Characterizing pyrethroid resistance and mechanisms in Anopheles gambiae (s.s.) and Anopheles arabiensis from 11 districts in Uganda

• DOI: 10.1016/j.crpvbd.2022.100106
• Publication Date: 2022-12-10T07:01:28Z
• Authors: Henry Ddumba Mawejje; David Weetman; Adrienne Epstein; Amy Lynd; Jimmy Opigo; Catherine Maiteki...; Jo Lines; Moses R. Kamya; Philip J. Rosenthal; Martin J. Donnelly; Grant Dorsey; Sarah G. Staedke
• Keywords: Anopheles gambiae; Piperonyl butoxide; Indoor residual spraying

Insecticide resistance threatens recent progress on malaria control in Africa. To characterize pyrethroid Uganda, Anopheles gambiae (s.s.) and arabiensis were analyzed from 11 sites with varied vector strategies. Mosquito larvae collected between May 2018 December 2020. Sites categorized as receiving no indoor-residual spraying ('no IRS', n ​= ​3); where IRS was delivered 2009 to 2014 2017 then discontinued ('IRS stopped', ​4); had been sustained since active', ​4). included bendiocarb, pirimiphos methyl clothianidin. All received long-lasting insecticidal nets (LLINs) 2017. Adult mosquitoes exposed pyrethroids; or without piperonyl butoxide (PBO). An. identified using PCR. genotyped for Vgsc-995S/F, Cyp6aa1, Cyp6p4-I236M, ZZB-TE, Cyp4j5-L43F Coeae1d, while examined Vgsc-1014S/F. Overall, 2753 (s.l.), including 1105 1648 evaluated. Species composition by site; only nine 'IRS active' sites, precluding species-specific comparisons. mortality following exposure permethrin deltamethrin 18.8% (148/788) 74.6% (912/1222) arabiensis. Mortality significantly lower than 'no IRS' (permethrin: 16.1 vs 67.7%, P ​< ​0.001; deltamethrin: 24.6 83.7%, ​0.001) stopped' 11.3 63.6%, 25.6 88.9%, ​0.001). When PBO added, increased Most the Vgsc-995S/F mutation (95% frequency) Cyp6p4-I236M allele (87%), frequency of Cyp4j5 Coeae1d (52% 55%, respectively). Resistance pyrethroids widespread higher (s.s.). Where active, dominated. Addition mortality, supporting deployment LLINs. Further surveillance insecticide assessment associations genotypic markers phenotypic outcomes are needed better understand mechanisms guide control.