Colorado Tick Fever - Transmission and Symptoms

Transmission and Symptoms

Colorado tick fever is acquired by tick bite. There is no evidence of natural person-to-person transmission. However, rare cases of transmission from blood transfusions have been reported. The virus which causes Colorado tick fever may stay in the blood for as long as four months after onset of the illness.

First signs or symptoms can occur about three to six days after the initial tick bite, although it can have incubation periods of up to 20 days. Patients usually experience a two-staged fever and illness which can continue for three days, diminish, and then return for another episode of one to three days. The virus has the ability to live in the blood stream for up to 120 days; therefore coming in contact without proper precautions and the donation of blood are prohibited.

Initial symptoms include fever, chills, headaches, pain behind the eyes, light sensitivity, muscle pain, generalized malaise, abdominal pain, nausea, and vomiting, as well as a flat or pimply rash. During the second phase of the virus, a high fever can return with an increase in symptoms. CTF can be very severe in cases involving children and have even required hospitalization. Complications with this disease have included aseptic meningitis, encephalitis, and hemorrhagic fever, but these are rare.

CTF is seasonal, mostly occurring in the Rocky Mountain region of the United States and usually in altitudes from 4,000 to 10,000 feet. Patients with CTF are mostly campers and young males, who most likely have been bitten because of their occupational activities.