New Strain Adds to Complexity of Lyme Disease

May 1, 2023

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The Centers for Disease Control and Prevention, in collaboration with the Mayo Clinic and health officials from Minnesota, Wisconsin, and North Dakota, report the discovery of a new species of bacteria (Borrelia mayonii) that causes Lyme disease. Until now, Borrelia burgdorferi was the only species believed to cause Lyme disease in North America.

Scientists first suspected a new bacteria after lab tests from six people with suspected Lyme disease produced unusual results, according to the findings published in The Lancet Infectious Diseases. Additional genetic testing at the Mayo Clinic and CDC found that the bacteria, provisionally named Borrelia mayonii, is closely related to B. burgdorferi.

The latest report comes amid a 25% rise in the number of US tick borne disease cases overall, including Lyme disease. According to the CDC, the number of babesiosis cases reported increased from 40,795 in 2011 to 50,856 in 2019.

Found in Upper Midwest

To date, evidence suggests that the concentration of B. mayonii is limited to the upper midwestern US. The new species was not identified in any of the approximately 25,000 blood samples from residents of 43 other states with suspected tickborne disease taken during the same period—including states in the Northeast and Mid-Atlantic regions, where Lyme disease is common.

Like B. burgdorferi, B. mayonii causes fever, headache, rash, and neck pain in the early stages of infection (days after exposure) and arthritis in later stages of infection (weeks after exposure). Unlike B. burgdorferi, however, B. mayonii is associated with nausea and vomiting, diffuse rashes—rather than a single “bullseye” rash—and a higher concentration of bacteria in the blood.

Researchers believe that, like B. burgdorferi, B. mayonii is transmitted to humans by the bite of an infected blacklegged (or “deer”) tick. B. mayonii has been identified in blacklegged ticks collected in at least two counties in northwestern Wisconsin. The likely exposure sites for the patients described in Lancet Infectious Diseases are in north central Minnesota and western Wisconsin.

Another “Great Imitator”

Every year nearly half a million people in the US contract Lyme disease, and most of them face symptoms that last a few weeks after the tick bite transmits the disease. But for some patients, the symptoms can last much longer. The medical community has been slow to recognize this form of long-lasting Lyme disease and to find treatments for it.

A swollen knee, an arthritic expression, is a distinct sign of Lyme disease—but one most people—including physicians—would not recognize as such. The rash can take many shapes and may go unseen. That’s why scientists call the disease the “new great imitator”—so named because like the original “great imitator,” syphilis, it presents similarly to a large variety of other diseases, which can complicate diagnosis.

Although it emerged in the mid 1970s, chronic Lyme disease was hotly debated well into the 1990s—and something the medical community is still trying to unravel. In an attempt to define Lyme from epidemiological standpoint—and in the hope for a vaccine—scientists zeroed in on two symptoms: the bullseye rash and arthritis to define Lyme disease. Even today, patients who exist outside a narrow subset of symptoms have difficulty seeking the necessary treatment. The system of managed care has further constricted the definition. Often, doctors are not allowed to treat outside specific guidelines.

With a push toward more robust research and more money allocated to the study of Lyme, however, there has been a paradigm shift. The latest research yields more clues. In one study, biochemist Brandon Jutras at Virginia Tech found that Borrelia burgdorferi shed a cellular component called peptidoglycan that can cause excessive inflammation. “This discovery will help researchers improve diagnostic tests and may lead to new treatment options for patients suffering with Lyme arthritis,” Jutras says. He’s also looking into how these components relate to neurological expressions of Lyme.

At Tulane, Northeastern, and Johns Hopkins universities, scientists are exploring infection that survives the standard treatment. Researchers are studying slow-metabolizing or dormant forms of the pathogens called “persisters,” which are seen following antibiotic treatment for almost every infectious disease.

Current Treatments

The CDC’s report suggests that current tests available from the Food and Drug Administration can be used to conclusively test patients infected with B. mayonii. Specific identification of the organism can be made by using polymerase chain reaction assays (PCR), which detects the DNA of the Lyme disease bacteria. Patients were also treated successfully with the antibiotics commonly used to treat Lyme disease caused by B. burgdorferi.

At present, the CDC is working closely with state health departments in Minnesota, North Dakota, and Wisconsin to better understand B. mayonii and plan other investigations, including better descriptions about the clinical aspects of the illness and the geographic extent of the infected ticks.

What’s more, the agency is investing in advanced technology to bring study of tickborne infections into a new era. According to Ben Beard, Ph.D., chief of CDC’s Bacterial Diseases Branch, “Coupling technology with teamwork between federal, state, and private entities will help improve early and accurate diagnosis of tickborne diseases.”

To reduce the risk of tick bites and tickborne diseases, the CDC recommends that people spending time outdoors should practice tick bite prevention:

• Wear long pants.
• Avoid wooded and brushy areas with high grass and leaf litter.
• Use tick repellent. (Products that contain permethrin on clothing.)
• Bathe or shower as soon as possible after to wash off and more easily find ticks.
• Conduct a full-body tick check after spending time outdoors.
• Examine gear and pets, as ticks can travel on these and later attach to people.

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