Colorado tick fever
nounMedical Definition of Colorado tick fever
: a mild disease of the western United States and western Canada that is characterized by intermittent fever, malaise, headaches, myalgia, and the absence of a rash and is caused by a reovirus (species Colorado tick fever virus of the genus Coltivirus) transmitted by the Rocky Mountain wood tick
Colorado tick fever is caused by a virus that replicates in blood-forming stem cells, prompting blood count to drop.— Daniel C. Weaver, Discover, July 1999