Alzheimer’s and Herpes: The Role the Virus Plays in the Disease

A number of new Alzheimer’s studies have found that the disease could be linked to an especially common type of infection: herpes. Alzheimer's and Herpes: The Role the Virus Plays in the Disease

Read more about the research, the role the virus plays in the disease and its impact on Alzheimer’s prevention.

Alzheimer’s and Herpes: It Isn’t Just What You Think

A lot of people have come to associate the word “herpes” with the STI that’s just one of many versions of the infection. In fact, the medical community has identified a number of strains of the infection – many of which are extremely common.

Nearly two-thirds of all people have been infected with HSV-1, a herpes strain that causes cold sores for some, but lies dormant in the body for many. HHV-6, a version of herpes most commonly associated with the childhood skin rash roseola, infects nearly everyone. VZV or (HHV-3), the virus responsible for chicken pox and shingles, is yet another prevalent strain. Those are just three of the most common versions of herpes.

In short, most people have some version of herpes (or several) long before they reach their adult years and no one should view any of the strains as something shameful. They’re merely a part of life.

The Link Between Alzheimer’s and Herpes

A growing amount of research has found a clear link between Alzheimer’s and different strains of herpes. In fact, over 100 research papers have described a correlation between HSV-1 and Alzheimer’s risk.

Scientists are quick to note, however, that correlation doesn’t equal causation. Most of the researchers involved in these tests pose a number of theories about why the two illnesses may be linked.

One of the most recent studies on the subject at the Icahn School of Medicine at Mount Sinai looked at brain tissue from healthy people and people who had died from the disease to see what differences and similarities they could find. They were surprised to find that the viruses HHV-6A and HHV-7 showed up twice as often in the brain tissue of people with Alzheimer’s as they did in normal brain tissue. These strains of herpes are extremely common but remain inactive in the brain for decades, so the research suggests their presence plays some role in increasing the risk of Alzheimer’s.

The Link Between Amyloid Beta and Herpes

Researchers have long known that people with Alzheimer’s have a buildup of protein clusters in the brain called amyloid beta. A team at MassGeneral Institute for Neurodegenerative Disease recently tested the theory that amyloid beta, an element that had generally been seen as something entirely negative, may actually have a positive role to play by fighting off infection.

Starting with mice, they tried out their theory by injecting HSV-1 into brains of mice with normal brains, as well as mice that had a high amount of amyloid beta in their brains. As they expected, the ones with amyloid beta resisted the virus more successfully than the normal mice. They repeated the test with human cell tissue and the HHV-6 virus to similar results.

The research supports the idea that amyloid beta may start out in a helpful role to support your body in fighting against common infections. With age, the immune system weakens and more infections take hold, which creates a build up of amyloid beta – something that scientists believe then contributes to Alzheimer’s.

What This Research Means for People With Alzheimer’s

Two Taiwanese studies have already demonstrated ways the link between Alzheimer’s and herpes can contribute to better treatments. The studies tracked the health of people who had been diagnosed with a version of herpes (one focused on HSV-1, the other VZV) and found that people who had the virus were more likely to develop Alzheimer’s – in the case of the HSV-1 study, they were 2.5 times more likely.

Notably, in both cases, the people who received treatment for herpes saw their risk drastically decrease. In one study, the decrease was 45%; in the other it was an even more impressive 80%.

This initial research shows that anti-herpes and infection drugs appear to have real promise in helping prevent Alzheimer’s.

Were you aware of the link between Alzheimer’s and herpes? What about the research were you most surprised to find? We’d like to hear from you in the comments below.

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