Lyme disease in the U.S. is caused by a form of bacteria, the spirochete Borrelia burgdorferi, infecting humans by tick bites. It typically begins with a bull’s-eye skin rash, accompanied by fever, muscle aches, or other flu-like symptoms. If diagnosed early, Lyme can be treated successfully within a month with either oral or intravenous antibiotics. Nearly 60 percent of patients who do not receive antibiotic therapy early in the illness develop intermittent or persistent arthritis, particularly affecting the knees. Moreover, a small percentage of Lyme patients who do receive antibiotic therapy suffer from persistent arthritis for months or even several years after 2-3 months of oral and intravenous antibiotic therapy. This confounding condition has been termed antibiotic-refractory, or slowly resolving, Lyme arthritis.
