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

This study evaluated the molecular resistance profile to insecticides and the genetic diversity of <i>Anopheles albimanus</i> populations from malaria endemic comarcas in Panama, a country in Mesoamerica aiming to eliminate local malaria transmission. Molecular screening was performed in 891 <i>An. albimanus</i>, distributed in 162 pools, and collected between 2011 and 2023. Pools were molecularly examined to detect natural infection with <i>Plasmodium</i> and sequenced to assess mutations in genes (<i>vgsc</i>, <i>ace-1</i> and <i>rdl</i>) associated with resistance to commonly used insecticides. A high molecular infection rate by <i>Plasmodium vivax</i> was detected in all comarcas throughout the study period, and <i>P. falciparum</i> 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 <i>rdl</i> gene, associated with resistance to cyclodienes and neonicotinoids, were also frequently present. <i>Anopheles</i> 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.