Chronic Fatigue Syndrome: Study Casts Doubt on Mouse Virus Link

New research casts doubt on a theory linking chronic fatigue to a mouse virus.

September 26, 2011, 5:47 PM

Sept. 27, 2011— -- Becky Blanton was a fit 36-year-old training for a half-marathon when chronic fatigue syndrome hit her "like a truck." Unable to get out of bed, she became overweight, unemployed and the butt of constant criticism from disbelieving friends.

"They'd say, 'You're lazy; it's all in your mind; you're just looking for an excuse," said Blanton, now 55. "Oh, and, 'You don't look sick.' If I have to hear that one more time…"

But a 2009 study linking chronic fatigue syndrome to a mouse virus gave patients validation and hope for a cure. Two-thirds of study subjects with chronic fatigue had the virus, called XMRV, in their blood compared with only 3.9 percent of healthy people, according to the report published in Science.

For Blanton, a freelance journalist in Richmond, Va., the virus link made sense. She had battled what she thought was the flu two months before her diagnosis. And in the 19 years since, her symptoms have relapsed and remitted like those of multiple sclerosis, an autoimmune disease thought by some to be triggered by an infection.

But new research published in Science casts doubt on the mouse virus theory. None of nine labs that participated in the rigorous study were able to reproduce the 2009 results, including the lab from University of Nevada's Whittemore Peterson Institute that originally produced them, a finding that suggests contamination landed the virus in patients' blood after it was drawn.

"This points to the need for studies like ours earlier in process," said study senior author Dr. Michael Busch, director of Blood Systems Research Institute and professor of laboratory medicine at University of California, San Francisco. "You really need to confirm that somewhat surprising or potentially revolutionary study is real before you put it out there."

In the two years that the mouse virus theory was out there, some patients started taking anti-retroviral drugs used to control HIV, Busch said. And researchers spent millions of dollars trying to replicate the results.

"One of the possible silver linings in this is the enormous amount of additional research going on trying to find a viral trigger," said Busch, adding that chronic fatigue could well be caused by a virus other than XMRV. "A lot of new groups are searching and a lot of patients have stepped forward to try to identify a new virus."

Kim McCleary, president and CEO of the Chronic Fatigue and Immune Dysfunction Syndrome Association of America, echoed Busch's optimism.

"We're determined to translate the heightened attention and deeper engagement XMRV has attracted into sustainable progress," she said in a statement. "There are many other solid leads that merit the same rigorous follow-up as XMRV has received over the past two years."

The research interest is helping patients shake the stigma of chronic fatigue syndrome, a condition still misunderstood by the public.

"I think they get some comfort in knowing the medical community acknowledges it as something real," said Dr. Keith Armitage, an infectious disease specialist at University Hospitals Case Medical Center in Cleveland who sees patients with chronic fatigue. "It provides some validation; that it's not in their heads."

And it could one day lead to a treatment. In the meantime though, Blanton finds some relief with supplements and anti-inflammatory drugs that dull the pain in her aching muscles. Moderate exercise helps too, she said.

Her advice: "Ask other people what works for them. And keep trying things until you find what works."

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