How do lice transfer to another person? - briefly
Lice spread primarily through direct head‑to‑head contact or by sharing items that touch hair, such as hats, combs, or hairpins; they cannot jump or fly.
How do lice transfer to another person? - in detail
Lice move between hosts primarily through direct head‑to‑head contact. When an infested person’s hair brushes against another’s, adult insects or nymphs crawl onto the new scalp within seconds. This route accounts for the overwhelming majority of new infestations, especially among children who engage in close play.
Secondary pathways involve personal items that retain live lice or viable eggs. Objects that contact hair can serve as temporary carriers:
- Combs, brushes, hair ties, and clips
- Hats, scarves, helmets, and headbands
- Pillows, blankets, and mattress covers
- Upholstered furniture where hair may accumulate
Lice survive off the host for only a short period, typically 24–48 hours. Eggs (nits) are more resilient; they can remain viable for up to a week in a warm, humid environment. Consequently, sharing or reusing contaminated items shortly after exposure can lead to transmission.
Environmental factors influence the likelihood of spread. High population density, poor hygiene, and limited access to effective treatment increase risk. The lice life cycle—egg, nymph, adult—means that a single female can lay 6–10 eggs per day, producing a rapid rise in numbers once a new host is colonized.
Preventive measures focus on eliminating direct contact and decontaminating shared objects. Regular inspection of hair, immediate removal of nits, and washing of clothing, bedding, and accessories in hot water (≥ 130 °F) or using a dryer on high heat are essential steps to halt further spread.