A louse is a parasitic insect that typically infests the hair or feathers of animals, including humans, and feeds on their blood. These small insects have flattened bodies and specialized mouthparts for piercing the skin and sucking blood. They reproduce rapidly and can spread easily through close contact or shared belongings. Lice infestations, known as pediculosis, can be treated with various methods including insecticidal shampoos and meticulous removal of the insects and their eggs (nits) from the affected area.