New review maps human and canine leptospirosis patterns in China

A newly published systematic review and meta-analysis in Preventive Veterinary Medicine examines the epidemiology of human and canine leptospirosis in China, synthesizing studies identified through six databases through November 11, 2025. The authors position the paper as a One Health overview, aimed at estimating prevalence patterns and identifying associated factors across both species in a country where leptospirosis remains a recognized, if unevenly distributed, zoonotic threat. (sciencedirect.com)

That framing matters because leptospirosis in China has changed rather than vanished. National trend data published in 2025 showed human incidence declining from 0.047 per 100,000 people in 2010 to 0.009 in 2018, before edging back up to 0.019 in 2023. Reported human cases fell from 679 in 2010 to 156 in 2018, then rose modestly to 304 in 2023. At the provincial level, recent work from Anhui described persistent hotspots and sporadic outbreaks, particularly after heavy rainfall and flooding, underscoring that local transmission risk still tracks with geography and environment. (idpjournal.biomedcentral.com)

The new review appears to address a gap that has been difficult for clinicians and policymakers alike: most leptospirosis discussions in China have focused on human surveillance or wildlife reservoirs, while canine data have been scattered across regions, study designs, and diagnostic methods. The article’s abstract emphasizes shared environmental exposure between humans and dogs, and its stated goal is to support surveillance and prevention planning. That aligns with a growing body of recent literature suggesting dogs can serve as useful sentinels for human risk, particularly in urbanizing regions where companion animals, wildlife, flooding, and human exposure overlap. (sciencedirect.com)

Additional recent evidence helps explain why that matters in practice. A 2025 study of 1,517 canine serum samples collected from 2021 to 2023 across the Yangtze River region reported an overall seroprevalence of 46.41%, with Canicola and Icterohaemorrhagiae among the predominant serogroups detected. The investigators also isolated a strain classified as L. interrogans serovar Australis, sequence type ST93, from a dog that died with severe pulmonary hemorrhage. The authors said those findings support the idea that dogs in the region may reflect broader environmental circulation of pathogenic Leptospira. (pmc.ncbi.nlm.nih.gov)

Expert and industry guidance outside China points in the same direction on clinical risk. CDC states that infected animals can continue shedding the organism in urine for up to three months if not fully treated, creating ongoing exposure risk for people and other animals. The 2023 ACVIM consensus statement recommends standard hygiene precautions in veterinary settings because even apparently healthy dogs can shed pathogenic leptospires, and it stresses counseling clients about zoonotic risk. WSAVA’s 2024 vaccination guidance and U.S. outbreak reporting have also reflected a broader shift toward taking canine leptospirosis seriously as both an individual-patient and public health issue. (cdc.gov)

Why it matters: For veterinarians, the biggest takeaway isn’t just that leptospirosis persists in China. It’s that canine surveillance may offer practical early warning value in places where human disease is now relatively uncommon at the national level but still clusters locally. That has implications for diagnostic suspicion, biosafety, vaccination conversations, and case reporting. It also reinforces the need to think beyond classic textbook risk profiles. As with other countries, exposure can be shaped by rainfall, rodent ecology, free-roaming dog populations, and rapid urban change, meaning clinics may need to reassess who counts as “at risk.” (idpjournal.biomedcentral.com)

There are still limits to what can be concluded from the available evidence. The review synthesizes heterogeneous studies, and leptospirosis prevalence estimates are often highly sensitive to region, season, test method, and sampled population. Even the Anhui investigators noted that host density and animal carriage data were not fully captured in their provincial analysis. So the strongest inference is not that China is facing a uniform canine leptospirosis problem, but that risk appears patchy, environmentally driven, and well-suited to integrated surveillance. (sciencedirect.com)

What to watch: The next step to watch is whether Chinese researchers or public health authorities build on this review with standardized, prospective dog-and-human surveillance, especially in historically affected central and southern provinces and in flood-prone regions. If that happens, it could sharpen regional prevention strategies and eventually influence vaccine use, diagnostic protocols, and One Health reporting frameworks. (sciencedirect.com)