How do lice get into the head? - briefly
Lice reach a scalp by moving from an infested person or contaminated item through direct head‑to‑head contact or by sharing objects such as hats, combs, or bedding. They cannot jump or fly; they crawl and cling to hair shafts to transfer.
How do lice get into the head? - in detail
Head lice (Pediculus humanus capitis) spread primarily through direct contact with an infested person’s hair. The insects cling to hair shafts near the scalp, where warmth and blood supply support their development. When two individuals touch heads, share a hairbrush, or rest a hat or scarf on each other’s heads, lice can crawl from one scalp to another within seconds.
Transmission occurs in several specific ways:
- Head‑to‑head contact: The most common route; even brief, close proximity allows a female or nymph to move onto a new host.
- Shared personal items: Combs, brushes, hair ties, helmets, headphones, or caps that have not been cleaned can harbor live lice or viable eggs (nits) and serve as vectors.
- Contaminated surfaces: Upholstery, pillows, or bedding that have been in prolonged contact with an infested scalp may retain nits, though this route is less efficient because lice require a living host to survive.
Lice do not jump or fly; they rely on crawling. A female adult can lay up to eight eggs per day, attaching each to a hair strand within a millimeter of the scalp. These eggs hatch in about a week, producing nymphs that mature to reproductive adults in another week. The rapid life cycle sustains the population and increases the likelihood of spread during the period when insects are actively moving.
Preventive measures focus on minimizing direct head contact and ensuring that personal grooming tools are regularly disinfected. Cleaning protocols typically involve soaking combs and brushes in hot water (at least 130 °F/54 °C) for ten minutes or using an alcohol‑based solution. Items that cannot be washed should be isolated for two weeks, the duration needed for any attached lice to die without a blood meal.
Understanding these mechanisms clarifies why infestations proliferate in settings such as schools, camps, or households where close head contact is frequent and personal items are shared without proper sanitation.