Berlin.
According to a study, after certain viral infections, people have an increased risk of developing diseases such as Alzheimer’s.
Anyone staying in bed with the flu rarely thinks about more than headaches and body aches, fever and tiredness. However, infection with the influenza virus or certain other viruses could increase the risk of developing a neurodegenerative disease like this in the future Alzheimer, developing dementia, Parkinson’s or multiple sclerosis.
A current study from the USA, which has now been published in the specialist journal “Neuron”, suggests this connection. The researchers from the National Institutes of Health (NIH) analyzed hundreds of thousands of data from two biodatabases in Finland and the United Kingdom and found: people who determined viral infections had an increased risk of diseases affecting the nervous system up to 15 years after infection.
German experts who were not involved in the study consider the work to be very relevant, but point out methodological limitations.
Scientists searched 800,000 records for diagnoses
Kristin S. Levine’s team combed through 800,000 patient records for one of the following diagnoses: Alzheimer’s, amyotrophic lateral sclerosis (ALS), dementia, Multiple sclerosis, Parkinson’s. The researchers then looked at whether these people had been hospitalized for a viral disease at any time in the past.
The team found the strongest connection between viral encephalitis, i.e. inflammation of the brain, and Alzheimer’s. In people who are due to a flu viruses pneumonia caused by the disease were hospitalized, the researchers were able to link it to several diagnoses, including dementia, Parkinson’s disease and amyotrophic lateral sclerosis (ALS).
“Neurodegenerative disorders are a collection of diseases that have very few effective treatments and many risk factors,” said Andrew B. Singleton, director of the NIH Center for Alzheimer’s-Related Dementia (CARD) and one of the study’s authors, according to a release. “Our findings support the idea that viral infections and associated inflammation in the nervous system may be common — and potentially preventable — risk factors for these types of disorders.”
Read here: Viruses everywhere: How you can strengthen your immune system now
Link between multiple sclerosis and Epstein-Barr virus
Scientists have long suspected that certain viruses could play a role in the development of neurodegenerative diseases. Last year, researchers were able to establish a connection between the Epstein-Barr virus and show multiple sclerosis. “Researchers have been dealing with this topic for about 20 or 30 years and it has gained new impetus with the corona pandemic,” says Professor Martin Korte from the Helmholtz Center for Infection Research in Braunschweig. “So the study is very relevant.”
It becomes particularly relevant when you have an idea of how these connections could come about, says Korte. “In studies on mouse models, we were already able to show in 2018 that an influenza infection in particular can also lead to strong stimulation of the immune system immune system activated in the brain.” The so-called microglial cells are suspected of damaging nerve cells if they are active for weeks and months. “Our hypothesis is that this neuroinflammation may increase the risk of neurodegenerative diseases.”
Also interesting: Dementia expert: “Many sufferers are plundered”
Study shows no causal relationships
However, the authors emphasize that their work shows no causal relationship between viral infections and neurodegenerative diseases. It shows correlation, not causation. “It could also be the case, for example, that people who tend to get severe viral infections are also at an increased risk of neurodegenerative diseases have,” says Professor Klaus Überla, Director of the Institute of Virology at the University Hospital Erlangen.
And emphasizes: “Before vaccinations are now recommended to protect against neurodegenerative diseases, it would be important to show that the vaccinations indeed reduce the incidence of neurodegenerative diseases.”
Even if the results of the study are interesting, it currently seems premature to draw far-reaching conclusions from this work, agrees Klemens Ruprecht from the Neurology Clinic in Berlin charity. Ultimately, the individual observed associations would now have to be examined in detail and in methodologically robust studies. “Only when definitive causal relationships with certain neurodegenerative diseases can be confirmed for individual viral pathogens can one then draw possible consequences, for example in the form of a vaccination,” says Ruprecht.
More articles from this category can be found here: Life
