täid

Täid are small parasitic insects of the order Phthiraptera that infest humans and their clothing, feeding on blood. The three species most commonly associated with humans are the head louse (Pediculus humanus capitis), the body louse (Pediculus humanus corporis), and the pubic louse (Pthirus pubis).

Life cycle and habitat: Adult lice are wingless and range in size from 1 to 3 mm. Females lay eggs, or nits, that glue to hair shafts near the scalp for head lice or to clothing fibers for body lice. Nits hatch after about 7–14 days, producing nymphs that molt three times before becoming adults. Adults live roughly 30 days and require regular blood meals to survive.

Transmission and symptoms: Lice spread mainly through close personal contact and by sharing combs, hats, or bedding. Head lice stay on the scalp hair; body lice reside in clothing seams and must move to the skin to feed; pubic lice inhabit coarse body hair. Symptoms typically include intense itching and visible nits or live lice. Scratching can lead to skin irritation or infection. Diagnosis is usually based on discovering live lice or nits on hair shafts or clothing.

Treatment and prevention: Treatments include topical pediculicides (for example, products containing permethrin or malathion) or oral ivermectin, along with mechanical removal using fine-toothed combs. It is important to wash or dry clean contaminated clothing and bedding at high temperature and to vacuum living areas. People close to an infested individual should be checked and treated if necessary to prevent re-infestation. Avoid sharing personal items; tie back long hair; check children regularly.

Public health notes: While head lice are not generally linked to disease transmission, body lice can carry pathogens that cause epidemic typhus, trench fever, and relapsing fever, particularly in crowded or unsanitary conditions.