Most people are aware of the necrotic wounds—in which the flesh literally dies—that may result from the bite of a brown recluse spider. They may not be aware that this notorious but nondescript species lives only in an area from the central Midwest to the Gulf. And yet in recent decades, brown recluse bites by the thousands have been diagnosed in states far outside its range, from California to New Hampshire. Anthrax, Lyme disease, cancer, and diabetic lesions have all been mistaken for necrotizing spider bites. Unfortunately, a misdiagnosis can be dangerous, leading to a potentially fatal delay in treatment of the drug-resistant staph infection known as MRSA, for example, or so-called flesh-eating bacterial infections, which require immediate treatment with antibiotics. Brown recluse bites are rare even in areas where the spider cohabits with people. In 2001, a Kansas family trapped more than 2,000 brown recluses in their home over a six-month period, and no one was bitten.
