How is a subcutaneous tick transmitted in humans? - briefly
A subcutaneous tick penetrates the dermis after attaching to the skin during a bite, often entering through hair or small skin openings when a person contacts infested vegetation. The tick then remains beneath the epidermis, feeding on blood while remaining hidden from the surface.
How is a subcutaneous tick transmitted in humans? - in detail
A subcutaneous tick becomes a human parasite when an engorged nymph or adult, already attached to a mammalian host, penetrates the skin and embeds its mouthparts in the dermal layer. The parasite’s life cycle begins with eggs laid in the environment; larvae hatch and seek a blood meal on small vertebrates. After feeding, larvae molt into nymphs, which then hunt larger hosts, including humans. When a nymph or adult encounters a suitable host, it climbs onto the body, typically via grass or low vegetation, and initiates attachment.
The attachment process involves the following steps:
- Questing behavior: The tick climbs to the tip of a blade of grass and extends its forelegs, detecting carbon dioxide, heat, and movement.
- Host contact: Physical contact with the host’s skin triggers the tick to crawl upward, searching for a thin, hair‑free area.
- Insertion: The tick inserts its hypostome, a barbed feeding structure, into the epidermis and advances into the dermis, anchoring itself with cement proteins.
- Engorgement: Blood is drawn through a canal in the hypostome. The tick can remain attached for several days, enlarging as it fills with blood.
- Detachment: After completion of the blood meal, the tick releases its grip and drops off, often leaving only the mouthparts embedded.
Transmission to humans occurs when the tick’s questing activity brings it into contact with exposed skin, especially in humid, wooded, or grassy environments where tick populations thrive. Factors that increase risk include:
- Walking or working in tick‑infested habitats without protective clothing.
- Wearing short sleeves, shorts, or footwear that leaves skin exposed.
- Lack of regular body checks after outdoor activities.
During feeding, the tick may inoculate pathogens present in its salivary glands, leading to diseases such as Lyme borreliosis, anaplasmosis, or babesiosis. Prompt removal of the tick, preferably with fine‑point tweezers grasping the mouthparts close to the skin and pulling steadily upward, reduces the likelihood of pathogen transmission. Early detection and removal are essential because the probability of infection rises with the duration of attachment, typically becoming significant after 24–48 hours.