Sandfly identification — DTM&H MCQ

Correct answer: E — Phlebotomus

The correct answer is E, Phlebotomus. This genus comprises small (2 to 3 mm), densely hairy sandflies with a characteristic silent, hopping flight and wings held erect in a V shape over the body at rest, exactly as described in the stem. Phlebotomus species are the proven vectors of Old World leishmaniasis, including the visceral and cutaneous forms endemic to the Indian subcontinent (kala-azar caused by Leishmania donovani in Bihar and neighbouring states). Their breeding sites (cracks in mud walls, animal burrows, rubbish) and crepuscular biting behaviour underpin vector control advice such as residual insecticide spraying and bed nets in endemic areas of India. Why the other options are wrong: C. Lutzomyia: this sandfly genus has an identical hopping flight and erect wing posture but is confined to the New World, transmitting American cutaneous and mucocutaneous leishmaniasis in Central and South America, not India. A. Glossina: the tsetse fly is a larger, robust fly with a forward-projecting proboscis and wings that fold flat and overlap over the back at rest; it transmits African trypanosomiasis, not leishmaniasis. D. Simulium: the blackfly is a small, humpbacked, non-hairy fly with fast, direct flight near fast-flowing rivers; it is the vector of Onchocerca volvulus (river blindness), not Leishmania. B. Culicoides: biting midges are minute flies with wings held flat and overlapped at rest; they transmit arboviruses and filarial worms such as Mansonella, not leishmaniasis. Key point: erect, V-shaped wings plus a hairy body and hopping flight in an Indian setting identifies Phlebotomus, the Old World sandfly vector of leishmaniasis.

Reference: UK Health Security Agency (HAIRS group), Qualitative Assessment on Canine Leishmaniasis, gov.uk, 2022 (confirms Phlebotomus sandflies as the vectors of Old World Leishmania species): https://assets.publishing.service.gov.uk/media/61eed5bb8fa8f5058a4b2f01/20220121_Canine_leishmaniasis.pdf