Louse

Exclusively on the bodies of host animals or humans, often in hair, clothing, or feathers.

Obligate parasites that feed on the blood of their host or on skin debris and secretions.

They are wingless and crawl between hosts through direct contact; they lay eggs (nits) that glue firmly to hair shafts or clothing fibers.

They cause intense itching and skin irritation. Some species, like body lice, are vectors for diseases such as typhus, while others are primarily a nuisance. They provide no known benefit to humans.