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Adaptation and evaluation of the bottle assay for monitoring insecticide resistance in disease vector mosquitoes in the Peruvian Amazon.

Zamora Perea E, Balta León R, Palomino Salcedo M, Brogdon WG, Devine GJ - Malar. J. (2009)

Bottom Line: A diagnostic dose of 10 microg a.i./bottle was identified as the most sensitive discriminating dose for characterizing resistance in An. darlingi and Ae. aegypti.Treated bottles, prepared using locally sourced solvents and insecticide formulations, can be stored for > 14 days and used three times.Bottles can be stored and transported under local conditions and field-assays can be completed in a single evening.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratorio de Salud Pública, Iquitos, Perú. elvirazamoraperea@hotmail.com

ABSTRACT

Background: The purpose of this study was to establish whether the "bottle assay", a tool for monitoring insecticide resistance in mosquitoes, can complement and augment the capabilities of the established WHO assay, particularly in resource-poor, logistically challenging environments.

Methods: Laboratory reared Aedes aegypti and field collected Anopheles darlingi and Anopheles albimanus were used to assess the suitability of locally sourced solvents and formulated insecticides for use with the bottle assay. Using these adapted protocols, the ability of the bottle assay and the WHO assay to discriminate between deltamethrin-resistant Anopheles albimanus populations was compared. The diagnostic dose of deltamethrin that would identify resistance in currently susceptible populations of An. darlingi and Ae. aegypti was defined. The robustness of the bottle assay during a surveillance exercise in the Amazon was assessed.

Results: The bottle assay (using technical or formulated material) and the WHO assay were equally able to differentiate deltamethrin-resistant and susceptible An. albimanus populations. A diagnostic dose of 10 microg a.i./bottle was identified as the most sensitive discriminating dose for characterizing resistance in An. darlingi and Ae. aegypti. Treated bottles, prepared using locally sourced solvents and insecticide formulations, can be stored for > 14 days and used three times. Bottles can be stored and transported under local conditions and field-assays can be completed in a single evening.

Conclusion: The flexible and portable nature of the bottle assay and the ready availability of its components make it a potentially robust and useful tool for monitoring insecticide resistance and efficacy in remote areas that require minimal cost tools.

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A. The effect of different solvents and formulations on the mortality of mosquitoes exposed to a range of deltamethrin doses for 2 h [means ± 95% confidence limits]. B. A comparison of time-series relationships for different formulations and solvents at 2 μg/bottle [means ± 95% confidence limits].
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Figure 1: A. The effect of different solvents and formulations on the mortality of mosquitoes exposed to a range of deltamethrin doses for 2 h [means ± 95% confidence limits]. B. A comparison of time-series relationships for different formulations and solvents at 2 μg/bottle [means ± 95% confidence limits].

Mentions: Mosquitoes exhibited no differences in mortality associated with the use of different solvents (F > 0.06 < 3.71, p > 0.057 < 0.79). This was true at every time interval (only the 2 h reading is illustrated in Figure 1A). Exposure to formulated material however (a 2.5% wettable powder) gave consistently greater mortality than exposure to technical insecticide (F > 7.4 < 38.9, p < 0.01). This was true at all doses except the highest (2 μg), which after 2 h had killed > 98% of all mosquitoes regardless of solvent or formulation. The time-mortality response was similar between solvents (Figure 1B), but significantly different between technical and formulated compounds.


Adaptation and evaluation of the bottle assay for monitoring insecticide resistance in disease vector mosquitoes in the Peruvian Amazon.

Zamora Perea E, Balta León R, Palomino Salcedo M, Brogdon WG, Devine GJ - Malar. J. (2009)

A. The effect of different solvents and formulations on the mortality of mosquitoes exposed to a range of deltamethrin doses for 2 h [means ± 95% confidence limits]. B. A comparison of time-series relationships for different formulations and solvents at 2 μg/bottle [means ± 95% confidence limits].
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2742550&req=5

Figure 1: A. The effect of different solvents and formulations on the mortality of mosquitoes exposed to a range of deltamethrin doses for 2 h [means ± 95% confidence limits]. B. A comparison of time-series relationships for different formulations and solvents at 2 μg/bottle [means ± 95% confidence limits].
Mentions: Mosquitoes exhibited no differences in mortality associated with the use of different solvents (F > 0.06 < 3.71, p > 0.057 < 0.79). This was true at every time interval (only the 2 h reading is illustrated in Figure 1A). Exposure to formulated material however (a 2.5% wettable powder) gave consistently greater mortality than exposure to technical insecticide (F > 7.4 < 38.9, p < 0.01). This was true at all doses except the highest (2 μg), which after 2 h had killed > 98% of all mosquitoes regardless of solvent or formulation. The time-mortality response was similar between solvents (Figure 1B), but significantly different between technical and formulated compounds.

Bottom Line: A diagnostic dose of 10 microg a.i./bottle was identified as the most sensitive discriminating dose for characterizing resistance in An. darlingi and Ae. aegypti.Treated bottles, prepared using locally sourced solvents and insecticide formulations, can be stored for > 14 days and used three times.Bottles can be stored and transported under local conditions and field-assays can be completed in a single evening.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratorio de Salud Pública, Iquitos, Perú. elvirazamoraperea@hotmail.com

ABSTRACT

Background: The purpose of this study was to establish whether the "bottle assay", a tool for monitoring insecticide resistance in mosquitoes, can complement and augment the capabilities of the established WHO assay, particularly in resource-poor, logistically challenging environments.

Methods: Laboratory reared Aedes aegypti and field collected Anopheles darlingi and Anopheles albimanus were used to assess the suitability of locally sourced solvents and formulated insecticides for use with the bottle assay. Using these adapted protocols, the ability of the bottle assay and the WHO assay to discriminate between deltamethrin-resistant Anopheles albimanus populations was compared. The diagnostic dose of deltamethrin that would identify resistance in currently susceptible populations of An. darlingi and Ae. aegypti was defined. The robustness of the bottle assay during a surveillance exercise in the Amazon was assessed.

Results: The bottle assay (using technical or formulated material) and the WHO assay were equally able to differentiate deltamethrin-resistant and susceptible An. albimanus populations. A diagnostic dose of 10 microg a.i./bottle was identified as the most sensitive discriminating dose for characterizing resistance in An. darlingi and Ae. aegypti. Treated bottles, prepared using locally sourced solvents and insecticide formulations, can be stored for > 14 days and used three times. Bottles can be stored and transported under local conditions and field-assays can be completed in a single evening.

Conclusion: The flexible and portable nature of the bottle assay and the ready availability of its components make it a potentially robust and useful tool for monitoring insecticide resistance and efficacy in remote areas that require minimal cost tools.

Show MeSH