Diversity and ecology of sand flies (Psychodidae: Phlebotominae): foci of cutaneous leishmaniasis in Amazon Region, Brazil

Abstract

The aim of this study was to describe the phlebotomine sand fly fauna and its respective ecological indexes in risk zones of cutaneous leishmaniasis (CL). The study was carried out in the Municipality of Santarém, Pará State, Brazil. From the total of 102 records of CL patients in 2010 and 2011, infected with different Leishmania species, 31 were selected. Kernel density analysis was performed. CDC light traps were placed (6 p.m.-6 a.m., three nights, height of 1.5 m) in the identified risk zones (indoors, chicken sheds and surrounding forest) in two occasions: rainy and dry seasons of 2012. Shannon traps were installed in the forest during 3 h (7 p.m.-9 p.m., one night). Shannon (H'), Pielou (J') and Dominance (D) indexes were calculated and two spatial clusters (SC) of CL, SC1 (urban-rural) and SC2 (rural farm), were identified. Phlebotomines were sampled in SC1 (243) and SC2 (174). In the whole sample (417) there were 24 species of 10 genera, but only 12 species were found in both risk zones. Ecological indexes varied widely (H' = 0.5-1.72; J = 0.44-0.78; D = 0.46-0.91). The highest D values in the forest (≥ 0.75) were associated to Psychodopygus complexus during both seasons in SC1 and Psychodopygus davisi during the rainy season in SC2. Other CL vectors were identified in smaller frequence. A great diversity of phlebotomine species was described in each risk zone. The CL vectors sampled were well-matched with the Leishmania species infecting the patients. The epidemiological importance of dominant species may vary with climatic seasons and risk zones in Santarém.