Molecular Detection of Insecticide Resistance-Associated Mutations in vgsc, ace-1, and rdl Genes of Anopheles albimanus in Panama

Abstract

This study evaluated the molecular resistance profile to insecticides and the genetic diversity of Anopheles albimanus populations from malaria endemic comarcas in Panama, a country in Mesoamerica aiming to eliminate local malaria transmission. Molecular screening was performed in 891 An. albimanus, distributed in 162 pools, and collected between 2011 and 2023. Pools were molecularly examined to detect natural infection with Plasmodium and sequenced to assess mutations in genes (vgsc, ace-1 and rdl) associated with resistance to commonly used insecticides. A high molecular infection rate by Plasmodium vivax was detected in all comarcas throughout the study period, and P. falciparum infections were detected in the last two years (2022–2023) in the east region. Mutations associated with pyrethroids/DDT resistance (H973Y and L1014F/C) and to organophosphorus/carbamate resistance (G119S) were detected at high frequencies (50.8% and 70%, respectively) in eastern comarcas but were absent from comarcas located west of the Panama Canal. Mutations in the rdl gene, associated with resistance to cyclodienes and neonicotinoids, were also frequently present. Anopheles populations from the western side were highly homogenous, suggesting a clonal expansion, contrasting with eastern samples, which exhibited a high genetic diversity. Our study provides a valuable baseline for planning future molecular vector surveillance studies in the region. It also provides valuable information to the vector control program in Panama to guide insecticide selection for IRS.