Ceylon Journal of Science (Jun 2023)
Insecticide resistance spectrum and prevalence of L1014F <em>kdr</em> type mutation in <em>Anopheles gambiae s.l.</em> in Abia State, Nigeria
Abstract
Anopheles gambiae s.l. is the primary vector of malaria, a debilitating disease responsible for substantial mortality and morbidity in Sub-saharan Africa. This study evaluated the insecticide resistance status and the frequency of L1014F kdr mutation in An. gambiae [Diptera: Culicidae, Giles 1902] within Abia State, Nigeria. Immature stages of An. gambiae (s.l.) were collected from Umudike, Agalaba, and Ebem communities and reared to adulthood. Batches of 25 sugar-fed female mosquitoes, aged 3–5 days, were exposed to four types of WHO insecticide-impregnated papers, i.e., 4% DDT, 0.75% Permethrin, 0.1% Bendiocarb, and 5% Malathion, for one hour and the mortalities were recorded after a recovery period of 24 h. Mosquito species were identified using morphological and molecular methods, and kdr mutation L1014F was genotyped. Anopheles gambiae (s.l.) was highly resistant to permethrin (Umudike-18.8% mortality, Agalaba-17.5%, Ebem- 49.0%) but showed no resistance to DDT (0.0%) in the three locations. Conversely, all the locations recorded complete susceptibility to malathion (100%). Although complete susceptibility to bendiocarb was reported from Umudike (100%) and Ebem-Ohafia (100%), resistance was reported from Agalaba (87.5%). PCR analyses showed that An. gambiae (s.l.) were predominantly An. gambiae s.s. in Umudike (90.0%), Agalaba (67.5%) and Ebem (67.5%), whereas the rest were An. coluzzii. Very high frequencies of the L1014F kdr mutation was observed in all locations [Umudike (1.00), Agalaba (0.98), and Ebem-ohafia (0.95)]. The worrisome resistance to bendiocarb in Agalaba suggests the existence of metabolic resistance that needs to be clarified. The high occurrence of L1014F resistance mutation in populations calls for urgent implementation of integrated vector control strategies in Abia State.
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