Small, flat, wingless, grey parasites about 2mm long with strong claw legs and which feed on human blood. There are two distinct forms of this sort of louse - the head louse and the body louse, but they are similar in appearance.
The pearly, oval eggs or “nits” stick to hairs or fibres of clothing and the nymphs moult three times before maturing, feeding as they go. The life cycle takes about 18 days. Past epidemics of typhus and trench fever transmitted by lice are now unlikely, but irritating bites can produce impetigo and similar afflictions.
Having lice does not necessarily imply that one is dirty, but the sooner treatment is sought, and the source eliminated, the better.
Biology
How to get rid of Lice
Effective clinical preparations are available for head and body lice but should only by used under medical direction.
The family pet sometimes acquires dog lice especially at the base of the neck, base of the tail and behind the ears. If a dog persistently scratches these areas, take it to the vet who will prescribe a purpose-made veterinary shampoo or powder.
Bird lice may accidentally get into the house, but these soon die in the absence of their winged host.
For more information also see Head Lice and Body Lice.