Brown recluse spider gets a bum rap
Can a spider be a scapegoat? That certainly seems to be the case for the brown recluse spider, at least in Georgia and other states of the Deep South. Blamed for numbers of injuries way out of proportion to its presence here, and with a bite far less severe than supposed, this little fellow—about the size of a quarter when its legs are extended—suffers not only from mistaken identity but also from a general arachnophobia that presumes even non-bites to be spider-derived.
Thus while many Georgia doctors have diagnosed a patient’s wound as a brown recluse spider bite, over the past six years only 19 brown recluse spiders—that’s 19 individuals—have been identified in the state, said Nancy Hinkle, an entomologist in UGA’s College of Agricultural and Environmental Sciences. Throughout the state’s recorded history, brown recluse spiders have been collected a total of only 58 times in Georgia.
From 2002 to 2008, Hinkle tracked brown recluse reports in Georgia. She published the study’s findings, which basically give the brown recluse spider a major reprieve, in the January 2009 issue of the Journal of Medical Entomology. “Hundreds of entomologists, extension agents from across the state, thousands of pest control inspectors, and millions of citizens have been able to find brown recluse spiders in only 31 Georgia counties,” she said.
Thus unless the few brown recluse spiders in the state are incredible workaholics moving at super-speed, their bites are actually quite rare in Georgia. Hinkle said there is only one confirmed account of anyone being bitten by a brown recluse spider in the state. Yet 963 reports of their bites in 103 counties have been filed at Georgia poison centers over the last five years.
The Southern House Spider, common throughout the state, is often mistaken for a Brown Recluse.
Misdiagnosis is also a problem elsewhere in the region. Hinkle said South Carolina physicians diagnosed 738 bites in 2004, but only 44 brown recluse spiders have been found there in the state’s history. Similarly, Floridians claimed 95 brown recluse bites in 2000, but Florida has recorded brown recluse spiders at only 11 places in more than 100 years.
Hinkle’s study was prompted by her arrival from California. “When I first came to Georgia I heard several people say they knew someone who’d seen or been seriously wounded by a recluse,” she said, “but I found that odd. The recluse is a Midwesterner, not a Southerner.”
Hinkle hopes that the study will educate Georgia’s medical community and reduce the number of erroneous recluse bite diagnoses, as a mark on the skin that looks like a spider bite could be something more serious. In fact, she believes that many assumed brown recluse bites could be methicillin-resistant Staphylococcus aureus (MRSA)—a type of staph infection resistant to antibiotics such as penicillin, amoxicillin, and oxacillin. MRSA causes mild skin infections that result in pimples or boils, but it can also produce more serious skin lesions or infect surgical wounds.
Incorrectly diagnosing MRSA as a spider bite, or vice versa, can result in a patient getting the wrong therapy, Hinkle observes. “MRSA infections require a specific set of antibiotics,” she said. “Brown recluse spider bites, on the other hand, cause tissue damage through salivary secretions in their venom, and antibiotics have no effect on salivary secretions.”
Other wounds diagnosed as spider bites could actually be infections, diabetes, bed sores, Lyme disease, anthrax, or necrotizing bacteria, among other problems, some of which can be fatal if not treated fast, she said.
On the rare occasion when someone suffers a bite from a brown recluse spider, it will likely heal without medical intervention, according to Hinkle. And despite all the horror stories, only one percent of such cases require medical attention.
Brown recluse spiders aren’t vicious and are not looking to bite people, said Rick Vetter, an entomologist at the University of California, Riverside, and the U.S. expert on these critters. Consider, for example, a Kansas family that collected more than 2,000 brown recluses from their home in six months. “They’ve been living there for eight years and still have shown no evidence of a single bite,” he said.
In any case, “just being brown does not make a spider a brown recluse,” said Hinkle. “Most spiders are brown because it’s a good camouflage color. And recluses are reclusive; so if you see a spider, it’s probably not a recluse.”
Hinkle said that of the more than 2,000 samples submitted for the study the most common was the Southern House Spider, the spider most commonly mistaken for a brown recluse. “It is also the most common spider found in Georgia homes,” she said.
Sharing your home with spiders may not actually be such a bad thing. They are harmless to humans and provide biological control of many home-invading pests such as centipedes, cockroaches, and ants. Still, some arachnophobes may rather the spiders move out.
“If you are concerned about having spiders in your home, the solution is to starve them out,” Hinkle said. “Obviously, there are enough insects getting inside the structure to feed the spiders. If you seal up all the cracks through which these insects are entering, the spiders can’t survive.”
For more information, contact Nancy Hinkle at: firstname.lastname@example.org