5/09/2011 Spider safety in Mid-South is serious business!

Spider safety in Mid-South is serious business!

by Dean Davis, Safety Specialist, Memphis District, USACE

Overview

Most spiders are absolutely harmless to humans. In fact, of the 20,000 different species of spiders that inhabit the Americas, only 60 are capable of biting humans. Within that small group, only four are known to be dangerous to humans: brown recluse, black widow, hobo or aggressive house spider, and the yellow sac spider. Within this select group, only the brown recluse and the black widow spider have ever been associated with significant disease and very rare reports of death.

These spiders are not aggressive and bite only when threatened, usually when pressed up against the victim's skin. They seek out dark, warm, dry environments such as attics, closets, porches, barns, basements, woodpiles, and old tires. Its small, haphazard web, found mostly in corners and crevices, is not used to capture prey. Most bites occur in the summer months.

Outlook

The majority of brown recluse bites cause little permanent skin damage, although, in some cases, moderate to severe tissue destruction is possible. The full extent of damage to tissues is not known for days. It may take many months for the wound to completely heal. Brown recluse bites are noted for somewhat slow development and often take up to 12 hours to reveal themselves. Necrosis of skin (death of the skin), if it occurs, does so in the first 96 hours. Bites older than this not revealing tissue death have not been reported to worsen.

Black widow spider bites result in a halo lesion consisting of a pale circular area surrounded by a ring of redness. The initial bite of the black widow spider is usually painful and the victim will often note the spider during the bite. This bite can result in numbness, tingling, rashes, sweating, nausea, vomiting, dizziness, cramps, rigid abdominal muscles, chest tightness, weakness, and difficulty breathing. The abdominal pain due to the spider bite can be so severe that it mimics abdominal medical conditions such as pancreatitis.

Spider Bite Treatment

If a black widow spider or brown recluse spider bite is suspected, you should see your doctor or go to an emergency department immediately. Wash the bite with soap and water and remove all jewelry. Swelling can occur and will make it difficult to remove some jewelry. The pain resulting from a black widow spider bite is usually so severe that it will require strong pain medications such as opioids. Definitely DO NOT cut into the wound or apply suction.

Prevention

Reducing the possibility of an encounter with a brown recluse spider starts with eliminating known spider habitations. Perform routine, thorough house cleaning and reduce clutter in garages, attics, and basements. Move all firewood, building materials, and debris away from the foundation, install tight-fitting window screens and door sweeps, and clean behind outside shutters. Consider installing yellow or sodium vapor light bulbs outside entrances because these lights are less attractive to insects and draw fewer spiders to the area, and if needed consider professional pest elimination.

Identification

Brown recluse                                        Black widow

 

 

                       courtesy photo                                              Jon Wilson photo

Brown recluse spiders are notable for their characteristic violin pattern on the body part to which the legs attach. The violin pattern is seen with the base of the violin at the head of the spider and the neck of the violin pointing to the rear. These small non-hairy spiders are yellowish-tan to dark brown in color with darker legs. They measure with legs about 1 inch in length.

The black widow spider is a shiny, inky black spider with a large round tail segment (abdomen). Including its legs, the black widow generally measures from one-half inch to one inch in length. Red to orange-colored markings, usually in the shape of an hourglass, are found on the underside of the belly.