Investigating population structure and mechanisms driving pyrethroid resistance in Anopheles funestus reveals a selective sweep in Southern Africa



Barnes, Kayla
Investigating population structure and mechanisms driving pyrethroid resistance in Anopheles funestus reveals a selective sweep in Southern Africa. PhD thesis, University of Liverpool.

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Abstract

Resistance to pyrethroids, the only insecticide class approved for bednets, threatens the control of the major African malaria vectors, Anopheles funestus. In Malawi, where resistance has been previously reported, little is known about the nation-wide resistance profile, mechanisms and patterns of gene flow driving the spread of resistance. To manage resistance effectively, it is crucial to understand the dynamics and evolution of resistance. To fill this gap in knowledge, this study has determined the levels of insecticide resistance in Malawi in a South/North transect across the highly endemic and densely populated lake and southern agricultural area. An. funestus was resistant to pyrethroids, carbamates, and DDT but fully susceptible to organophosphates. Microarray and qRT-PCR analysis revealed the key role of cytochrome P450 genes including as CYP6P9a, CYP6P9b and CYP6M7. However, a significant shift in the over-expression of these CYP450s was detected across a south/north transect, with CYP6M7 more highly over-transcribed in the two northern locations and CYP6P9a and CYP6P9b more greatly over-transcribed in the south. CYP6M7 was under neutral selection while CYP6P9a and CYP6P9b were directionally selected, which was more pronounced in the South than in the North. Additionally, a new CYP450 gene, CYP6AA1, located on the pyrethroid resistance QTL (rp1) near CYP6P9a and CYP6P9b, was consistently overexpressed in resistant mosquitoes (5.20

Item Type: Thesis (PhD)
Additional Information: Date: 2015-09-15 (completed)
Subjects: ?? Q1 ??
Depositing User: Symplectic Admin
Date Deposited: 08 Jan 2016 14:46
Last Modified: 17 Dec 2022 00:48
DOI: 10.17638/02029380
URI: https://livrepository.liverpool.ac.uk/id/eprint/2029380