New Cause of Lyme Disease: Borrelia Mayonii Bacteria

Researchers have identified a new species of bacteria carried by the blacklegged deer tick, whose bite can cause Lyme disease. CDC

Scientists at the U.S. Centers for Disease Control and Prevention (CDC), along with researchers at the Mayo Clinic, have identified a new species of bacteria that causes Lyme disease. Borrelia mayonii is carried by blacklegged deer ticks, and people who become infected display many of the same symptoms—and a few new ones—as those infected with Borrelia burgdorferi, the bacteria traditionally associated with Lyme disease.

Their findings were published Monday in Lancet Infectious Diseases in a paper that also calls for close collaboration between state and federal health officials to understand whether this new bacteria poses a unique public health threat.

The researchers identified this new species of bacteria after an analysis of 9,000 blood samples taken from people suspected to have Lyme disease in Minnesota, Wisconsin and North Dakota. They noticed variations in DNA sequences in six of the samples. The Mayo Clinic researchers sent two of the blood samples to the CDC, where the agency cultured the bacteria. They then confirmed that it is a new species different from the bacteria known to cause Lyme disease in the U.S.

Within a few days of exposure to the B. mayonii bacteria through a tick bite, patients will develop early-stage Lyme disease symptoms, including fever, headache, a rash and neck pain. Weeks after exposure, patients developed arthritis. This is very similar to the response to a B. burgdorferi infection. However, a B. mayonii infection appears to come with additional symptoms that haven't been previously seen in people with Lyme disease. These patients also had nausea, vomiting and a higher level of bacteria in their blood. While one of the first signs of Lyme disease is a single "bull's-eye" rash, patients infected with this new species of bacteria instead had a generalized rash. Thankfully, the six patients were responsive to the usual course of antibiotics used to treat Lyme disease.

The paper suggests that this new species of bacteria so far exists only in the upper Midwestern region of the U.S., since it was not identified in some 25,000 blood samples from 43 other states taken from patients suspected to have Lyme disease. The CDC is working with researchers and public health officials in the three states to gather more information about the bacteria and its short- and long-term impact on those who become infected.