Tick-borne Relapsing Fever
Also called: TBRF
Pathogen
Borrelia hermsii and related species
Carried by
Soft ticks (Ornithodoros); hard-tick form via Borrelia miyamotoi
Tick-borne Relapsing Fever is caused by Borrelia bacteria — cousins of the Lyme spirochete — and produces its signature pattern of fever that comes, goes, and comes back. The classic soft-tick form is linked to sleeping in rodent-infested cabins in the mountainous West. A related 'hard-tick' relapsing fever (Borrelia miyamotoi) is spread by the same blacklegged ticks that carry Lyme.
Symptoms
- Recurring cycles of high fever (roughly 3 days fever, 7 days well)
- Headache and muscle aches
- Nausea
- Fatigue between episodes
Testing
A blood smear taken during a fever episode can show the spirochetes; PCR and antibody testing also help. Timing the test to a febrile period improves detection.
Labs often used in the Lyme community:
See our Testing Guide to understand your options.
Geography
The soft-tick form occurs in mountainous Western states (California, Colorado, Idaho, Utah, Washington, Montana, Arizona, New Mexico), classically at 1,500–8,000 feet. The Borrelia miyamotoi form follows the range of the blacklegged tick.
Explore the Where Ticks Live map to see what's carried in your region.
Treatment overview
Doxycycline or other tetracyclines are first-line (erythromycin as an alternative). A Jarisch-Herxheimer reaction — a temporary worsening as bacteria die off — is common when treatment starts.
Frequently asked questions
How is this related to Lyme?
Both are caused by Borrelia bacteria. Relapsing fever species produce cyclical fevers, while the Lyme species (B. burgdorferi) causes the more familiar rash-and-migrating-symptoms picture. Borrelia miyamotoi is spread by the same tick as Lyme.