Aedes aegypti control — DTM&H MCQ

Correct answer: E — Eliminating or covering small artificial water containers around households

The correct answer is E, eliminating or covering small artificial water containers around households. Aedes aegypti is a highly domesticated, container breeding mosquito that lays eggs in small volumes of clean, stagnant water found in discarded tyres, flowerpots, water storage drums, gutters and other peridomestic containers rather than in large open water bodies. Because these breeding sites are numerous, small and widely dispersed within households and yards, sustainable control depends on community based environmental management: removing, covering, emptying or inverting containers to physically deny oviposition sites. This source reduction approach is recommended as the cornerstone of Aedes control because it produces durable, long term reductions in vector density without the resistance and re-infestation problems seen with chemical methods. Why the other options are wrong: A. Widespread adulticidal fogging: fogging kills only flying adult mosquitoes at the time of spraying, has poor penetration indoors where Aedes rests, and provides no lasting effect because larvae in containers are unaffected and rapidly repopulate. D. Introducing larvivorous fish into rivers: Aedes aegypti does not breed in rivers or large natural water bodies, so fish introduced there have no impact on the actual container breeding sites driving transmission. C. Draining surrounding wetlands: wetland drainage targets Anopheles or Culex habitats, not the small artificial containers exploited by the peridomestic Aedes aegypti. B. Applying temephos to irrigation canals: temephos is a larvicide appropriate for treating water storage containers, not irrigation canals, and canals are not the primary habitat for this species; this misdirects a valid tool to the wrong site. Key point: Aedes aegypti breeds almost exclusively in small peridomestic artificial water containers, so household level source reduction (removal or covering of containers) is the most effective and sustainable control strategy.

Reference: NaTHNaC/UKHSA TravelHealthPro, Dengue factsheet: Aedes aegypti breed in water containers around households; source reduction (removing standing water in containers) is recommended to reduce breeding sites. https://travelhealthpro.org.uk/factsheet/13/dengue