Scientists have seen further evidence of the connection between the Epstein-Barr virus and the incidence of multiple sclerosis. Researchers from the Harvard School of Public Health, the Walter Reed Army Institute of Research and a team of collaborators, for the first time, have observed that MS risk in a patient increases multiple times following an Epstein-Barr virus infection. The findings show that EBV might be considered a contributory cause to multiple sclerosis.
Multiple sclerosis is a debilitating disease that affects the central nervous system characterized by symptoms that might include cognitive, movement and balance problems. EBV on the other hand is a type of herpes virus and considered as one of the most common of human viruses. An infection that happens in early childhood may show no symptoms. An infection late in life often causes infectious mononucleosis. Over 95 percent of adults in the US are infected with EBV but show no symptoms. For symptomatic EBV infections, there is currently no known effective treatment.
The study that looked into the connection between MS and EBV involved a study population composed of active duty personnel from the US Army, Navy and Marines that had at least one blood sample in the Department of Defense Serum Repository. The electronic databases of the US Army and Navy were then searched for individuals whose records indicated a possible MS diagnosis reported between 1992 and 2004.
The researchers ultimately selected 305 individuals who were diagnosed with MS and who also had blood specimens collected prior to the date of their diagnosis. Two controls for each chosen individual were then selected from the serum database and matched.
The results showed that MS risk may be extremely low among those individuals who were not infected with EBV. But the risk increases sharply for the same individuals following an EBV infection.
According to Alberto Ascherio, professor of epidemiology and nutrition at Harvard School of Public Health and senior author of the study, "The observation that MS occurred only after EBV is a big step forward. Until now we knew that virtually all MS patients are infected with EBV, but we could not exclude two non-causal explanations for this finding: that EBV infection is a consequence rather than a cause of MS, and that individuals who are EBV negative could be genetically resistant to MS. Both of these explanations are inconsistent with the present findings".
"The evidence is now sufficiently compelling to justify the allocation of more resources to the development of interventions targeting EBV infection, or the immune response to EBV infection, as these may contribute to MS prevention," Ascherio further added.
Source: Harvard School of Public Health. "Further Evidence Links Epstein-Barr Virus and Risk of Multiple Sclerosis." ScienceDaily 5 March 2010. 23 March 2010