Followup: More Evidence against the XMRV Virus as a Cause of Chronic Fatigue Syndrome

A mouse leukemia retrovirus, xenotropic murine leukemia virus-related virus (XMRVretrovirus), has been under consideration as a possible cause of chronic fatigue syndrome (CFS, and also prostate cancer). In a study published in Science in October 2009, Lombardi et al. found XMRV in 67% of CFS patients and 3.7% of controls. Several subsequent studies in the