Mouse virus not responsible for Chronic Fatigue Syndrome, new study finds

Two years ago, a widely publicized scientific report plucked an old mouse virus out of obscurity and held it up as a possible cause of Chronic Fatigue Syndrome. According to a new study published today by a group of researchers in California, Wisconsin and Illinois, that report was wrong.

The mouse virus is not the culprit in Chronic Fatigue Syndrome, said University of California, San Francisco Professor Jay A. Levy, MD, the senior author on the study, published this week by the journal Science.

"There is no evidence of this mouse virus in human blood," said Levy, a professor in the Department of Medicine and director of the Laboratory for Tumor and AIDS Virus Research at UCSF.

Most likely, Levy said, the mouse virus was detected two years ago in blood samples from Chronic Fatigue Syndrome patients because chemical reagents and cell lines used in the laboratory where it was identified were contaminated with the virus.

The bottom line, he said, is that scientists need to keep looking for the real cause - or causes - of Chronic Fatigue Syndrome.

This study may have an immediate impact in terms of treatment for some patients with the illness, said Konstance Knox, PhD, of the Wisconsin Virus Research Group in Milwaukee, the first author on the study.

"Individuals with Chronic Fatigue Syndrome need to know that taking antiretroviral therapies will not benefit them, and may do them serious harm" said Knox. "Physicians should not be prescribing antiviral compounds used in the treatment of HIV/AIDS to patients on the basis of a Chronic Fatigue Syndrome diagnosis or a XMRV test result."