Genetic structure of Anopheles gambiae s.s populations following the use of insecticides on several consecutive years in southern Benin

• Published in: Tropical Medicine and Health
• Main Authors: Arsène Jacques Y. H. Fassinou, Come Z. Koukpo, Razaki A. Ossè, Fiacre R. Agossa, Benoit S. Assogba, Aboubakar Sidick, Wilfrid T. Sèwadé, Martin C. Akogbéto, Michel Sèzonlin
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2019
• Subjects: Anopheles gambiae s.l; Genetic structure; Malaria; Resistance; Benin; Arctic medicine. Tropical medicine; RC955-962; Arctic
• Online Access: https://doi.org/10.1186/s41182-019-0151-z; https://doaj.org/article/f0c1d291aef64939b825616c2daaf57b

Abstract Background Several studies have reported the strong resistance of Anopheles gambiae s.l. complex species to pyrethroids. The voltage-dependent sodium channel (Vgsc) gene is the main target of pyrethroids and DDT. In Benin, the frequency of the resistant allele (L1014F) of this gene varies along the north-south transect. Monitoring the evolution of resistance is necessary to better appreciate the genetic structure of vector populations in localities subject to the intensive use of chemicals associated with other control initiatives. The purpose of this study was to map the distribution of pyrethroid insecticide resistance alleles of the Kdr gene in malaria vectors in different regions and ecological facies in order to identify the evolutionary forces that might be the basis of anopheline population dynamics. Methods The characterization of Anopheles gambiae s.l. populations and resistance mechanisms were performed using adult mosquitoes obtained from larvae collected in the four agroecological zones in southern Benin. Genomic DNA extraction was performed on whole mosquitoes. The extracted genomic DNA from them were used for the molecular identification of species in Anopheles gambiae s.l. complex and the identification of genotypes related to pyrethroid resistance as the Kdr gene amino acid position 1014 in sodium channel. Molecular speciation and genotyping of Kdr resistant alleles (1014) were done using PCR. Genepop software version 4.2 was used to calculate allelic and genotypic frequencies in each agroecological zone. The p value of the allelic frequency was determined using the binomial test function in R version 3.3.3. The Hardy-Weinberg equilibrium was checked for each population with Genetics software version 1.3.8.1. The observed heterozygosity and the expected heterozygosity as well as the fixation index and genetic differentiation index within and between populations were calculated using Genepop software version 4.2. Results During the study period, Anopheles coluzzii was the major species in ...