009

PLoS One. 2016 Apr 4;11(4):e0151555. doi: 10.1371/journal.pone.0151555. eCollection 2016.

Abstract

Background: Leptospirosis is an emerging but neglected public health challenge in the Asia/Pacific Region with an annual incidence estimated at 10-100 per 100,000 population. No accurate data, however, are available for at-risk rural Cambodian communities.

Method: We conducted anonymous, unlinked testing for IgM antibodies to Leptospira spp. on paired sera of Cambodian patients <20 years of age between 2007-2009 collected through active, community-based surveillance for febrile illnesses in a convenience sample of 27 rural and semi-rural villages in four districts of Kampong Cham province, Cambodia. Leptospirosis testing was done on paired serological samples negative for Dengue, Japanese encephalitis and Chikungunya viruses after random selection. Convalescent samples found positive while initial samples were negative were considered as proof of acute infection. We then applied a mathematical model to estimate the risk of fever caused by leptospirosis, dengue or other causes in rural Cambodia.

Results: A total of 630 samples are coming from a randomly selected subset of 2358 samples. IgM positive were found on the convalescent serum sample, among which 100 (15.8%) samples were IgM negative on an earlier sample. Seventeen of these 100 seroconversions were confirmed using a Microagglutination Test. We estimated the probability of having a fever due to leptospirosis at 1. 03% (95% Credible Interval CI: 0. 95%-1. 22%) per semester. In comparison, this probability was 2. 61% (95% CI: 2. 55%, 2. 83%) for dengue and 17. 65% (95% CI: 17. 49%, 18. 08%) for other causes.

Conclusion: Our data from febrile cases aged below 20 years suggest that the burden of leptospirosis is high in rural Cambodian communities. This is especially true during the rainy season, even in the absence of identified epidemics.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Antibodies, Bacterial / blood
  • Cambodia / epidemiology
  • Child
  • Child, Preschool
  • Dengue / blood
  • Dengue / epidemiology
  • Female
  • Humans
  • Immunoglobulin M / blood
  • Infant
  • Infant, Newborn
  • Leptospirosis / blood
  • Leptospirosis / epidemiology*
  • Male
  • Rural Population*
  • Social Planning

Substances

  • Antibodies, Bacterial
  • Immunoglobulin M

Grant support

This study was supported by the World Health Organization and the European Union and Pediatric Vaccine Dengue Initiative project (PDVI) from the International Vaccine Institute (IVI). Aside from coauthor NA who helped discuss the study results and edit the article, the funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.