The debilitating symptoms of CFS may be triggered by a virus.

RODALE NEWS, EMMAUS, PA—Scientists have found a possible viral link to the mysterious chronic fatigue syndrome (CFS), a debilitating disease that affects at least 17 million people around the world but that was once dubbed "yuppie flu" and thought to be all in the patient's head. The finding is published this month in the journal Science. "Everyone is both hopeful and cautious about these results," says William Schaffner, MD, chair of the department of preventive medicine at Vanderbilt University in Nashville, TN, and president-elect of the National Foundation for Infectious Diseases. He says a series of studies are likely to be undertaken to see whether the virus identified in the study actually causes CFS, or if it simply tends to occur along with the syndrome. "If it's a fellow traveler, the virus presence would be incidental, so treatment wouldn't be useful," explains Dr. Schaffer. "We all have bacteria in our throats, but we're not treating them because they're harmless."

THE DETAILS: A group of researchers from the Whittemore Peterson Institute, National Cancer Institute, and the Cleveland Clinic looked for a virus called XMRV in 101 CFS patients, and in 218 healthy people. They found the virus, which is classified as a "retrovirus" and has also been linked to a form of prostate cancer, in nearly 70 percent of CFS patients, but in just 3 percent of the healthy people.

"The discovery of XMRV in two major diseases, prostate cancer and now chronic fatigue syndrome, is very exciting. If cause-and-effect is established, there would be a new opportunity for prevention and treatment of these diseases," says study coauthor Robert Silverman, PhD, professor in the department of Cancer Biology at the Cleveland Clinic Lerner Research Institute. It's not known how the germ might be transmitted; viruses like XMRV are not airborne.

WHAT IT MEANS: While this research is provocative and could lead to better diagnosis and treatment for patients living with CFS, it's important to remember that this is still a hypothesis, and much more research is needed. In the 1990s, there was a lot of buzz surrounding the theory of a viral link to CFS, but those studies did not pan out. However, if researchers do find a cause-and-effect relationship between XMRV and CFS, doctors may be able to treat patients with antiviral drugs, including those used to treat HIV, which is also a retrovirus.

CFS symptoms include extreme fatigue after physical or mental exertion, sleep problems, difficulty concentrating, muscle and joint pain, headaches, sore throat, and tender neck or armpit lymph nodes. Some people gradually get better over time, but others remain sick for years. The syndrome may produce psychological effects, but that doesn't disqualify it as a true physical illness, says Dr. Schaffner. "Some people could be depressed or suffering from other personality disorders, but in that core of people with symptoms, most think there's something else going on, and medical science hasn't caught up with that group yet," he says.