Infestation of an urban area by Aedes aegypti and relation with socioeconomic levels

Abstract

OBJECTIVE: To assess the association between Aedes aegypti larvae infestation rates and socioeconomic factors. METHODS: Infestation rates in the urban area of the city of São José do Rio Preto, Southeastern Brazil, were calculated in January of 2005 and subsequently geocoded by address. The urban census tracts were grouped by means of main component analysis, thus producing four socioeconomic clusters (1-4, in a decreasing order of socioeconomic level) and a fifth cluster (5) with a level below the others and not belonging to the urban census tracts (new districts and irregular residential development projects). The Breteau index (BI), the house index (HI), and the container index (CI), as well as the averages of existing containers surveyed per home, were calculated for each cluster. RESULTS: The values of infestation indices did not show significant differences among socioeconomic clusters 1 to 4, even though they were lower than the indices obtained for cluster 5. The averages of existing containers surveyed were higher for cluster 1 in relation to clusters 2 to 4, but did not show significant differences when compared to cluster 5. CONCLUSIONS: Larval indices did not show association with the different socioeconomic levels of the cluster that corresponds to the urban census tracts. Nonetheless, new districts, irregular residential development projects and locations adjacent to those with the worst basic sanitary conditions showed the highest values for these indicators.