Evolution of the Ace-1 and Gste2 Mutations and Their Potential Impact on the Use of Carbamate and Organophosphates in IRS for Controlling Anopheles gambiae s.l., the Major Malaria Mosquito in Senegal

Abstract

Widespread of insecticide resistance amongst the species of the Anopheles gambiae complex continues to threaten vector control in Senegal. In this study, we investigated the presence and evolution of the Ace-1 and Gste2 resistance genes in natural populations of Anopheles gambiae s.l., the main malaria vector in Senegal. Using historical samples collected from ten sentinel health districts, this study focused on three different years (2013, 2017, and 2018) marking the periods of shift between the main public health insecticides families (pyrethroids, carbamates, organophosphates) used in IRS to track back the evolutionary history of the resistance mutations on the Ace-1 and Gste2 loci. The results revealed the presence of four members of the Anopheles gambiae complex, with the predominance of An. arabiensis followed by An. gambiae, An. coluzzii, and An. gambiae–coluzzii hybrids. The Ace-1 mutation was only detected in An. gambiae and An. gambiae–coluzzii hybrids at low frequencies varying between 0.006 and 0.02, while the Gste2 mutation was found in all the species with a frequency ranging between 0.02 and 0.25. The Ace-1 and Gste2 genes were highly diversified with twenty-two and thirty-one different haplotypes, respectively. The neutrality tests on each gene indicated a negative Tajima’s D, suggesting the abundance of rare alleles. The presence and spread of the Ace-1 and Gste2 resistance mutations represent a serious threat to of the effectiveness and the sustainability of IRS-based interventions using carbamates or organophosphates to manage the widespread pyrethroids resistance in Senegal. These data are of the highest importance to support the NMCP for evidence-based vector control interventions selection and targeting.

Transcriptomic analyses of differentially expressed genes, micro RNAs and long-non-coding RNAs in severe, symptomatic and asymptomatic malaria infection

“…The recent World Health Malaria Report estimated about 241 million malaria cases and 627,000 deaths, and 95% of the cases and deaths are from sub-Saharan Africa (WHO, 2021). As a result of the growing threat of parasite and vector resistance to antimalarial drug and insecticides (Abruquah et al, 2010; Adams et al, 2018; Alam et al, 2011; Awolola et al, 2018; Diallo et al, 2022; Fukuda et al, 2021; Hawkes et al, 2015; Oboh et al, 2018; Patel et al, 2017; Straimer et al, 2022; Tacoli et al, 2016; Traoré et al, 2019; Tumwebaze et al, 2021), attention is now focused, more than ever on other control measures that can be deployed for malaria control. Unfortunately, vaccine development has also not been spared from parasite evasive mechanisms.…”