Can the virus increase the risk of dementia?

Co-authored by Lærke Storgaard Duerlund, MD, and Arun Venkatesan

Dementia is a catastrophic condition that affects Memorythinking, and the ability to carry out daily activities. As global groups age, the number of people living with dementia is expected to increase dramatically. By 2050, more than 150 million people could be affected worldwide.¹ Risk increases dramatically with age. Nearly one in three people over 90 can develop conditions.

However, dementia is not a single illness. This is an umbrella term that includes various types such as Alzheimer’s disease, vascular dementia, and more. Rewey Body dementia. Age is the strongest risk factor, but many other people, including hypertension, are well-recognized, smoking, depressionand hearing loss.² But one question has been debatable for decades. Can certain viral infections play a role in the development of dementia, particularly herpes virus?

What is herpes virus?

Herpes viruses are a large family of viruses, but only eight people are known to infect humans. The most common are herpes (simplexvirus type 1, or HSV-1), genital herpes (HSV-2), chickenpox and shingles (water cell zoster virus, or VZV), monoco or glandular fever (Epstein Bal virus), and viruses that cause immunocompromisation (immunocompromisation), immunocompromisation (Epstein Bal virus), and immunocompromisation (Epstein Bal virus). These viruses share amazing properties. If you get infected, you will never really leave your body. Instead, they become dormant, where they often hide in neurons and can be re-activated in later years.

It is estimated that up to 80% of adults carry HSV-1, which causes herpes. VZV usually causes chicken pox Childhood It can return as shingles decades later. All herpes viruses can rarely lead to serious brain infections such as meningitis and encephalitis. Considering the ability to sleep during Nervous systemit’s reasonable to ask: can they also affect the brain in a more subtle and long-term way?

Herpes Chemistry Link: What do we know?

Interest in herpetic dementia connections began in the 1990s when researchers discovered HSV-1 DNA in brain tissues in patients with Alzheimer’s disease.^4,5 This raised an important question: is the virus contributing to the disease, or is it likely to be seen in already vulnerable people?

Since then, researchers have been investigating whether people with previous herpesvirus infections are at a higher risk of developing dementia. Some studies have found a higher association between HSV-1 or VZV and a higher rate of dementia in later years, whereas others do not. One more interesting finding comes from a large-scale new study in Wales. Here, people who received the shingles (VZV) vaccine were at a 20% lower risk of developing dementia.⁶ But does this mean that the vaccine is protective? Or are vaccinated people generally healthy and engaged in activities that reduce the risk of dementia?

How does a virus affect the brain?

Scientists have proposed several mechanisms that could link the herpes virus to dementia.

• inflammation: When herpes virus reactivates, it causes inflammation. Chronic inflammation is thought to contribute to the pathology of Alzheimer’s disease, including the accumulation of toxic amyloid plaques in the brain.
• Blood-brain barrier destruction: Infections can damage the blood-brain barrier, allowing potentially harmful substances or immune cells to enter the brain.
• Vascular Effects: Infections like VZV can increase the risk of stroke, causing damage and accelerate brain tissue Cognitive decline.

In short, herpes viruses may not directly cause dementia, but they may contribute to a complex series of events that lead to neurodegeneration in vulnerable individuals.

Why the evidence remains uncertain

Despite decades of research, the role of herpesvirus in dementia remains uncertain. Some studies show strong links, others show nothing. One major challenge is that correlation is not causal. For example, those who carry lighters are more likely to develop lung cancer. This is not because the writer is likely to smoke, but because it is more likely to cause cancer. Therefore, just because people with herpes infection have a higher rate of dementia does not mean that one causes the other. Instead, other factors such as age and the immune system can increase the risk of both.

It is also difficult to eliminate hidden factors. For example, people who develop shingles and herpes development can differ in many ways from people who are not in terms of health, immune or socioeconomic background.

Another complication is that almost everyone is exposed to the herpes virus. If these viruses play a role, why do only some people continue to develop dementia? There may be an answer Geneticstiming of viral reactivation, immune response, or interaction with other risk factors.

Is prevention possible?

The link for herpes dementia is not fully established, but be careful Optimism In the science community. If the virus contributes a small amount to the risk of dementia, treatment or vaccines can make meaningful differences at the population level.

• Antiviral agents: A large Taiwanese study found that people with herpesvirus infection treated with antiviral drugs have a lower risk of developing dementia. Clinical trials focusing on patients with both herpesvirus infection and Alzheimer’s disease are of particular importance as antiviral properties Treatment These may represent potential disease modification strategies in these patients.
• vaccination: The Shingles (VZV) vaccine is already recommended to prevent painful rashes and complications for older people. Whether it reduces the risk of dementia is still under investigation.

In the meantime, maintain overall health through exercise, dietblood pressure control, and staying socially and cognitively active, remains the most evidence-based approach to reducing the risk of dementia.

Conclusion

So, can the virus cause dementia? The honest answer is that we still don’t know. Herpes virus may be one of the much bigger puzzles. It may not be the main cause of dementia, but it can play a role in triggering or accelerating the process, particularly in combination with other risk factors.

The good news is that research into the link between infectious diseases and dementia is moving forward. Many questions remain, but such studies can help to clarify how common viruses affect long-term brain health. The brain appears to be shaped not only by age and genetics, but also by the infections we have had for years.

About the author:

Lerke Stogaard Durland, Maryland, is a member of the Johns Hopkins Encephalitis Centre, Department of Neurology, Johns Hopkins University, Department of Neurology, Baltimall, Maryland, and the Department of Infectious Diseases, 9000 Aarborg Hospital, Denmark, and Earlborg University Hospital.

Arun Venkatesan is a professor at the Johns Hopkins Encephalitis Center at the Johns Hopkins School of Neurology, Johns Hopkins University, School of Medicine, Baltimore, Maryland.