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HTLV-1 and Strongyloides — SCE Infectious Diseases MCQ

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HardParasitologyHTLV-1 and StrongyloidesSCE Infectious Diseases

A 45-year-old man presents with a subacute illness: fever, malaise, hepatosplenomegaly, and peripheral blood eosinophilia (6.2 × 10⁹/L). He emigrated from Japan 10 years ago. HTLV-1 serology is positive. Stool examination shows rhabditiform larvae. What is the most important concern?

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Correct answer: C — Strongyloides hyperinfection syndrome — HTLV-1 impairs Th2 immunity needed to control Strongyloides; immunosuppression in HTLV-1 carriers permits hyperinfection

HTLV-1 is a specific risk factor for Strongyloides hyperinfection syndrome through impairment of the Th2 immune response (which is critical for helminth control). HTLV-1 carriers have reduced IgE production and impaired eosinophil-mediated killing of Strongyloides larvae. The combination of HTLV-1 and Strongyloides is a recognised dangerous duo — hyperinfection can occur even without exogenous immunosuppression. Treatment is Ivermectin 200 µg/kg daily for at least 7–14 days (rather than the standard 2-day course for uncomplicated infection). Monitoring for bacterial superinfection from larvae carrying enteric organisms is essential.

Reference: WHO 2022 – Strongyloides; BHIVA 2022 – HTLV-1 guidelines