Colorado Tick Fever: Symptoms, Treatment, and Prevention

Colorado tick fever (CTF) is a viral illness transmitted by the bite of an infected Rocky Mountain wood tick (Dermacentor andersoni). It's the most common tick-borne disease in the Rocky Mountain region of the U.S. and Canada.

Symptoms (Typically 3–6 Days Post-Bite)

• Fever (often biphasic—fever, remission, then fever again)
• Chills, headache, muscle and joint aches
• Fatigue, nausea, vomiting, diarrhea
• Swollen lymph nodes
• Rash (sometimes on palms and soles)

Treatment

• No specific antiviral; care is supportive.
• Rest, hydration, over-the-counter pain and fever relievers (acetaminophen, ibuprofen).
• Most recover in 2–3 weeks.
• Severe cases (rare) may require hospitalization for IV fluids and monitoring.

Prevention

• Avoid tick habitat (brushy, grassy areas at 4,000–10,000 ft elevation) when possible.
• Use EPA-registered repellent: ≥20% DEET, picaridin, or IR3535 on skin; permethrin on clothing and gear.
• Wear light-colored long sleeves and pants; tuck pants into socks.
• Do thorough tick checks after outdoor activity; shower within 2 hours.
• Remove attached ticks promptly with fine-tipped tweezers—grasp close to skin, pull straight up.

See a doctor if you develop symptoms after a tick bite or time in endemic areas. Mention tick exposure to aid diagnosis.