The recent identification of retrovirus XMRV and a second retrovirus of a different subtype in chronic fatigue syndrome has aroused much interest, not least among sufferers. However, it remains highly controversial whether the detection of these viruses represents true infection or laboratory artifacts. In this paper, Professor Robin Weiss, the UK’s leading authority on retroviruses, gives his critical appraisal of this confusing data and concludes:
Many people suffering from CFS greeted the first report with enthusiasm and relief because of the persistent skepticism of physicians about whether CFS is a defined disease with a single cause. If the association of at least two kinds of murine-related retrovirus with the syndrome stands the test of time, it will represent a very important discovery. CSF patients would then be assured of having a recognized infection with the possibility of effective treatment – indeed, some of them are already so convinced they have started treatment with anti-retroviral drugs (first developed against HIV) in the hope of clearing infection and their symptoms. Blood banks would have to consider whether to screen donations for the implicated retroviruses. But before such steps could be justified, it will be essential to perform truly blinded tests on cases and proper controls in several laboratories. Profoundly disappointing as this would be for patients, without such additional studies, laboratory artifacts cannot be ruled out; also, with the signal exceptions of HIV and human T-lymphotrophic virus, the history of retroviral associations with human disease is not encouraging.