How do earth fleas bite humans? - briefly
Earth fleas (chiggers) latch onto the skin, inject enzymes that break down tissue, and their tiny chelicerae pierce the epidermis to feed. The enzymatic digestion triggers a red, itchy bite site that develops within a few hours.
How do earth fleas bite humans? - in detail
Earth fleas, commonly referred to as chigger larvae, attach to human skin by locating a suitable site, usually where the epidermis is thin or where hair provides a foothold. The larva uses its three pairs of hooked mouthparts to pierce the stratum corneum, not the deeper living layers. Once the puncture is made, the mite inserts a feeding tube called a stylostome, which it creates by secreting digestive enzymes and anticoagulant saliva. This tube remains open to the external environment, allowing the larva to ingest liquefied host tissue.
The feeding process proceeds as follows:
- The larva secures itself with its chelicerae, anchoring the stylostome in the epidermal cells.
- Saliva containing proteolytic enzymes breaks down cellular proteins, while anticoagulants prevent clotting.
- The resulting fluid is drawn up through the stylostome into the mite’s digestive tract.
- Feeding continues for several days, after which the larva detaches and drops to the ground to develop into the next life stage.
Human reaction to the bite is primarily an immune response to the mite’s saliva. Histamine release causes localized itching, erythema, and, in some cases, a papular rash. The skin lesion typically appears 2–24 hours after contact and may persist for a week or longer if scratched.
Preventive measures focus on reducing exposure:
- Wear long sleeves and trousers in infested areas.
- Apply acaricidal repellents containing DEET or permethrin.
- Shower and wash clothing promptly after outdoor activity to remove unattached larvae.
Understanding the precise mechanism of attachment and feeding clarifies why the bite does not involve a traditional insect sting but rather a prolonged enzymatic extraction of host tissue. This knowledge informs both treatment—topical corticosteroids or antihistamines to alleviate symptoms—and prevention strategies aimed at minimizing contact with the larval stage.