High frequencies of F1534C and V1016I mutations and association with pyrethroid resistance in from Somgandé (Ouagadougou), Burkina Faso.

Background: Resistance to pyrethroid insecticides involving mutations is widespread in (L.) (Diptera: Culicidae) and potentially could impact control efforts in endemic countries. Dengue cases had been sporadic in Burkina Faso for over a decade prior to the 2016-2017 outbreak that resulted in 15,074 suspected cases and 36 deaths, mainly in Ouagadougou. These outbreaks highlighted the lack of information on numerous aspects of the biology, behaviour and insecticide status of local dengue vector populations that are fundamental to vector control.

Results: We investigated the insecticide resistance profiles and the mutations involved in pyrethroid resistance of . from Somgandé, a district of Ouagadougou. WHO bioassays revealed that the local . populations were highly resistant to pyrethroids with mortalities of 15% for permethrin and 37% for deltamethrin. Resistance to carbamates was also detected with mortalities of 55% for propoxur and 90% for bendiocarb, but high mortalities (> 97%) to organophosphates (malathion and fenitrothion) indicated susceptibility. Allele-specific PCR and voltage-gated sodium channel gene sequencing showed a very high frequency (97%) of the F1534C allele whilst the V1016I mutation frequency was 46%. Association of dual-locus mutations was detected for permethrin resistance.

Conclusion: We conclude that in this locality of Burkina Faso, . is resistant to pyrethroid and carbamate insecticides but remains susceptible to organophosphates, providing useful information for possible future control.