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People with chronic fatigue syndrome have often felt their disease is considered fake. It is a mysterious ailment with no clear cause. More than a million Americans suffer from it. They feel tired even after a good night's sleep. Many also have debilitating pain in their muscles or joints and trouble concentrating. Well, now researchers have found a virus that might be responsible for chronic fatigue syndrome.
NPR's Jon Hamilton has that story.
JON HAMILTON: Scientists have suspected for a long time that chronic fatigue might be caused by a virus. Judy Mikovits, a molecular biologist, says one reason is what happens when people first get sick.
Dr. JUDY MIKOVITS (Research Director, Whittemore Peterson Institute): Often it's a flu-like onset where they get a flu, get a very bad flu, flu-like symptoms and essentially never recover.
HAMILTON: Most viruses don't make people sick for very long. But there is one unusual type known to linger: retroviruses. So when scientists found a new retrovirus called XMRV a couple of years ago, Mikovits wondered whether there might be a connection to chronic fatigue. She was in a position to find out. After many years at the NIH, she'd become research director of a new institute at the University of Nevada, founded to help people with problems like chronic fatigue. Mikovits began checking patients' blood for XMRV.
Dr. MIKOVITS: We simply did a screen of the sickest of the sick of our patients because we figured that would be where we would find the most virus. And lo and behold, there it was.
HAMILTON: To confirm the finding, Mikovits worked with a team of researchers to test blood from more than 100 patients with chronic fatigue, as well as more than 200 healthy people. They found XMRV in 67 percent of the sick people, but just four percent of healthy ones. Others tests showed the virus was infectious and was provoking an immune response in people with chronic fatigue.
Dr. MIKOVITS: So we can see and really explain by a retroviral infection the entire spectrum of symptoms that have come to be known as chronic fatigue syndrome.
HAMILTON: And perhaps find a way to treat it. That's the sort of news patients have been waiting decades to hear. Annette Whittemore helped create Whittemore Peterson Institute where Mikovits works. She has an adult daughter who's had chronic fatigue since she was 12.
Ms. ANNETTE WHITTEMORE (Founder, Whittemore Peterson Institute): It's the best news ever. I mean, we've always known that there was something out there and now we see its face and we feel like the next step is going after those treatments.
Professor JOHN COFFIN (Molecular Biology and Microbiology, Tufts University): This is a very striking initial finding, but it is only an initial finding. We have a lot of work to do.
HAMILTON: John Coffin, a molecular biologist at Tufts University, says scientists have tried to blame other viruses for chronic fatigue and been proved wrong. But this time the evidence is stronger. And he says a retrovirus could explain why chronic fatigue can last a lifetime.
Prof. COFFIN: Retroviruses in general give rise to infections that persist indefinitely. That's for all retroviruses: HIV and HTOV and many other retroviruses. By and large, once an individual is infected, the infection does not go away.
HAMILTON: XMRV doesn't have much in common with HIV. But because both are retroviruses, researchers are hoping they can treat chronic fatigue patients with drugs designed to fight HIV. In the meantime, scientists like Judy Mikovits are concerned about the study suggestion that nearly four percent of healthy people may be infected with XMRV.
Dr. MIKOVITS: Retroviral infections cause neurological diseases, immune deficiency, inflammatory diseases and cancer.
HAMILTON: But scientists are still trying to figure out what this one does. The new study appears in the online journal Science Express.
Jon Hamilton, NPR News.