Spatial distribution and effects of land use and cover on cutaneous leishmaniasis vectors in the municipality of Paracambi, Rio de Janeiro, Brazil

Abstract

The municipality of Paracambi (Rio de Janeiro, Brazil) reports sporadic cases of American cutaneous leishmaniasis (ACL). Previous studies detected Nyssomyia intermedia (Diptera: Psychodidae) as the main vector in the region, but its spatial distribution and the presence of other vector species have not been evaluated. This study aims at filling this knowledge gap, by studying the ecology of sand flies, their spatiotemporal distribution, and correlation with land use/cover. Two campaigns of monthly sand fly collections using light traps and manual captures were conducted in 1992–1994 and 2001–2003. Females were dissected to detect natural Leishmania infections. The spatial distribution of sand flies was assessed using kernel density maps. Correlations with land use/cover were evaluated by extracting satellite imagery data around the capture points. A total of 17,232 sand flies from 13 species were captured. Medically important species included Ny. intermedia, Migonemyia migonei, Pintomyia fischeri and Ny. whitmani. No Leishmania-infected females were detected. Highest densities were detected in the peri-urban areas Cascata and Sabugo, and in rural areas São José and Mutirão. Ny. intermedia had statistically significant correlations with pasture and agricultural areas. Present results strengthened that Ny. intermedia and Mg. migonei are the main local ACL vectors. Correlations with land use evidence the association between ACL and anthropic environmental change.