Higher abundance of the vector Aedes aegypti in rural areas than in urban areas in Managua, Nicaragua

TL;DR

This study found more Aedes aegypti mosquitoes in rural areas of Nicaragua than in urban areas, challenging the belief that they are mainly urban pests.

Contribution

The study provides new evidence that Aedes aegypti is more abundant in rural than urban areas in Nicaragua.

Findings

All entomological indices were significantly higher in rural communities than in urban areas across both years and seasons.

Rural households had greater mosquito densities, with pupal productivity concentrated in large water storage containers.

Vector control strategies should target both rural and urban communities to mitigate disease transmission risks.

Abstract

Ae. aegypti is the primary vector of dengue, chikungunya, and Zika viruses, traditionally associated with urban environments. However, its presence and abundance in rural settings remain understudied. This study compares Ae. aegyptipopulations between rural and urban communities in Managua, Nicaragua, across different seasons over multiple years.

Entomological surveys were conducted in 500 randomly selected households (250 rural, 250 urban) during the rainy and dry seasons of 2022 and 2023. Immature mosquitoes were collected from water-holding containers, and adult mosquitoes were sampled using aspirators. Entomological indices, including Stegomyia, pupal, and adult indices, were compared across seasons and localities.

All entomological indices were significantly higher in rural communities than in urban areas across both years and seasons. Rural households had greater mosquito densities, with pupal productivity concentrated in large water storage containers. Adult mosquito collections confirmed a greater Ae. aegypti presence in rural areas, suggesting sustained transmission risk. We observed pupal thresholds in water-holding containers for female adult collections.

Contrary to the conventional view of Ae. aegypti as an urban mosquito, our findings highlight its substantial presence in rural settings, likely driven by water storage practices and environmental conditions. These results align with findings from other regions reporting high mosquito abundance in rural areas, challenging assumptions about urban dominance.

Rural areas play a crucial role in sustaining Ae. aegypti populations. Vector control strategies should target both rural and urban communities, with seasonally tailored interventions to mitigate disease transmission risks.

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