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Colorado tick fever

Mountain tick fever; Mountain fever; American mountain fever

Colorado tick fever is a viral infection. It is spread by the bite of the Rocky Mountain wood tick (Dermacentor andersoni).

Causes

This disease is usually seen between March and September. Most cases occur in April, May, and June.

Colorado tick fever is seen most often in the western United States and Canada at elevations higher than 4,000 feet (1,219 meters). It is transmitted by a tick bite or, in very rare cases, by a blood transfusion.

Symptoms

Symptoms of Colorado tick fever most often start 3 to 6 days after the tick bite. A sudden fever continues for 3 days, goes away, then comes back 1 to 3 days later for another few days. Other symptoms include:

  • Feeling weak all over and muscle aches
  • Headache behind the eyes
  • Lethargy (sleepiness) or confusion
  • Nausea and vomiting
  • Rash (may be light-colored)
  • Sensitivity to light (photophobia)
  • Skin pain
  • Sweating

Exams and Tests

The health care provider will examine you and ask about your signs and symptoms. If the provider suspects you have the disease, you will also be asked about your outdoor activity.

Blood tests will usually be ordered. Antibody tests can be done to confirm the infection. Other blood tests may include:

Treatment

There are no specific treatments for this viral infection.

The provider will make sure the tick is fully removed from the skin.

You may be told to take a pain reliever if you need it. DO NOT give aspirin to a child who has the disease. Aspirin has been linked with Reye syndrome in children. It may also cause other problems in Colorado tick fever.

If complications develop, treatment will be aimed at controlling the symptoms.

Outlook (Prognosis)

Colorado tick fever usually goes away by itself and is not dangerous.

Possible Complications

Complications may include:

  • Infection of the membranes covering the brain and spinal cord (meningitis)
  • Irritation and swelling of the brain (encephalitis)
  • Repeated bleeding episodes for no apparent cause

Call your provider if you or your child develops symptoms of this disease, if symptoms worsen or do not improve with treatment, or if new symptoms develop.

Prevention

When walking or hiking in tick-infested areas:

  • Wear closed shoes
  • Wear long sleeves
  • Tuck long pants into socks to protect the legs

Wear light-colored clothing, which shows ticks more easily than darker colors. This makes them easier to remove.

Check yourself and your pets frequently. If you find ticks, remove them right away by using tweezers, pulling carefully and steadily. Insect repellent may be helpful.

References

Beckham JD, Tyler KL. Encephalitis. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Disease, Updated Edition. 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 91.

Bolgiano EB, Sexton J. Tick-borne illnesses. In: Marx JA, Hockberger RS, Walls RM, et al, eds. Rosen's Emergency Medicine. 8th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 134.

    • Ticks

      Ticks - illustration

      There are many species of ticks. Of these, a large proportion are capable of carrying disease. Diseases carried by ticks include Lyme disease, Erlichiosis, Rocky Mountain Spotted Fever, Colorado Tick Fever, tularemia, typhus, hemorrhagic fever, and viral encephalitis. (Image courtesy of the Centers for Disease Control and Prevention.)

      Ticks

      illustration

    • Tick imbedded in the skin

      Tick imbedded in the skin - illustration

      This is a close-up photograph of a tick embedded in the skin. Ticks are important because they can carry diseases such as Rocky Mountain spotted fever, tularemia, Colorado tick fever, Lyme disease, and others.

      Tick imbedded in the skin

      illustration

    • Antibodies

      Antibodies - illustration

      Antigens are large molecules (usually proteins) on the surface of cells, viruses, fungi, bacteria, and some non-living substances such as toxins, chemicals, drugs, and foreign particles. The immune system recognizes antigens and produces antibodies that destroy substances containing antigens.

      Antibodies

      illustration

    • Deer ticks

      Deer ticks - illustration

      Diseases are often carried by ticks, including Rocky Mountain Spotted Fever, Colorado Tick Fever, Lyme disease, and tularemia. Less common or less frequent diseases include typhus, Q-fever, relapsing fever, viral encephalitis, hemorrhagic fever, and babesiosis.

      Deer ticks

      illustration

      • Ticks

        Ticks - illustration

        There are many species of ticks. Of these, a large proportion are capable of carrying disease. Diseases carried by ticks include Lyme disease, Erlichiosis, Rocky Mountain Spotted Fever, Colorado Tick Fever, tularemia, typhus, hemorrhagic fever, and viral encephalitis. (Image courtesy of the Centers for Disease Control and Prevention.)

        Ticks

        illustration

      • Tick imbedded in the skin

        Tick imbedded in the skin - illustration

        This is a close-up photograph of a tick embedded in the skin. Ticks are important because they can carry diseases such as Rocky Mountain spotted fever, tularemia, Colorado tick fever, Lyme disease, and others.

        Tick imbedded in the skin

        illustration

      • Antibodies

        Antibodies - illustration

        Antigens are large molecules (usually proteins) on the surface of cells, viruses, fungi, bacteria, and some non-living substances such as toxins, chemicals, drugs, and foreign particles. The immune system recognizes antigens and produces antibodies that destroy substances containing antigens.

        Antibodies

        illustration

      • Deer ticks

        Deer ticks - illustration

        Diseases are often carried by ticks, including Rocky Mountain Spotted Fever, Colorado Tick Fever, Lyme disease, and tularemia. Less common or less frequent diseases include typhus, Q-fever, relapsing fever, viral encephalitis, hemorrhagic fever, and babesiosis.

        Deer ticks

        illustration

      A Closer Look

       

      Review Date: 11/27/2016

      Reviewed By: Arnold Lentnek, MD, Infectious Diseases Medical Practice of NY and Clinical Research Centers of CT. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

      The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
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