Q & A Library

An important new discovery does suggest that a virus called XMRV (for xenotropic murine leukemia virus-related virus) is associated with chronic fatigue syndrome (CFS). We don’t know yet whether it actually causes CFS or how it might contribute to this disorder, which is characterized by persistent, severe fatigue and body aches. However, the new circumstantial evidence indicates that XMRV could play a key role. In an article published online on October 8, 2009, in the journal Science, a consortium of researchers from the Whittemore Peterson Institute in Reno, NV, the National Cancer Institute, and the Cleveland Clinic reported that 67 percent of the 101 CFS patients they studied were infected with XMRV, which was found in only 3.7 percent of 218 healthy people studied. The lead author of the study, Judy A. Mikovits, Ph.D., was quoted by the New York Times as saying that research since the initial report was written found the virus in nearly 98 percent of about 300 CFS patients.

This is exciting news about a mysterious disorder. Over the years, many researchers suspected that a virus or other chronic infectious agent was a contributing factor to CFS, but since medical tests revealed no known pathogen, many physicians chalked the condition up to psychological problems.

For the record, XMRV is not an airborne virus. It is a retrovirus, a type that carries genetic information in RNA, not DNA, and inserts itself in its host’s genetic material for life. Retroviruses can activate a number of other latent viruses, which could explain why the Epstein-Barr virus (EBV) has also been linked to CFS. This is the first time that XMRV has been isolated from patients, although it has been found in cells taken from prostate cancers.

The next step in the research is to test antiretroviral drugs (some of which are used to treat HIV) to see if they help CFS patients. If the treatment works, it will further pinpoint XMRV as the cause of the illness. Stay tuned.

Andrew Weil, M.D.