THE VIRUS THAT CAUSES MULTIPLE SCLEROSIS HAS BEEN IDENTIFIED

Multiple sclerosis (MS), a neurodegenerative disease that affects around 50,000 people in Spain and approximately 2.8 million people worldwide, could have an infectious origin.

MS is a chronic autoimmune disease that damages myelin, a fatty substance that surrounds and protects nerves, allowing them to transmit electrical impulses quickly between the brain and the rest of the body. In people with MS, the immune system mistakenly attacks the body's own tissue, and the development of the disease is usually triggered by a combination of genetic and environmental factors.

It is also the most common chronic neurological disease among young adults between 20 and 40 years old in Europe and North America, particularly affecting women.

STUDY ON THE ORIGIN OF MULTIPLE SCLEROSIS

According to a study carried out by a team of researchers from the Harvard T.H. Chan School of Public Health (USA), published on Thursday 13 January in the journal Science, the main cause associated with multiple sclerosis is the Epstein-Barr virus (EBV), commonly known as the virus responsible for mononucleosis.

The research analysed cases diagnosed over a period of twenty years from a sample of more than 10 million people in the United States.

As explained by Alberto Ascherio, lead author of the study:

"For years, our group and others have investigated the hypothesis that EBV causes MS, but this is the first study providing convincing evidence of causality."

He also highlighted that this discovery represents an important step forward because it suggests that many cases of MS could potentially be prevented by stopping EBV infection. Furthermore, focusing on this virus could help researchers find new treatments or even a possible cure for MS in the future.

THE VIRUS ASSOCIATED WITH MULTIPLE SCLEROSIS

Although the exact cause of MS was previously unknown, EBV had long been considered one of the main suspects. This herpes virus can cause infectious mononucleosis and remains permanently in the body after infection.

Approximately 95% of adults worldwide are infected with EBV, but until now it had been difficult to establish a direct relationship between the virus and MS because the first symptoms of the disease usually appear years after EBV infection, often after a period of around ten years.

The study suggests that a vaccine against EBV or antiviral treatments specifically targeting this virus could potentially prevent or treat MS. However, there is currently no approved method to prevent or effectively eliminate EBV infection.

RESULTS OF THE NEW MULTIPLE SCLEROSIS STUDY

To determine the relationship between EBV infection and MS, researchers analysed more than 10 million young adults serving in the United States military, identifying 955 individuals who developed MS during their service period.

Every two years, researchers analysed serum samples collected by the military to determine the participants' EBV status at the time of their first sample and to study the relationship between EBV infection and the later development of MS.

The results showed that the risk of developing MS increased 32-fold after EBV infection, while no similar increase was observed following infection with other viruses.

After EBV infection, blood tests also showed a significant increase in biomarkers associated with the typical nerve degeneration seen in MS, supporting the conclusion that EBV plays a major role in triggering the disease.

FUTURE BENEFITS OF THE MULTIPLE SCLEROSIS STUDY

Although there is currently no effective way to prevent or treat EBV infection, researchers believe that:

"A vaccine against EBV or antiviral drugs specifically targeting EBV could, we think, prevent or cure MS."

Identifying the possible trigger of MS opens the door to new research into treatments and prevention strategies.

However, it is important to understand that EBV infection may be a necessary but not sufficient factor for developing multiple sclerosis. Other elements, including genetic and environmental factors, may also be required for the disease to appear.

In the future, antiviral treatments targeting EBV could become an effective therapeutic option if they are administered at the appropriate stage of infection or before the disease develops.