Virus Linked to Chronic Fatigue Syndrome

Scientists have new evidence that viruses may play a role in chronic fatigue syndrome (CFS). This debilitating disease affects millions of people nationwide.

A main symptom of CFS is profound fatigue that persists even after resting. Other symptoms include problems thinking or remembering, sleeping difficulties, achy joints, headache and stomach and digestive problems.

No definite cause for CFS has yet been found. Last year, scientists reported that the blood of patients with CFS contained evidence of a virus called XMRV. It’s related to a virus that causes leukemia in mice. However, other research groups were later unable to find traces of similar viruses in CFS patients.

To take a closer look, scientists from NIH and the U.S. Food and Drug Administration searched for DNA evidence of similar viruses in both CFS patients and healthy blood donors. The researchers found traces of the mouse-related viruses in 32 of 37 (86.5%) of the CFS patients, compared to only 3 of 44 (6.8%) healthy donors.

The study doesn’t prove that the viruses cause CFS, but suggests there’s some type of association. It’s possible that viruses related to mouse leukemia virus cause CFS in only some patients. “At this point, we just don’t know. We haven’t studied enough people,” says study coauthor Dr. Harvey J. Alter of NIH’s Clinical Center.

Complicating the matter is the fact that no specific test is yet available to confirm that someone has CFS. NIH is now leading an effort to test and develop standardized laboratory techniques for detecting XMRV and related viruses.