Louse-borne relapsing fever is caused by the spirochete bacterium Borrelia recurrentis, transmitted by body lice (Pediculus humanus humanus), not head lice. The disease was first described by Hippocrates (460β370 BC). Initial symptoms include a high fever, chills, headache, and muscle pain, followed by a relapse after about a week.
The pathogen evades the host immune system through antigenic variation, changing its surface proteins to avoid detection. This mechanism allows the bacteria to cause recurrent febrile episodes. The disease is most common in regions with poor hygiene and overcrowding, such as parts of Africa, Asia, and South America.
Diagnosis is typically made by microscopic examination of blood smears during febrile episodes, revealing the spirochetes. Treatment involves antibiotics such as tetracycline or erythromycin, but a Jarisch-Herxheimer reaction may occur. Prevention focuses on improving hygiene and controlling louse infestations.
