Alzheimer’s disease could occur several years after contracting a virus causing encephalitis.
- Alzheimer’s disease affects 1.2 million people in France.
- About 80% of the viruses examined in this study can invade the nervous system and trigger the immune system’s inflammatory response.
In recent months, research has shown a link between the Epstein-Barr virus and an increased risk of developing multiple sclerosis. “After reading about the Epstein-Barr virus cohort, we realized that for years scientists had been looking, one by one, for links between a neurodegenerative disease and a specific virus. That’s when we decided to try a different approach, more based on data science”said Michael Nalls, head of the NIH CARD Advanced Analytics Expert Group, in a statement.
With several American researchers, he decided to carry out a study to examine the potential links between viral exposures and the risk of neurodegenerative disease. For this, the scientists used the medical records of 300,000 people. In detail, they identified patients who had been diagnosed with one of six neurodegenerative disorders: Alzheimer’s disease, amyotrophic lateral sclerosis, generalized dementia, multiple sclerosis, Parkinson’s disease or vascular dementia. . Next, the team checked whether the participants had been hospitalized with a viral infection before.
Alzheimer’s: 20 times more risk if you have suffered from viral encephalitis
According to results published in the journal Neuron45 viral exposures significantly associated with an increased risk of neurodegenerative diseases were identified. “We then found 22 associations after a second search”, the authors said. Of all the neurodegenerative disorders, generalized dementia had the most associations, specifically links to six different viral exposures.
The researchers found that people who had viral encephalitis were at least 20 times more likely to be diagnosed with Alzheimer’s disease than those who had not been exposed to this virus. “Exposure to influenza and pneumonia was significantly associated with five of the six neurodegenerative diseases studied. Some of these exposures were linked to an increased risk of neurodegeneration up to 15 years after infection”, can we read in the works.
Vaccination, a way to reduce the risk of neurodegenerative diseases
The authors recalled that vaccines were available to combat some of the associated viruses. “The fact that commonly used vaccines reduce the risk or severity of many of the viral illnesses observed in this study raises the possibility that the risks of neurodegenerative disorders may also be mitigated,” concluded Michael Nalls.
