Blood is the only source of nourishment.
Infestations can cause persistent itching and scratching on the scalp. Body Louse and Head Louse Pediculosis is spread mainly by direct contact with an infested person or stray hairs containing nits, personal items such as wigs, combs, hairbrushes, hair rollers, towels, pillowcases and clothing, especially hats, sweaters, scarves, etc. Treatment should be made immediately since lice populations can spread rapidly and throughout the family, school and other close living quarters. Human lice are not transmitted by pets such as dogs, cats, gerbils, birds, etc. These lice do not survive on domestic animals.