Socio-Economic Effects on the Temporal Importance of Breeding Site Types for Aedes aegypti in a Tropical Epidemic City.

Abstract

Introduction: Aedes aegypti (Diptera: Culicidae) is the vector of dengue, Zika, chikungunya, and yellow fever, arboviruses of major public health importance. The mosquito has a high adaptability, requiring the elimination of its primary breeding sites. In Brazil, breeding sites are classified by the Rapid Survey of Indices for Aedes aegypti (LIRAa) as water-holding containers suitable for larval development. They are categorized into five groups: A (A1-elevated water tanks, A2-ground-level water deposits), B (mobile containers), C (fixed containers), D (D1-tires, D2-trash), and E (natural breeding sites). This study aimed to verify whether the types of breeding sites changed in the course of 2 years and if socio-economic factors, neighbourhood population density, and illiteracy rates impact the occurrence of these types of breeding sites.

Method: Data were obtained from the larval surveillance program of the Vector-borne Disease Control Coordination (CCEV) and socio-economic data from the Brazilian Institute of Geography and Statistics (IBGE). Spatiotemporal variations were assessed using an Additive Multinomial Multilevel Statistical Model with a Bayesian approach. We hypothesized that areas with higher human population density would show a higher presence of mobile containers and trash, while areas with higher illiteracy rates would show a frequency of water tanks and trash. Regarding seasonality, we hypothesized that water-filled water tanks and mobile containers would be more frequently present throughout the year.

Results: Our findings highlight the predominance of trash and mobile containers, while natural breeding sites were the least relevant throughout the years analysed. Mobile containers' frequency increased in overcrowded neighbourhoods, and water tanks' frequency decreased. This finding suggests that urban density influences the frequency of these types of breeding sites. Areas with higher illiteracy rates showed a decrease in movable and fixed containers but an increase in trash and water tanks, indicating potential knowledge gaps or structural limitations in water storage practices.

Conclusion: In conclusion, the variety of container types found in different urban and socioeconomic contexts emphasizes the need for interventions that are tailored to local conditions. These findings offer valuable insights for health agencies to improve entomological control strategies, potentially leading to a reduction in the incidence of arboviral diseases in Campo Grande, MS.