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Insecticide resistance in Aedes aegypti from Tapachula, Mexico: Spatial variation and response to historical insecticide use

BACKGROUND: Insecticide use continues as the main strategy to control Aedes aegypti, the vector of dengue, Zika, chikungunya, and yellow fever. In the city of Tapachula, Mexico, mosquito control programs switched from pyrethroids to organophosphates for outdoor spatial spraying in 2013. Additionally...

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Autores principales: Solis-Santoyo, Francisco, Rodriguez, Americo D., Penilla-Navarro, R. Patricia, Sanchez, Daniel, Castillo-Vera, Alfredo, Lopez-Solis, Alma D., Vazquez-Lopez, Eduardo D., Lozano, Saul, Black, William C., Saavedra-Rodriguez, Karla
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8475978/
https://www.ncbi.nlm.nih.gov/pubmed/34570792
http://dx.doi.org/10.1371/journal.pntd.0009746
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author Solis-Santoyo, Francisco
Rodriguez, Americo D.
Penilla-Navarro, R. Patricia
Sanchez, Daniel
Castillo-Vera, Alfredo
Lopez-Solis, Alma D.
Vazquez-Lopez, Eduardo D.
Lozano, Saul
Black, William C.
Saavedra-Rodriguez, Karla
author_facet Solis-Santoyo, Francisco
Rodriguez, Americo D.
Penilla-Navarro, R. Patricia
Sanchez, Daniel
Castillo-Vera, Alfredo
Lopez-Solis, Alma D.
Vazquez-Lopez, Eduardo D.
Lozano, Saul
Black, William C.
Saavedra-Rodriguez, Karla
author_sort Solis-Santoyo, Francisco
collection PubMed
description BACKGROUND: Insecticide use continues as the main strategy to control Aedes aegypti, the vector of dengue, Zika, chikungunya, and yellow fever. In the city of Tapachula, Mexico, mosquito control programs switched from pyrethroids to organophosphates for outdoor spatial spraying in 2013. Additionally, the spraying scheme switched from total coverage to focused control, prioritizing areas with higher entomological-virological risk. Five years after this strategy had been implemented, we evaluated the status and variability of insecticide resistance among Ae. aegypti collected at 26 sites in Tapachula. METHODOLOGY/PRINCIPAL FINDINGS: We determined the lethal concentrations at 50% of the tested populations (LC(50)) using a bottle bioassay, and then, we calculated the resistance ratio (RR) relative to the susceptible New Orleans strain. Permethrin and deltamethrin (pyrethroids), chlorpyrifos and malathion (organophosphates), and bendiocarb (carbamate) were tested. The frequencies of the substitutions V1016I and F1534C, which are in the voltage-gated sodium channel and confer knockdown-resistance (kdr) to pyrethroid insecticides, were calculated. Despite 5 years having passed since the removal of pyrethroids from the control programs, Ae. aegypti remained highly resistant to permethrin and deltamethrin (RR > 10-fold). In addition, following 5 years of chlorpyrifos use, mosquitoes at 15 of 26 sites showed moderate resistance to chlorpyrifos (5- to 10-fold), and the mosquitoes from one site were highly resistant. All sites had low resistance to malathion (< 5-fold). Resistance to bendiocarb was low at 19 sites, moderate at five, and high at two. Frequencies of the V1016I ranged from 0.16–0.71, while C1534 approached fixation at 23 sites (0.8–1). Resistance profiles and kdr allele frequencies varied across Tapachula. The variability was not associated with a spatial pattern at the scale of the sampling. CONCLUSION/SIGNIFICANCE: Mosquito populations respond to selection pressure at a focal scale in the field. Spatial variation across sites highlights the importance of testing multiple sites within geographical regions.
