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HSE and the BROWN RECLUSE SPIDER, the Hazard Alert worth reading!

I for one have never been a real OH LET ME SEE or We should have one for a pet, spider person and although most spiders are absolutely harmless to humans. In fact, of the over 20,000 different species of spiders that inhabit the North Americas, only 60 are capable of biting humans. Within that small group, only four are known to be dangerous to humans: the brown recluse, the black widow, the 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.

  • Deaths from brown recluse spiders have been reported only in children younger than seven years. With increasing travel, individual spiders and spider bites can be found in areas where the spider is not endemic, and health care practitioners should consider this when treating suspected bites.
  • Most false sightings are due to confusion with one of the 13 other species found in the same family.
  • No deaths have ever been reported from non-brown recluse spiders. Bites from these cousins produce mild to moderate local skin disease.
  • Brown recluse spider bites often go unnoticed initially because they are usually painless bites. Occasionally, some minor burning that feels like a bee is noticed at the time of the bite. Symptoms usually develop 2-8 hours after a bite. Keep in mind that most bites cause little tissue destruction.
  • Initially the bite site is mildly red and upon close inspection may reveal fang marks. Within a few hours, the redness gives way to pallor with a red ring surrounding the area, or a “bull’s-eye” appearance. The lesion will often appear to flow downhill over the course of many hours. The center area will then often blister, which over 12-48 hours can sink, turning bluish then black as this area of tissue dies.

The name “reclusa” describes the spider’s behavior – it avoids humans and human activity, lives in dark and quiet places, such as basements and woodpiles, is active at night, hides its web and is rarely seen. Even though it avoids humans, it bites when threatened. This usually happens when a previously dark and quiet place – like the garden gloves or boots you had stored in your garage – is suddenly disturbed when you put them on.

Features: Brown recluse spiders are notable for their characteristic violin pattern on the back of the cephalothorax, 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 have legs about one inch in length. The name of the genus, Loxosceles,means six eyes. Most other spiders have eight eyes. Yet this unique feature of the brown recluse is lost on the casual observer because the eyes are too small to be seen with the naked eye.

Habits: 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.

The brown recluse venom is extremely poisonous, even more potent than that of a rattlesnake. Yet recluse venom causes less disease than a rattlesnake bite because of the small quantities injected into its victims. The venom of the brown recluse is toxic to cells and tissues.

  • This venom is a collection of enzymes. One of the specific enzymes, once released into the victim’s skin, causes destruction of local cell membranes, which disrupts the integrity of tissues leading to local breakdown of skin, fat, and blood vessels. This process leads to eventual tissue death (necrosis) in areas immediately surrounding the bite site.
  • The venom also induces in its victim an immune response. The victim’s immune systemreleases inflammatory agents-histamines, cytokines, and interleukins-that recruit signal specific disease-fighting white blood cells to the area of injury. In severe cases, however, these same inflammatory agents can themselves cause injury. These secondary effects of the venom, although extremely rare, can produce these more significant side effects of the spider bite:
    • Destruction of red blood cells
    • Low platelet count
    • Blood clots in the capillaries and loss of ability to form clots where needed
    • Acute renal failure (kidney damage)
    • Coma
    • Death

The wound formed from the venom can quickly and easily allow an infection to set in, worsening the wound-healing process. The infection as well as the venom can also spread to the rest of the body and possibly become life-threatening.

It is very difficult to diagnose a brown recluse spider bite unless the victim felt the bite and saw and correctly identified the culprit. Many other conditions can mimic the bite of a brown recluse spider: bacterial, viral or fungal infections; other insect bites; and medical conditions that affect blood circulation. An educated guess can often be made based on a careful history obtained from the patient.

There is no antidote for the brown recluse venom. Treatment is targeted towards specific symptoms.

  • Antihistamines can be given to relieve itching.
  • Antibiotics prevent or treat infection.
  • Surgical intervention may be needed for deep or infected wounds.
  • Tetanus vaccinations must be up-to-date. A booster is usually given if the person’s vaccine status is unknown.

Although it is not easy to completely avoid the bite of a brown recluse spider, there are a few steps that can reduce the risk.

  • Shake outitems such as gloves, boots, shoes, clothing and blankets before using them, especially if they are not used often or have been in storage.
  • Warn the spiders by making noise or vibrations (i.e. stomping your feet) before entering basements, attics, storage areas and unused closets.
  • Avoid clutter. Brown recluse spiders love to hide in the nooks and crannies of your home, or in between or under items.
  • Glue traps can be useful.
  • Contact a professional pest control operator if you suspect an infestation of brown recluse spiders within your home.
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