How does a bite from an encephalitic tick occur? - briefly
A female tick attaches to the host’s skin, inserts its chelicerae and hypostome, and begins to feed while its saliva, which may contain the encephalitis virus, is introduced into the wound. Transmission typically occurs after several hours of attachment, when the tick’s salivary glands have had time to release infectious particles.
How does a bite from an encephalitic tick occur? - in detail
A female Ixodes tick searches for a host by detecting carbon dioxide, heat, and movement. When a suitable animal or human passes within a few centimeters, the tick climbs onto the skin using its forelegs, which are equipped with sensory organs called Haller’s cells. The tick then walks toward a protected area—often around the scalp, neck, armpits, or groin—where the skin is thin and hair provides shelter.
Attachment begins when the tick inserts its chelicerae and barbed hypostome into the epidermis. The hypostome’s backward‑facing teeth anchor the arthropod, preventing removal. Salivary glands secrete a cocktail of anticoagulants, anti‑inflammatory compounds, and immunomodulators that keep blood flowing and mask the bite from the host’s immune response.
During the first 24–48 hours of feeding, the tick ingests only a small volume of blood. The encephalitis‑causing virus (commonly tick‑borne encephalitis virus, TBEV) resides in the salivary glands. Transmission typically occurs after the pathogen has replicated and migrated to the saliva, which is usually delayed until the tick has been attached for at least 48 hours. The virus is released into the host’s dermal capillaries along with the saliva, entering the bloodstream and eventually the central nervous system.
Key steps in the process:
- Host detection via CO₂, heat, and movement cues.
- Climbing and locomotion to a sheltered skin region.
- Penetration of the epidermis with the hypostome.
- Secretion of pharmacologically active saliva to facilitate feeding.
- Replication and migration of the virus within the tick’s salivary glands.
- Release of the virus into the host after prolonged attachment.
Removal of the tick within the first 24 hours greatly reduces the risk of viral transmission because the pathogen has not yet reached the saliva. Proper extraction using fine tweezers, grasping the tick close to the skin and pulling straight upward, minimizes tissue damage and prevents the tick from regurgitating infected material.