Body lice are slightly larger than head lice and can transmit diseases, such as trench fever and typhus, which head lice do not. Also, body lice can survive away from their hosts up to 30 days, while head lice die within 48 hours if separated from their hosts.
Body lice and head lice are subspecies of the human louse, Pediculus humanus. Both types of louse spread through direct contact between people and through contact with infested objects, such as clothes, hats or bed linens.
Head lice are more common and infest six to 12 million people in the United States every year, mostly children in preschools, elementary schools and day-care centers. Head-lice infestations affect all socioeconomic levels and are not closely related to personal hygiene. The lice live directly on the head and neck, and lay their eggs along the hair shafts. Parents can treat head-lice infestations by using anti-lice shampoos, and combing the hair with a fine-toothed comb to remove eggs and nits. Prevention includes teaching children not to share hats, caps, combs or brushes.
Body-lice infestations are common in areas where poor personal hygiene and overcrowding are problems. Body lice live on clothing, usually along the seams, and move to their hosts' skin to feed. The best treatment is providing a bath and clean clothes to the victim, and washing and drying the victim's clothing and bed linens in hot cycles. One should vacuum carpets and furniture as well, and throw away the vacuum bag immediately.