Objective To perform spatial analysis on dengue transmission in a medium

The lack of an association between risk of occurrence of dengue and socioeconomic levels in almost all years studied indicates that this issue deserves further study, and may vary depending on the settings found in each municipality. It will be important to determine the spatial relationship between dengue transmission and other variables, such as degree of immunity in the population, effectiveness of control measures, degree of infestation by the vector; and population habits and behaviors, among others.

No abstract

ResumoObjetivo Estudar a população de Aedes aegypti em área de transmissão de dengue sob o ponto de vista de freqüência, distribuição espacial, paridade, desenvolvimento ovariano e conteúdo do intestino médio. Métodos O estudo foi realizado na cidade de São José do Rio Preto, SP. Foram selecionados dois setores, um com nível socioeconômico baixo e outro com nível médio. As observações foram realizadas entre 1996 e 1997. Foram feitas capturas no intra e peridomicílios com capturadores elétricos manuais. São dados detalhes das dissecções para estudo do estado fisiológico das fêmeas e da classificação utilizada. Resultados Capturaram-se 188 machos e 189 fêmeas. Obteve-se um índice de 0,46 fêmeas por casa. Dos machos e das fêmeas capturados, estavam no intradomicílio, respectivamente, 82,4% e 87,3%. Encontrou-se maior proporção de fêmeas no setor de nível socioeconômico mais baixo e com maior concentração populacional. Foram analisadas 148 fêmeas, sendo 27,0% nulíparas e 10,1% oníparas. As demais foram classificadas nas fases III a V de Christophers e Mer (C&M) com 28,0% destas contendo sangue de coloração vermelha no intestino médio. Das fêmeas, 87,9% já haviam praticado a hematofagia. Conclusões A espécie revelou grande tendência à endofilia. A proporção de nulíparas foi superior a de oníparas, apesar da maioria das fêmeas ser classificada nas fases III a V de C&M. Chama atenção o elevado percentual das fêmeas que praticaram a hematofagia e a ocorrência de não concordância gonotrófica. AbstractObjective A Aedes aegypti population from an area of dengue transmission was studied to determine mosquito's frequency, spatial distribution, parity, its ovarian development and midgut contents. MethodsThe study carried out in São José do Rio Preto country,

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 fi fth 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 signifi cant 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 signifi cant 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.