Anthropic effects on sand fly (Diptera: Psychodidae) abundance and diversity in an Amazonian rural settlement, Brazil.

Sand flies (Diptera: Psychodidae) are responsible for the transmission of protozoan parasites that cause leishmaniases. They are found predominantly in forests, but some species exploit environments that have been subject to deforestation and subsequent human colonization. Studies conducted in Brazil over the past 30 years show that some species are adapting to peri-urban and urban settings. We evaluated sand fly diversity and abundance in the rural settlement of Rio Pardo, Presidente Figueiredo Municipality, Amazonas State, Brazil. Settlement households were divided into four categories. These categories were determined by the human population density and the degree of deforestation in the immediate area. We used CDC light traps to sample the area surrounding 24 households (6 households in each category). Samples were taken on six occasions during September-November 2009 and June-August 2010. A total of 3074 sand fly specimens were collected, including 1163 females and 1911 males. These were classified into 13 genera and 52 species. The greatest abundance of sand flies and the greatest richness of species were observed in areas where human population density was highest. Our results show that changes in the human occupancy and vegetation management in rural settlements may affect the population dynamics and distribution of sand fly species, thereby affecting the local transmission of cutaneous leishmaniases.