Adult: 2,5–3 mm
A fully grown lice has no wings. It is a quite flat parasite that is either whitish or grey in colour.
Head louse (Pediculus humanus capitis) only lives in hair and perishes in a few days without any body heat. It attaches its eggs, less than a millimetre long, into the base of the hair.
It spreads easily through headdresses, brushes and combs. They can also spread directly from head to head in close contact.
Body louse (Pediculus humanus corporis) lives in clothing. The body louse lays its eggs into the seams of clothing.
The crab louse (Phthirus pubis) usually lives in pubic hair and spreads through sexual contact. Sometimes, they may be caught from damp towels or brushes used in a sauna. The crab louse can survive one day without a host.
The head louse is not known to spread any diseases, but the body louse may spread typhus or relapsing fever. Crab louse infection causes severe itching, a rash and hair-loss.
Prevention and extermination
The head louse lives in hair. The applied treatments are shampoos or solutions sold in pharmacies. If necessary, please contact your health care centre.
Clean all premises carefully, also vacuum the mattress and the bed and wash all bed clothes at +60 °C. Throw out the dust bag after vacuuming. In public events, it is better to keep your headdress with you, instead of leaving it on a coat rack shelf with other headdresses, from which the louse could easily spread over. When exterminating head lice, the whole family needs to be treated.
The body louse lives in clothing. If you discover a body louse problem, please contact your health care centre. Clean all premises carefully, also vacuum the mattress and the bed and throw away the dust bag afterwards. Also, throw away any contaminated textiles or wash them at +60 °C. Contact your building manager, in order to start an extermination process carried out by professionals.
Solutions intended for the extermination of crab louse are sold at pharmacies, prescription free.
Terveyskirjasto has information on head louse and the treatment of infection