Occurrence of Aedes aegypti (Diptera, Culicidae) in a Dengue Transmission Area at Coastal Maranhão State, Brazil

Abstract

This study aimed to estimate the occurrence of Aedes aegypti adults at distinct climatic seasons at neighborhoods from the municipality of São Luís, Maranhão State, Brazil, as well as to verify the presence of Dengue virus (DENV) in the specimens collected. A total of 320 properties were visited in eight neighborhoods that were previously randomly chosen. Samplings were made at three periods: dry season/2008, rainy season/2009 and dry season/2009. A total of 563 Ae. aegypti mosquitoes were collected, with 141 of them collected during dry season/2008, 272 during rainy season/2009 and the remnant, during dry season/2009. Specimen were divided into lots and subjected to RT-semi-nestedPCR analysis and virus isolation was carried out using cell culture (C6/36 clone) of Ae. albopictus. The number of adults significantly varied at the neighborhoods of Coréia de Baixo, Lira, João Paulo, and Conjunto Cohatrac I. Molecular analyses of specimens showed no positivity for DENV. At the municipality of São Luís, seasonal climate variation might influence the density of Ae. aegypti adults, however, other factors such as population density, sanitation conditions, and the presence of mosquito breeding sites ought to be assessed as important parameters influencing vector dispersion.