Habitat characteristics that favour the presence of Aedes aegypti (Diptera: Culicidae) in households in the city of Córdoba, a temperate area of Argentina

Abstract

Background Aedes aegypti is the vector of dengue fever and chikungunya in the city of Córdoba, Argentina, a city situated at the southern limit of disease transmission by the vector in a temperate area. This study aims to characterise the habitat of juvenile Ae. aegypti in households and assess the influence of microenvironmental and environmental variables on its occurrence.Methods Monthly surveys were conducted from 2019 to 2020 and in 2021 in peridomiciles. Water containers where Ae. aegypti were found were classified according to their material, class and capacity. Using generalised linear mixed models, we evaluated the influence of surrounding vegetation, water container availability and weather conditions (air temperature and precipitation during autumn, summer and spring) on the presence and abundance of juvenile Ae. aegypti.Results Of the 689 containers surveyed, 109—found in 36.7% (77/210) of the households—contained juvenile Ae. aegypti. Small (1–8 l) and very small (< 0.5 l) containers accounted for 80.4% of the containers positive for juvenileAe. aegypti, with plastic jars being the most common. Vases and tarpaulins/plastic covers were the most produc‐tive containers. Containers shaded by vegetation were 2.5‐fold more likely to harbour juveniles than those exposed to sunlight or artificial shade. The strong interaction between tree cover and shade provided by vegetation sug‐ gested that vegetation cover enhances mosquito abundance. Juvenile abundance increased with container capacity, while higher precipitation and minimum temperature in the previous weeks also favoured the presence of juveniles.Conclusions Household containers, which are widely available and diverse in size and material in Córdoba City, pro‐ vide favourable conditions for the persistence of Ae. aegypti. Abandoned nonfunctional and cryptic sites, such as tar‐ paulins and plastic covers, can provide breeding sites that enable Ae. aegypti mosquitoes endure the cold and dry seasons. During the warm and wet seasons, the presence and abundance of Ae. aegypti are influenced by microen‐ vironmental conditions, such as shade provided by vegetation, high minimum temperatures and precipitation. The variety and number of available containers, together with shelter and feeding conditions, suggest that female mos‐ quitoes can still find breeding sites even after selective household control measures have been implemented. These results, supported by generalised linear mixed models, which consider the lack of independence between containers within the same household or block, highlight the importance of incorporating fine‐scale environmental variables into vector control planning.