Lices

Lices is not a standard scientific term. In English, the correct plural is lice; “lices” is an informal or erroneous form. Lice are small, wingless parasitic insects that infest warm-blooded hosts and belong to the order Phthiraptera.

The main human lice are head lice (Pediculus humanus capitis), body lice (Pediculus humanus corporis), and pubic lice (Pthirus pubis). They are about 1–3 mm long. Head and pubic lice live on the host’s body, while body lice spend much of their life on clothing and move to the skin to feed.

Lifecycle and transmission: Females lay eggs (nits) on hair shafts; eggs hatch in about 7–10 days. Nymphs mature to adults in 1–2 weeks. Adults live for a few weeks. Lice survive poorly off the host; transmission occurs by close contact (head), infested clothing or bedding (body), or sexual contact or shared fabrics (pubic).

Impact and treatment: Infestations cause itching and scratching. They do not usually spread serious diseases, though body lice have historically carried pathogens in unsanitary conditions. Treatments include topical pediculicides such as permethrin or pyrethrin, and alternatives like malathion or ivermectin. Wash clothing and bedding, and vacuum to reduce re-infestation; check and treat close contacts as advised.

Prevention and public health: Avoid direct contact and sharing items such as combs, hats, and towels. Regular screening, especially in schools or camps, helps early detection. Because resistance emerges, follow local guidelines and complete the full treatment course.