How does a flea attack a person? - briefly
A flea detects a human by heat, movement, and carbon‑dioxide, then inserts its needle‑like mouthparts into the skin and injects saliva that contains anticoagulants, causing itching and potentially transmitting disease agents. The result is a tiny, red, raised spot that may become a cluster of irritations if several fleas feed.
How does a flea attack a person? - in detail
Fleas locate a host by detecting body heat, carbon‑dioxide, and movement. Once a suitable target is identified, the insect jumps onto the skin, often from a pet’s fur or from the environment. The flea’s hind legs generate a powerful thrust, allowing it to cover distances up to 150 cm in a single leap.
After landing, the flea searches for a thin area of skin, typically around the ankles, lower legs, waist, or neck. Its mouthparts consist of a pair of piercing stylets and a sucking tube. The stylets pierce the epidermis, creating a tiny puncture that is usually invisible to the naked eye. Saliva is injected simultaneously; it contains anticoagulants and anesthetic compounds that prevent blood clotting and reduce the host’s immediate perception of the bite.
Blood is drawn through the sucking tube into the flea’s digestive tract. Each feeding episode lasts several minutes, during which the insect may ingest up to 0.5 µL of blood. After feeding, the flea releases the mouthparts and may remain on the host or fall off to seek another feeding site. Repeated bites can cause localized erythema, pruritus, and, in some individuals, an allergic reaction known as papular urticaria.
Key stages of the process:
- Detection of host cues (heat, CO₂, movement)
- Jumping onto the skin
- Selection of a thin skin area
- Penetration with stylets and saliva injection
- Blood extraction
- Detachment and possible relocation
Understanding each step clarifies why flea bites often appear in clusters and why they provoke intense itching despite the minute size of the wound.