The
body louse (
Pediculus humanus
humanus, sometimes called
Pediculus humanus corporis)
is a
louse which infests humans. The condition
of being infested with
head lice, body
lice, or
pubic lice is known as
pediculosis.
Origins
Genetic analysis suggests that the human body louse may have
originated about 107,000 years ago from the head louse after the
invention of clothing, with the ancestor of all human lice emerging
about 770,000 years ago.
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 (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 burned 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 12 mg 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.
References
- Page on website of CIGNA
See also
External links