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. . Specimen were divided into lots and subjected to RT-semi-nested-PCR 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.

Natural Infection of Aedes aegypti by Chikungunya and Dengue type 2 Virus in a Transition Area of North-Northeast Brazil

“…aegypti occurs even in the months of low rainfall, due to the residents' habit to store water for domestic activities in large deposits, such as tanks and barrels, providing continuous availability of breeding sites. This vector's behavior has been reported in other studies performed in the municipalities of the interior of Maranhão [31][32][33]35,36].…”

“…The state of Maranhão, located in Northeast Brazil, is considered one of the poorest areas of the country [29] and presents, in most municipalities, high Ae. aegypti infestation levels [30], which corroborates with several studies conducted in the region [31][32][33][34][35]. This scenario highlights the role of monitoring viral circulation in periods that precede the outbreaks, especially by entomovirological surveillance investigations.…”

“…This result reinforces other entomological studies carried out in the state, such as those in the municipalities of Caxias and São Luís, which have already registered the presence of Ae. aegypti throughout the year, with variations in its population indices [31][32][33]35]. Several aspects favor the proliferation of Ae.…”

“…Currently, entomovirological surveillance is being used worldwide, as it allows the early detection of viruses and enables the implementation of vector control strategies, minimizing the impact of the epidemics. DENV entomological surveillance has been performed on the island of São Luís, Maranhão in the past, but no viral detection was reported [32]. Recently, CHIKV was detected in Ae.…”