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Comparative evaluation of an improved test method for bioefficacy of insecticidal fabrics against dengue and malaria vectors

BACKGROUND: Insecticidal fabrics are important personal protective measures against mosquitoes, ticks and other disease vectors. In the absence of internationally accepted guidelines, bioefficacy tests have been carried out using continuous exposure and three minutes exposure bioassay methods. Recen...

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Autores principales: Gopalakrishnan, Reji, Mazumder, Avik, Yadav, Ruchi, Meher, Damayanti, Singh, Ram, Sukumaran, Devanathan, Thakare, Vikas B., Palit, Meehir
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6664487/
https://www.ncbi.nlm.nih.gov/pubmed/31358045
http://dx.doi.org/10.1186/s13071-019-3637-y
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author Gopalakrishnan, Reji
Mazumder, Avik
Yadav, Ruchi
Meher, Damayanti
Singh, Ram
Sukumaran, Devanathan
Thakare, Vikas B.
Palit, Meehir
author_facet Gopalakrishnan, Reji
Mazumder, Avik
Yadav, Ruchi
Meher, Damayanti
Singh, Ram
Sukumaran, Devanathan
Thakare, Vikas B.
Palit, Meehir
author_sort Gopalakrishnan, Reji
collection PubMed
description BACKGROUND: Insecticidal fabrics are important personal protective measures against mosquitoes, ticks and other disease vectors. In the absence of internationally accepted guidelines, bioefficacy tests have been carried out using continuous exposure and three minutes exposure bioassay methods. Recently, we have reported an improved method for bioefficacy testing of insecticidal fabrics, which involves continuous exposure of mosquitoes to the test fabrics. The present paper reports the comparative evaluation of the outcomes of the continuous exposure bioassay and the three minutes bioassay on the same fabric samples. METHODS: Permethrin content in the treated fabric samples was determined through HPLC analysis and NMR studies were performed to establish the stability of the analyte. Bioefficacy tests were carried out against dengue vector Aedes aegypti and malaria vector Anopheles stephensi as per the improved test method and the three minutes bioassay method. RESULTS: The permethrin doses in the fabric samples ranged from 60 to 3000 mg/m(2) and 36.2% of permethrin was retained after 10 washings. The extraction and chromatographic analysis were not found to affect the stability of permethrin. In continuous exposure, all fabric samples showed bioefficacy, as the mean complete knockdown time for both Ae. aegypti (10.5–34.5 min) and An. stephensi (14.5–36.8 min) was ≤ 71.5 min. The same samples were found to be not effective when tested using the three minutes bioassay method, since the knockdown and mortality percentages were well below the required bioefficacy values. The bioefficacy of the fabric samples in terms of complete knockdown time was significantly higher against Ae. aegypti in comparison to An. stephensi. The mean complete knockdown time of Ae. aegypti increased to 48.3 min after 10 washings indicating a significant reduction in bioefficacy. CONCLUSIONS: Bioefficacy testing of the insecticidal fabrics using the improved method resulted in outcomes, which could be correlated better with the permethrin content in the fabric samples. The improved method is more appropriate for the testing of insecticidal fabrics than the three minutes bioassay method. Further evaluation of the improved method using different test arthropods could help in the formulation of specific guidelines for the bioefficacy testing of insecticidal fabrics.
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spelling pubmed-66644872019-08-05 Comparative evaluation of an improved test method for bioefficacy of insecticidal fabrics against dengue and malaria vectors Gopalakrishnan, Reji Mazumder, Avik Yadav, Ruchi Meher, Damayanti Singh, Ram Sukumaran, Devanathan Thakare, Vikas B. Palit, Meehir Parasit Vectors Research BACKGROUND: Insecticidal fabrics are important personal protective measures against mosquitoes, ticks and other disease vectors. In the absence of internationally accepted guidelines, bioefficacy tests have been carried out using continuous exposure and three minutes exposure bioassay methods. Recently, we have reported an improved method for bioefficacy testing of insecticidal fabrics, which involves continuous exposure of mosquitoes to the test fabrics. The present paper reports the comparative evaluation of the outcomes of the continuous exposure bioassay and the three minutes bioassay on the same fabric samples. METHODS: Permethrin content in the treated fabric samples was determined through HPLC analysis and NMR studies were performed to establish the stability of the analyte. Bioefficacy tests were carried out against dengue vector Aedes aegypti and malaria vector Anopheles stephensi as per the improved test method and the three minutes bioassay method. RESULTS: The permethrin doses in the fabric samples ranged from 60 to 3000 mg/m(2) and 36.2% of permethrin was retained after 10 washings. The extraction and chromatographic analysis were not found to affect the stability of permethrin. In continuous exposure, all fabric samples showed bioefficacy, as the mean complete knockdown time for both Ae. aegypti (10.5–34.5 min) and An. stephensi (14.5–36.8 min) was ≤ 71.5 min. The same samples were found to be not effective when tested using the three minutes bioassay method, since the knockdown and mortality percentages were well below the required bioefficacy values. The bioefficacy of the fabric samples in terms of complete knockdown time was significantly higher against Ae. aegypti in comparison to An. stephensi. The mean complete knockdown time of Ae. aegypti increased to 48.3 min after 10 washings indicating a significant reduction in bioefficacy. CONCLUSIONS: Bioefficacy testing of the insecticidal fabrics using the improved method resulted in outcomes, which could be correlated better with the permethrin content in the fabric samples. The improved method is more appropriate for the testing of insecticidal fabrics than the three minutes bioassay method. Further evaluation of the improved method using different test arthropods could help in the formulation of specific guidelines for the bioefficacy testing of insecticidal fabrics. BioMed Central 2019-07-29 /pmc/articles/PMC6664487/ /pubmed/31358045 http://dx.doi.org/10.1186/s13071-019-3637-y Text en © The Author(s) 2019 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research
Gopalakrishnan, Reji
Mazumder, Avik
Yadav, Ruchi
Meher, Damayanti
Singh, Ram
Sukumaran, Devanathan
Thakare, Vikas B.
Palit, Meehir
Comparative evaluation of an improved test method for bioefficacy of insecticidal fabrics against dengue and malaria vectors
title Comparative evaluation of an improved test method for bioefficacy of insecticidal fabrics against dengue and malaria vectors
title_full Comparative evaluation of an improved test method for bioefficacy of insecticidal fabrics against dengue and malaria vectors
title_fullStr Comparative evaluation of an improved test method for bioefficacy of insecticidal fabrics against dengue and malaria vectors
title_full_unstemmed Comparative evaluation of an improved test method for bioefficacy of insecticidal fabrics against dengue and malaria vectors
title_short Comparative evaluation of an improved test method for bioefficacy of insecticidal fabrics against dengue and malaria vectors
title_sort comparative evaluation of an improved test method for bioefficacy of insecticidal fabrics against dengue and malaria vectors
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6664487/
https://www.ncbi.nlm.nih.gov/pubmed/31358045
http://dx.doi.org/10.1186/s13071-019-3637-y
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