What are the causes of multiple sclerosis?
Most sufferers of multiple sclerosis (MS) contract it before the age of 15. Migration studies after World War II suggested that if you migrate as a child of under 15 years of age, you will suffer from the MS of the area you're migrating to. If you migrate at the age of 15, you'll suffer from the MS of where you're migrating from. So there's a suggestion that there's a cut-off age. You may not contract the disease for 3 years. But it seems to be something that you contract before age 15. The most likely environmental trigger is an infection because over the last 6 years almost everything else has changed and the MS disease really has not changed very much, the prevalence of MS is not very different. To provide an example, lead levels have gone up. There have been different nutritional issues that have come up. There are different medicines on the market and so forth, and different toxins in the environment. That doesn't seem to really make a major impact. However, the virus infections have not changed and therefore we think that it's probably a virus or many viruses. The virus that seems to have the best supporting evidence is the Epstein-Barr virus. Some work had been carried out on that. But it's hard to prove it as the cause of the disease, what we are studying is, "Is it the trigger of the disease?" In other words, what triggers multiple sclerosis? We don't know that yet.
