Date Published: May 14, 2019
Publisher: Public Library of Science
Author(s): Suellem Petilim Gomes Barrios, Luciana Escalante Pereira, Neiva Zandonaide Nazário Monaco, Gustavo Graciolli, Aline Etelvina Casaril, Jucelei de Oliveira Moura Infran, Everton Falcão de Oliveira, Wagner de Souza Fernandes, Antônio Conceição Paranhos Filho, Alessandra Gutierrez de Oliveira, Nagila Francinete Costa Secundino.
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 Corumbá 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 Corumbá, 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.
Leishmaniasis, a disease whose etiological agents involve roughly 20 species of the genus Leishmania (Kinetoplastida: Trypanosomatidae), is transmitted to animals and humans through the bites of female insects of the order Diptera, family Psychodidae, subfamily Phlebotominae. Six countries alone account for 90% of all cases of visceral and tegumentary leishmaniasis in the world. In the Americas, Brazil is the only country on this list [1, 2].
Fourteen phlebotomine species in eight genera were collected during a 24-month period: Brumptomyia brumpti, Evandromyia aldafalcaoae, Ev. corumbaensis, Ev. lenti, Ev. sallesi, Ev. walkeri, Lutzomyia cruzi, Lu. forattinii, Martinsmyia oliveirai, Micropygomyia peresi, Nyssomyia whitmani, Psathyromyia bigeniculata, Pa. hermanlenti and Sciopemyia sordellii (Table 2). This is the first report of Pa. hermanlenti presence in Corumbá.
This is the first study of sand fly synanthropy conducted in Midwest Brazil. The species Lu. cruzi had exhibited high synanthropic index and high population density. The Pantanal floodplain comprises both terrestrial and aquatic environments harboring a huge diversity of dipterous species, particularly species that, although restricted to wild environments, act as vectors of human pathogens. Destruction of the original vegetation, environmental imbalance, deforestation, agricultural development, human migration, and poor-quality, unplanned urbanization cause wild vectors and reservoirs of several parasites to adapt to rural and urban environments. The Pantanal floodplain is no exception to this phenomenon [6, 43].