Key points
- Symptoms of Colorado tick fever can include fever, chills, headache, body aches, and feeling tired.
- Rarely, Colorado tick fever can be severe and affect the central nervous system.
- If you think you or a family member might have Colorado tick fever, talk to your healthcare provider.
Symptoms
The time from tick bite to onset of illness (incubation period) for Colorado tick fever ranges from about 1 to 14 days.
Common symptoms
The most common symptoms include:
- Fever
- Chills
- Headache
- Body aches
- Feeling tired
- Some patients also have sore throat, vomiting, abdominal pain, or skin rash
About half of patients have a "biphasic" fever. This means they have several days of fever, feel better for several days, and then have a second short period of fever and illness.
Severe illness
In rare cases, some patients may develop more severe illness that affects the central nervous system with symptoms that include:
- Stiff neck
- Confusion
Outcomes
Most people who get sick have mild illness and recover completely. However, weakness and fatigue may last several weeks.
Colorado tick fever rarely causes life-threatening illness or death.
Testing and diagnosis
If you think you or a family member might have Colorado tick fever, talk to your healthcare provider.
Healthcare providers diagnose Colorado tick fever based on:
- Signs and symptoms
- History of living in or traveling to an area where Colorado tick fever virus is known to circulate
- History of possible exposure to ticks that can spread Colorado tick fever virus
- Laboratory tests
Your healthcare provider can order tests for Colorado tick fever virus and other infections that can cause similar symptoms.