CSU ext

Lice -infect all domestic animals including birds.  They are wingless, flattened, insect with 3 pairs of legs, and  feed on the skin of their host. Lice are ‘host specific’ meaning that a louse from a cow will not under normal conditions infect another species of animal. Similarly the lice that infect people do not come from animals.

Lice are small 2-3 mm in lenght

How are lice transmitted? Lice are transmitted from animal to animal contact especially when animals are crowded together. Animals infected with lice can be treated with an insecticidal spray or dusting powder.


What are the signs in animals? Depending on the species of lice infestation, signs can vary from very mild scaliness of the skin to intense itching, rubbing, hair loss and weight loss. The lice can often be seen crawling on the skin and between the hair, wool or feathers and their eggs (‘nits’) can be seen attached to the hair shafts.

Lice and nits
Eggs or "nits" of a louse can be seen attached to the base of the hair or wool folicle

Other skin and hair parisites are Ticks and Keds.
It is important to differentiate ‘sheep keds’ and ticks from lice. Keds are insects that are common on sheep are rarely a problem like lice. Keds (Melophagus ovinus) are wingless flies, with 3 pairs of legs, and are usually 2-3 times the size of a louse. Ticks are 4 legged insects capaple of transmitting diseases.

sheep ked
Ked have 3 legs on one side vs. a Tick has 4 legs

Sheep ked and ticks can be seen easily on sheep where a louse it 3 x smaller and very difficult to see

What are the symptoms in humans? People with lice infestations exhibit similar signs of itching, scratching, and hair loss.


More information at Merck Vet Manual: