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Lice (
Phthiraptera
)
Lice have been associated with people
throughout written history.
Outbreaks are most often associated
with disasters or crowded and unsanitary
conditions when people cannot bathe or
wash their clothing regularly.
However, we also know that human lice
are not restricted to any particular
socioeconomic level in our communities
and may become a problem in
seemingly sanitary environments.
Lice (
Phthiraptera
)
Chewing and sucking lice are found on
all continents, including Antarctica.
The distribution of lice is roughly similar
to that of the birds and mammals on
which they live.
However, their distribution within the host
population is not uniform.
They are usually quite patchy or
concentrated in some areas.
There are 4,927 species of lice
worldwide, with about 780 species in the
United States and Canada.
Lice (
Phthiraptera
)
The order Phthiraptera has been traditionally
divided into two groups according to their different
feeding habits:
Mallophaga – Chewing lice
Anoplura - sucking lice.
Chewing lice with their large head and mandibles
comprise the largest group with some 2900
species.
These are separable into three distinct
superfamilies - the Amblycera, Ischnocera and
Rhyncophthirina.
Lice (
Phthiraptera
)
Mallophaga – Chewing lice
Biting Lice feed mainly on particles of skin,
feathers and fur.
Some species take blood, sometimes puncturing
the skin with their own jaws, but more often
feeding at small wounds made when the host birds
or animals scratch themselves.
Most lice are confined to one host or a group of
closely related host species. Some are of great
economic importance when they infest domestic
poultry or other livestock, but none are directly
associate with humans.
These are separable into three distinct
superfamilies - the Amblycera, Ischnocera and
Rhyncophthirina.
Lice (
Phthiraptera
)
Amblycera
The Amblycera are a large suborder of
lice, parasitic on both birds and
mammals.
The Amblycera are considered the
most primitive suborder of lice.
They roam freely over the surface of
their host and, unlike other lice, do not
form permanent attachments.
They feed by chewing soft areas of
skin, causing an area of localized
bleeding from which they drink.
Antennae are recessed into the head
Lice (
Phthiraptera
)
Ischnocera
The louse suborder Ischnocera
contains 3060 currently described
species from over 150 genera.
These lice are permanent obligatory
ectoparasites of a diverse selection of
birds and mammals with a worldwide
distribution.
Morphological character variation is
extensive
Antennae are filiform (thin and linear)
