The mild type of typhus fever that is caused by recrudescence of an initial attack of epidemic typhus is known as which disease?

• A. Brill-Zinsser disease
• B. Q fever
• C. São Paulo typhus
• D. Tsutsugamushi disease

Answer: (A)

Brill-Zinsser disease represents a recrudescent, milder form of epidemic typhus caused by reactivation of latent Rickettsia prowazekii after someone has had the initial outbreak. After apparent recovery, the bacteria can persist in the body for years, especially in tissues like fat, and may reactivate later, producing another febrile illness with rash that is typically less severe than the first episode. This concept—disease reactivation from a dormant infection explaining a mild, later typhus outbreak—is what makes Brill-Zinsser disease the best answer. Other conditions listed involve different pathogens and transmission patterns (for example, Q fever from Coxiella burnetii, scrub typhus from Orientia tsutsugamushi), and are not recrudescent forms of epidemic typhus.