New Tick-Borne Disease Is Discovered
A new tick-borne disease that may be stealthily infecting some Americans has been discovered by Yale researchers working with Russian scientists.
The disease is caused by a spirochete bacterium called Borrelia miyamotoi, which is distantly related to Borrelia burgdorferi, the spirochete that causes Lyme disease.
B. miyamotoi has been found — albeit relatively rarely — in the same deer tick species that transmit Lyme, and the Yale researchers estimate that perhaps 3,000 Americans a year pick it up from tick bites, compared with about 25,000 who get Lyme disease.
But there is no diagnostic test for it in this country, so it is not yet known whether it has actually made any Americans sick.
The same short course of antibiotics that normally cures Lyme also seems to cure it.
In Russia, where a team in the Siberian city of Yekaterinburg developed a test that can distinguish miyamotoi from other tick-borne spirochetes, it caused higher fevers than Lyme disease typically does. In about 10 percent of cases, the fevers repeatedly disappear and return after a week or two.
The study by the two teams is to be published soon in the journal Emerging Infectious Diseases. Since the disease was only recently discovered, it is unknown whether it does serious long-term damage, as untreated Lyme disease can.
The Yale medical school researchers — Durland Fish, an entomologist, and Dr. Peter J. Krause, an epidemiologist — have recently won a grant from the National Institutes of Health to study the symptoms and develop a rapid diagnostic kit.
Dr. Fish found B. miyamotoi in American ticks 10 years ago, but was repeatedly refused a study grant until the Russians proved it caused illness. “It’s been like pulling teeth,” he said. “Go ask the N.I.H. why.”
The discovery will no doubt add to the controversy surrounding Lyme disease. While most Lyme victims are cured by a two-week course of antibiotics, some have symptoms that go on for years and believe they have persistent infections that the antibiotics did not reach.
Most medical authorities, including the Centers for Disease Control and Prevention and the Infectious Disease Society of America, take the position that “chronic Lyme disease” does not exist and that those victims either have other illnesses or are hypochondriacs. They oppose the solution demanded by some self-proclaimed victims: long-term intravenous antibiotics.
Dr. Krause said it was unlikely that the new spirochete could be responsible for chronic Lyme, because the symptoms do not match: Most of those who think they have chronic Lyme complain of fatigue and joint pain, not repeated fevers.
But he said doctors might consider the new infection, especially in patients who think they have been bitten by ticks, come up negative on Lyme tests and have recurrent episodes of fever.
B. miyamotoi does not appear to cause the “bull’s-eye rash” that helps doctors diagnose Lyme disease, the Russian team found.
“People shouldn’t panic,” Dr. Krause said. “And they also should not jump to the conclusion that we’ve found the cause of chronic Lyme disease. It’s not highly likely, but it’s possible. We just don’t know.”
The miyamotoi spirochete was discovered in Japan in 1995. It was at first believed to be limited to those islands.
In 2001, Dr. Fish found it in about 2 percent of the deer ticks in the Northeast and Upper Midwest and proved that mice could pick it up from tick bites.
Source = NY Times
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