Insecticide resistance and target site mutations (G119S ace-1 and L1014F kdr) in Anopheles gambiae s.l. in Enugu state, Southeastern Nigeria

Abstract

A study of insecticide resistant status and detection of G119S and L1014F mutation genes in Anopheles gambiae sensu lato. in Enugu State was conducted between May, 2019 and June, 2020. The aim was to investigate the resistance status of An. gambiae s.l. to four classes of insecticides used in vector control in the area and to identify the target site resistant genes present in resistant mosquitoes. Three randomly selected communities; Awkunanaw (Enugu East), Obukpa (Enugu North) and Awgu (Enugu West senatorial districts) were used as sampling sites. Anopheles gambiae s.l. larvae were collected by dip method and reared to adult for the study. WHO Tube Bioassay was used to determine resistance status. Polymerase Chain Reaction (PCR) was employed for detection of resistance mechanisms. The average mortality of An. gambiae s.l. tested with DDT was 28.3%, deltamethrin 63.53%, bendiocarb 88.33%, while malathion had the highest average mortality rate of 100%. The Acetycholinesterase Resistance Gene (GII9S Ace-1) mutation was detected at low frequencies in 75(100%) randomly selected An. gambiae s.l. from the three senatorial districts while the Knockdown Resistance Gene (LI0I4F kdr) mutation was not detected. Implementation of insecticide resistance management strategies in the state to control the spread of resistance is recommended.