Epidemiology and associated factors of human and canine leptospirosis in China: a systematic review and meta-analysis.

Abstract

Leptospirosis, a neglected zoonotic disease caused by pathogenic Leptospira spp., poses ongoing challenges in China due to shared environmental exposure of humans and dogs. To summarize available epidemiological evidence, we conducted a PRISMA-compliant systematic review and meta-analysis of human and canine leptospirosis in China. Six databases (PubMed, Web of Science, ScienceDirect, CNKI, Wanfang, and VIP) were searched for eligible studies published up to 11 November 2025. Cross-sectional data were synthesized using random-effects models, with subgroup analyses applied to explore heterogeneity. A total of 109 studies from 29 provinces were included, comprising 111,542 human samples and 8875 dog samples. The pooled prevalence was estimated at 25.00% in humans and 12.00% in dogs, with substantial heterogeneity across studies. In humans, higher prevalence estimates were generally observed in central regions, earlier decades, middle-aged adults, populations classified as having higher exposure, and rural areas. Serovar distributions also differed across populations, with Icterohaemorrhagiae predominating in humans. In dogs, prevalence and serovar distributions varied across studies, with Canicola being the most frequently reported serogroup, and higher prevalence estimates commonly observed in unvaccinated and free-roaming animals. Overall, this study provides a descriptive synthesis of leptospirosis in humans and dogs in China. Given the substantial heterogeneity, wide confidence intervals, and data limitations, the findings should be interpreted cautiously as reflecting broad epidemiological patterns rather than confirmatory evidence of causal risk factors. Nonetheless, the results highlight populations, regions, and serovars that may warrant prioritization in surveillance and One Health-oriented prevention efforts.