There are two kinds of this tiny wingless insect that attacks the llama/alpaca - the sucking louse which feeds entirely on blood and can cause anemia and the biting louse which nibble on hair and debris on the alpaca's skin surface. Lice can be spread among the animals by direct contact or by close housing quarters. Signs of lice include rubbing the affected areas, dandruff, and fiber loss in large patches. Watch for lice especially during the winter months when the llamas are usually in close quarters. The biting louse are white or light tan and can be found moving near the skin surface when disrupted. Examine the skin at the base of the neck or tail and inside the back thighs. Treatment may be a topical dust or a pour on medication. Treatment for the sucking lice is injectible Ivomec SQ, or fenthion pour on (Tiguvon) applied topically at the shoulder blades. Treatment for the biting lice is 50% Methovychlor (Marlate at WalMart) or 50% Rose Dust, (Captains at WalMart) applied topically. Ivomec is not effective for the biting lice.(Source - Dr. Norman Evans, DVM)