Effect of salinity on the behavior of Aedes aegypti populations from the coast and plateau of southeastern Brazil

Mosquito larvae can develop in fresh, salty and brackish water. The larvae of Aedes aegypti develop in fresh water. However, in laboratory studies, tolerance of this species for oviposition and hatchingin brackish water was observed. Immature forms of Ae. aegypti have also been found developing in brackish water in coastal areas. The purpose of the study was to compare the effects of salt on the biological cycle of Ae. aegypti populations from coastal and plateau areas of southeastern Brazil...

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

Measure the populations of Ae. aegypti and Ae. albopictus adults according to sex and location insideor 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 on going 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 maleand 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 offe males and the number of residents in both intradomiciliary and peridomiciliary premises (r2 = 0.92; p < 0.001 andr2 = 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; r2 = 77%) than intradomiciliary premises in both cases (p = 0.01; r2 = 48%). Minimum temperature was associated in both environments, exhibiting the same coefficient of determination (p = 0.02; r2 = 40%). The low frequency of Ae. albopictus (seven females and two males) did not allow for detailed evaluation...

Assessment of Aedes aegypti Pupal Productivity during the Dengue Vector Control Program in a Costal Urban Centre of São Paulo State, Brazil

The control of dengue relies on the elimination of vector breeding sites. This study identified the container categories most productive for A. aegypti within the framework of the São Paulo dengue vector control program (DVCP) in São Sebastião, a large city located on the state’s coast where dengue cases have occurred since 2001. Containers were inspected monthly for the occurrence of mosquito immature stages during two consecutive vector-breeding seasons in 2002–2004. Containers were classified by their material, use, and fixed or removable status. Pupal productivity differed significantly among container types, items made of metal and plastic, and boats being those with the highest relative contribution. Significant correlations between traditional indices of A. aegypti abundance (Container Index, House Index, and Breteau Index) and pupal productivity/demographic indices (Pupae/Container, Pupae/House, Pupae/ha, and Pupae/Person) ranged 0.56–0.65; correlations were not statistically significant for any combination involving the Pupae/Container index. The assessment of pupal productivity indices could be incorporated into the DVCP without any additional operational onus, allowing vector control managers to determine appropriate control actions targeting the most productive containers and sites. Further studies are needed to assess whether pupal productivity indices may be used as epidemiological indicators of risk of dengue transmission...

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

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...