Of all the viruses EBV is the clear leader of the pack as being the most likely cause of MS. Could a specific strain of EBV cause MS? A superficial look at has not revealed obvious difference between EBV strains in people with MS and control subjects.
Brennan R, et al. Strains of Epstein-Barr virus infecting multiple sclerosis patients. Mult Scler. 2010 Mar 29. [Epub ahead of print]
Opinion: a deeper look is required before abandoning the possibility that a specific strain may cause the disease. The million dollar question is how and where to look?