Animals Involved
Rodents; also found in porcupines, lagomorphs, deer, elk, and other mammals
Known Distributions
Rocky Mountain region of North America
Probable Means of Spreading
Tick bites (primary vector is Dermacentor andersoni)
Clinical Manifestations in People
Nonspecific febrile illness; pharyngitis, rash, or GI signs possible; biphasic or triphasic in some; complications (eg, neurologic signs, hemorrhages, pericarditis, myocarditis, orchitis) uncommon but can occur in severe cases; deaths rare