Association of 410L, 1016I and 1534C kdr mutations with pyrethroid resistance in Aedes aegypti from Ouagadougou, Burkina Faso, and development of a one-step multiplex PCR method for the simultaneous detection of 1534C and 1016I kdr mutations

Abstract Background: Since 2000, Burkina Faso has experienced regular dengue cases and outbreaks making dengue a health concern for the country. Previous studies in Burkina Faso reported the resistance of Aedes aegypti to pyrethroid insecticides associated with F1534C and V1016I kdr mutations. The current study reports high resistance of Ae. aegypti populations to pyrethroid insecticides supported by 410L/1016I/1534C kdr haplotypes; and a new multiplex PCR-based diagnostic of 1534C and 1016I kdr mutations is proposed. Methods: Larvae of Ae. aegypti were collected from three health districts of Ouagadougou in 2018. The resistance status of Ae. aegypti to pyrethroid insecticides was tested using CDC-bottle bioassays, and to malathion using WHO tube tests. Bioassay results were interpreted according to used protocols. Results: Females from each health district were strongly resistant to permethrin and deltamethrin (<20% mortality) but were fully susceptible to 5% malathion. The F1534C and V1016I kdr mutations were successfully detected using a newly-developed multiplex PCR, which was validated by comparison with fluorescent probe-based TaqMan assays for each mutation. The V410L kdr mutation was detected using an allele-specific-PCR, which was confirmed by TaqMan assays, and owing to novelty in local Ae. aegypti populations, also direct DNA sequencing. The 1534C kdr allele was near fixation, while V1016I and V410L kdr alleles were strongly correlated with allelic frequencies range from 0.5 to 0.7 across the three-health districts. The 1534C/1016I/410L haplotype was correlated with permethrin resistance (χ21=33.7; p<0.001) but not with deltamethrin resistance (χ21=0.03; p=0.86), however, the test power was limited by a low frequency of dead individuals. Conclusions: The trio of kdr mutations (F1534C, V1016I and V410L) may explain the high resistance to pyrethroids, however lack of substantial resistance to malathion suggests that this remains a viable option for dengue vectors control in Ouagadougou.