Leptospirosis outbreak in an urban setting: epidemiological and clinical characteristics of the 2025 epidemic in Sarajevo Canton, Bosnia and Herzegovina.

BACKGROUND: Leptospirosis is an emerging public-health concern in urban settings, but data from temperate European cities remain limited. This study describes the 2025 leptospirosis outbreak in Sarajevo Canton, Bosnia and Herzegovina. METHODS: A descriptive observational study was conducted using mandatory surveillance data and a supplementary epidemiological questionnaire based on the WHO Leptospirosis Surveillance Tool. Cases were classified according to the ECDC case definition. Epidemiological, clinical, laboratory, and exposure characteristics were analysed. RESULTS: A total of 119 cases were recorded; 63.9% were male and the mean age was 45.8±13.2 years. The overall incidence was 2.84 per 10,000 population, highest in Novi Grad municipality. Common symptoms included weakness, fever, chills, myalgia, and headache. Elevated liver enzymes were the only independent predictor of hospitalisation. CONCLUSION: The outbreak indicates a shift toward urban leptospirosis, likely linked to environmental contamination and rodent activity rather than traditional rural or flood-related exposure.