Integrated analysis of dengue transmission risk and insecticide resistance in Aedes aegypti from Vichada, Colombia

Abstract

Dengue is the primary arbovirus transmitted by Aedes aegypti mosquitoes. Effective management of dengue demands a multidisciplinary approach. The aim of this study was to conduct an integrated analysis of dengue transmission, focusing on its vector mosquitoes, to establish a baseline for dengue control and prevention in an endemic region of Colombia. The study was conducted from 2015 to 2018 across four municipalities in the Vichada department near the Venezuelan border. Five complementary approaches were employed: (1) determining the natural infection rate and circulation of various dengue virus serotypes in mosquitoes; (2) evaluating the insecticide susceptibility status and examining mosquito genotypes for three knockdown (kdr) mutations linked to insecticide resistance; (3) performing a phylogenetic analysis to identify the lineage of Ae. aegypti; (4) creating risk maps for dengue transmission based on predictive models in two municipalities in the department; and (5) empowering the community. Molecular analysis using RT-PCR indicated dengue virus infections in all municipalities of the Vichada department. Eleven positive pools for serotypes DENV-1, DENV-2, DENV-3, and DENV-4 were detected. The highest minimum infection rate (MIR) was found in Cumaribo, followed by La Primavera, which showed the greatest diversity of dengue virus serotypes. Mosquitoes from all three populations showed susceptibility to malathion and lambda-cyhalothrin pyrethroid, except for mosquitoes from Puerto Carreño, which presented moderate resistance to lambda-cyhalothrin (resistance ratio of 8). Importantly, all mosquitoes had the F1534C mutation, while the V1016I and V419L mutations were found at lower frequencies. Risk classification maps for Puerto Carreño and La Primavera showed neighborhoods with high risk, indicating potential hotspots for intervention and vector control. This study established a necessary baseline for the ongoing monitoring and improvement of the early warning system for all municipalities in the Vichada department. The integrative approach employed in this study highlights the importance of incorporating these methodologies into dengue epidemiological surveillance in endemic regions.