Clinical Disease

Tick-borne Relapsing Fever spirochetes
Peripheral blood smear. The TBRF bacteria are long and spiral-shaped. The circular objects are red blood cells. The irregular purple object in the top right corner is a white blood cell.

Tick-borne relapsing fever (TBRF) is a rare infection linked to sleeping in rustic cabins, particularly cabins in mountainous areas of the western United States. The main symptoms of TBRF are high fever (e.g., 103° F), headache, muscle and joint aches. Symptoms can reoccur, producing a telltale pattern of fever lasting roughly 3 days, followed by 7 days without fever, followed by another 3 days of fever. Without antibiotic treatment, this process can repeat several times.

Relapsing fever is characterized by an incubation period of roughly one week, followed by an episode of fever lasting several days, followed by an interval without fever. This process can recur from 1 to 4 times if untreated.
General timeline for TBRF relapse intervals.