Evolution of human leptospirosis in French Guiana, 2016-2022.

BACKGROUND: Leptospirosis is a re-emerging zoonotic disease. In French Guiana (FG), updating its epidemiology is essential to guide prevention strategies. This study aimed to describe human leptospirosis cases from 2016 to 2022 and compare them to the cases from 2007 to 2014 (using similar diagnostic criteria). METHODOLOGY/PRINCIPAL FINDINGS: A multicentric cross-sectional study was conducted in the three hospitals of FG and the remote health centers. Cases were identified via biological diagnostics, defined by a compatible clinical picture and a positive biological test and classified according to the test as confirmed (positive PCR or Microscopic agglutination test [MAT] ≥400) or probable (MAT = 200 or positive IgM only without alternate diagnosis). Severe cases involved renal, circulatory, or respiratory failure, or death. A total of 188 cases were included, of which 138 (73.4%) were confirmed. Median (IQR) age was 38 (28-52) years, with a male-to-female ratio of 3.1. Twenty-six (13.8%) cases were severe, including 4 deaths (2.1%). Most patients had multiple exposure factors with rodent exposure being the most common; 67.5% (available data) had both domestic and non-domestic exposures. Notably, over a third of patients were in a situation of precarity, uninsured or lived in informal settlements. The mean (SD) annual number of cases increased from 5.8 (2.7) per 100,000 of the adult population in the 2007-2014 period to 14.0 (9.2) in the recent study period (p = 0.03). Early clinical suspicion improved, while the proportion of severe cases remained stable. DISCUSSION/CONCLUSION: Leptospirosis is an increasing public health issue in FG which particularly affects socioeconomically vulnerable populations. Routes of transmission appear multiple.