Lymphatic Filariasis — SCE Infectious Diseases MCQ

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ModerateTropical & Imported InfectionsLymphatic FilariasisSCE Infectious Diseases

A 30-year-old man from rural Brazil presents with chronic painless lymphoedema of the right leg, recurrent episodes of acute dermatolymphangioadenitis (ADLA), and a thickened scrotum. Nocturnal blood film shows microfilariae. What is the most likely organism?

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Correct answer: D — Wuchereria bancrofti

Chronic lymphoedema and hydrocele with nocturnal microfilariae in a patient from Brazil is consistent with lymphatic filariasis caused by Wuchereria bancrofti. W. bancrofti is the most common cause of lymphatic filariasis worldwide and is the only species found in the Americas. Episodes of ADLA represent secondary bacterial infection of lymphoedematous tissue. Long-term management includes DEC (in non-Onchocerca co-endemic areas), hygiene-based lymphoedema care, and surgery for hydrocele.

Reference: WHO 2022 – Lymphatic filariasis; UKHSA 2023 – Filariasis