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, São Paulo, Brazil.

BACKGROUND: Measure the populations of Ae. aegypti and Ae. albopictus adults according to sex and location inside or outside the residence, estimate Ae. 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 São Sebastião, Brazil, from February 2011 to February 2012. RESULTS: Of the 1,320 specimens collected, 1,311 were Ae. aegypti, and nine were Ae. albopictus. A total of 653 male and 658 female of Ae. aegypti were recorded, of which 80% were intradomiciliary. The mean density of Ae. 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 Ae. albopictus (seven females and two males) did not allow for detailed evaluation. CONCLUSIONS: Ae. 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 Ae. 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.

Spatial distribution of the risk of dengue and the entomological indicators in Sumaré, state of São Paulo, Brazil.

Dengue fever is a major public health problem worldwide, caused by any of four virus (DENV-1, DENV-2, DENV-3 and DENV-4; Flaviviridae: Flavivirus), transmitted by Aedes aegypti mosquito. Reducing the levels of infestation by A. aegypti is one of the few current strategies to control dengue fever. Entomological indicators are used by dengue national control program to measure the infestation of A. aegypti, but little is known about predictive power of these indicators to measure dengue risk. In this spatial case-control study, we analyzed the spatial distribution of the risk of dengue and the influence of entomological indicators of A. aegypti in its egg, larva-pupa and adult stages occurring in a mid-size city in the state of São Paulo. The dengue cases were those confirmed by the city's epidemiological surveillance system and the controls were obtained through random selection of points within the perimeter of the inhabited area. The values of the entomological indicators were extrapolated for the entire study area through the geostatistical ordinary kriging technique. For each case and control, the respective indicator values were obtained, according with its geographical coordinates and analyzed by using a generalized additive model. Dengue incidence demonstrated a seasonal behavior, as well as the entomological indicators of all mosquito's evolutionary stages. The infestation did not present a significant variation in intensity and was not a limiting or determining factor of the occurrence of cases in the municipality. The risk maps of the disease from crude and adjusted generalized additive models did not present differences, suggesting that areas with the highest values of entomological indicators were not associated with the incidence of dengue. The inclusion of other variables in the generalized additive models may reveal the modulatory effect for the risk of the disease, which is not found in this study.

Study of the distribution and abundance of the eggs of Aedes aegypti and Aedes albopictus according to the habitat and meteorological variables, municipality of São Sebastião, São Paulo State, Brazil.

BACKGROUND: This study focused on the distribution and abundance of the eggs of Aedes aegypti and Aedes albopictus. METHODS: Eighty ovitraps were exposed for four days of each month in peri- and intradomiciliary environments of 40 urban residences on 20 street blocks that were drawn monthly in Sebastião, SP, between February 2011 and February 2012. The monthly distribution of positive ovitrap indices (POI) and mean egg counts per trap (MET) of Ae. aegypti and Ae. albopictus were analyzed using the Kruskal-Wallis test, followed by the Dwass-Steel-Critchlow-Fligner (DSCF) test. Spearman's rank correlation coefficient and simple linear regression were used to determine the association between the meteorological variables of temperature and rainfall and the number of ovitraps with eggs and the egg count. RESULTS: The POI and MET of Ae. aegypti were higher in peridomiciliary premises. A positive correlation was found between the temperature and the number of ovitraps with eggs and the egg count of this species in domestic environments. There was no difference in the POI and MET of Ae. albopictus between the environments. A positive correlation was found between temperature and positive ovitraps of Ae. albopictus in peridomiciliary premises. The POI and MET of Ae. aegypti were higher than those of Ae. albopictus. CONCLUSIONS: Peridomiciliary premises were the preferred environments for oviposition of Ae. aegypti. The use of ovitraps for surveillance and vector control is reiterated.

[Spotted fever in Campinas region, State of São Paulo, Brazil]. / Situação da febre maculosa na Região Administrativa de Campinas, São Paulo, Brasil.

Brazilian spotted fever was detected for the first time in the State of S o Paulo in 1929. However, there is no systematic reporting of the disease in the State. In 1985, three cases of the disease occurred in the municipality of Pedreira, located in the Campinas Region, belonging to the 5th Administrative Region, in the Northeast part of the State, including 88 municipalities. An investigation was conducted at the time, but the lack of case registry limited its scope. The present study was undertaken with the aim of recovering the history of the disease in the Region. Data recovered from several public health services for 1985-2000 were used to analyze incidence patterns. It was observed that the transmission area expanded and the number of suspected cases increased, especially after 1996, when mandatory reporting was established. Deaths due to spotted fever were observed in most of the years under study. The study concluded that spotted fever incidence is increasing in the Campinas Region. Complementary bio-ecological studies are currently under way to better understand the epidemiology of this disease, recognized worldwide as an emerging public health problem.