title: Estimating the Burden of Leptospirosis among Febrile Subjects Aged below 20 Years in Kampong Cham Communities, Cambodia, 2007-2009.
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.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Institut Pasteur in Cambodia, Phnom Penh, Cambodia.
authors.forename: Sopheak
authors.initials: S
authors.lastname: Hem
authors.affiliation: Institut Pasteur in Cambodia, Phnom Penh, Cambodia.
authors.forename: Sowath
authors.initials: S
authors.lastname: Ly
authors.affiliation: Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, Paris, France.
authors.forename: Irene
authors.initials: I
authors.lastname: Votsi
authors.affiliation: Masters of Science in Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Florian
authors.initials: F
authors.lastname: Vogt
authors.affiliation: World Health Organization, Phnom Penh, Cambodia.
authors.forename: Nima
authors.initials: N
authors.lastname: Asgari
authors.affiliation: Institut Pasteur in Cambodia, Phnom Penh, Cambodia.
authors.forename: Philippe
authors.initials: P
authors.lastname: Buchy
authors.affiliation: Institut Pasteur in Cambodia, Phnom Penh, Cambodia.
authors.forename: Seiha
authors.initials: S
authors.lastname: Heng
authors.affiliation: Institut Pasteur, National Reference Center and WHO Collaborating Center for Leptospirosis, Paris, France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Picardeau
authors.affiliation: Communicable Diseases Control Department of the Ministry of Health, Phnom Penh, Cambodia.
authors.forename: Touch
authors.initials: T
authors.lastname: Sok
authors.affiliation: Communicable Diseases Control Department of the Ministry of Health, Phnom Penh, Cambodia.
authors.forename: Sovann
authors.initials: S
authors.lastname: Ly
authors.affiliation: National Dengue Control Program, National Center for Entomology, Parasitology, and Malaria Control, Phnom Penh, Cambodia.
authors.forename: Rekol
authors.initials: R
authors.lastname: Huy
authors.affiliation: Institut Pasteur in Cambodia, Phnom Penh, Cambodia.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Guillard
authors.affiliation: Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, Paris, France.
authors.forename: Simon
authors.initials: S
authors.lastname: Cauchemez
authors.affiliation: Institut Pasteur in Cambodia, Phnom Penh, Cambodia.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Tarantola
mesh_terms: D000293:Adolescent; D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood; D002160:Cambodia / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003715:Dengue / Q000097:blood / Q000453:epidemiology; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000097:blood; D007223:Infant; D007231:Infant, Newborn; D007922:Leptospirosis / Q000097:blood / Q000453:epidemiology*; D008297:Male; D012424:Rural Population; D012939:Social Planning
chemical_list: D000907:Antibodies, Bacterial; D007075:Immunoglobulin M