Análise espacial do perfil epidemiológico de Leishmania infantum em Nordelândia, Lagoa Azul (Natal/RN)

Abstract

Visceral leishmaniasis (VL) is a zoonosis of great relevance in Brazil, with dogs acting as the main reservoirs and the sand fly Lutzomyia longipalpis as the vector. The present study analyzed the spatial and temporal distribution of the vector and possible reservoirs of Leishmania infantum in the community of Nordelândia, Natal/RN, between 2021 and 2023. Entomological monitoring was carried out weekly using CDC traps at nine fixed points. Serological (ELISA) and molecular (qPCR) tests in dogs and humans were conducted exclusively in 2021 to determine prior exposure to L. infantum. Using geoprocessing tools, heat maps were created to assess the overlap between vector presence and canine and human seropositivity. Seasonal variation in vector abundance was observed, with peaks between March and May, as well as a spatial migration of collection hotspots over the years. The detection of L. infantum DNA in the intestines of sand flies was mainly associated with human and canine DNA, identified as the vectors’ blood sources, reinforcing their importance in maintaining the transmission cycle. In 2021, the seroprevalence of anti-L. infantum antibodies in dogs was 31.5%, and L. infantum DNA was detected in the peripheral blood of 33.7% of dogs. Among humans, 12.4% tested positive for anti-L. infantum antibodies, L. infantum DNA was detected in 10.9% of peripheral blood samples, and 38.7% of those evaluated produced IFN-γ in response to L. infantum antigens, indicating a high rate of exposure. Despite expectations of spatial overlap between vectors and exposed hosts, such a pattern was not clearly observed. These results highlight the complexity of VL epidemiology and the importance of considering other transmission routes, such as vertical and venereal transmission, especially among dogs, for a broader understanding of L. infantum persistence in urban areas. The use of geotechnologies proved essential in identifying risk areas and guiding more effective control actions, taking into account the complexity of parasite transmission.