Lice are small, flightless insects that live in the hair or feathers of animals and people. Most lice are of the biting or chewing type, including the cat louse (Felicola subrostrata). Lice are most often seen on older, longhaired cats that are no longer able to groom themselves. With the widespread use of monthly flea and tick preventive treatments, lice infestations are now rare in cats and dogs. When seen, infestations are usually seen on debilitated, feral, stray, or shelter animals.
Lice live within the environment provided by the skin and hair. They move from host to host by direct contact. In temperate regions, lice are most common during the colder months and hard to find in the summer. Most chewing lice have definite preferences as to their hosts: they will often live on only one species or several closely related species.
Lice have claws on their legs that are adapted for clinging to hair. Females glue their eggs, known as nits, to the hairs of the host near the skin. The nits are tightly attached and ordinary shampooing will not dislodge them. It takes about 3 to 4 weeks for most lice to go from nit to adult.
Infestations with lice can result in skin disease and may possibly spread some infectious diseases (such as parasitic "worms"). The first signs that your cat may have lice are scratching, biting, and rubbing of infested areas. If the lice are abundant, the hair might also be matted or missing. The cat may also appear restless. Usually, diagnosis is made by seeing lice or, more likely, their eggs on the infested cat. Parting the hair often reveals the lice or eggs. Lice are active and may be seen moving through the hair. The eggs are pale, translucent, and almost oval in shape. A magnifying glass or scope may be necessary to see the eggs or lice.
Using a fine-toothed comb to dislodge nits is a tedious process that will not kill lice that have hatched. Cats and other pets are more frequently treated with spot-on products, shampoos, collars,, sprays, or dusts that kill lice. Do not use an insecticide on your cat without discussing it with your veterinarian. Some insecticides are poisonous to cats. Your veterinarian can recommend an appropriate control product for your cat and provide directions for its use.
Lice dropped or pulled from the host die in a few days, but eggs may continue to hatch over 2 to 3 weeks. Thus, lice control treatments should be repeated 7 to 10 days after the first treatment. Careful inspection of your cat’s coat should be continued daily for at least 2 weeks after you see the last louse. Be sure to carefully collect any lice (dead or alive) removed from your pet and dispose of them promptly in a sealed container (such as a zip-closure plastic bag). Other cats that have contact with an infested cat should be treated to prevent the spread of disease.
If your cat is heavily matted or has long hair, your veterinarian may recommend that you clip its fur to facilitate treatment. In severe louse infestations, a cat may damage its skin by scratching. Bacterial infections and scratch wounds are common. If these conditions are present, your veterinarian may prescribe an antibiotic or other medication. Your veterinarian will also treat any other nutritional or health issues.
In addition to killing the lice on your cat, you will want to be sure that lice are not infesting your cat’s bedding, collar, grooming tools (including bushes or combs), and other similar objects in your cat’s environment. Bedding should be washed frequently in hot, soapy water or treated with an appropriate spray until the infestation is controlled. Careful cleaning and inspection of these objects can help provide your pet with continued relief from the irritation caused by lice.
The lice that infest cats and other pets are not normally attracted to humans. Therefore, while care in dealing with the lice infesting your pet is recommended, owners should understand that people rarely get lice from their pets.
Also see professional content regarding lice.