Human body louse

The body louse (Pediculus humanus humanus) is a louse which infests humans. The condition of being infested with head lice, body lice, or pubic lice is known as Pediculosis.

Entomology and pathology
Pediculus humanus humanus (the body louse) is indistinguishable in appearance from Pediculus humanus capitis (the head louse) and under laboratory conditions they will interbreed. In their natural state, however, the two subspecies do not interbreed and occupy different habitats. In particular, body lice have evolved to attach their eggs to clothes, whereas head lice attach their eggs to the base of hairs.

Body lice are a nuisance in themselves and cause intense itching. They are however, also vectors (transmitters) of other diseases such as epidemic typhus and louse-borne relapsing fever.

Treatment
Delousing can be practically achieved by boiling all clothes and bed clothes. In fact, a temperature of 130° F or 55° C for 5 minutes will kill most of the adults and prevent eggs from hatching. Where this is not practical or possible, powder dusting with 10% DDT, 1% malathion or 1% permethrin is also effective. If insecticide is not available, louse-infested clothes and bedding should be burnt on an open fire.

Medication is usually not necessary, as the problem normally goes away with daily bathing and wearing of clean clothes.

Oral ivermectin at a dose of 12mg on days 0, 7 and 14 has been used in a small trial of 33 people in Marseilles, but did not result in complete eradication, although there was a significant fall in the number of parasites and proportion of people infected. At the moment, ivermectin cannot be routinely recommended for the treatment of body lice.