Colorado tick fever is an infection that is spread to humans by the bite of an infected tick.
Colorado tick fever is caused by the Colorado tick fever virus. Humans can get the virus through the bite of an infected tick. The Rocky Mountain wood tick is the main carrier of the Colorado tick virus in the United States (US). This tick can be found in the western US states (not just in Colorado). It can be found in areas above 5,000 feet in elevation.
The virus is also carried by other small mammals, including ground squirrels, porcupines, and chipmunks. There have been reports of rare cases of Colorado tick fever caused by exposure in a laboratory setting and a blood transfusion.
Factors that increase your chance of Colorado tick fever include:
Colorado tick fever. These symptoms may be caused by other, less serious health conditions. Symptoms usually appear 4-5 days after a tick bite occurs and may last for three weeks.
Colorado tick fever may cause:
Your doctor will ask about your symptoms and medical history. A physical exam will be done.
Tests may include the following:
There is no specific treatment for Colorado tick fever. Complications are extremely rare and include aseptic meningitis, encephalitis, and hemorrhagic fever. The fever and pain may be treated with acetaminophen (such as Tylenol) and other pain relief medications. It is important to stay hydrated by drinking enough fluids. It is believed that immunity against re-infection occurs after exposure to Colorado tick fever.
To help reduce your chance of Colorado tick fever:
Centers for Disease Control and Prevention
National Institute of Allergy and Infectious Diseases
Brackney MM, Marfin AA, et al. Epidemiology of Colorado tick fever in Montana, Utah, and Wyoming, 1995-2003. Vector Borne Zoonotic Dis. 2010;10(4):381-385.
Colorado tick fever. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated July 20, 2010. Accessed November 4, 2014.
Colorado tick fever fact sheet. Oregon Health Authority website. Available at: http://public.health.oregon.gov/DiseasesConditions/DiseasesAZ/coloradotickfever/Pages/facts.aspx. Accessed November 4, 2014.
Leiby DA, Gill JE. Transfusion-transmitted tick-borne infections: a cornucopia of threats. Transfus Med Rev. 2004;18(4):293-306.
Tick avoidance and removal. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated May 23, 2014. Accessed November 4, 2014.
Last reviewed December 2014 by David L. Horn, MD, FACP
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.