How do ticks get under the skin? - briefly
Ticks insert their barbed mouthparts, called chelicerae and a hypostome, into the host’s epidermis and dermis. They release saliva with anticoagulants to prevent clotting, allowing the parasite to remain attached and feed for several days.
How do ticks get under the skin? - in detail
Ticks attach to a host by a sequence of mechanical and biochemical actions. First, a questing tick climbs onto vegetation and waits with forelegs extended, detecting carbon dioxide, heat, and movement. When a suitable animal brushes past, the tick clamps onto the hair or skin with its front legs and begins to crawl toward a favorable site, usually a thin‑skinned area such as the scalp, armpit, or groin.
The tick then inserts its mouthparts, called the capitulum, which consist of chelicerae and a hypostome. The chelicerae cut through the outer epidermis, creating a tiny incision. The hypostome, a barbed, tube‑like structure, is then driven into the dermis. The barbs prevent easy removal, anchoring the parasite securely.
While the hypostome penetrates, the tick secretes saliva containing a complex cocktail of compounds. These include anticoagulants that inhibit clotting, immunomodulators that dampen the host’s inflammatory response, and enzymes that facilitate tissue breakdown. The saliva also creates a localized anesthetic effect, reducing the host’s sensation of the bite.
After insertion, the tick’s feeding tube, formed by the hypostome, remains open to the host’s blood vessels. Blood is drawn through the tube into the tick’s gut, where it can be stored for several days to weeks, depending on the species and life stage. During this period, the tick periodically releases additional saliva to maintain the feeding site and suppress host defenses.
Key steps in the penetration process:
- Detection of host cues (CO₂, heat, vibration) while questing.
- Physical attachment using forelegs.
- Migration to a thin‑skinned region.
- Cutting of the epidermis with chelicerae.
- Insertion of the barbed hypostome into the dermis.
- Injection of saliva containing anticoagulants, immunosuppressants, and anesthetics.
- Establishment of a feeding channel for prolonged blood intake.
The entire mechanism enables ticks to embed themselves beneath the surface without immediate detection, allowing them to feed for extended periods while transmitting potential pathogens.