The bacterial organism behind a newly identified tick-borne illness found halfway across the world showed up in Durland Fish’s lab in Connecticut a decade ago.

At the time, it seemed like a mistake.

Fish’s lab was studying Lyme disease transmission using ticks and mice, exposing ticks to mice that had been infected, and to others that had not. But the ticks exposed to uninfected mice appeared to be infected.

“I gave everybody in the lab hell for wasting a lot of time and resources and stuff, because they screwed up the experiment,” said Fish, a professor of epidemiology at the Yale School of Public Health. “And they felt really bad and they couldn’t understand how that happened.”

In fact, the ticks had a different bacterial organism, not the one that causes Lyme, but a distant relation called Borrelia miyamotoi. It had been identified six years earlier in Japan, but no one knew if it caused illness in humans. Fish spent the better part of a decade trying to get funding to study it, with little success.

Then, at a meeting in Cyprus, he met a Russian researcher who said he’d seen that organism in ticks and had evidence that it infected people. They began to work together. The result: Confirmation of a new tick-borne illness, the B. miyamotoi infection.

In a paper being published in the journal Emerging Infectious Diseases, Fish, Peter J. Krause, a senior research scientist in the Yale School of Public Health, and Russian scientists led by Alexander E. Platonov described 46 patients with the disease.

The patients were treated at the Municipal Clinical Hospital No. 33 in Yekaterinburg City, Russia, and had symptoms similar to Lyme disease, including flu-like symptoms and fevers as high as 103 degrees. Antibiotics appeared to clear the infection.

Although some symptoms resembled Lyme disease, there were differences. About 90 percent of patients with Lyme disease have a red rash, Krause said, but only about 10 percent of the patients with the B. miyamotoi infection did.

In addition, Borrelia miyamotoi causes fevers that last for a couple days, go away, then return as many as 10 times. In the patients researchers studied, 10 percent had recurring fevers, but Krause said those patients’ therapy was delayed, and researchers believe that other patients would have experienced similar fevers if they had not been treated as quickly.

Although there is no diagnostic test for the infection in the U.S., researchers identified it using a tool Russian researchers have that can identify it by its DNA. In Russia, ticks can cause Lyme disease as well as tick-borne encephalitis, a viral condition that can cause meningitis and encephalitis, an inflammation of the brain. “They take tick-borne diseases very seriously over there,” Fish said.

It’s not clear whether the illness exists outside Russia–although the researchers said it probably does–or how common it is. Fish said it’s unlikely to be as common as Lyme. Only about 2 percent of deer ticks are infected with the spiral-shaped bacteria–known as spirochetes–that cause the B. miyamotoi infection, compared to about 20 percent of ticks infected with the spirochetes that cause Lyme disease.

Fish and Krause plan to work on developing diagnostic tools, and to see if people in the U.S. are getting infected with the organism. Fish received notification last week that the National Institutes of Health will fund further research.

“Having found this organism in ticks so long ago, we’re quite anxious to get going and see what the public health implication of this thing is, if any,” Fish said. “We really don’t know at this point, but I think it’s important that we do know.”

Fish and Krause don’t expect the finding will clarify is the controversy over the Lyme disease. Most mainstream doctors and scientists believe that Lyme can be treated with a short course of antibiotics and does not exist in a chronic form. Some patients and physicians believe that Lyme can be a long-term illness that can require extended courses of antibiotics.

Fish and Krause said B. miyamotoi is probably not related to what people believe is chronic Lyme disease. Fish noted that the Borrelia miyamotoi infection is susceptible to antibiotics, and Krause said the presentations differ: People with Borrelia miyamotoi infection had recurring fevers, while people with Lyme disease tend to have fatigue, joint aches and muscle aches.

“I don’t think” the new disease is related to chronic Lyme, Krause said, “but it’s possible.”