A geospatial study in New South Wales that analyzed nearly 300 human cases and 79 canine cases of leptospirosis found limited evidence of dog-to-human transmission and identified distinct transmission pathways for each species, researchers from the University of Sydney reported. The research was recently published in Science in One Health.

The study matters because it challenges the assumption that pets are a primary bridge for this bacterial disease between animals and people. By mapping human and canine cases across the state, the researchers sought to clarify whether infections clustered together in space — evidence that shared transmission routes might be driving both sets of cases.

Researchers from the University of Sydney led the analysis, using geospatial methods to compare the distribution of human and canine leptospirosis cases across New South Wales. Their findings point to distinct geographic patterns for the two groups rather than a single, overlapping distribution that would indicate frequent interspecies transmission.

Canine cases were predominantly clustered in the Greater Sydney metropolitan area and the South Coast, according to the study. Human cases were concentrated on the North Coast, a separation the authors describe as evidence that transmission pathways differ by species.

The study places its findings in the context of recent outbreaks and environmental events in the state. It references a major human outbreak among raspberry farm workers in 2018 and notes a widespread mouse plague in 2021 as part of the backdrop for rising leptospirosis activity in New South Wales.

By separating where infections occurred in people and dogs, the research reframes the risk conversation around leptospirosis in the state. It suggests that mitigation and surveillance strategies may need to be tailored to the different sources and settings tied to human and canine infections rather than relying on a single, shared approach.

The study also aligns with broader One Health thinking that connects human, animal and environmental health, an approach discussed in literature such as The Lancet Infectious Diseases. Environmental surveillance methods for detecting Leptospira in public spaces have also been explored in work such as Water Research, which provides complementary context for interpreting spatial findings.

Although the study documents separate clusters for human and canine cases, its publication calls for integrated surveillance that can detect species-specific pathways and inform targeted public-health responses. The authors emphasize a refined One Health strategy that recognizes those distinct pathways while keeping coordinated monitoring across sectors.

The University of Sydney researchers present the study as a contribution to understanding how leptospirosis has emerged in New South Wales and how control measures might be better aligned with real-world transmission patterns. The paper was published recently in the journal Science in One Health.

Source

Original reporting: view the original article.