Mayo researchers have discovered a new strain of Lyme disease that is raising concerns because it does not produce the bull's-eye rash that typically alerts people to the condition.
The culprit is a new species of bacteria found in the Upper Midwest and reported in the online medical journal, the Lancet Infectious Diseases.
"It was a fortuitous discovery," said Dr. Bobbi Pritt, director of the Clinical Parasitology Laboratory at Mayo Clinic in Rochester. "We weren't setting out to find a new organism."
Before the discovery, scientists believed that only one species of bacteria — called Borrelia burgdorferi — caused Lyme disease in humans. But when scientists tested samples from patients for evidence of Lyme disease they found a new bacteria in a small number of the cases. It is carried by the black-legged tick, or deer tick, as it's commonly known.
Most of the patients infected with the new bacteria showed different symptoms than the classic Lyme disease signs. A low-grade fever, body aches and chills are common symptoms. But the new bacteria caused many of the patients to experience nausea and vomiting too.
"One of the most important differences was their rash," Pritt said. Most of the patients infected with the new bacteria suffered from a diffuse rash all over their body instead of the typical bull's-eye rash.
That's why Pritt is urging doctors and patients to be aware of the symptoms found in people with the new bacteria and to get tested for Lyme disease if you've been exposed to ticks and exhibit any of the symptoms.
Each year, about 300,000 people in the United States are diagnosed with Lyme disease, according to the Centers for Disease Control and Prevention, which also contributed to the study. Most cases are concentrated in the Northeast and Upper Midwest.
