Chrysops vector — DTM&H MCQ

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ModerateEntomology and vector controlChrysops vectorDTM&H

A man in Cameroon has Calabar swellings and a subconjunctival worm. He recalls painful daytime bites from flies in swampy forest. What is the vector or intermediate host most relevant to this infection?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: E — Chrysops deerfly

Chrysops deerfly is the single best answer because Loa loa is transmitted by Chrysops deerflies, which bite during the day in forested areas. Anopheles mosquito 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 knowledge is important before mass ivermectin programmes in co-endemic regions.

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