Mayo Clinic researchers have identified a new species of bacteria that causes Lyme disease.

They first detected the organism in 2012, but only recently published a study of six patients from Minnesota, North Dakota and Wisconsin who tested positive for the bacteria.

Their illnesses differed from the typical course of Lyme disease. Patients experienced nausea and vomiting and two were hospitalized because they were so sick, said study author Dr. Bobbi Pritt, director of the Clinical Parasitology Laboratory at Mayo Clinic.

And their rashes did not look like the tell-tale bulls eye-shaped inflammation associated with Lyme disease, Pritt said.

"What the takeaway message is for our physicians is that there might be some slightly different symptoms and they should consider testing for Lyme in that case," she said. "And, secondly, that those symptoms could be relatively severe."

A Mayo analysis suggests 3 percent of blacklegged ticks may carry the new bacteria.

Of 600 blacklegged ticks collected in Wisconsin, three percent carried DNA from the new bacteria. The new organism is named Borrelia mayonii after the Mayo brothers who founded the clinic.

Since the original research was conducted, Pritt says at least two more patients have been diagnosed with infections caused by the new bacteria.

Mayo researchers are not sure how the bacteria got to the Upper Midwest. So far it has only infected patients who had possible exposure to ticks in Minnesota or Wisconsin.