Where do lice come from and how can they be eliminated? - briefly
Lice infestations arise from direct head‑to‑head contact or sharing items such as combs, hats, or bedding that contain live insects or eggs. Effective eradication requires meticulous combing with a fine‑toothed lice comb, application of an approved insecticidal shampoo, and follow‑up treatments to eliminate any remaining nits.
Where do lice come from and how can they be eliminated? - in detail
Lice are obligate ectoparasites that survive exclusively on the blood of mammals. Human head‑lice (Pediculus humanus capitis) spread primarily through direct head‑to‑head contact; occasional transmission occurs via shared combs, hats, pillows, or clothing that have recently contacted an infested scalp. The insects cannot jump or fly, so proximity of hair is the critical factor for infestation. Their life cycle—egg (nit), nymph, adult—lasts about three weeks, during which a single female can lay up to 10 eggs per day, enabling rapid population growth.
Effective eradication requires a three‑step approach:
- Physical removal – Use a fine‑toothed nit comb on wet, conditioned hair. Comb from scalp to tip in sections, cleaning the comb after each pass. Repeat every 2–3 days for at least two weeks to capture newly hatched nymphs.
- Chemical treatment – Apply a pediculicide approved by health authorities (e.g., 1 % permethrin, 0.5 % malathion, or 0.05 % ivermectin). Follow label directions precisely, covering hair and scalp for the recommended exposure time. A second application after 7–10 days eliminates survivors that emerged from remaining eggs.
- Environmental control – Wash clothing, bedding, and personal items used within the previous 48 hours in hot water (≥ 60 °C) and dry on a high‑heat setting for at least 30 minutes. Non‑washable items should be sealed in a plastic bag for two weeks to starve any hidden lice.
Monitoring after treatment involves inspecting the scalp daily for live insects or viable nits. Persistence of infestation beyond two weeks suggests resistance to the chosen pediculicide; in such cases, switch to an alternative agent or consult a healthcare professional for prescription‑strength options. Consistent application of the above measures eliminates the parasite and prevents re‑infestation.