Profiling insecticide resistance phenotypes and genotypes in Aedes aegypti populations across four regions in Puerto...

Vector-borne diseases exert a considerable toll on global health. The efficacy of vector control strategies is being threatened by the emergence and spread of insecticide resistance worldwide. In this study, we collected Aedes aegypti mosquitoes from five regions of Puerto Rico to investigate their insecticide resistance phenotypes and genotypes.  Insecticide resistance intensity CDC bioassays were employed to determine the response to deltamethrin and malathion. In parallel, next generation targeted amplicon sequencing was used to investigate the presence of insecticide resistance-conferring mutations in nine targets across four genes: the voltage gated sodium channel (vgsc); GABA receptor (resistance to dieldrin, rdl); acetylcholinesterase (ace-1); and glutathione-S-transferase epsilon 2 (GSTe2). We observed high resistance intensity to deltamethrin and malathion in Ae. aegypti mosquitoes Resistance was supported by molecular evidence revealing five mutations (V410L (vgsc), V1016I/G (vgsc), F1534C (vgsc), A296S (rdl)), previously linked to insecticide resistance. A previously undocumented mutation, L944I (L921I in Ae. aegypti, vgsc), was identified. While not yet reported in Aedes spp. vectors, this mutation has been associated with pyrethroid resistance in other medically important vectors and agricultural pests. Our research highlights the presence of insecticide resistance and associated mutations in Puerto Rico, which is valuable for vector control programs, providing information to guide decisions regarding the implementation of effective control interventions.