Acetylcholinesterase (ace-1R) target site mutation G119S and resistance to carbamates in Anopheles gambiae (sensu lato) populations from Mali

Abstract

Background: The long-lasting insecticidal nets (LLINs) and indoor residual spraying of insecticide (IRS) are major malaria vector control strategies in Mali. The success of control strategies depends on a better understanding of the status of malaria vectors with respect to the insecticides used. In this study we evaluate the level of resistance of Anopheles gambiae (sensu lato) to bendiocarb and the molecular mechanism that underlies it. Methods: Larvae of An. gambiae (s.l.) were collected from breeding habitats encountered in the three study sites and bioassayed with bendiocarb. The ace-1 target site substitution G119S was genotyped using a TaqMan assay. Results: The three species of the An. gambiae complex in Mali, i.e. An. arabiensis, An. coluzzii and An. gambiae (s.s.) were found in sympatry in the three surveyed localities with different frequencies. We observed a resistance and suspicious resistance of the three species to bendiocarb with a mortality rate ranging from 37% to 86%. The allelic frequency of the G119S mutation was higher in An. gambiae (s.s.) compared to the other two species; 42.86%, 25.61% and 16.67% respectively in Dangassa, Koula, and Karadié. The allelic frequency of G119S in An. coluzzii ranged from 4.5% to 8.33% and from 1.43% to 21.15% for An. arabiensis. After exposure to bendiocarb, the G119S mutation was found only in survivors. The survival of Anopheles gambiae (s.l) populations from the three surveyed localities was associated with the presence of the mutation. Conclusions: The study highlights the implication of G119S mutation in bendiocarb resistance in An. gambiae (s.s.), An. arabiensis and An. coluzzii populations from the three surveyed localities.

Widespread occurrence of copy number variants and fixation of pyrethroid target site resistance in Anopheles gambiae (s.l.) from southern Côte d’Ivoire

“…gambiae ( s.s. ), respectively ( Grau-Bové et al., 2021 ). Unlike some previous studies in Côte d’Ivoire where the resistant alleles were found only in heterozygous form ( Edi et al., 2012 ; Assogba et al., 2016 ; Keïta et al., 2020 ), our study revealed the presence of homozygous resistant genotypes in both An. coluzzii and An.…”

Impact of agrochemical pollutant mixtures on the selection of insecticide resistance in the malaria vector Anopheles gambiae. Insights from experimental evolution and transcriptomics

“…This absence of bendiocarb resistance was associated with a slow decrease of the G119S ace1 mutation commonly associated to carbamate and organophosphate resistance in An. gambiae (16,25,(70)(71)(72). This trend might be explained by the low initial frequency of the ace1 mutation in the parental line and its signi cant genetic cost (16, 73), or by the lower selection pressure exerted by carbamates and organophosphates present in the agrochemical mixtures as compared to other compounds such as pyrethroids and organochlorines.…”

A Decade of Progress Accelerating Malaria Control in Mali: Evidence from the West Africa International Center of Excellence for Malaria Research

“…Phenotypic resistance was also observed with carbamates to the three species, which was consistent with acetylcholinesterase (ace-1 R ) target-site mutation in all vector species studied. 31 The three species of A. gambiae s.l. were fully susceptible to the organophosphates (pirimiphos-methyl) at each study site.…”