for National Geographic News
Despite their negative reputation, brown recluse spiders get blamed for crimes they did not commit, says an arachnologist who is doing his best to set the record straight.
"People are very wrong to believe really bad things about them," said Rick Vetter, of the University of California, Riverside. Doctors misdiagnose hundreds of brown recluse bites around the country every year, Vetter said, often in places where the creepy-crawlers don't even live. Meanwhile the spiders have lived with people for years, apparently without biting them.
In extreme cases, the poisonous venom of a brown recluse bite produces nasty effects. First, the flesh around a bite starts to rot within 12 to 24 hours. The wound turns into a multi-color lesion that can last for up to three weeks. Theoretically, people can die from the venom. But fatal bites are considered highly unlikely, and more than 90 percent of recluse bites heal without complications, though bites can leave permanent scars.
But in the vast majority of cases, spider bite victims develop a negligible wound or show no symptoms whatsoever.
One reason the spiders have earned their bad reputation is that no one knows how many people are bitten by brown recluses each year. And doctors commonly mistake other maladies for brown recluse spider bites.
Epidemic of Fear
Vetter hopes his research will help doctors better treat their patients. Spider bite misdiagnoses can mask serious health problems, like flesh-eating bacteria or cancer, which require specific and immediate care.
Brown recluse spiders caught Vetter's attention in 1992, when a woman in California, who lost her arms, legs, and part of her nose to amputation, said she remembered being bitten by a spider. The media ran with it. Since then, doctors have routinely blamed mysterious splotches of rotting human flesh on bites by brown recluse spiders, regardless of whether the victim ever saw a spider, and often without knowing whether those spiders even live in the area.
"It's like a bunch of people telling you the world is flat," Vetter said. "The myth of the brown recluse is kept alive by a medical community who diagnoses brown recluse bites and the general public who believes the diagnosis."
At least 30 other medical conditions can cause those same symptoms, Vetter said, including bacterial infections, blood disorders, drug reactions, Lyme disease, and poison ivy. In one famous case in New York in October, 2001, a 7-month-old boy who was initially diagnosed with a brown recluse bite turned out to be infected with anthrax.
In fact, fewer than a hundred recluse spider bites have ever been documented, and there have been no confirmed deaths, said Sean Bush, an emergency room doctor at California's Loma Linda University Medical Center. Bush specializes in venomous bites and stings.
"Suspicion of spider bites is exceedingly common," he said. "I call it a pandemic. All over the world, people come in with wounds and think they've been bitten by a spider. This is one of the most controversial areas of medicine," Bush said.
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