How does a tick inject venom? - briefly
When a tick attaches, its hypostome pierces the skin and its salivary glands release anticoagulant‑rich saliva through a narrow canal into the host’s tissue. The fluid contains enzymes that suppress clotting and immune responses, allowing the tick to feed.
How does a tick inject venom? - in detail
Ticks attach to a host using specialized mouthparts called chelicerae and a barbed hypostome. The hypostome, driven into the skin, anchors the parasite while the chelicerae cut through the epidermis. Once the feeding cavity is formed, the tick’s salivary glands open into the mouth opening.
Saliva is transported through a narrow duct that ends at the tip of the hypostome. Muscular contractions of the pharynx and hemocoel generate pressure, forcing the fluid into the host’s tissue. The process occurs continuously during the multi‑day blood meal.
Key components of the injected fluid include:
- Anticoagulants (e.g., apyrase, prostaglandin‑E₂) that prevent clot formation.
- Immunomodulators (e.g., Salp15) that suppress local immune responses.
- Enzymes (e.g., metalloproteases) that degrade extracellular matrix, facilitating deeper penetration.
- Bioactive peptides that induce vasodilation, increasing blood flow to the feeding site.
The tick regulates secretion through neural control of the salivary glands. When the host’s skin detects the bite, the parasite adjusts the volume and composition of saliva to maintain a stable feeding environment. The combination of mechanical anchoring and chemically active saliva enables efficient transfer of toxic and therapeutic agents into the host.