Synanthropy and diversity of Phlebotominae in an area of intense transmission of visceral leishmaniasis in the South Pantanal floodplain, Midwest Brazil

Abstract

Phlebotomines have been recorded from a wide variety of habitats, and some of these vector species have shown preference for human environments, with high levels of adaptation. This study evaluated the degree of preference of these vectors for urban, rural, and forested environments (synanthropic behavior), as well as the diversity of these species, in three areas (forested, rural, and urban, exhibiting different degrees of anthropogenic changes) in a region of intense transmission of visceral leishmaniasis in Corumba´ county, Mato Grosso do Sul, Brazil. Using light traps, sand fly specimens were collected from the three environments simultaneously, from May 2015 to April 2017, totaling 7 213 sand flies of 14 species in eight genera. Nuorteva’s synanthropy index was determined for the species Lutzomyia cruzi, Brumptomyia brumpti, Micropygomyia peresi, Lu. forattinii, Martinsmyia oliveirai and Evandromyia corumbaensis. Lutzomyia cruzi, the vector of Leishmania infantum in Corumba´, was the most abundant vector species, recorded from all three areas and sampling plots, on all 24 months investigated. This species exhibited the highest synanthropic index (+75.09), indicating a strong preference for urban environments. Brumptomyia brumpti, Micropygomyia peresi, Lu. forattinii, and Martinsmyia oliveirai showed preference, albeit not strong, for urban environments. Overall, males were more abundant than females (W = 490; p < 0.0001). High density, high synanthropic index, and sustained indoor presence were found for Mi. peresi in the rural area. Monitoring changes in the ecological behavior of sand flies is of vital importance, as these changes may indicate an increased likelihood of leishmaniasis emergence or reemergence.