Lice are insects that can be seen with the naked eye. They are flattened and possess no wings. They are very host-specific and do not tend to leave their preferred animal. Lice spend their entire life cycle on the pet. Lice (singular: louse) are insects belonging to either the Mallophaga for chewing lice and Anoplura for sucking lice. There are about 460 species of sucking lice and 3,000 species of chewing lice.

Transmission of lice is by direct contact with an infested pet. Unlike fleas and ticks, lice do not persist or travel in the environment. Grooming instruments may, however, serve as a source of transmission. Lice lay eggs (termed nits) on the hair shafts. The life cycle takes about 21 days to complete.

SIGNS

The most noted sign of a louse infestation is a scruffy, dry hair coat. Hair loss may occur and the animal may itch, at times severely. In very heavy infestations of blood-sucking lice (biting), one may detect anaemia, especially in puppies and kittens. A diagnosis can usually be accomplished with the naked eye. Nits tend to be more visible than the actual louse, but both can be seen.

Lice are highly host-specific. Lice do not survive long if they are removed from their host, so they live on the host all the time.

Table: Common chewing (biting) lice affecting animals

Table: Common sucking lice affecting animals

Mallophaga – Biting Lice or Chewing Lice

Biting lice have mouthparts designed for chewing; not sucking and they feed on feathers, hair and skin scales. They live on mammals and birds. An infestation of lice is called pediculosis.

Chewing lice (Mallophaga) represent the larger of the two traditional suborders of lice (sucking lice).

Mallophaga is divided into three separate suborders:

• Boopidae
• Gyropidae
• Laemobothriidae
• Menoponidae
• Ricinidae
• Trimenoponidae

The families are:

• Heptapsogasteridae
• Goniodidae
• Philopteridae
• Trichodectidae

Anoplura – Sucking Lice

Sucking lice feed solely on blood and have mouthparts designed for sucking. Their mouthparts penetrate the skin and actually fit into a blood vessel from which the blood meal is drawn. Sucking lice only occur on mammals. Blood sucking lice causes severe irritation because they penetrate the skin of your pet in order to feed.

Sucking lice (Anoplura) have around 460 species and represent the smaller of the two traditional suborders of lice. The Anoplura are all blood-feeding ectoparasites of mammals. They can cause localised skin irritations and are vectors of several blood-borne diseases.

Infestations with lice are not life threatening, unless the lice carry some sort of disease organisms. The lice normally cause red papules and cause severe itching which can lead to dermatitis and secondary infection

Treatment:

Treatment is very simple. Both biting and chewing lice are easily killed with flea and tick products. We prefer to bathe weekly with a pyrethrin shampoo. Once the pet is dry, powder heavily with a flea and tick powder. Repeat this process weekly for four weeks. It usually is not necessary to treat the environment, but flea and tick foggers may help, especially in severe cases. Keep all grooming utensils clean.

Effects of Lice

A single animal may be infested with thousands of lice. Their feeding activity results in hair or feather loss, blood loss, skin irritation and secondary infection. Lousy animals may be weak and susceptible to other infestations or diseases. Infested animals will scratch frequently, worsening the condition. However, grooming by the host animal may remove lice and help lessen the effects of lice activity. Also, an animal’s immune system may affect lice and reduce their numbers. Some animals may be infested with lice and show no ill effects.