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Relapsing Fever — SCE Infectious Diseases MCQ

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ModerateTropical & Imported InfectionsRelapsing FeverSCE Infectious Diseases

A 30-year-old man from Ethiopia is diagnosed with relapsing fever. He presents with cyclical high fevers (39–41°C) every 5–7 days with intervening afebrile periods. Blood film during a febrile episode shows spirochaetes. He reports living in overcrowded housing. What is the most likely causative organism?

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Correct answer: C — Borrelia recurrentis (louse-borne relapsing fever)

Cyclical fevers with spirochaetes on blood film in a patient from Ethiopia with overcrowded living conditions is classic for louse-borne relapsing fever (LBRF) caused by Borrelia recurrentis, transmitted by the human body louse (Pediculus humanus corporis). Ethiopia is the global epicentre of LBRF. Treatment is a single dose of Doxycycline 100 mg (or Erythromycin if Doxycycline is contraindicated). A Jarisch-Herxheimer reaction (fever spike, rigors, hypotension) occurs in up to 80% of treated patients and should be anticipated.

Reference: UKHSA 2023 – Relapsing fever; WHO 2020 – Louse-borne relapsing fever