Chikungunya — DTM&H MCQ

Correct answer: D — Chikungunya

Chikungunya (D) is correct: it causes abrupt fever with a rash and severe, often symmetrical, small-joint polyarthralgia that is characteristically debilitating and prolonged, sometimes for weeks to months, following travel to endemic Indian Ocean and Indian subcontinent regions such as Mauritius. UKHSA notes that chikungunya is characterised by sudden onset fever usually accompanied by joint pain, with joint symptoms often more severe in the small joints, and that pain and arthritis may persist for weeks or longer. Mild thrombocytopenia is a recognised laboratory finding in acute chikungunya, unlike the marked thrombocytopenia and plasma leakage seen in dengue. The combination of prolonged, severe small-joint arthralgia plus only mild platelet reduction is the discriminating clue pointing away from dengue and towards chikungunya. Why the other options are wrong: E. Dengue fever: typically causes more pronounced thrombocytopenia with risk of plasma leakage, haemorrhage and shock; joint pain is usually myalgia/arthralgia (dengue fever) but not the prolonged, disabling small-joint polyarthritis typical of chikungunya, and it resolves within days rather than persisting for weeks. A. Parvovirus B19: causes symmetrical small-joint arthropathy, particularly in adult women, but presents with slapped-cheek rash in children or a lacy rash in adults, lacks the abrupt high fever and travel-associated Aedes exposure pattern, and does not cause thrombocytopenia. C. Zika virus infection: produces a milder illness with maculopapular rash and conjunctivitis, but arthralgia is mild and transient, not severe or persistent for weeks, and thrombocytopenia is not a typical feature. B. Rheumatic fever: follows streptococcal pharyngitis, not mosquito exposure, and presents with migratory large-joint arthritis plus carditis or chorea, not fixed symmetrical small-joint disease after travel. Key point: severe, symmetrical, small-joint polyarthralgia lasting weeks after tropical travel with only mild thrombocytopenia points to chikungunya, distinguishing it from the marked thrombocytopenia and shorter course of dengue.

Reference: UK Health Security Agency, Chikungunya guidance, GOV.UK, 2025 (https://www.gov.uk/guidance/chikungunya)