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Which Poisonous Spiders are Common in this Area?

Poisonous spiders are out there. Do you know which spiders you need to look out for here in Western North Carolina?

There are many different species of spiders throughout the United States. Some are harmless and others are dangerous. The two kinds of spiders in Western North Carolina that you should be familiar with are the Black Widow and the Brown Recluse. Both spiders have very distinctive features and both are poisonous.

The female Black Widow is shiny black, usually with a reddish hourglass shape on the underside of her spherical abdomen. Her body is about 1.5 inches long. Adult males are harmless, about half the female's size, with smaller bodies, longer legs and usually have yellow and red bands and spots over the back.

Black Widows spin webs that lack shape and form. Their webs are erratic in appearance and the silk is stronger than almost all other arachnids. The Black Widow spider is shy and nocturnal in habit, usually staying hidden in her web, hanging belly upward. Although not aggressive, she may rush out and bite when her web is disturbed or when accidentally trapped in clothing or shoes.

Black Widows are usually found on the underside of ledges, rocks, plants and debris, or wherever a web can be strung. Cold weather and drought may drive these spiders into buildings. Be very careful when working around areas where black widow spiders may be established. Take proper precautions -- wear gloves and pay attention to where you are working.

The bite of the Black Widow is often not painful and may go unnoticed. But the poison injected by the Black Widow bite can cause abdominal pain similar to appendicitis as well as pain to muscles or the soles of the feet. Other symptoms include alternating excessive salivation and dry-mouth, paralysis of the diaphragm, profuse sweating and swollen eyelids.

If bitten, clean the site well with soap and water. Apply a cool compress over the bite location and keep the affected limb elevated to about heart level. Aspirin or Tylenol may be used to relieve minor symptoms. The reaction to a Black widow bite can be painful, and the victim should go to the doctor immediately and/or call the Poison Center for additional information.  Poison Centers across the country now have a new national emergency phone number - 1-800-222-1222.

The Brown Recluse spider has a well defined dark violin marking. Adult Brown Recluse spiders have a leg span about the size of a quarter. Their bodies are about 3/8 inches long and about 3/16 inches wide. Males are slightly smaller in body length than females, but males have proportionally longer legs. Both sexes are venomous.

The Brown Recluse spider is not aggressive, and it normally bites only when crushed, handled or disturbed. Some people have been bitten in bed after inadvertently rolling over onto the spider. Others have been bitten after accidentally touching the spider when cleaning storage areas. Some bites occur when people put on seldom used clothing or shoes inhabited by a Brown Recluse.

Brown Recluse spiders generally occupy dark, undisturbed sites and they can occur indoors or outdoors. In favorable habitats, their populations are usually dense. They thrive in human-altered environments. Indoors, they may be found in attics, basements, crawl spaces, cellars, closets, and ductwork or registers. They may seek shelter in storage boxes, shoes, clothing, folded linens, and behind furniture. They also may be found in outbuildings such as barns, storage sheds, and garages. Outdoors, Brown Recluse spiders may be found underneath logs, loose stones in rock piles, and stacks of lumber.

The physical reaction to a Brown Recluse spider bite depends on the amount of venom injected and an individual's sensitivity to it. Initially, the bite may feel like a pinprick or go unnoticed. Some may not be aware of the bite for 2 to 8 hours. Others feel a stinging sensation followed by intense pain. Infrequently, some victims experience general systemic reactions that may include restlessness, generalized itching, fever, chills, nausea, vomiting, or shock.

In some cases, the bite of the Brown Recluse spider can result in a painful, deep wound that takes a long time to heal. A small white blister usually rises at the bite site surrounded by a swollen area. The affected area enlarges, becomes red, and the tissue is hard to the touch for some time. The lesion from a Brown Recluse spider bite is a dry, blue-gray or blue-white irregular sinking patch with ragged edges and surrounding redness -- termed the "red, white, and blue sign." The lesion usually is 1½ inches by 2¾ inches or smaller.

When there is a severe reaction to the bite, the site can erupt into a "volcano lesion" (a hole in the flesh due to damaged, gangrenous tissue). The open wound may range from the size of an adult's thumbnail to the span of a hand. The dead tissue gradually sloughs away, exposing underlying tissues. The sunken, ulcerating sore may heal slowly up to 6 to 8 weeks. Full recovery may take several months and scarring may remain.

If bitten, remain calm and immediately seek medical attention (contact your physician, hospital and/or poison control center). Apply an ice pack directly to the bite area to relieve swelling and pain. If possible, collect the spider (even a mangled specimen has diagnostic value) for positive identification by a spider expert. A plastic bag, small jar, or pill vial is useful and no preservative is necessary, but rubbing alcohol will help to preserve the spider. Although fatalities are extremely rare, bites are most dangerous to young children, the elderly, and those in poor physical condition.

An effective commercial anti-venom is not available. The surgical removal of tissue was once standard procedure, but now this is thought to slow down wound healing. Some physicians administer high doses of cortisone-type hormones to combat hemolysis and other systemic complications. Treatment with oral dapsone (an antibiotic used mainly for leprosy) has been suggested to reduce the degree of tissue damage. However, an effective therapy has not yet been found in controlled studies. 

For more information, call Buncombe County Cooperative Extension at 255-5522.