An endogenous reinfection associated with the "carrier state" in persons who previously had epidemic typhus fever; it is arather mild disease and may be mistaken for endemic (murine) typhus; first described by Brill in New York City but notrecognized as a recrudescent form of epidemic typhus until after the work of Zinsser. Syn: Brill's disease, recrudescenttyphus fever, recrudescent typhus.