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The development of insecticide resistance in African malaria vectors threatens the continued efficacy of important vector control methods that rely on a limited set of insecticides. To understand the operational significance of resistance we require quantitative information about levels of resistance in field populations to the suite of vector control insecticides. Estimation of resistance is complicated by the sparsity of observations in field populations, variation in resistance over time and space at local and regional scales, and cross-resistance between different insecticide types. Using observations of the prevalence of resistance in mosquito species from the Anopheles gambiae complex sampled from 1,183 locations throughout Africa, we applied Bayesian geostatistical models to quantify patterns of covariation in resistance phenotypes across different insecticides. For resistance to the three pyrethroids tested, deltamethrin, permethrin, and λ-cyhalothrin, we found consistent forms of covariation across sub-Saharan Africa and covariation between resistance to these pyrethroids and resistance to DDT. We found no evidence of resistance interactions between carbamate and organophosphate insecticides or between these insecticides and those from other classes. For pyrethroids and DDT we found significant associations between predicted mean resistance and the observed frequency of kdr mutations in the Vgsc gene in field mosquito samples, with DDT showing the strongest association. These results improve our capacity to understand and predict resistance patterns throughout Africa and can guide the development of monitoring strategies.

Original publication

DOI

10.1073/pnas.1801826115

Type

Journal article

Journal

Proceedings of the national academy of sciences of the united states of america

Publication Date

06/2018

Volume

115

Pages

5938 - 5943

Addresses

Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, OX3 7LF Oxford, United Kingdom; hancock.penelope@gmail.com janet.hemingway@lstmed.ac.uk catherinemoyes@gmail.com.

Keywords

Animals, Culicidae, Malaria, DDT, Pyrethrins, Permethrin, Nitriles, Insecticides, Models, Statistical, Insecticide Resistance, Genes, Insect, Mosquito Vectors