Is routine dengue vector surveillance in central Brazil able to accurately monitor the Aedes aegypti population? Results from a pupal productivity survey
Autor(es): Pilger, Daniel; Lenhart, Audrey; Manrique-Saide, Pablo; Siqueira, Joao Bosco; da Rocha, Welington Tristao; Kroeger, Axel
Resumo: To assess how well the Aedes aegypti infestation rapid survey, Levantamento Rapido de Indice para Aedes aegypti (LIRAa), is able to accurately estimate dengue vector densities and target the most important breeding sites in Goiania, Brazil. Methods In February 2009, a pupal productivity survey was conducted in 2 districts of the city of Goiania, central Brazil. The results were compared to those of LIRAas conducted in the same districts during the months before and after the pupal productivity survey. Results In the pupal productivity survey, 2024 houses were surveyed and 2969 water-holding containers were inspected. Discarded small water containers most frequently contained immature Ae. aegypti. The most pupal-productive containers were elevated water tanks, roof gutters and water holding roofs. Combined, these three containers accounted for 70% of all pupae. In the two districts where the pupal productivity survey was conducted, the house indices were 5.1 and 4.6 and the Breteau indices were 5.9 and 6.0. In contrast, the two LIRAs conducted in the same two districts resulted in an average house index of 1.5 and Breteau index of 2.5, with discarded items identified as the most frequently infested container type. Conclusion Both the LIRAa and the pupal productivity survey identified discarded items as being most frequently infested with immature stages of Ae. aegypti, but the pupal productivity survey showed that elevated containers produced the greatest proportion of Ae. aegypti pupae (a proxy measure of adult vector density) and that the values of the Stegomyia indices were substantially underestimated by LIRAa. Although both surveys differ considerably in terms of sampling method and manpower, in the case of this study the LIRAa did not accurately identify or target the containers that were the most important to adult mosquito production.Original Abstract: Objetivo: Evaluar que tan precisa es la estimacion de la densidad del vector del dengue al utilizar la prueba rapida de infestacion de Aedes aegypti, LIRAa (Levantamento Rapido del Indice para Aedes aegypti), e identificar los lugares de reproduccion mas importantes en Goiania, Brasil. Metodos: En Febrero del 2009, se realizo un estudio de productividad de pupas en 2 distritos de la ciudad de Goiania, Brasil central. Los resultados se compararon con los obtenidos con los LIRAas en los mismos distritos durante los meses anteriores y posteriores al estudio de productividad de pupas. Resultados: En el estudio de productividad de pupas, se inspeccionaron 2024 hogares y 2969 contenedores de agua. Los pequenos contenedores de agua que habian sido descartados contenian formas inmaduras de Ae. aegypti. Los contenedores mas productivos en cuanto a pupas eran los tanques de agua elevados, las canaletas en los techos y los techos con agua estancada. Combinados, estos contenedores eran responsables de 70% de todas las pupas. En los dos distritos en donde se realizo el estudio de productividad de pupas, los indices de viviendas eran del 5.1 y 4.6 y los indices de Breteau eran 5.9 y 6.0. En contraste, los 2 LIRAs conducidos en los mismos 2 distritos resulto en un indice promedio de viviendas de 1.5 y un indice de Breteau de 2.5, habiendose identificado a los contenedores descartados como el tipo de contenedor mas frecuentemente infestado. Conclusion: Tanto los LIRAa como el estudio de productividad de pupas identificaron los items descartados como los mas frecuentemente infestados con estadios inmaduros de Ae. aegypti, pero el estudio de productividad de pupas mostro que los contenedores elevados producian la mayor proporcion de pupas de Ae. aegypti (una medida proxy de la densidad de vectores adultos) y que los valores de los indices Stegomyia estaban significativamente subestimados por los LIRAa. Ambos estudios diferian en terminos del metodo de muestreo y mano de obra. En este estudio, el LIRAa no identifico de forma precisa los contenedores mas importantes en la produccion de mosquitos adultos.
Palavras-Chave: Environmental monitoring; Human diseases; Breeding sites; Pupae; Vectors; Aquatic insects; Public health; Infestation; Dengue; Aedes aegypti
Imprenta: Tropical Medicine and International Health, v. 16, n. 9, p. 1143-1150, 2011.
Descritores: Aedes aegypti - Dengue ; Aedes aegypti - Public health
Data de publicação: 2011
