Ecological Niche Modeling of Pathogenic Leptospira spp. and Risk Prediction of Canine Leptospirosis Occurrence in the Russian Federation.

Leptospirosis remains a significant worldwide zoonotic threat, with domestic dogs playing a pivotal role in pathogen circulation across anthropogenic landscapes. This study aimed to assess the spatial distribution of ecological niches of pathogenic Leptospira spp. and conduct epizootic risk mapping within the Russian Federation. A two-stage modeling approach based on the maximum entropy algorithm (MaxEnt) was deployed. At the first stage, the abiotic model revealed the fundamental survival niche of the pathogen, identifying precipitation (700-1200 mm) and temperature (7-12 °C) as critical determinants. The accuracy of this model was AUC = 0.908 ± 0.007. At the second stage, the biotic model achieved a predictive accuracy of AUC = 0.980 ± 0.003, demonstrating that dog population density was the primary driver of risk, exhibiting a distinct threshold pattern (200-300 animals/km2). Furthermore, while rodent density remains the foundational ecological reservoir capable of independent transmission, the presence of additional domestic reservoirs, including livestock and dog populations, synergistically amplifies the transmission pathways, shaping the highest-risk zones within shared environments. These findings indicate distinct spatial risk boundaries within shared human-animal landscapes, suggesting that domestic dogs function as effective indicators for proactive zoonotic monitoring under the "One Health" framework.