TBRF

Tick‑borne relapsing fever (TBRF) is an infectious disease caused by spirochete bacteria of the genus Borrelia that are transmitted to humans by soft tick vectors, primarily species of the genus Ornithodoros. The disease is distinct from tick‑borne Lyme disease, which is caused by hard ticks and different Borrelia species. TBRF occurs in regions of southern Europe, the Middle East, Central America, and parts of Africa and the United States where the tick vectors are endemic. Human infection typically occurs when a person is exposed to tick-infested environments such as caves, abandoned buildings, or wooden cabins, or by contact with tick‑infested animals.

Clinically, TBRF presents with cyclical episodes of fever separated by periods of remission, known as relapses. Each relapse is usually brief, lasting one to three days, and is accompanied by headache, myalgias, arthralgias, and occasionally rash. Severe complications can arise if the infection is untreated, including meningitis, myocarditis, and hemolytic anemia. Diagnosis is established by detection of spirochetes in peripheral blood smear during febrile periods or by polymerase chain reaction assays targeting Borrelia DNA. Serology may be useful but can cross‑react with other tick‑borne spirochetes.

The principal treatment is antibiotic administration. Penicillin G remains the drug of choice for uncomplicated cases, although doxycycline is effective in patients with penicillin allergy or mild disease. Treatment duration typically spans 7–14 days, but subsequent relapses may require repeated courses. Prevention focuses on reducing tick exposure: use of insect repellents containing DEET, wearing protective clothing, and avoiding known tick habitats. Animal reservoir management and environmental tick control can also reduce human incidence.

Research on TBRF remains limited compared with Lyme disease. Efforts are underway to better understand the genetics of the Borrelia species involved, to develop rapid point‑of‑care diagnostics, and to evaluate vaccine candidates. The World Health Organization has designated TBRF as a neglected zoonotic disease, emphasizing the need for increased surveillance and improved public health interventions.