How did lice get on the head? - briefly
Lice are transferred to a person through direct head‑to‑head contact or via personal items such as combs, hats, or bedding that have been contaminated. Once on the hair, the insects lay eggs (nits) that hatch and develop into a new infestation.
How did lice get on the head? - in detail
Head lice colonize a human scalp primarily through direct contact between hair shafts. Because the insects lack the ability to jump or fly, they must crawl from one host to another. When two individuals press heads together, adult lice or newly hatched nymphs move across the hair, locating a suitable feeding site.
Secondary pathways involve personal items that retain live insects or viable eggs. Items such as combs, brushes, hats, helmets, scarves, and hair accessories can harbor lice or nits. If these objects are used by another person without proper disinfection, the parasites transfer to the new host’s hair.
Key biological factors facilitate infestation:
- Lice require a temperature around 30–34 °C and a constant supply of blood; the scalp provides both.
- Females lay eggs (nits) close to the scalp, cementing them to hair shafts. Eggs hatch in 7–10 days, releasing mobile nymphs that immediately seek a blood meal.
- Nits remain viable for up to two weeks if not removed, creating a reservoir that can re‑infest the host after treatment.
Environmental conditions that increase risk include crowded settings, frequent head‑to‑head interaction (e.g., schools, sports teams), and limited access to personal hygiene resources. Effective control therefore requires eliminating direct hair contact, disinfecting shared items, and removing nits through thorough combing or chemical treatment.