Age-specific epidemiology of human leptospirosis in New Caledonia, 2006-2016

PLoS One. 2020 Nov 30;15(11):e0242886. doi: 10.1371/journal.pone.0242886. eCollection 2020.

Abstract

With over one million cases worldwide annually and a high fatality in symptomatic forms, human leptospirosis is a growing public health concern for the most vulnerable populations, especially in the context of global warming and unplanned urbanization. Although the Asia-Pacific region is particularly affected, accurate epidemiological data are often lacking. We conducted an eleven-year retrospective laboratory-based epidemiological survey of human leptospirosis in New Caledonia. From 2006 to 2016, 904 cases were laboratory-confirmed, including 29 fatalities, corresponding to an average annual incidence of 30.6/100,000 and a case fatality rate of 3.2%. Over the period, there was a major shift from indirect serological diagnosis by MAT to direct diagnosis by real-time PCR, a more specific and sensitive test when performed early in the course of the disease. The systematic implementation of genotyping informed on the variety of the infective strains involved, with a predominance of serogroups Icterohaemorrhagiae and Pyrogenes. The epidemiological pattern showed a marked seasonality with an annual peak in March-April. Interestingly, the seasonal peak in children of school age was significantly earlier and corresponded to school holidays, suggesting that attending school from February on could protect children from environment-borne leptospirosis.

MeSH terms

  • Adolescent
  • Adult
  • Age Factors*
  • Aged
  • Aged, 80 and over
  • Asia / epidemiology
  • Child
  • Child, Preschool
  • Female
  • Humans
  • Infant
  • Leptospira / genetics
  • Leptospira / pathogenicity*
  • Leptospirosis / blood
  • Leptospirosis / epidemiology*
  • Leptospirosis / microbiology
  • Leptospirosis / pathology
  • Male
  • Middle Aged
  • New Caledonia / epidemiology
  • Real-Time Polymerase Chain Reaction
  • Retrospective Studies
  • Serogroup
  • Young Adult

Grants and funding

The author(s) received no specific funding for this work.