Anopheles identification — DTM&H MCQ

Correct answer: D — Anopheles mosquito

The correct answer is D, Anopheles mosquito. A resting posture angled away from the wall (typically 30 to 45 degrees, abdomen tilted upward) combined with maxillary palps that are as long as the proboscis are the classic morphological and behavioural discriminators used in entomological surveys to identify Anopheles species. Anopheles is the only mosquito genus whose females transmit human Plasmodium species, making correct field identification directly relevant to malaria vector control and to targeting indoor residual spraying and bed net interventions in endemic villages. This identification underpins UK travel medicine guidance on malaria risk assessment, which relies on knowing local Anopheles behaviour (indoor resting, night biting) to advise on bite avoidance and chemoprophylaxis. Why the other options are wrong: C. Sandfly: Sandflies transmit leishmaniasis and sandfly fever via Phlebotomus or Lutzomyia species; they have a characteristic hopping flight and hairy wings, not the angled resting posture or long palps described. B. Culex mosquito: Culex rests with its body parallel (flat) to the resting surface and has short palps well below proboscis length; it is the principal vector of lymphatic filariasis (Wuchereria bancrofti) and several arboviruses, not malaria. E. Mansonia mosquito: Mansonia also rests parallel to surfaces and has short palps; its larvae attach to aquatic vegetation for oxygen and it transmits Brugia malayi filariasis, unrelated to the malaria parasite. A. Aedes mosquito: Aedes rests close to and parallel with the substrate, has palps much shorter than the proboscis, and is the vector for dengue, chikungunya, Zika and yellow fever, not malaria. Key point: An angled resting posture plus palps equal in length to the proboscis are the field hallmarks that identify Anopheles as the sole vector of human malaria.

Reference: UKHSA UK Malaria Expert Advisory Group, Guidelines for malaria prevention in travellers from the UK, 2024, gov.uk/government/publications/malaria-prevention-guidelines-for-travellers-from-the-uk