From this story on msnbc.com:
_U.S. scientists have discovered a new deer tick-borne disease in humans, with the viral-like illness sharing similarities both with Lyme disease and relapsing fever infections. __The as-yet unnamed ailment is one of five caused by the Borrelia miyamotoi pathogen carried by blacklegged ticks, said Dr. Peter Krause, senior research scientist at Yale School of Public Health and lead author of a study published in the New England Journal of Medicine on Thursday. A distant relative of Lyme, the bacterium was first found in ticks in Japan in 1995, and then was identified by Yale researchers in Connecticut in 2001 and again in Russia in 2011, the study said. The illness also can resemble another disease caused by a bacterium in the Borrelia family transmitted by ticks and body lice that is marked by repeated episodes of fever.
According to the story, symptoms of the illness include fever, aches, headaches and fatigue, with some patients also developing a rash. But what sets this new illness apart is the recurrence of fever in some patients. Apparently, the fever keeps coming back, which differs from Lyme disease. Patients not treated with antibiotics after their first bout of fever often had the fever return a week or so later. The good news is antibiotics used to treat Lyme seem to work well with this new mystery illness. The bad news is occurrences of the disease have been found not only in the traditional Lyme areas of the northeast and upper midwest, but in far western states as well, and, not surprisingly, seems to occur more frequently in spring, summer and early fall.