The ticks that can transmit relapsing fever live on squirrels, mice, chipmunks, and other rodents. The animals bring the ticks into their nests inside homes, under flooring, and between walls. The tick usually gets its blood meal from rodents, but may seek out other warm-blooded animals, including humans, if rodents are scarce. Soft ticks feed quickly at night, usually within 15 to 30 minutes. Then they drop off their host, so people usually don't know they have been bitten.
Fever comes on abruptly, along with chills, headaches and muscle aches.
Other possible symptoms include nausea, vomiting, abdominal pain and rash. The symptoms may continue for several days, then disappear. Several days to a week later symptoms commonly come back, and may recur up to five or six times. Anybody that develops symptoms like these should see their physician. Although many cases eventually resolve on their own, some people become critically ill with relapsing fever.