Insecticide resistance monitoring — DTM&H MCQ

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HardEntomology and vector controlInsecticide resistance monitoringDTM&H

A malaria programme notes reduced effectiveness of pyrethroid-treated nets. Entomologists collect local Anopheles mosquitoes for susceptibility testing. What is the most appropriate investigation?

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Correct answer: A — WHO tube or bottle bioassay testing

WHO tube or bottle bioassay testing is the single best answer because standard bioassays assess mosquito susceptibility and inform insecticide-resistance management. Widal agglutination testing is plausible in a related presentation, but it is less appropriate because it does not fit the key discriminator in this vignette. The teaching point is that vector control programmes require entomological surveillance as well as case surveillance.

Reference: WHO Global Vector Control Response; Manson's Tropical Diseases; CDC Yellow Book 2026