Colorado tick fever in the United States, 2013-2022. Fagre A., et al. Am. J. Trop. Med. Hyg., 111(3), 2024, pp. 598–602 doi:10.4269/ajtmh.24-0044
Abstract [condensed]. Colorado tick fever (CTF) virus is an arbovirus maintained in an enzootic cycle between Rocky Mountain wood ticks (Dermacentor andersoni) and rodent species in the western United States. Individuals with CTF typically present with symptoms including fever, headache, myalgia, and lethargy, with a biphasic illness frequently occurring. ‘Authors’ reviewed data on CTF cases reported to the national U.S. arboviral disease surveillance system and identified through testing at the CDC to characterize the epidemiology of CTF from 2013–2022. During this period, 148 CTF cases were identified, all likely infected in an endemic area in one of six states (Montana, Wyoming, Oregon, Colorado, Utah, Idaho). These findings substantiate the continued circulation of CTF virus in the western United States, highlighting the importance of implementing approaches to ensure CTF awareness for medical providers and providing education on tick bite prevention strategies for residents and visitors to risk areas.
Note: Although CTF cases have not be reported from California, the authors’ distribution maps show the presence of the principal vector D. andersoni in the Sierra, Tehachapi and northern Coast Ranges.