Irritant effect, prevention of blood feeding and toxicity of nets impregnated with different pyrethroids on An. stephensi

A resistant strain of An. stephensi was confirmed to have high resistance to knock down and kill by four different pyrethroids in bioassays in comparison with a susceptible strain. Permethrin, lambda-cyhalothrin and deltamethrin were more irritant to the susceptible strain than the resistant as judg...

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Bibliographic Details
Published inJournal of vector borne diseases Vol. 40; no. 1-2; pp. 54 - 59
Main Authors Hodjati, M H, Mousavi, N, Curtis, C F
Format Journal Article
LanguageEnglish
Published India Wolters Kluwer Medknow Publications 01.03.2003
Subjects
An. stephensi
Animals
Anopheles - drug effects
Bedding and Linens
Biological Assay
Insect Vectors
Insecticide Resistance
Insecticides - pharmacology
Mosquito Control - methods
Pyrethrins - pharmacology
pyrethroid impregnated bednets
Species Specificity
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Summary:A resistant strain of An. stephensi was confirmed to have high resistance to knock down and kill by four different pyrethroids in bioassays in comparison with a susceptible strain. Permethrin, lambda-cyhalothrin and deltamethrin were more irritant to the susceptible strain than the resistant as judged by time for first take-off, but nets treated with alphacypermethrin appeared to be more irritant to the resistant An. stephensi than the susceptible. With all the pyrethroids tested, the resistant strain spent a longer time in contact with a treated net, which was in contact with a human arm, than did the susceptible strain. With permethrin the resistant strain fed significantly more successfully through the treated netting than did the susceptible strain. With deltamethrin there was a non-significant tendency in the same direction in comparing the two strains. However, with alphacypermethrin there was a non-significant tendency in the reverse direction. After 15 min in the cage which tested for the ability to feed through a pyrethroid treated net, observed mortality was higher with the susceptible than the resistant strain. Thus there was no sign that the longer resting of the resistant strain on treated netting would compensate for the fact that a higher dose was needed to kill this strain. Such compensation has been suggested with West African An. gambiae where treated nets continue to work well against a highly resistant wild population. However, this does not seem to apply to our resistant An. stephensi.
ISSN:0972-9062