There are between 200 - 300 cases reported a year. Symptoms include a sudden onset of fever, chills, severe headache, muscle aches and occasionally a faint rash, which lasts about a week. After a 2-3 day remission, symptoms accompanied by a drop in white blood cells, may occur.
Diagnosis is assisted by a serologic test.
The primary vector is the Rocky Mountain wood tick. To my knowledge, there has never been a death associated with Colorado Tick Fever.