How do ticks bite humans? - briefly
Ticks detect a host, pierce the skin with their hypostome, and inject saliva containing anticoagulants while they ingest blood. Their mouthparts lock in place, enabling continuous feeding for several days.
How do ticks bite humans? - in detail
Ticks attach to human skin through a sequence of precisely timed actions. The insect climbs vegetation, extends its forelegs, and waits for a host to brush past. Sensory receptors on the front legs detect heat, carbon dioxide, and movement, triggering the search for a suitable feeding site.
The mouthparts consist of two short chelicerae that cut the epidermis and a barbed hypostome that penetrates deeper layers. The hypostome’s backward‑pointing teeth anchor the parasite, preventing dislodgement while the tick expands its body.
The feeding process proceeds as follows:
- Questing and host detection.
- Grasping the skin with forelegs.
- Inserting chelicerae to create a small incision.
- Driving the hypostome into the dermis.
- Secreting saliva that contains anticoagulants, vasodilators, and immunomodulatory proteins.
- Engorging on blood over several days.
- Detaching when fully engorged and dropping off.
Saliva components inhibit clot formation and suppress local immune responses, allowing uninterrupted blood intake. The anticoagulant «factor Xa inhibitor» and the vasodilator «prostacyclin» are among the most active substances. Immunosuppressive proteins reduce inflammation, facilitating prolonged attachment.
Engorgement can increase the tick’s weight by 100‑fold. After feeding, the parasite releases its grip, slides out of the wound, and falls to the ground to molt or lay eggs. The bite site often remains painless because the saliva also contains anesthetic agents, making detection by the host unlikely during the feeding period.