What is the disease caused by a subcutaneous tick? - briefly
The disease transmitted by a subcutaneous tick is Lyme disease, caused by the bacterium Borrelia burgdorferi. Typical manifestations include a characteristic expanding rash, fever, fatigue, and joint pain.
What is the disease caused by a subcutaneous tick? - in detail
The illness transmitted when a tick embeds beneath the skin is a bacterial infection caused by Borrelia burgdorferi and related spirochetes. This condition, commonly referred to as Lyme disease, is the most prevalent tick‑borne disease in temperate regions.
The pathogen is introduced during the feeding phase of hard‑shell ticks of the genus Ixodes (e.g., I. scapularis in North America, I. ricinus in Europe). Transmission typically requires the tick to remain attached for at least 36–48 hours, allowing the spirochetes to migrate from the tick’s midgut to its salivary glands and then into the host’s subcutaneous tissue.
Key clinical manifestations
- Early localized stage (3–30 days post‑bite): erythema migrans rash, flu‑like symptoms (fever, headache, fatigue, myalgias), and occasional arthralgia.
- Early disseminated stage (weeks to months): multiple erythema migrans lesions, cardiac involvement (atrioventricular block), facial nerve palsy, and neurologic signs such as meningitis or radiculitis.
- Late chronic stage (months to years): migratory arthritis, particularly of large joints, and neurocognitive deficits.
Diagnostic approach
- Clinical assessment based on characteristic rash and exposure history.
- Serologic testing employing a two‑tier algorithm: initial enzyme‑linked immunosorbent assay (ELISA) followed by confirmatory Western blot for IgM and IgG antibodies.
- Polymerase chain reaction (PCR) on synovial fluid or cerebrospinal fluid in selected cases.
Therapeutic regimen
- Early disease: oral doxycycline 100 mg twice daily for 10–21 days; alternatives include amoxicillin or cefuroxime axetil for patients unable to tolerate tetracyclines.
- Neurological or cardiac involvement: intravenous ceftriaxone 2 g once daily for 14–28 days.
- Late-stage arthritis: extended oral doxycycline or a combination of intravenous ceftriaxone followed by oral therapy, guided by symptom resolution.
Prevention measures
- Avoidance of tick habitats during peak activity (spring–early summer).
- Use of repellents containing DEET or picaridin on skin, and permethrin on clothing.
- Prompt removal of attached ticks with fine‑tipped tweezers, grasping close to the skin, and steady upward traction without crushing.
- Regular body checks after outdoor exposure; immediate cleaning of bite sites.
Understanding the pathogen’s life cycle, the timeline of transmission, and the spectrum of clinical presentations enables effective diagnosis, timely treatment, and reduction of long‑term complications associated with this tick‑borne disease.