Ecological aspects of phlebotomine sand flies in foci of leishmaniasis in the eastern Amazon, Pará State, Brazil

Abstract

This study describes the phlebotomine communities and their seasonal variation in areas of leishmaniasis transmission in the urban-rural interface of the mining municipality of Juruti, Pará State, in the Amazon Region. Monthly captures of phlebotomine sand flies were performed over two years in two sentinel locations: Santa Maria and Paraense. CDC traps were placed on intra and peridomestic environments. A sample of 36,408 phlebotomine sand flies contained 32 species. The most frequent were Lutzomyia longipalpis (76.8%) and Lutzomyia walkeri (19%). Species richness was greater in Paraense, despite the abundant presence of Lu. longipalpis (85%, 23,878/27,951), especially during the Amazonian winter (r = 0.8; p < 0.05). In Santa Maria, the presence of Lu. longipalpis, which occurs rarely, showed no seasonal variation. In the interior of residences, exclusively in Paraense, there was also the occurrence of phlebotomine sand flies naturally infected by Leishmania sp.: Lu. longipalpis (0.12%; 1/821), vector of Leishmania (Leishmania) infantum and Lutzomyia antunesi (1.16%; 2/173), most likely the vector of Leishmania (Viannia) lindenbergi. The high frequency of Lu. longipalpis during the rainy season, but only in Paraense, reveals local influences that determine the phlebotomine community composition and the abundance of species. Integrated actions for the prevention of leishmaniasis must be continuous and preferably intensified from September to November, months preceding rainfall in that region.