Abundance of the Aedes aegypti and other adult gnats, in urban areas of endemic municipality for dengue, São Sebastião, North Coast Region in São Paulo State, Brazil

Abstract

 This study aims to determine the frequency and richness of adult gnats in inter and peripheral   domiciles in real states located in urban areas, with emphasis on Ae. aegypti, in endemic municipality of dengue, São Sebastião, North Coast Region in São Paulo State, Brazil. The  collections were carried out from February 2011 to February 2012, by using net to catch   shrimps and portable electrical capturer driven by battery in inter and peripheral environments  of the real states. Results: 8.667 individuals distributed in 7 genders and 17 species were  collected. The most frequent species were Cx. quinquefasciatus (81,85%), Ae. aegypti (15,13%)             and Ae. scapularis (1,26%). According to the verified environment, Cx. quinquefasciatus and  Ae. aegypti were more abundant in the inter domicile environment and Ae. scapularis had  similar distribution in the both studied environments. Ae. aegypti females and males were more  frequent in the inter one. However, the Cx. quinquefasciatus and Ae. scapularis males showed  a tendency of being more frequent in the peripheral environments and the females in the inter  ones. 1.320 adults were captured, 1.311 Ae aegypti and 9 Ae. albopictus. The frequency of 5  females and 4 males Ae. albopictus incapacitated a more detailed evaluation. 658 Ae aegypti             females and 653 males were collected, both more abundant indoor. From the total of positive real states, approximately 85 % presented up to 2 Ae. aegypti females. The IPA suggested low dispersion among the blocks. The IDA average revealed a density of 1,61 female per house. The  IFM was of 0,42 female per inhabitant. The number of Ae. aegypti females captured indoors   and outdoor had association with the number of inhabitants, being such an association larger  in the inter domicile. Conclusion: A high abundance of Cx. quinquefasciatus, Ae. aegypti and  Ae. scapularis adults in the urban area of São Sebastião, north coast region of São Paulo state  suggests the possibility of transmission of pathogenic agents of epidemiological importance Such an aspect points out to precaution measures for prevention of arboviruses. The proportion  of Aedes aegypti females indoor was higher, reiterating it as an endophilic and endophagic  species. The strong association between the number of Ae. aegypti females and the abiotic  variables reflects its influence in the infestation levels. The number of Ae. aegypti females found out, suggests low vector density, since in the most of positive residential and non residential  real states were registered the presence of up to 02 females of that species. So, it is confirmed  the need of studies with female adult mosquitoes, since besides of providing information on its  bioecology, it constitutes an important tool for the vector control.