While scientists do not know the exact cause of multiple sclerosis (MS), many believe that it is the result of a unique interplay between a person’s genetic and specific environmental factors. Some of these factors may include vitamin D deficiency, smoking, and past viral infections.
Greater focus has also been placed on the Epstein-Barr virus (EBV) and the role it appears to play in the development of MS.
How the Epstein Barr Virus Works
The Epstein-Barr virus is the most common cause of infectious mononucleosis (a condition popularly referred to as “mono”). It is a member of the herpes family of viruses and is easily spread from person to person through body fluids, primarily saliva.
It is estimated that most people will get infected with EBV at some point in their life, usually in childhood, although the majority will never get ill. If they do, symptoms may include:
- Body aches
- An inflamed throat
- Swollen lymph nodes in the neck
- Enlarged spleen
- Swollen liver
Symptoms can sometimes be physically draining, requiring extended bed rest, but tend resolve in two to four weeks.
Once infected, the virus never disappears but rather integrates its genetic material into a host cell and remains there in an inactive state. During this period of so-called “latency,” the virus is unable to infect.
However, certain things can cause the latent virus to reactivate. If this happens, the person may suddenly experience symptoms and be able to pass the virus onto others.
The Connection Between MS and EBV
In exploring the possible causes of MS, scientists have long believed that viruses somehow contribute to the development of the disease. In fact, as many as 95 percent of people with MS will have evidence of a past infection in the form of antibodies.
Antibodies are defensive proteins produced by the body in response to an infective agent. Each is specific to that agent and that agent alone and serve as a cellular “footprints” to a past infection. While it is not unusual to have viral antibodies in our blood—all of us do—there are certain viruses that seem closely linked to MS.
The Epstein-Barr virus is one of them. According to a study from the Harvard School of Public Medicine published in 2011, EBV was different from other viruses in its association with MS. Among the findings:
- EBV antibodies were significantly higher in people who eventually developed MS than in a matched set of individuals who did not get the disease.
- The risk of MS increased significantly following an EBV infection.
- People with a specific gene (HLA-DRB1) and high levels of EBV antibodies were nine times more likely to develop MS than those without the gene and with low levels of EBV antibodies.
Moreover, current or previous smokers with the highest levels of EBV antibodies were 70 percent more likely to develop MS than those with neither risk factor.
Other Viruses Linked to MS
In their totality, these findings offer the strongest evidence that EBV acts as the trigger for a disorder that affects more than 400,000 Americans.
But it may, in fact, not be the only virus. Human herpesvirus-6 (HHV-6), a virus similar to EBV for which almost everyone is infected, usually before the age of three.
Insofar as multiple sclerosis is concerned, HHV-6 is not only associated with a three-fold increase in the risk of progressive MS in women, high levels of HHV-6 antibodies appears closely linked to the risk of MS relapse.
While none of this suggests any breakthrough in either the treatment or prevention MS, it may one day provides us the means to predict the course of the disease by tracking EBV, HHV-6, or similar herpes viruses.