Borrelia Recurrentis

Borrelia recurrentis is the causative agent of louse-borne relapsing fever. As a spirochete, Borrelia displays a spiral shape, best visualized by dark field microscopy or Wright-Giemsa stain on peripheral blood smears. Importantly, it avoids immune detection through antigenic variation - frequently changing the surface proteins of its outer membrane. This bacterium primarily affects individuals living in suboptimal conditions, such as under-resourced nations affected by war or famine, and crowded living conditions. It is primarily transmitted via the human body louse. Once in the bloodstream, and after about a week's incubation, B. recurrentis causes sudden-onset illness characterized by cyclic high fever, along with a range of symptoms including headache, chills, sweats, muscle and joint pain, and nausea. An essential note is the ""crisis phase"" following each febrile episode marked by severe fluctuations in temperature, heart rate, and blood pressure. Standard treatment includes penicillin G or doxycycline, with careful monitoring for the Jarisch-Herxheimer reaction upon antibiotics' initiation.