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Does insecticide resistance contribute to heterogeneities in malaria transmission in The Gambia?

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Show simple item record Opondo, K. O. Weetman, D. Jawara, M. Diatta, M. Fofana, A. Crombe, F. Mwesigwa, J. D'Alessandro, U. Donnelly, M. J. 2016-05-27T12:45:56Z 2016-05-27T12:45:56Z 2016
dc.identifier.issn 1475-2875
dc.identifier.other ITG-H8A
dc.identifier.other DPH
dc.identifier.other U-ECMAL
dc.identifier.other JIF
dc.identifier.other DOI
dc.identifier.other FTA
dc.identifier.other OAJ
dc.identifier.other Abstract
dc.identifier.other UPD62
dc.description.abstract BACKGROUND: Malaria hotspots, areas with consistently higher than average transmission, may become increasingly common as malaria declines. This phenomenon, currently observed in The Gambia, may be caused by several factors, including some related to the local vectors, whose contribution is poorly understood. METHODS: Using WHO susceptibility bioassays, insecticide resistance status was determined in vector populations sampled from six pairs of villages across The Gambia, each pair contained a low and high prevalence village. RESULTS: Three vector species were observed (23.5 % Anopheles arabiensis, 31.2 % Anopheles gambiae, 43.3 % Anopheles coluzzii and 2.0 % An. coluzzii x An. gambiae hybrids). Even at a fine scale, significant differences in species composition were detected within village pairs. Resistance to both DDT and deltamethrin was more common in An. gambiae, most markedly in the eastern part of The Gambia and partly attributable to differing frequencies of resistance mutations. The Vgsc-1014F target site mutation was strongly associated with both DDT (OR = 256.7, (95 % CI 48.6-6374.3, p < 0.001) and deltamethrin survival (OR = 9.14, (95 % CI 4.24-21.4, p < 0.001). A second target site mutation, Vgsc-1575Y, which co-occurs with Vgsc-1014F, and a metabolic marker of resistance, Gste2-114T, conferred additional survival benefits to both insecticides. DDT resistance occurred significantly more frequently in villages with high malaria prevalence (p = 0.025) though this did not apply to deltamethrin resistance. CONCLUSION: Whilst causality of relationships requires further investigation, variation in vector species and insecticide resistance in The Gambia is associated with malaria endemicity; with a notably higher prevalence of infection and insecticide resistance in the east of the country. In areas with heterogeneous malaria transmission, the role of the vector should be investigated to guide malaria control interventions. en_US
dc.language English en_US
dc.subject Protozoal diseases en_US
dc.subject Malaria en_US
dc.subject Plasmodium falciparum en_US
dc.subject Vectors en_US
dc.subject Mosquitoes en_US
dc.subject Anopheles en_US
dc.subject Drug resistance en_US
dc.subject Impact en_US
dc.subject Disease transmission en_US
dc.subject Heterogeneity en_US
dc.subject DDT en_US
dc.subject Deltamethrin en_US
dc.subject Frequency en_US
dc.subject Mutations en_US
dc.subject Metabolic mechanisms en_US
dc.subject Markers en_US
dc.subject Gambia en_US
dc.subject Africa, West en_US
dc.title Does insecticide resistance contribute to heterogeneities in malaria transmission in The Gambia? en_US
dc.type Article-E en_US
dc.citation.issue 166 en_US
dc.citation.jtitle Malaria Journal en_US
dc.citation.volume 15 en_US
dc.citation.pages 1-10 en_US
dc.citation.jabbreviation Malar J en_US

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