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Aging partially restores the efficacy of malaria vector control in insecticide-resistant populations of Anopheles gambiae s.l. from Burkina Faso

BACKGROUND: The operational impact of insecticide resistance on the effectiveness of long-lasting insecticide nets (LLINs) and indoor residual spraying (IRS) is poorly understood. One factor which may prolong the effectiveness of these tools in the field is the increase in insecticide susceptibility...

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Autores principales: Jones, Christopher M, Sanou, Antoine, Guelbeogo, Wamdaogo M, Sagnon, N'Fale, Johnson, Paul CD, Ranson, Hilary
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3312828/
https://www.ncbi.nlm.nih.gov/pubmed/22269002
http://dx.doi.org/10.1186/1475-2875-11-24
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author Jones, Christopher M
Sanou, Antoine
Guelbeogo, Wamdaogo M
Sagnon, N'Fale
Johnson, Paul CD
Ranson, Hilary
author_facet Jones, Christopher M
Sanou, Antoine
Guelbeogo, Wamdaogo M
Sagnon, N'Fale
Johnson, Paul CD
Ranson, Hilary
author_sort Jones, Christopher M
collection PubMed
description BACKGROUND: The operational impact of insecticide resistance on the effectiveness of long-lasting insecticide nets (LLINs) and indoor residual spraying (IRS) is poorly understood. One factor which may prolong the effectiveness of these tools in the field is the increase in insecticide susceptibility with mosquito age. In this study, LLINs and IRS were tested against young (three to five days) and old (17-19 days) pyrethroid resistant Anopheles gambiae s.l. from Burkina Faso. METHODS: Blood-fed adult Anopheles gambiae s.l. were collected from south-west Burkina Faso and identified to species/form level. Cohorts of the F1 progeny of An. gambiae s.s. S-forms were exposed to deltamethrin (0.05%) at three to five or 17-19 days post-emergence and tested for the frequency of the resistance allele 1014F. Isofemale lines of the M, S- form of An. gambiae s.s. and Anopheles arabiensis were exposed in WHO cone tests to either a) LLINs deployed in households for two years or (b) bendiocarb sprayed walls. RESULTS: Mortality rates in response to deltamethrin (0.05%) increased from levels indicative of strong resistance in three to five day old F1 mosquitoes, to near full susceptibility in the 17-19 day old cohort. On exposure to LLINs sampled from the field, the mortality rate in isofemale lines was higher in older mosquitoes than young (OR = 5.28, CI 95% = 2.81-9.92), although the mortality estimates were affected by the LLIN tested. In general, the LLINs sampled from the field performed poorly in WHO cone bioassays using either laboratory susceptible or field caught mosquito populations. Finally, there was a clear relationship between mortality and age on exposure to bendiocarb-sprayed walls, with older mosquitoes again proving more susceptible (OR = 3.39, CI 95% = 2.35-4.90). CONCLUSIONS: Age is a key factor determining the susceptibility of mosquitoes to insecticides, not only in laboratory studies, but in response to field-based vector control interventions. This has important implications for understanding the epidemiological impact of resistance. If mosquitoes old enough to transmit malaria are still being suppressed with available insecticides, is resistance potentially having less of an impact than often assumed? However, the poor performance of LLINs used in this study in Burkina Faso, is a cause for concern and requires urgent investigation.
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spelling pubmed-33128282012-03-27 Aging partially restores the efficacy of malaria vector control in insecticide-resistant populations of Anopheles gambiae s.l. from Burkina Faso Jones, Christopher M Sanou, Antoine Guelbeogo, Wamdaogo M Sagnon, N'Fale Johnson, Paul CD Ranson, Hilary Malar J Research BACKGROUND: The operational impact of insecticide resistance on the effectiveness of long-lasting insecticide nets (LLINs) and indoor residual spraying (IRS) is poorly understood. One factor which may prolong the effectiveness of these tools in the field is the increase in insecticide susceptibility with mosquito age. In this study, LLINs and IRS were tested against young (three to five days) and old (17-19 days) pyrethroid resistant Anopheles gambiae s.l. from Burkina Faso. METHODS: Blood-fed adult Anopheles gambiae s.l. were collected from south-west Burkina Faso and identified to species/form level. Cohorts of the F1 progeny of An. gambiae s.s. S-forms were exposed to deltamethrin (0.05%) at three to five or 17-19 days post-emergence and tested for the frequency of the resistance allele 1014F. Isofemale lines of the M, S- form of An. gambiae s.s. and Anopheles arabiensis were exposed in WHO cone tests to either a) LLINs deployed in households for two years or (b) bendiocarb sprayed walls. RESULTS: Mortality rates in response to deltamethrin (0.05%) increased from levels indicative of strong resistance in three to five day old F1 mosquitoes, to near full susceptibility in the 17-19 day old cohort. On exposure to LLINs sampled from the field, the mortality rate in isofemale lines was higher in older mosquitoes than young (OR = 5.28, CI 95% = 2.81-9.92), although the mortality estimates were affected by the LLIN tested. In general, the LLINs sampled from the field performed poorly in WHO cone bioassays using either laboratory susceptible or field caught mosquito populations. Finally, there was a clear relationship between mortality and age on exposure to bendiocarb-sprayed walls, with older mosquitoes again proving more susceptible (OR = 3.39, CI 95% = 2.35-4.90). CONCLUSIONS: Age is a key factor determining the susceptibility of mosquitoes to insecticides, not only in laboratory studies, but in response to field-based vector control interventions. This has important implications for understanding the epidemiological impact of resistance. If mosquitoes old enough to transmit malaria are still being suppressed with available insecticides, is resistance potentially having less of an impact than often assumed? However, the poor performance of LLINs used in this study in Burkina Faso, is a cause for concern and requires urgent investigation. BioMed Central 2012-01-23 /pmc/articles/PMC3312828/ /pubmed/22269002 http://dx.doi.org/10.1186/1475-2875-11-24 Text en Copyright ©2012 Jones et al; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research
Jones, Christopher M
Sanou, Antoine
Guelbeogo, Wamdaogo M
Sagnon, N'Fale
Johnson, Paul CD
Ranson, Hilary
Aging partially restores the efficacy of malaria vector control in insecticide-resistant populations of Anopheles gambiae s.l. from Burkina Faso
title Aging partially restores the efficacy of malaria vector control in insecticide-resistant populations of Anopheles gambiae s.l. from Burkina Faso
title_full Aging partially restores the efficacy of malaria vector control in insecticide-resistant populations of Anopheles gambiae s.l. from Burkina Faso
title_fullStr Aging partially restores the efficacy of malaria vector control in insecticide-resistant populations of Anopheles gambiae s.l. from Burkina Faso
title_full_unstemmed Aging partially restores the efficacy of malaria vector control in insecticide-resistant populations of Anopheles gambiae s.l. from Burkina Faso
title_short Aging partially restores the efficacy of malaria vector control in insecticide-resistant populations of Anopheles gambiae s.l. from Burkina Faso
title_sort aging partially restores the efficacy of malaria vector control in insecticide-resistant populations of anopheles gambiae s.l. from burkina faso
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3312828/
https://www.ncbi.nlm.nih.gov/pubmed/22269002
http://dx.doi.org/10.1186/1475-2875-11-24
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