(SAN FRANCISCO) -- 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.
But new research published in Science casts doubt on the link.
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 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."
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