Recrudescent typhus [Brill's disease]

This code represents a mild, recurrent form of epidemic typhus caused by Rickettsia prowazekii. It occurs years after an initial infection, typically in individuals with waning immunity, and is characterized by a milder clinical course than primary epidemic typhus.

Assign this code when documentation explicitly states "Brill's disease" or "recrudescent typhus." This diagnosis is typically made based on a history of prior epidemic typhus infection and current clinical presentation, often confirmed by serological testing.

• Differentiate from primary epidemic typhus (A75.0) which is a more severe, acute infection.
• Ensure documentation clearly specifies "recrudescent" or "Brill's disease" to avoid miscoding.
• Consider additional codes for any associated complications or manifestations, if documented.