Until recently, only one bacterium in North America was known to cause the disease: Borrelia burgdorferi. (In Europe, two other species are more common.)This year, researchers at Mayo Clinic testing blood and synovial fluid samples from people infected with Lyme disease discovered six infections that did not trace to B. burgdorferi. In addition to a rash, fever and other classic Lyme symptoms, those patients also experienced confusion, nausea and vomiting. “Not so typical for Lyme disease,” Mead observed.
A previously unknown species of Borrelia was causing the disease, the Mayo team reported in the May issue of Lancet Infectious Diseases. Infections from the newly named Borrelia mayoniiappear to cause unusually high concentrations of bacteria in the blood. The patients recovered after receiving the same antibiotics that treat Lyme disease. As of now, samples taken from ticks show that B. mayonii is only found in the Upper Midwest.