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

Mawejje, Henry Ddumba, Weetman, David ORCID:, Epstein, Adrienne, Lynd, Amy ORCID:, Opigo, Jimmy, Maiteki-Sebuguzi, Catherine, Lines, Jo, Kamya, Moses R, Rosenthal, Philip J, Donnelly, Martin ORCID:, Dorsey, Grant and Staedke, Sarah G (2022) 'Characterizing pyrethroid resistance and mechanisms in Anopheles gambiae (s.s.) and Anopheles arabiensis from 11 districts in Uganda'. Current Research in Parasitology and Vector-Borne Diseases, Vol 3, p. 100106.

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

Item Type: Article
Subjects: QX Parasitology > QX 20 Research (General)
QX Parasitology > Insects. Other Parasites > QX 515 Anopheles
QX Parasitology > Insects. Other Parasites > QX 600 Insect control. Tick control
Faculty: Department: Biological Sciences > Vector Biology Department
Digital Object Identifer (DOI):
SWORD Depositor: JISC Pubrouter
Depositing User: JISC Pubrouter
Date Deposited: 17 Jan 2023 15:40
Last Modified: 17 Jan 2023 15:40


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