How do lice infect humans? - briefly
Lice spread mainly via direct head‑to‑head contact or by sharing personal items such as combs, hats, or bedding, enabling the insects to crawl onto the scalp. After attachment, they feed on blood and lay eggs that hatch within a few days.
How do lice infect humans? - in detail
Lice colonize human hosts through direct physical contact and by sharing personal items. Adult females deposit eggs (nits) on hair shafts or body hair; the eggs hatch in 7‑10 days, releasing nymphs that mature after three molts, typically within 2‑3 weeks. The insects feed on blood several times daily, anchoring with specialized mouthparts that pierce the epidermis.
Transmission pathways include:
- Skin‑to‑skin contact, especially head‑to‑head interaction among children.
- Transfer via clothing, hats, scarves, or hair accessories that have retained viable eggs or mobile lice.
- Contact with bedding, towels, or upholstered furniture that have been recently infested.
- Shared equipment in schools, camps, or sports facilities, such as helmets or helmets liners.
Factors that increase infestation risk are crowding, prolonged close contact, and environments where personal items are exchanged frequently. Lice do not jump or fly; they move by crawling, which limits spread to situations where hosts are in immediate proximity or share contaminated objects.
Once attached, lice reproduce continuously, maintaining a population that can reach dozens of individuals on a single host. The presence of eggs and the irritation caused by feeding stimulate scratching, which can lead to secondary bacterial infection if the skin barrier is breached. Effective control requires simultaneous removal of live insects, destruction of eggs, and decontamination of fomites.