infectious diseases
Epidemic Typhus
Key Points
Epidemic typhus is prevalent worldwide; humans are the natural reservoir. Infection is transmitted among humans by body lice when louse feces are scratched or rubbed into louse bites, wounds, or mucous membranes. Small, pink macules rapidly cover the body, later, becoming dark and maculopapular. Mortality increases with age; vascular collapse, renal insufficiency, encephalitic signs, ecchymosis with gangrene, and pneumonia are poor prognostic signs. Suspect epidemic typhus based on clinical manifestations and signs of louse infestation and recent residence in or travel to an endemic region; confirm with fluorescent antibody staining of skin biopsy. Treat withdoxycycline. Brill-Zinsser disease, a mild recrudescence of epidemic typhus, can occur years after the initial infection if host defenses falter. 