Body louse

The body louse (Pediculus humanus humanus, also known as Pediculus humanus corporis) is a hematophagic ectoparasite louse that infests humans. It is one of three lice which infest humans, the other two being the head louse, and the crab louse or pubic louse. Despite the name, body lice do not directly live on the host. They lay their eggs on fibres of clothing and only come into contact with the host whenever they need to feed. Since body lice cannot jump or fly, they spread by direct contact with another person or more rarely by contact with clothing or bed sheets that are infested. Body lice are disease vectors and can transmit pathogens that cause human diseases such as epidemic typhus, trench fever, and relapsing fever. In developed countries, infestations are only a problem in areas of poverty where there is poor body hygiene, crowded living conditions, and a lack of access to clean clothing. Outbreaks can also occur in situations where large groups of people are forced to live in unsanitary conditions. These types of outbreaks are seen globally in prisons, homeless populations, refugees of war, or when natural disasters occur and proper sanitation is not available. Pediculus humanus humanus (the body louse) is indistinguishable in appearance from Pediculus humanus capitis (the head louse), and the two subspecies will interbreed under laboratory conditions. In their natural state, however, they occupy different habitats and do not usually meet. They can feed up to five times a day and as adults can live for about thirty days, but if they are separated from their host they will die within a week. If the conditions are favorable, the body louse can reproduce rapidly. After the final molt, female and male lice will mate immediately. A female louse can lay up to 200–300 eggs during her lifetime. The life cycle of the body louse consists of three stages: egg, nymph, and adult. Eggs (also called nits, see head louse nits) are attached to the clothes by the female louse, using a secretion of the accessory glands that holds the egg in place until it hatches, while the nits (empty egg shells) may remain for months on the clothing.