Overview

Colorado tick fever is caused by a virus that you get from a tick bite. Some people remember getting a bite. Others don't. The symptoms usually start about 1 to 14 days after you get the tick bite. Symptoms include muscle aches, fever, chills, and headache. Sometimes the fever goes away for a few days and then comes back. Some people also notice that they are sensitive to light.

The illness usually gets better in about a week. But some people may feel tired and weak for a month or two. Treatment can reduce the symptoms. Most people with the illness have mild symptoms and recover completely.

Colorado tick fever occurs in the mountain regions of western Canada and the western United States. The tick that carries the virus is the Rocky Mountain wood tick (Dermacentor andersoni). It is found at an elevation of 1,200 to 3,000 metres (4,000 to 10,000 feet).

Do not donate blood or bone marrow for 6 months after you have been diagnosed with Colorado tick fever. The virus may stay in your blood for several months. If you donate blood or marrow, you may pass the disease to other people.

How can you care for yourself at home?

Easing symptoms

• Rest when you feel tired.
• Ask your doctor if you can take an over-the-counter pain medicine, such as acetaminophen (Tylenol), ibuprofen (Advil, Motrin), or naproxen (Aleve). Read and follow all instructions on the label.
• To prevent dehydration, drink plenty of fluids. Choose water and other clear liquids until you feel better. If you have kidney, heart, or liver disease and have to limit fluids, talk with your doctor before you increase the amount of fluids you drink.

Prevention

• When you come in from outdoors, check your body for ticks. Make sure to check your groin, head, and underarms.
• Cover as much of your body as you can when you work or play in grassy or wooded areas. Wear a hat, a long-sleeved shirt, and long pants with the legs tucked into your socks. Keep in mind that it is easier to spot ticks on light-coloured clothes.
• Use insect repellents with DEET. Do not use these products on your hands, eyes, and mouth.
• Use products that contain 0.5% permethrin on your clothing and outdoor gear, such as your tent. You can also buy clothing already treated with permethrin. Although permethrin is not available in Canada, travel health clinics can advise you how to purchase permethrin and pretreated gear.