Density of Aedes aegypti and Aedes albopictus and its association with number of residents and meteorological variables in the home environment of dengue endemic area, Sao Paulo, Brazil

Abstract

Background: Measure the populations of Aedes aegypti and Aedes albopictus adults according to sex and location inside or outside the residence, estimate Aedes aegypti female density per house and per resident, and test the association with abiotic factors. Methods: Adult mosquitoes were collected monthly with a hand net and portable electric catcher in the peridomiciliary and intradomiciliary premises of residences in an urban area with ongoing dengue transmission in the municipality of Sao Sebastiao, Brazil, from February 2011 to February 2012. Results: Of the 1,320 specimens collected, 1,311 were Aedes aegypti, and nine were Aedes albopictus. A total of 653 male and 658 female of Aedes aegypti were recorded, of which 80% were intradomiciliary. The mean density of Aedes aegypti adult females was 1.60 females/house and 0.42 females/resident. There was an association between the number of females and the number of residents in both intradomiciliary and peridomiciliary premises (r(2) = 0.92; p < 0.001 and r(2) = 0.68; p < 0.001, respectively). There was an association between the number of females and the mean and total rainfall; the correlation was better in peridomiciliary premises (p = 0.00; r(2) = 77%) than intradomiciliary premises in both cases (p = 0.01; r(2) = 48%). Minimum temperature was associated in both environments, exhibiting the same coefficient of determination (p = 0.02; r(2) = 40%). The low frequency of Aedes albopictus (seven females and two males) did not allow for detailed evaluation. Conclusions: Aedes aegypti is well established within the urban area studied, and the frequency of isolation is higher inside the houses. Female density was directly proportional to the number of residents in the houses. Our data show that human population density positively affects the number of Aedes aegypti females within the residence. Meteorological variables also affected mosquito populations. These data indicate a high probability of human-vector contact, increasing the possible transmission and spread of the DEN virus. Entomological indicators of adult females revealed important information complimenting what was obtained with traditional Stegomyia indices. This information should be a part of an interconnected data set for evaluating and controlling the vector.