Predicted distribution of sand fly (Diptera: Psychodidae) species involved in the transmission of Leishmaniasis in Sao Paulo state, Brazil, utilizing maximum entropy ecological niche modeling

Leishmaniasis is a public health problem worldwide. We aimed to predict ecological niche models (ENMs) for visceral (VL) and cutaneous (CL) leishmaniasis and the sand flies involved in the transmission of leishmaniasis in Sao Paulo, Brazil. Phlebotomine sand flies were collected between 1985 and 2015. ENMs were created for each sand fly species using Maximum Entropy Species Distribution Modeling software, and 20 climatic variables were determined. Nyssomyia intermedia (Lutz & Neiva, 1912) and Lutzomyia longipalpis (Lutz & Neiva, 1912), the primary vectors involved in CL and VL, displayed the highest suitability across the various regions, climates, and topographies. L. longipalpis was found in the border of Parana an area currently free of VL. The variables with the greatest impact were temperature seasonality, precipitation, and altitude. Co-presence of multiple sand fly species was observed in the cuestas and coastal areas along the border of Parana and in the western basalt areas along the border of Mato Grosso do Sul. Human CL and VL were found in 475 of 546 (86.7%) and 106 of 645 (16.4%) of municipalities, respectively. Niche overlap between N. intermedia and L. longipalpis was found with 9208 human cases of CL and 2952 cases of VL. ENMs demonstrated that each phlebotomine sand fly species has a unique geographic distribution pattern, and the occurrence of the primary vectors of CL and VL overlapped. These data can be used by public authorities to monitor the dispersion and expansion of CL and VL vectors in Sao Paulo state.

Automated summary

The study aimed to predict ecological niche models for visceral (VL) and cutaneous (CL) leishmaniasis and the sand flies involved in their transmission in Sao Paulo, Brazil. The primary vectors, Nyssomyia intermedia and Lutzomyia longipalpis, showed the highest suitability across different regions, climates, and topographies. Factors such as temperature seasonality, precipitation, and altitude had the greatest impact on the distribution of sand flies.