(American Society for Microbiology) Contrary to previous findings, new research finds no link between chronic fatigue syndrome and the viruses XMRV (xenotropic murine leukemia virus-related virus) and pMLV (polytropic murine leukemia virus). A study to be published on Sept. 18 in mBio® reveals that research that reported patients with chronic fatigue syndrome carried these two viruses was wrong and that there is still no evidence for an infectious cause behind chronic fatigue syndrome.