What does Wikipedia say about lice? - briefly
According to Wikipedia, lice are tiny, wingless insects of the order Phthiraptera that inhabit the skin, hair, or feathers of mammals and birds as external parasites. The entry outlines three primary types—head, body, and pubic lice—details their life cycle and symptoms such as itching, and lists standard treatments, chiefly topical pediculicides.
What does Wikipedia say about lice? - in detail
According to Wikipedia, lice belong to the order Phthiraptera, a group of obligate ectoparasites that feed exclusively on the blood or skin debris of mammals and birds. The order is divided into two suborders: Anoplura (sucking lice) and Mallophaga (chewing lice). Human‑infesting species are all Anoplura and include three distinct taxa: head lice (Pediculus humanus capitis), body lice (Pediculus humanus corporis), and pubic lice (Pthirus pubis).
Head lice inhabit the scalp, attaching their claws to hair shafts. Their life cycle comprises three stages—egg (nit), nymph, and adult—lasting approximately 30 days from oviposition to the emergence of a reproductive adult. Females lay 6–10 eggs per day, cementing them to hair strands. Nymphs undergo three molts before reaching maturity. Body lice reside in clothing seams, moving to the skin only to feed. Their development mirrors that of head lice but requires a stable clothing environment. Pubic lice infest the coarse hair of the genital region and occasionally other body hair; they exhibit a similar three‑stage life cycle, with a slightly longer developmental period of about 40 days.
Geographically, all three species exhibit a worldwide distribution, with prevalence influenced by socioeconomic conditions, hygiene practices, and crowding. Head lice infestations affect an estimated 6–12 % of school‑age children in industrialized nations, while body lice are associated with homelessness, refugee camps, and situations of prolonged clothing contamination. Pubic lice prevalence varies, often linked to sexual contact.
Health implications include itching, secondary bacterial infection from scratching, and, in the case of body lice, transmission of pathogens such as Rickettsia prowazekii (epidemic typhus), Borrelia recurrentis (relapsing fever), and Bartonella quintana (trench fever). Head and pubic lice are not known vectors of serious disease.
Treatment recommendations rely on topical insecticides (e.g., permethrin 1 % lotion, pyrethrins with piperonyl‑butoxide) applied to hair or genital areas, combined with mechanical removal of nymphs and nits using fine‑toothed combs. For body lice, regular laundering of clothing at temperatures ≥ 60 °C or dry cleaning eliminates infestations. Resistance to pyrethroids has been documented, prompting the use of alternative agents such as ivermectin (oral) or spinosad in refractory cases.
Prevention strategies emphasize personal hygiene, avoidance of sharing personal items (combs, hats, clothing), and maintaining clean living environments. In institutional settings, routine screening and prompt treatment reduce outbreak potential.
Taxonomically, Pediculus humanus is classified within the family Pediculidae, while Pthirus pubis belongs to the family Pthiridae. Molecular studies suggest that head and body lice are conspecific, differing only in ecological niche and behavior.
Historical records trace human lice back to ancient Egypt, with depictions on tomb walls and references in classical literature. Their persistence across millennia underscores their adaptation to human hosts and the importance of ongoing public‑health measures.