Spiders
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Many species of spiders
are common household pests in the United States. Certain
common household spiders spin webs overs
lamps, in corners and in basements. This creates an unsightly
mess but causes no real harm. Remember that every "cobweb"
was made by a spider. |
Although all spiders
use venom when they bite and kill their prey, the black
widow and the brown recluse spiders
are the only spiders in North America dangerous
to humans. Even though their is little danger of complications
from spider bites, be advised that all
spider bite victims should take the spider
with them when consulting their physician. |
Black
Widow Spider |
The black widow
spider is a spider notorious for its neurotoxic
venom. It is a large widow spider found throughout the world.
Adult female black widow spiders are shiny
black with an hourglass shaped marking on the bottom of
its abdomen which, although most commonly red, may range
in color from white to yellow to various shades of orange
and red. A large female black widow spider can grow to 1.5
inches (38 mm), counting legspan. The body is about 0.5
inches (13 mm).
The chief danger from black widow spiders
lies in their venom. Widow spider venom is one of the few
medically significant venoms possessed by a spider in North
America.
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Widow spiders, although
not aggressive, do occasionally bite humans. Bites occur
most often when someone accidentally presses the spider
into his or her flesh by handling something on which the
spider has attached its web. This is where the widow spider's
habit of nesting in woodpiles or in between boxes and crates
in garages and warehouses becomes significant. In general,
widow spiders are a very timid group of spiders that will
only bite when threatened. |
The bite from the widow
spider causes a set of symptoms in the bite victim known
collectively as latrodectism. Latrodectism is caused by
the neurotoxic venom injected by the widow. The initial
bite is often painless and goes unnoticed; at worst it will
feel like a pinprick. The toxin then travels through the
nervous system. The first significant symptom is a dull,
numbing ache in the region of the actual bite. This ache
may progress to painful muscle cramps in the large muscle
masses of the body, particularly the abdomen. |
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Additional symptoms may include
sweating, nausea, a rise in blood pressure, leg
cramps, muscle tremors, loss of muscle tone, heartbeat
irregularities, and vomiting. Symptoms and pain
begin between 15 and 60 minutes after the bite and
generally peak within one to three hours. Symptoms
are usually completely dissipated within 12 to 24
hours. In extremely rare cases (< 1%), death
may occur. Very young children and elderly adults
are the most susceptible to the widow venom and,
therefore, the most likely to experience severe
symptoms. |
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If you suspect that you
or one of your children have been bitten by a widow spider,
seek medical attention immediately and, if possible, bring
the spider with you to the medical center for positive identification. |
Brown
Recluse Spider |
| The brown recluse
spider is a venomous spider. It is usually between
1/4 and 3/4 inch but may grow larger. It is brown and usually
has markings on the dorsal side of its thorax, with a black
line coming from it that looks like a violin with the neck
of the violin pointing to the rear of the spider resulting
in the nickname "fiddleback spider". Coloring
varies from light tan to brown and the violin marking may
not be visible.
Recluse spiders build irregular webs that frequently include
a shelter consisting of disorderly threads. People get bitten
when they unintentionally squeeze them in clothing and bedding. |
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The severity of the bite
may vary. The symptoms may vary from no harm at all to a
reaction that is very severe. Often there is a systemic
reaction within 24-36 hours characterized by restlessness,
fever, chills, nausea, weakness, and joint pain. Where the
bite occurs there is often tissue death and skin is sloughed
off. In some severe cases, a wound may develop that lasts
several months.
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In all cases, a physician
should be notified. If at all possible, kill and take the
spider to the physician for positive identification. |
Common
House Spiders |
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The
Common house spider, sometimes called the American
house spider, is an extremely common spider.
There are several species sharing many common features.
They build their tangled web in secluded locations,
which can also house eggs contained in one or more
spherical sacs.
Their behavior on webs is quiet and efficient. They
are generally dull in appearance, with patterns consisting
of brown shades for coloration. Their average body
size is a quarter-inch long. These traits combined
allow the spiders to blend into the background and
escape notice |
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These spiders are not aggressive.
They are not known to bite people frequently, nor is their
venom known to be dangerous to human beings. When removed
from their webs their poor vision renders them helpless.
Their only concern seems to be to find and return to their
own web or build another one. They do not wander around
inside houses except to find a secure place to build a web.
Some people tend to fear all spiders, but since these spiders
in particular are harmless and their diet consists of pests
such as flies and mosquito, tolerating their presence in
homes is beneficial. |
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