Multiple Sclerosis (MS) appears to be a complication of Epstein-Barr Virus infection

When I was just shy of 16, I got mononucleosis (mono AKA the kissing disease). After ~2 weeks of a somewhat sore throat, exhaustion and nausea, I finally got hit with the *real* mono - I couldn't get out of bed, couldn't eat solid food, and was living on about 4 Tylenol 3s and 12 Advil a day to keep the swelling down (it was still excruciatingly painful). I was in this state for about a week and a half, but it felt like the end of the world at the time.

Mono is a virus that's caused by being exposed to the Epstein-Barr Virus (EBV). It's as easy as catching a cold, and so it affects more than 90% of the worldwide population. It also affects different people differently - some people get really sick like I did, while others barely even notice that they're sick.

However, none of this compares to the reality of living with multiple sclerosis (MS).

MS in a neurodegenerative disease that affects the central nervous system (brain and spinal cord). It eats away at the myelin sheath, an insulating layer that enwraps neurons and allows them to conduct faster electrical signals. When the myelin sheath starts to break down, these neuronal signals become harder and harder to conduct, and loss of control over the legs, for example, can set in.

Illustration of the difference between health neuronal myelin and myelin that's being eaten away by MS

MS is a relapse-remitting disease, where patients go through times of active symptoms, with periods of no symptoms in between. While some people are able to keep symptoms under control, others have a worsening prognosis. Like mono, it affects people vastly differently, with some living relatively normal lives with it, while others become very incapacitated.

You might be wondering why I started this article on MS talking about my experience with mono as a teenager. Well...

A groundbreaking paper released in Science this week showed a very strong link between prior infection with EBV and the development of MS. A massive 20-year longitudinal study looking at 10 MILLION (yes you read that right) young adults in the US military showed that 99.5% of the 801 people diagnosed with MS during their service tested positive for Epstein-Barr antibodies (i.e. they had a prior infection). This strongly suggests that MS is a complication of the Epstein-Barr virus.

Now this doesn't mean that you should panic since you've likely contracted EBV in the past. Instead, it's likely that genetic and environmental factors converge to bring on MS; where immune cells that are meant to attack the EBV instead attack the body's neurons' myelin sheaths. It's also been been observed that MS disproportionately affects Canadians, and is likely due to the short periods of sunlight that are experienced so far north.

With the more certain knowledge that MS arises from EBV infection, whereas it was previously of unknown origin, scientists can study more targeted therapies, such as antivirals, to treat the 2.8 million people who have MS worldwide. This study is a game-changer, and I'm excited to see what treatments are developed to help people with MS from here on in!