Identification of key areas for Aedes aegypti control through geoprocessing in Nova Iguaçu, Rio de Janeiro State, Brazil

This study discusses the use of geoprocessing to identify key areas for Aedes aegypti control, based on the infestation index obtained in the Aedes aegypti Infestation Index Rapid Survey (LIRAa). The study was conducted in November 2004 in Nova Iguaçu, Rio de Janeiro State, Brazil. The results were analyzed on two scales, neighborhoods and blocks, with the building infestation index assigned to the neighborhood polygons and the Breteau index to the blocks. Kernel estimation was used in the spatial pattern analysis. The Breteau index spatial distribution showed five areas with high and medium density of positive Ae. aegypti breeding sites, highlighting small block clusters with high larval density, strategic for vector control. Based on the results, we recommend this method for dengue vector surveillance.

Este trabalho tem como objetivo discutir o uso da análise de dados espaciais na identificação de conglomerados urbanos chave para o controle de Aedes aegypti, tendo como base os resultados do Levantamento de Índice Rápido para Aedes aegypti (LIRAa), realizado em novembro de 2004 no Município de Nova Iguaçu, Estado do Rio de Janeiro, Brasil. Os dados foram analisados em duas escalas: bairros e quarteirões, sendo os índices de infestação predial atribuídos aos polígonos dos bairros e os índices de Breteau atribuídos aos quarteirões. A interpolação e alisamento por meio de Kernel foi utilizada na análise dos padrões espaciais dos índices. Foram trabalhados pelo LIRAa um total de 15.163 imóveis distribuídos em 2.182 quarteirões agrupados em 33 estratos. O padrão de distribuição espacial do índice de Breteau por quarteirões indicou cinco áreas com alta e média densidades de criadouros positivos para Ae. aegypti, evidenciando seis conglomerados de quarteirões com alta densidade larvária, estratégicos para as ações de controle. O método mostrou-se ideal para a análise espacial dos indicadores entomológicos e de fácil operacionalização pelo serviço.

Dispersal of Aedes aegypti and Aedes albopictus (Diptera: Culicidae) in an urban endemic dengue area in the State of Rio de Janeiro, Brazil

Experimental releases of female Aedes (Stegomyia) aegypti and Aedes (Stegomyia) albopictus were performed in August and September 1999, in an urban area of Nova Iguaçu, State of Rio de Janeiro, Brazil, to estimate their flight range in a circular area of 1,600 m where 1,472 ovitraps were set. Releases of 3,055 Ae. aegypti and 2,225 Ae. albopictus females, fed with rubidium (Rb)-marked blood and surgically prevented from subsequent blood-feeding, were separated by 11 days. Rb was detected in ovitrap-collected eggs by atomic emission spectrophotometry. Rb-marked eggs of both species were detected up to 800 m from the release point. Eggs of Ae. albopictus were more numerous and more heterogeneously distributed in the area than those of Ae. aegypti. Eggs positively marked for Rb were found at all borders of the study area, suggesting that egg laying also occurred beyond these limits. Results from this study suggest that females can fly at least 800 m in 6 days and, if infected, potentially spread virus rapidly