Borrelia recurrentis

Borrelia recurrentis is a type of spiral-shaped bacteria known as a spirochete. It is the cause of louse-borne relapsing fever, an infectious disease characterized by recurring high fevers. This illness typically spreads under conditions of poor hygiene and crowding, which favor the proliferation of lice that transmit the bacteria from person to person.123

The disease is marked by cycles of fever, chills, headache, and muscle aches, followed by periods of well-being. While antibiotics are effective treatments, relapses can occur. Historically, epidemics of relapsing fever have been associated with conditions like wars and famines.3