infections
Relapsing Fever
Relapsing fever caused by ticks (tick borne relapsing fever)
Asoft-bodied tickbecomes infected when it feeds on rodents (such as chipmunks and squirrels) that carry a species ofBorreliabacteria. The tick spreads the bacteria to a person when it bites. Tick-borne relapsing fever caused by soft-bodied ticks occurs in the Americas, Africa, Asia, and Europe. In the United States, the disease occurs mainly in the Western states, particularly between May and September. People who sleep in a rodent-infested cabin in the mountains are more likely to be bitten by infected ticks. However, because the ticks feed at night and do not remain attached for very long, people often do not recall a tick bite. People who explore caves (spelunking) are also at risk of infection. Soft ticks differ from hard ticks (such as the dog tick and the deer tick) in the following ways: Soft ticks remain attached for a short time, usually less than half an hour. Soft ticks do not wait for their prey in tall grass or brush. Instead, they live in rodent burrows, feeding as needed on the rodent as it sleeps. Hard-bodied ticksthat transmit relapsing fever are the same ticks that transmit Lyme disease. Thus, relapsing fever caused by hard-bodied ticks occurs in the same places where Lyme disease occurs in the United States—the Northeast and upper Midwest. When these ticks transmit relapsing fever, they may also transmit Lyme disease, and people may have more than one infection at a time. The ticks become infected when they feed on the blood of rodents (such as the white-footed mouse) that carry a species ofBorreliabacteria. The tick spreads the bacteria to a person when it bites. People who live in wooded areas or who walk through tall grass or wooded areas are more likely to be bitten by infected ticks. 