WebMD Medical News Laura J. Martin, MD Aug. 23, 2010 -- Murine
leukemia viruses (MLV), a family of retroviruses known to cause
cancer in mice, may be linked to chronic fatigue syndrome (CFS),
a study shows. The full name of the virus is xenotropic murine
leukemia virus-related virus. It is part of a family of viruses
known as murine leukemia viruses (MLV), which is a type of
retrovirus known to cause cancer in mice. The new study,
published in the Proceedings of the National Academy of
Sciences, conflicts with some earlier studies. Several U.S.
studies, including a recent report from the CDC and research
done in the U.K. and the Netherlands, found no evidence of MLV
in the blood of people with CFS. One recent study, however,
found evidence of an MLV-related virus called XMRV in blood
cells of patients with CFS. The new study shows that 86.5% of 37
people with CFS had evidence of murine leukemia virus in their
blood, as did 6.8% healthy blood donors. "There is a dramatic
association with CFS, [but] we have not