Why do lice seem to appear? - briefly
Lice infestations become noticeable after rapid reproduction and direct head‑to‑head transmission, which spreads the insects quickly among close contacts. Their eggs are difficult to detect at first, so the problem seems to emerge suddenly when the population reaches a visible level.
Why do lice seem to appear? - in detail
Lice infestations arise when three conditions converge: a viable population of parasites, a suitable host, and an environment that permits transmission. Adult female head‑lice lay 4–6 eggs (nits) per day, attaching them to hair shafts near the scalp. Eggs hatch in about a week, releasing nymphs that mature to reproductive adults within another week. This rapid life cycle creates a dense population in a short period, making the infestation noticeable.
Key factors that facilitate spread include:
- Direct head‑to‑head contact, the primary route of transfer.
- Sharing of personal items such as combs, hats, helmets, or headphones.
- Crowded settings where close proximity is common (schools, camps, shelters).
- Inadequate detection or treatment, allowing the colony to persist and expand.
- Environmental conditions that do not kill eggs, such as temperatures above 30 °C, which preserve nits on hair.
Human behavior also contributes. Frequent hair brushing can dislodge eggs, but insufficient inspection may leave them unnoticed. Re‑infestation occurs when treatment fails to eradicate all stages, especially the resilient nits, which require thorough removal.
Effective control relies on breaking the life cycle. Recommended actions are:
- Apply a proven pediculicide according to label instructions, ensuring contact with both live lice and eggs.
- Comb wet hair with a fine‑toothed nit comb at regular intervals for several days to remove residual nits.
- Wash or isolate personal items (bedding, clothing, accessories) at temperatures ≥ 60 °C or seal them for two weeks to kill hidden parasites.
- Conduct a systematic inspection of all close contacts and treat any additional cases promptly.
When these measures are consistently applied, the population collapses within two weeks, and the visible resurgence of lice is prevented.