Head lice cannot jump because they do not have knees or hind legs. Direct contact with another head or a personal item such as a pillow is required for lice to transfer from one person to another.
Direct contact is necessary because head lice lack the ability to jump or fly and must crawl quickly from one host to another. If a louse is away from its host, it dies within 24 hours, since it needs blood meals to live.
Head lice are most common in young children. This may be because of the way they play or their willingness to share personal items such as hairbrushes. There is a variety of treatments for head lice including chemicals, combing the head for lice and drowning lice with olive oil.