Eco-epidemiological factors associated with the incidence of Lutzomyia longipalpis (Diptera: Psychodidae: Phlebotominae), vector of American Visceral Leishmaniasis, in João Pessoa, Paraíba, Brazil.

Abstract

The first recorded human and canine cases of American Visceral Leishmaniasis (AVL) in the municipality of João Pessoa date back to the 1970s, coinciding with the identification of its vector, Lutzomyia longipalpis. This study aimed to investigate the socio-environmental factors associated with the occurrence of Lu. longipalpis and AVL cases in humans and dogs in João Pessoa. Additionally, it sought to detect Leishmania spp. DNA and identify the blood-feeding sources in female sand fly specimens. Light traps were placed of urban residences in João Pessoa per 21 months, and socio-environmental data on human and canine AVL cases were collected with the assistance of the Health Secretariat of the Municipality of João Pessoa. The multiplex PCR was used to detect Leishmania DNA in female Phlebotominae, and the study of the blood-feeding sources was conducted by sequencing cytochrome b gene. Human and canine AVL cases were mapped using Geographic Coordinate Reference System. A total of 1136 sand fly specimens were captured, belonging to five species: Brumptomyia brumpti, Lutzomyia longipalpis, Evandromyia (Aldamyia) evandroi, Psathyromyia (Forattiniella) brasiliensis and Sciopemyia sordellii, with Lu. longipalpis comprising 86.2 % of the specimens. Our study found that higher Lu. longipalpis abundance was associated with increased rainfall, the presence of poultry farming in households, and the absence of public pavimentation. The tests for detection of DNA of Leishmania infantum were positive for Lu. longipalpis, and the sequencing of the cytochrome b detected gene blood meals from Homo sapiens and Gallus gallus in Ev. evandroi. Moreover, the adaptation of the AVL vector to the urban environment of João Pessoa was evident through the distribution of human and canine cases across the municipality. Understanding the socio-environmental factors associated with the spread of AVL in urban areas is crucial for effective surveillance and control strategies.