Colorado tick fever

This code represents an acute viral infection transmitted by the Rocky Mountain wood tick, characterized by fever, chills, headache, myalgia, and often a biphasic course. It is a self-limiting illness, typically resolving within 1-2 weeks, though fatigue may persist.

Apply this code for confirmed cases of Colorado tick fever, typically diagnosed based on clinical presentation in an endemic area following a tick bite, and supported by serological testing or PCR. Use when the provider explicitly documents "Colorado tick fever" as the patient's diagnosis.

• Ensure documentation specifies "Colorado tick fever" to differentiate from other tick-borne illnesses.
• Do not use for suspected cases without definitive diagnostic confirmation.
• Consider co-reporting with Z83.0 (Family history of viral diseases) if applicable, or Z20.828 (Contact with and suspected exposure to other viral communicable diseases) for exposure.