How does borreliosis infection occur from a tick bite? - briefly
During feeding, the tick’s mouthparts penetrate the skin and, after several hours, Borrelia spirochetes migrate from the tick’s midgut to its salivary glands. The bacteria are then released with the saliva into the host’s dermal tissue, initiating infection.
How does borreliosis infection occur from a tick bite? - in detail
The bacterium that causes Lyme disease resides in the midgut of infected nymphal and adult ticks. When a tick attaches to human skin, it inserts its hypostome and secretes cement‑like proteins that secure the mouthparts. Saliva is released continuously during feeding; it contains anticoagulants, immunomodulators, and enzymes that facilitate blood intake and suppress host defenses.
Transmission begins only after the tick has been attached for a sufficient period. Studies show that a minimum of 24 hours of feeding is required for spirochetes to migrate from the midgut to the salivary glands. The migration is driven by changes in temperature and host‑derived cues that activate bacterial motility and expression of surface proteins essential for invasion.
Once in the salivary glands, the spirochetes are expelled with saliva into the bite site. The organisms penetrate the epidermis, encounter dermal fibroblasts and immune cells, and disseminate via the lymphatic system and bloodstream. Early local manifestations appear as erythema migrans, while later stages may involve joints, heart, and nervous tissue.
Factors influencing the likelihood of infection include:
- Tick life stage (nymphs are most responsible due to their small size and prolonged attachment)
- Duration of attachment (risk rises sharply after 24 hours)
- Ambient temperature (warmer conditions increase tick activity and feeding speed)
- Host immune status (immunocompromised individuals may experience faster spread)
Preventive measures focus on prompt removal of attached ticks, ideally within a few hours, and inspection of the skin after outdoor exposure. Early antibiotic therapy following confirmed bite or early symptoms reduces the chance of systemic complications.