Epidemiologically relevant container types, indices of abundance and risk conditions for aedes aegypti in Salto (Uruguay), a city under threat of dengue disease

Abstract

Objective: A study was conducted in Salto (Uruguay), a city recently invaded by Aedes aegypti (Diptera, Culicidae), in order to identify mosquito-producing containers, the relationship between different Aedes aegypti population indices and environmental risk conditions for the dengue vector. Due to uruguayan climatic characteristics, the vector population decreases abruptly during the winter and regrows when temperature rises, resulting in a particular population dynamic that differs from that of tropical regions. Methods: 20 clusters randomly selected (100 household each) were visited twice and water filled containers and immature mosquitoes were quantified. Pupae per person (PPI), pupae per hectare (PPH) and Stegomyia indices were calculated. The number of mosquitoes in each container type was analyzed, and their spatial location wasdescribed. Results: The study was able to detect important epidemiological containers (containers not in use and tanks). While PPI, PPH and Stegomyia indices for the different clusters were correlated, the Stegomyia indices increased significantly between the first and second sampling. Clusters with abundant vegetation, or located on lower groundshowed the highest PPI values. Conclusion: Due to its proximity to areas where dengue fever is endemic, Salto becomes valuable for case studies relevant to other areas in the world that could be invaded by this vector.