Alzheimer’ s maybe triggered by herpes virus

ALZHEIMER’S disease may be triggered by the herpes virus, a new study suggests, leading to hopes that antiviral medication could help prevent dementia.

Around 850,000 people are living with dementia in Ireland and Britain, and the majority of people have Alzheimer’s which occurs when sticky plaques of amyloid build up in the brain, killing brain cells.

But new research has found the brains of people who have died of Alzheimer’s have almost double the level of HHV-6A and HHV-7 herpes virus, as non-diseased brains, suggesting it is playing a role in the condition.

Researchers in the US believe the disease may trigger an immune ‘cascade’ which encourages the growth of amyloid plaques. It raises hopes that cases could be prevented through antiviral drugs.

The team did not set out to study the impact of herpes, but was looking for anything which might be different in six key brain regions in people with Alzheimer’s compared to those who were dementia free.

They began by sequencing DNA from the dead patients to find out information about inherited genes, followed by finding out how those genes were expressed.

“We didn’t go looking for viruses, but viruses sort of screamed out at us,” said lead author Ben Readhead, of Arizona State University.

“We saw a key virus, HHV6A, regulating the expression of quite a few Alzheimer’s risk genes and genes known to regulate the processing of amyloid, a key ingredient in Alzheimer’s neuropathology.”

The study authors say the findings suggests that Alzheimer’s could be ‘collateral damage’ caused by the brain’s response to the virus.

The research was published in the journal ‘Neuron’.