Body lice look virtually identical to head lice
look identical, but their location on people is a reasonably accurate
diagnostic clue. Head lice are found almost exclusively on the scalp,
whereas body lice may be found either on the body or clothing. Unlike
head lice, body lice attach their eggs to the fibers of undergarments,
particularly along inside seams and other areas of close body contact.
A female body louse usually deposits 9-10 eggs per day, and a total
of 270-300 eggs over her lifetime. The eggs are incubated by the
person's body heat and hatch in about one week. Temperatures above
100oF or below 75o F. reduce or completely stop egg hatch. Development
time (egg to adult) is about 3-5 weeks.
Body lice are most common during the winter months, when people
tend to wear layers of clothing, creating a warm, moist environment
that is ideal for louse development. An important point to note
is that body lice spend most of their life on clothing and crawl
onto the host to feed for short periods. Although as many as 1,000
body lice have been removed from heavily infested clothing, ten
lice per person is probably more typical. Body louse problems
are more likely to occur in situations where the same clothing
is worn constantly for several days or weeks. Since body lice
can survive away from a person for 24-48 hours, they can survive
in clothing that is removed nightly but worn again the following
day.
Although body lice can transmit certain disease organisms, this
problem is generally confined to underdeveloped countries where
poor sanitation and overcrowding are major contributing factors.
Feeding activity by the lice causes significant skin irritation,
swelling and the formation of red welt-like marks. Severe infestations
can lead to allergic reactions and skin disorders, such as impetigo
and eczema.
Epidemics of typhus and louse-borne relapsing fever have been
caused by body lice. Though typhus is no longer widespread, epidemics
still occur during times of war, civil unrest, natural disasters,
in refugee camps, and prisons where people live crowded together
in unsanitary conditions. Typhus still exists in places where
climate, chronic poverty, and social customs prevent regular changes
and laundering of clothing.
