What are domestic lice? - briefly
Domestic lice are small, wingless insects that feed on the blood of humans or household pets, causing itching and possible skin irritation. They belong to the order Phthiraptera and include species such as head lice (Pediculus humanus capitis) and body lice (Pediculus humanus corporis).
What are domestic lice? - in detail
Domestic lice are obligate ectoparasites that feed exclusively on human blood. Two species dominate the domestic environment: the head louse (Pediculus humanus capitis) and the body louse (Pediculus humanus humanus). Both belong to the order Phthiraptera and share a flattened, wingless body adapted for clinging to hair shafts or clothing fibers.
The life cycle consists of three stages. Eggs, called nits, are cemented to hair or fabric and hatch in 7–10 days. Nymphs emerge, undergo three molts over 5–9 days, and become mature adults. Adults live 30 days on a host, feeding several times daily. Females lay 6–10 eggs per day, ensuring rapid population growth under favorable conditions.
Symptoms arise from repeated feeding. Irritation, itching, and secondary bacterial infection are common. Body lice can transmit pathogens such as Rickettsia prowazekii (epidemic typhus), Borrelia recurrentis (relapsing fever), and Bartonella quintana (trench fever). Head lice rarely act as disease vectors but cause significant discomfort.
Diagnosis relies on visual inspection. Nits appear as oval, yellow‑white structures firmly attached to the base of hair shafts; they are not easily removed. Live lice move quickly when disturbed. Dermatoscopic examination can confirm identification.
Effective management combines mechanical and chemical measures. Recommended actions include:
- Wet combing with a fine‑toothed lice comb to extract nits and adults.
- Application of topical insecticides containing permethrin, pyrethrin, or dimethicone, following label instructions.
- Washing infested clothing and bedding at ≥ 60 °C or sealing them in airtight bags for two weeks to kill dormant lice.
- Regular inspection of all household members for at least four weeks after treatment.
Prevention focuses on minimizing direct head‑to‑head contact and avoiding sharing personal items such as hats, combs, and towels. Maintaining clean clothing and bedding, especially in crowded or unhygienic settings, reduces the risk of body‑lice infestations.
Understanding the biology, transmission pathways, and control strategies of these parasites enables prompt eradication and limits the spread of associated diseases.