Resistance to pyrethroids and DDT have been correlated with target-site mutations in the voltage-gated sodium channel ( vgsc) gene, also known as knock down resistance (kdr), as well as with metabolic resistance due to point mutations in the glutathione-s-transferase epsilon ( gste2) gene 4, 5. One of the main mechanisms associated with insecticide resistance is decreased target site sensitivity. However, the effectiveness of vector control is threatened by increasing insecticide resistance in multiple Anopheles vectors, which has now been documented in almost all African countries 2, 3. These approaches have contributed significantly to a decline of malaria incidence. Whilst for ITNs only pyrethroid insecticides are currently being used alone or in combination with a second active ingredient (the synergist piperonyl butoxide, the pyrrole chlorfenapyr or the juvenile growth hormone inhibition pyriproxyfen). The World Health Organization (WHO) recommends five chemical classes of insecticides (neonicotinoids, carbamates, organochlorines, organophosphates and pyrethroids) for IRS. Vector control strategies are based on two primary interventions, namely, insecticide-treated nets (ITN) and indoor residual spraying (IRS).
There were 241 million cases and 627,000 deaths reported in 2020 alone, predominantly in Sub-Saharan Africa 1. However, infection control progress has recently stalled with no further reductions in malaria-attributable mortality, and even reversal in some regions 1. In the last decade, malaria elimination strategies have contributed to a global fall in incidence rates.
Malaria, a mosquito-borne disease caused by Plasmodium parasites, is an important public health problem. gambiae complex mosquitoes in malaria endemic regions. Overall, we present a reliable and cost-effective high-throughput panel for surveillance of An. gambiae complex species, we identified a total of 15 non-synonymous mutations in the insecticide target genes, including previously described mutations associated with resistance and two new mutations (F1525L in vgsc and D148E in gste2). Using this amplicon sequencing approach with the four selected An. By amplifying and sequencing only 14 genetic fragments (500 bp each), we were able to simultaneously detect Plasmodium infection insecticide resistance-conferring SNPs in ace1, gste2, vgsc and rdl genes the partial sequences of nuclear ribosomal internal transcribed spacers (ITS1 and ITS2) and intergenic spacers (IGS), Short INterspersed Elements (SINE), as well as mitochondrial genes ( cox1 and nd4) for species identification and genetic diversity. In this study, we combined multiplex PCR, custom designed dual indexing, and Illumina next generation sequencing for high throughput single nucleotide polymorphism (SNP)-profiling of four species from the Anopheles (An.) gambiae complex ( An. Genetic barcoding of mosquitoes is a useful tool to assist the high-throughput surveillance of insecticide resistance, discriminate between sibling species and to detect the presence of Plasmodium infections. Surveillance of malaria vector species and the monitoring of insecticide resistance are essential to inform malaria control strategies and support the reduction of infections and disease.
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