First report of AChE1 (G119S) mutation and multiple resistance mechanisms in Anopheles gambiae s.s. in Nigeria

Abstract

First report of AChE1 (G119S) mutation and multiple resistance mechanisms in Anopheles gambiae s.s. in nigeria ifeoluwa Kayode fagbohun 1 ✉ , emmanuel taiwo idowu 1 , olubunmi Adetoro otubanjo 1 & taiwo Samson Awolola 2 Susceptibility and PBO synergist bioassays were done using 3-5 days old female Anopheles mosquito collected from Lagos State, Nigeria with WHO test papers DDT (4%), permethrin (0.75%), Bendiocarb (1%) and PBO (4%) according to standard procedures. The activities of cytochrome P450s, glutathione S-transferase and carboxylesterases were determined using biochemical assays. the presence of kdr-w, kdr-e and Ace-1 R mutations were examined using molecular assays. Resistance to DDt and permethrin in An gambiae s.s from the four Local Government Areas (LGAs) was recorded while suspected resistance to bendiocarb was recorded in mosquitoes from Alimosho and Kosofe LGAs. PBO synergist reduced the knockdown time and also recorded significantly (P < 0.05) higher 24 hrs percentage mortality compared to non-synergized bioassays. Increased activities of detoxifying enzymes was recorded in wild mosquito compared to the insecticides susceptible laboratory strain and this was significant (P < 0.05) in P450s, esterase α and β. Kdr-w was detected in An. gambiae s.s from all the LGAs, kdr-e (L1014S) was detected in Alimosho, Kosofe and ibeju-Lekki, while the Ace-1 R gene was detected in Alimosho and Kosofe. Results from this study provide evidence for resistance of An. gambiae from Lagos State to multiple classes of neurotoxic insecticides with multiple resistance mechanisms to these insecticides.

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

“…gambiae s.s. tested. This was contrary previous findings in Nigeria [26,28,29,31,33,37] where the L1014F mutation was found in mosquito populations. The result of the study also contrast others from several parts of West and Central Africa where L1014F mutation were observed [29,[38][39][40] .…”

“…gambiae s.s. tested from all the site were positive for G119S mutation. This is in agreement with recent results in Nigeria [33,42] where G119S mutation genes were detected. The Ace-1 R mutation has been linked to carbamates and organophosphate cross resistance in malaria vectors.…”

“…gambiae s.l. to DDT and pyrethroids has been reported in various studies in Nigeria [25][26][27][29][30][31][32][33][34] and in other parts of Africa [35] . This may be due to cross-resistance, use of agricultural insecticides and/or use of pyrethroids in LLINs and IRS.…”

Low frequency of knockdown resistance mutation (L1014F) and the efficacy of PBO synergist in multiple insecticide-resistant populations of Anopheles gambiae in Ikorodu, Lagos State, Nigeria

“…Suspected resistance was recorded in An. gambiae to bendiocarb in this study, previous studies have reported similar results in malaria vector in the Southwest and Northern Nigeria 27 , 30 , 32 though susceptibility was recorded in southeast Nigeria 28 . Carbamates are important in malaria vector control especially for IRS to reduce selection pressure on pyrethroid, the emergence of resistance to this class of insecticide may have a deleterious effect on the control of malaria in the study area.…”

“…The rapid emergence and spread in insecticidal resistance among the malaria vector population to WHO-approved insecticides presents a challenge to the control of malaria in sub-Saharan Africa 12 , 13 . In Nigeria, insecticides resistance to different classes of insecticides in malaria vectors has been reported in various parts of the country 14 – 16 , the presence of metabolic and knockdown resistance mechanisms has also been reported 17 – 19 .…”