What is the medical term for a louse? - briefly
The clinical designation for a louse infestation is pediculosis, derived from the genus Pediculus. The organism itself is called a pediculus (for example, Pediculus humanus).
What is the medical term for a louse? - in detail
The organism commonly known as a louse belongs to the order Phthiraptera. In clinical terminology the generic name for the head‑ and body‑infesting species is Pediculus humanus, while the pubic variety is classified as Phthirus pubis. The condition produced by these ectoparasites is termed pediculosis, which specifies an active infestation rather than the insect itself.
Key species and their medical relevance
- Pediculus humanus capitis – head louse; transmits Bartonella quintana and Rickettsia prowazekii under extreme conditions.
- Pediculus humanus corporis – body louse; vector for Rickettsia prowazekii, Borrelia recurrentis, and Ehrlichia species.
- Phthirus pubis – pubic or crab louse; primarily spreads through sexual contact, may cause secondary bacterial infection.
Morphology
- Adult head and body lice: dorsoventrally flattened, 2–4 mm long, six legs with clawed tarsi adapted for grasping hair shafts.
- Pubic lice: broader, crab‑shaped, 1–2 mm long, three pairs of legs, adapted for coarse pubic hair.
Life cycle
- Egg (nit) attached to hair shaft; incubation 7–10 days.
- Three nymphal instars; each stage lasts 3–4 days, requiring blood meals.
- Mature adult; lifespan 30 days on host, longer off‑host under favorable humidity.
Diagnosis
- Direct visual inspection of live insects or nits attached near the scalp or body hair.
- Dermatoscopic examination enhances detection of motile lice.
- In cases of body‑lice infestation, examination of clothing seams and bedding is essential.
Therapeutic options
- Topical pediculicides (permethrin 1 %, malathion 0.5 %).
- Oral ivermectin (200 µg/kg) for resistant cases.
- Mechanical removal of nits using fine‑toothed combs; repeated sessions over 10 days to cover hatching cycles.
- Environmental decontamination: washing clothes and bedding at ≥ 60 °C, sealing non‑washable items in sealed bags for 2 weeks.
Prevention
- Regular screening in communal settings (schools, shelters).
- Avoid sharing personal items such as combs, hats, and bedding.
- Prompt treatment of identified cases to interrupt transmission chains.
Thus, the precise medical designation for the insect is Pediculus humanus (head and body forms) or Phthirus pubis (pubic form), while the disease state is described as pediculosis.