What disease is caused by a tick bite, known as borreliosis? - briefly
The tick‑borne infection known as borreliosis is Lyme disease, caused by the spirochete Borrelia burgdorferi. It typically presents with a characteristic skin rash, fever, fatigue, and joint or neurological symptoms.
What disease is caused by a tick bite, known as borreliosis? - in detail
Lyme disease, the infection transmitted by ixodid ticks and identified as borreliosis, is caused by spirochetes of the genus Borrelia, primarily B. burgdorferi in North America and B. afzelii and B. garinii in Europe and Asia. The bacterium resides in the midgut of the tick and enters the human bloodstream during a blood meal that lasts 36–48 hours. The vector’s geographic distribution determines regional incidence; the United States reports roughly 30,000 confirmed cases annually, while Europe records a comparable burden.
Clinical presentation evolves in three stages.
- Early localized infection (3–30 days post‑bite) features erythema migrans—a expanding, often annular rash—and flu‑like symptoms such as fever, headache, myalgia, and fatigue.
- Early disseminated disease (weeks to months) may produce multiple erythema migrans lesions, cardiac involvement (atrioventricular block, myocarditis), neurologic signs (cranial nerve palsy, meningitis), and migratory arthralgias.
- Late disease (months to years) manifests as chronic arthritis, predominantly of large joints, and persistent neurologic deficits, including peripheral neuropathy and encephalopathy.
Diagnosis relies on a two‑tier serologic algorithm. The initial assay employs an enzyme‑linked immunosorbent test (ELISA) to detect IgM and IgG antibodies; a positive result triggers a confirmatory Western blot that identifies specific Borrelia protein bands. In early infection, when antibodies may be absent, polymerase chain reaction (PCR) testing of synovial fluid, cerebrospinal fluid, or skin biopsy can provide direct evidence of the pathogen.
Treatment follows established antimicrobial regimens. Oral doxycycline (100 mg twice daily for 10–21 days) is first‑line for most presentations, including early neurologic involvement. For pregnant patients, children under eight, or cases with severe cardiac manifestations, intravenous ceftriaxone (2 g daily for 14–28 days) is recommended. Adjunctive anti‑inflammatory agents may alleviate joint swelling, but they do not replace antibiotic therapy.
Prevention centers on tick avoidance and prompt removal. Effective measures include wearing long sleeves and trousers, applying permethrin‑treated clothing, using repellents containing DEET or picaridin, and performing thorough skin checks after outdoor exposure. If attachment exceeds 24 hours, a single prophylactic dose of doxycycline (200 mg) can reduce the risk of infection, provided no contraindications exist.
Understanding the pathogen’s lifecycle, recognizing the staged symptomatology, and applying accurate diagnostic protocols are essential for reducing morbidity associated with this tick‑borne illness.