New tick-borne disease discovered

YALE U. (US) — Scientists have discovered a new tick-borne disease that may be infecting humans in the U.S. and elsewhere.

The disease is caused by a spirochete bacterium called Borrelia miyamotoi—a distant relative to Borrelia burgdorferi, the bacterium that causes Lyme disease. The new bacterium, previously known only from ticks in Japan, was originally found in deer ticks in Connecticut in 2001, but it was not known if it also caused disease in humans.


The bacteria have since been found in all tick species that transmit Lyme disease throughout the United States and Europe.

By collaborating with a medical team studying tick-borne diseases in Russia, researchers led by Durland Fish, professor of epidemiology at Yale University, were able to compare disease symptoms in patients infected by the new spirochete in Russia with those having Lyme disease in the United States.

The new disease is characterized by high fever, which relapses without treatment and may be confused with Lyme disease. There are currently no diagnostic tests available, but Yale researchers have received a grant from the National Institutes of Health to develop a diagnostic test procedure to look for cases of this new disease in the United States.

“This is the first time we will have a chance to identify a new tick-borne disease in the United States based upon evidence that the agent occurs in ticks,” says Fish, co-author of a paper in the journal Emerging Infectious Diseases, and co-investigator on the NIH grant along with Peter Krause, a senior research scientist in the division of epidemiology of microbial diseases.

In the study, scientists report finding B. miyamotoi in about 2 percent of the deer ticks in the Northeast and upper Midwest and have been conducting experiments with mice in the laboratory that become infected when fed upon by deer ticks.

Because bites from deer ticks cause more than 25,000 cases of Lyme disease each year, according to the Centers for Disease Control, the Yale team is gearing up to determine if there is any illness that is caused by B. miyamotoi infection in the United States.

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