XMRV Update

It now seems almost certain that Xenotropic Murine-Leukaemia Retrovirus (XMRV) is not linked to ME. Researchers at the Whittemore Peterson Institute in 2009 were thought to have discovered XMRV in the blood of people with ME; however, most of the research done since then, including a comprehensive study concluded in 2012, has failed to find it. There are still some queries hanging over the issue (for instance no-one has adequately explained the results of the research in 2010 which found other Human Gamma Retroviruses (HGRVs) in the blood of people with ME), but it's now generally agreed that the original results were due to contamination.

There's a very good, comprehensive article about XMRV/HGRV research on the ME Research UK website, and a basic update about the 2012 study on the ME Association (MEA) website.

As the MEA point out, the lack of a link between XMRV and ME does not mean that ME is not caused by a virus or indeed by a retrovirus: it means that it is still not known what causes ME. It is known, however, that in most cases ME is triggered by a virus (ie people tend to develop ME following a viral infection such as 'flu, glandular fever, or hepatitis), and it is quite likely that it has a viral origin. Articles in the press which suggest that because ME is not caused by XMRV it therefore follows that it must not be a biomedical disease at all are misunderstanding or misrepresenting the recent study, and displaying a very poor grasp of science and a distinct lack of knowledge of other research in the field.

Note: I have deleted my original article about XMRV because the information in it was out of date and could have been confusing.