XMRV, or xenotropic murine leukemia virus-related virus, is a newly discovered gammaretrovirus which some medical researchers believe might be behind certain cases of prostate cancer as well as chronic fatigue syndrome. Since the possible link between XMRV and chronic fatigue syndrome was first identified in 2009, the subject has been controversial, and the link itself remains highly contested by other researchers.
XMRV was first discovered in 2006 by researchers at the Cleveland Clinic and the University of California at San Francisco, who were searching for evidence of viral RNA causing genetic defects leading to prostate cancer. XMRV was subsequently found to infect a small percentage of the population at any given time, possibly spreading through saliva, respiratory secretions, or even sexual contact. Because it does not appear to result in any particular illness immediately following infection, relatively little is known about how the disease is spread as well as how it can be combatted. In addition, follow-up studies cast some doubt on the initial theory about a link between prostate cancer and XMRV.
Beginning in 2009, however, a separate set of studies have begun to suggest that XMRV might be behind another ailment - chronic fatigue syndrome (CFS). Chronic fatigue syndrome is a disorder marked by extreme, long-term fatigue that is unrelated to any other underlying cause. As this definition suggests, the syndrome is poorly understood and the search for causes continues. In XMRV, one set of researchers thought they might just have stumbled across one of those causes.
The new group of XMRV researchers includes people at Nevada's Whittemore Peterson Institute for Neuro-Immune Disease, a new research institute which specializes in chronic fatigue syndrome. The Nevada study showed that whereas just 3.7% of the general population appears to be infected with XMRV, fully two-thirds of subjects with chronic fatigue syndrome were infected with the mysterious virus. If additional studies continue to confirm this unusual ratio, it would be a clear sign that many chronic fatigue syndrome cases are linked to an XMRV infection.
At the same time, very little is known about how XMRV might actually cause chronic fatigue syndrome - or how to go about treating it. The Peterson Institute claims that new tests show that as many as 95% of chronic fatigue syndrome sufferers are positive for XMRV - higher than their original studies indicated. However, the Centers for Disease Control (CDC) continue to take a cautious stance, noting that the precise relationship (if any) is still unknown and that further research is necessary before official guidelines can be set.
- Sources and More Information -
Centers for Disease Control (CDC). "Questions & Answers - XMRV."
Scientific American. "Retrovirus Linked to Chronic Fatigue Syndrome, Could Aid in Diagnosis."
Whittemore Peterson Institute. "XMRV Q&A."