What are the lice that live on hair called? - briefly
The insects that infest human hair are known as head lice, scientifically Pediculus humanus capitis. They are obligate ectoparasites that feed on blood from the scalp.
What are the lice that live on hair called? - in detail
Head lice, scientifically known as Pediculus humanus capitis, are the ectoparasites that inhabit human scalp hair. Adult specimens measure 2–4 mm, have a flattened, wingless body, and cling to hair shafts with clawed legs. Their coloration ranges from gray to brown, often appearing translucent after feeding.
The organism’s development proceeds through three distinct stages:
- Egg (nit): Oval, 0.8 mm long, firmly attached to the hair near the scalp by a cement-like substance. Incubation lasts 7–10 days.
- Nymph: Immature form undergoing three molts. Each instar lasts about 3–4 days, during which the nymph grows and begins feeding.
- Adult: Reaches reproductive maturity after approximately 9 days post‑hatching. Females lay 5–10 eggs per day, sustaining the infestation.
Feeding occurs every 3–4 hours; each blood meal provides a few microliters of host plasma. Over a 30‑day period, a single female can produce up to 150 eggs, leading to rapid population expansion.
Diagnosis relies on visual detection of live insects or viable nits attached within 1 cm of the scalp. Viable nits are identified by a firm, white, oval shape and a visible operculum at one end. Empty shells, or “shell nits,” are translucent and lack an operculum.
Control measures include:
- Topical pediculicides: Permethrin 1 % lotion, pyrethrin‑based formulations, or dimethicone preparations applied to dry hair for the recommended duration.
- Mechanical removal: Fine‑toothed nit combs used on wet, conditioned hair, repeated every 2–3 days for two weeks.
- Environmental decontamination: Washing bedding, clothing, and personal items in hot water (≥ 60 °C) or sealing non‑washable items in airtight bags for 14 days.
Resistance to common insecticides has been documented; in such cases, alternative agents such as spinosad or ivermectin may be prescribed under medical supervision.
Distinguishing head lice from body lice (Pediculus humanus humanus) is essential. Body lice inhabit clothing seams, feed less frequently, and are vectors for bacterial pathogens, whereas head lice remain confined to scalp hair and are not recognized disease carriers.
Effective eradication requires simultaneous treatment of the host, thorough combing, and proper handling of personal items to prevent reinfestation.