Infectious Disease Compendium

Colorado Tick Fever


An acute febrile illness and leukopenia after tick bite.

Epidemiologic Risks

Bit by a wood tick in the western United States and Canada. Dermacentor andersoni is the vector and found at 4000 to 10,000-foot elevations; it is my understanding that Colorado is particularly high, but in a different way than, say, Eugene, Oregon. Lets just say the sweetish haze in the air at U of O was not the burning of grass of a lawn kind.


Due to the Coltiviruses.

Empiric Therapy




ICD9 Codes (Soon to be supplanted by ICD10)

Colorado tick fever 066.1.