The latent form of typhus that may reactivate years after the initial infection is called what?

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

Answer: (A)

Brill-Zinsser disease is the recrudescent form of epidemic typhus, caused by reactivation of latent Rickettsia prowazekii infection years after the original illness. After the initial typhus infection, the bacteria can persist in the body in a dormant state and later reactivate, often presenting with milder symptoms. This reactivation typically occurs under stress or immune suppression. The other conditions are different rickettsial diseases: Q fever is due to Coxiella burnetii and is not a recrudescent typhus; Sao Paulo typhus and Tsutsugamushi disease are separate diseases with distinct etiologies and do not describe latent reactivation.