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spelling pubmed-84759782021-09-28 Insecticide resistance in Aedes aegypti from Tapachula, Mexico: Spatial variation and response to historical insecticide use Solis-Santoyo, Francisco Rodriguez, Americo D. Penilla-Navarro, R. Patricia Sanchez, Daniel Castillo-Vera, Alfredo Lopez-Solis, Alma D. Vazquez-Lopez, Eduardo D. Lozano, Saul Black, William C. Saavedra-Rodriguez, Karla PLoS Negl Trop Dis Research Article BACKGROUND: Insecticide use continues as the main strategy to control Aedes aegypti, the vector of dengue, Zika, chikungunya, and yellow fever. In the city of Tapachula, Mexico, mosquito control programs switched from pyrethroids to organophosphates for outdoor spatial spraying in 2013. Additionally, the spraying scheme switched from total coverage to focused control, prioritizing areas with higher entomological-virological risk. Five years after this strategy had been implemented, we evaluated the status and variability of insecticide resistance among Ae. aegypti collected at 26 sites in Tapachula. METHODOLOGY/PRINCIPAL FINDINGS: We determined the lethal concentrations at 50% of the tested populations (LC(50)) using a bottle bioassay, and then, we calculated the resistance ratio (RR) relative to the susceptible New Orleans strain. Permethrin and deltamethrin (pyrethroids), chlorpyrifos and malathion (organophosphates), and bendiocarb (carbamate) were tested. The frequencies of the substitutions V1016I and F1534C, which are in the voltage-gated sodium channel and confer knockdown-resistance (kdr) to pyrethroid insecticides, were calculated. Despite 5 years having passed since the removal of pyrethroids from the control programs, Ae. aegypti remained highly resistant to permethrin and deltamethrin (RR > 10-fold). In addition, following 5 years of chlorpyrifos use, mosquitoes at 15 of 26 sites showed moderate resistance to chlorpyrifos (5- to 10-fold), and the mosquitoes from one site were highly resistant. All sites had low resistance to malathion (< 5-fold). Resistance to bendiocarb was low at 19 sites, moderate at five, and high at two. Frequencies of the V1016I ranged from 0.16–0.71, while C1534 approached fixation at 23 sites (0.8–1). Resistance profiles and kdr allele frequencies varied across Tapachula. The variability was not associated with a spatial pattern at the scale of the sampling. CONCLUSION/SIGNIFICANCE: Mosquito populations respond to selection pressure at a focal scale in the field. Spatial variation across sites highlights the importance of testing multiple sites within geographical regions. Public Library of Science 2021-09-27 /pmc/articles/PMC8475978/ /pubmed/34570792 http://dx.doi.org/10.1371/journal.pntd.0009746 Text en https://creativecommons.org/publicdomain/zero/1.0/This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 (https://creativecommons.org/publicdomain/zero/1.0/) public domain dedication.
spellingShingle Research Article
Solis-Santoyo, Francisco
Rodriguez, Americo D.
Penilla-Navarro, R. Patricia
Sanchez, Daniel
Castillo-Vera, Alfredo
Lopez-Solis, Alma D.
Vazquez-Lopez, Eduardo D.
Lozano, Saul
Black, William C.
Saavedra-Rodriguez, Karla
Insecticide resistance in Aedes aegypti from Tapachula, Mexico: Spatial variation and response to historical insecticide use
title Insecticide resistance in Aedes aegypti from Tapachula, Mexico: Spatial variation and response to historical insecticide use
title_full Insecticide resistance in Aedes aegypti from Tapachula, Mexico: Spatial variation and response to historical insecticide use
title_fullStr Insecticide resistance in Aedes aegypti from Tapachula, Mexico: Spatial variation and response to historical insecticide use
title_full_unstemmed Insecticide resistance in Aedes aegypti from Tapachula, Mexico: Spatial variation and response to historical insecticide use
title_short Insecticide resistance in Aedes aegypti from Tapachula, Mexico: Spatial variation and response to historical insecticide use
title_sort insecticide resistance in aedes aegypti from tapachula, mexico: spatial variation and response to historical insecticide use
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8475978/
https://www.ncbi.nlm.nih.gov/pubmed/34570792
http://dx.doi.org/10.1371/journal.pntd.0009746
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