(RxWiki News) Only one bacterial species has been credited for causing Lyme disease in humans — until now.
In a new study, researchers from the Mayo Clinic and the Centers for Disease Control and Prevention (CDC), working with health officials in Minnesota, North Dakota and Wisconsin, have discovered a new bacterial species that causes Lyme disease in humans. This species is named Borrelia mayonii (B. mayonii).
Before this discovery, the only bacterial species known to cause Lyme disease in North America was Borrelia burgdorferi (B. burgdorferi).
Lyme disease is spread through the bite of infected blacklegged ticks. Symptoms include fever, headache, fatigue and rash. If left untreated, infection can spread to the heart, joints and nervous system.
Although it was the most commonly reported insect-borne illness in the US in 2014, according to the CDC, 96 percent of Lyme disease cases occurred in just 14 states — mostly in the Northeast and upper Midwest.
For their study, researchers tested blood samples taken from US patients between 2003 to 2014. From 2012 to 2014, researchers noticed unusual test results in 6 out of the estimated 9,000 samples taken from residents of Minnesota, North Dakota and Wisconsin.
"Using a laboratory-developed test with a method called 'melting temperature analysis,' we detected six specimens that produced a PCR result that was clearly different from B. burgdorferi," explained lead study author Bobbi Pritt, MD, in a press release. Dr. Pritt is the director of the Clinical Parasitology Laboratory at the Mayo Clinic.
Researchers believe that the new bacterial species only recently emerged in the upper Midwest. However, Dr. Pritt said that it’s possible the species has been present for a while but somehow avoided detection.
Dr. Pritt and colleagues said that B. mayonii is likely transferred in the same way as B. burgdorferi — through the bite of infected blacklegged ticks. Unlike its predecessor, however, B. mayonii causes nausea, vomiting and a different type of rash. It may also cause higher concentrations of bacteria in the blood.
According to the press release, patients infected with B. mayonii will test positive for Lyme disease using tests cleared by the US Food and Drug Administration (FDA). B. mayonii may also appear on a blood smear.
Patients in this study fully recovered when treated with the same antibiotics commonly used to treat Lyme disease caused by B. burgdorferi.
"At this time, there is no evidence that B. mayonii is present outside of the Upper Midwest," Dr. Pritt said. "However, the public should continue to take the recommended precautions against tick bites, as Lyme disease and other tick-borne diseases are well-established in much of the Northeast."
This study was published Feb. 5 in the journal The Lancet: Infectious Diseases.
The CDC and the Mayo Clinic funded this research. Several study authors are employed by the Mayo Clinic, and one received grant funding from Pfizer and other pharmaceutical companies.