Defining Seasonal Windows of Transmission: A High-Resolution Monthly Risk Map for Leishmania infantum to Optimize Control Strategies in Southwestern Europe

Zoonotic leishmaniasis, caused by Leishmania infantum, is an emerging public health concern in Southern Europe, where climate change is altering vector phenology. Traditional static risk maps fail to capture critical seasonal transmission dynamics. This study analyzed the monthly risk maps of L. infantum infection across Spain and Portugal, including the Balearic, Canary, Madeira, and Azores archipelagos. We developed Ecological Niche Models (MaxEnt) for the primary vector, Phlebotomus perniciosus, and integrated them with a temperature-dependent parasite development model to generate high-resolution monthly risk maps. The models exhibited high predictive power. In the Iberian Peninsula, human footprint was the primary driver, revealing a marked seasonal expansion of risk towards northern latitudes and higher altitudes during summer (June–September), with potential transmission windows extending into autumn. Conversely, in Macaronesia, temperature was the dominant factor. The Canary Islands and Madeira showed sustained high risk in coastal areas year-round, while the Azores, historically considered non-endemic, displayed climatic suitability hotspots in central islands. These findings confirm the tropicalization of transmission patterns and identify cryptic risk periods. This dynamic approach offers a robust tool for veterinary and public health authorities to transition from static, calendar-based prophylaxis to adaptive, evidence-based control strategies, optimizing resources in a changing climate.