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Description:As one of the primary natural hosts to the Rocky Mountain wood tick, Dermacentor andersoni (see PHIL 10865), this Columbian ground squirrel, Urocitellus columbianus, was infested by numerous nymphal-staged D. andersoni ticks. You can see these ticks obtaining their blood meal from this host, as they nestled around the animal’s right eye and ear. D. andersoni is the vector responsible for transmitting the Coltivirus, Colorado tick fever (CTF) to humans.
“Colorado tick fever is caused by a virus maintained in the environment in a rodent-tick-rodent cycle. The virus is transmitted to humans by the bite of an infected Rocky Mountain wood tick. Ticks begin to emerge in late February and March and seek for an animal host to take a blood meal which is necessary for their growth and reproduction.”

“The virus is transmitted to humans while an infected tick is obtaining a blood meal. Studies have shown that a tick must usually be attached for several hours to transmit enough virus to cause illness. If infected, a person will become ill in four to five days.” (See link below to Colorado Government site)

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Content Providers(s):CDC/ Donated by Nat. Instit. of Allergy and Infectious Diseases, Rocky Mountain Lab, Hamilton Montana
Creation Date:1974
Photo Credit:
Links:Colorado Dept. of Public Health and Environment; Div. of Disease Control and Environmental Epidemiology
CDC – National Institute for Occupational Safety and Health Education and Information Division; Workplace Safety & Health Topics: Tick-borne Diseases
CDC Organization
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Copyright Restrictions:None - This image is in the public domain and thus free of any copyright restrictions. As a matter of courtesy we request that the content provider be credited and notified in any public or private usage of this image.