Retrospective surveillance study maps leptospirosis trends across Sri Lanka’s 25 districts, 2006–2022

A retrospective descriptive analysis of national surveillance data found substantial geographic and temporal variation in reported leptospirosis across Sri Lanka’s 25 districts from 2006 through 2022. The study, summarized in an early, subject-to-revision version of a peer-reviewed article, recorded 82,086 cases reported to the Epidemiology Unit during the 17-year period.

Researchers extracted leptospirosis surveillance data from the Weekly Epidemiological Reports of the Epidemiology Unit and used Department of Census and Statistics population estimates to calculate district-level incidence rates per 100,000 population. They examined temporal trends and spatial distribution with R version 4.3.1. The available abstract does not report confidence intervals, measures of variability, or other uncertainty estimates, and it does not describe checks for changes in reporting or diagnostic practices. It therefore supports a descriptive assessment of reported cases and calculated rates rather than a causal explanation for the observed patterns.

The national totals included two major surges: 7,295 reported cases in 2008 and a peak of 8,323 in 2020. Ratnapura, Kalutara and Galle frequently exceeded 800–1,200 reported cases annually during peak transmission years, while the southwestern region remained the main area of reported transmission. District-level incidence also did not simply follow population size: Kegalle and Matale frequently had higher rates per 100,000 than the more populous districts of Colombo and Gampaha. The pattern shifted during the 2011 outbreak, when Kurunegala recorded the highest case count among all districts.

Eight consistently lower-burden districts were Jaffna, Kilinochchi, Mannar, Mullaitivu, Vavuniya, Batticaloa, Ampara and Trincomalee, each reporting comparatively low case numbers and incidence rates throughout the study period. The abstract concludes that leptospirosis remained a persistent public-health challenge characterized by spatial heterogeneity and periodic national surges. It identifies district-level surveillance and population-adjusted analysis as important for locating high-burden areas and says that stronger surveillance, expanded diagnostic capacity and occupational and environmental risk-reduction strategies in high-burden districts are needed to improve control. Because only the abstract and early article version were supplied, the full methods, results and limitations of the study could not be independently assessed.

Subject of Research: District-level leptospirosis surveillance trends in Sri Lanka from 2006 to 2022

Article Title: District–level epidemiological trends of leptospirosis in Sri Lanka, 2006–2022

Article References: Kumari, P., & Dabrera, T. (2026). District–level epidemiological trends of leptospirosis in Sri Lanka, 2006–2022. BMC Infectious Diseases. https://doi.org/10.1186/s12879-026-14495-w

Image Credits: AI Generated

DOI: 10.1186/s12879-026-14495-w

Keywords: leptospirosis, Sri Lanka, epidemiological surveillance, district-level analysis, incidence rates, spatial variation, temporal trends, public health, District, level, epidemiological, trends