Virus that 'most people are exposed to' could be the cause of Alzheimer's in some people

Scientists believe they have discovered a link between a gut infection caused by a common virus and later developing a type of Alzheimer's.

Arizona State University and Banner Alzheimer's Institute researchers believe they have made a noteworthy discovery regarding understanding Alzheimer's.

The disease, and its many variations, is considered particularly devastating as a person will shift from functioning perfectly normally to struggling with their memory and thinking skills over a few years. The disease is also considered to be fatal.

Brain’s immune cells, light blue and purple, shown interacting with amyloid plaques, red, linked to Alzheimer’s disease (Jason Drees/Arizona State University)

The new findings were recently published in the journal Alzheimer’s & Dementia and the minds behind it think understanding this link between a gut infection and Alzheimer’s could aid in healthy treatment and prevention.

What is the virus?

It is believed most humans are exposed to this virus; called cytomegalovirus or HCMV; during the first few decades of life. Cytomegalovirus is one of nine herpes viruses, however, this one is not considered to be a sexually transmitted disease.

According to the new research, in some people, this virus will lead to a chronic gut infection and the virus will linger here.

How does HCMV relate to Alzheimer's disease?

Eventually it may travel to the brain via the vagus nerve, a critical information highway that connects the gut and brain.

Once it reaches the brain, the virus can change the immune system and contribute to other changes associated with Alzheimer's disease.

Once in the brain, the virus is set to prompt immune cells called microglia to turn on their expression of a gene called CD83. This gene has previously been linked to other studies of Alzheimer’s.

What do these findings mean?

The study’s co-founder Dr Ben Readhead, explained the findings and what it could mean as a result.

Alzheimer's is known to be a particularly brutal and fatal disease(Getty Stock Image)

He said: “We think we found a biologically unique subtype of Alzheimer’s that may affect 25-45 per cent of people with this disease.”

More research is needed to help validate the study’s findings. However, it could eventually result in different steps being taken to prevent the disease in the first place.

Ultimately, existing antiviral drugs could be tested to treat or prevent this form of Alzheimer’s disease

It is believed that blood tests, currently in development, could help identify patients with an active HCMV infection.

Dr Readhead added: “This subtype of Alzheimer’s includes the hallmark amyloid plaques and tau tangles — microscopic brain abnormalities used for diagnosis – and features a distinct biological profile of virus, antibodies and immune cells in the brain.”