How ‘one-two punch’ of shingles could lead to Alzheimer’s disease

GETTING shingles could increase the risk of developing Alzheimer’s disease, researchers have warned.

There is already evidence to suggest HSV-1 – the herpes virus that causes cold sores – could be linked to the disorder by triggering changes in the brain.

These changes resemble differences seen in the brains of dementia patients, including particular proteins clumping together, inflammation and decreased functionality. Now a study suggests a different type of herpes virus could also play a role.

Scientists used laboratory-grown brain cells and a 3D brain model to see what impact varicella-zoster virus (VZV) – which causes chickenpox and shingles – has on the brain.

They discovered that VZV infection did not directly trigger the development of Alzheimer’s features but appeared to reactivate the cold sore virus, which usually lies dormant in the body.

This ‘one-two punch’ could in turn lead to Alzheimer’s-like brain damage.

Professor Ruth Itzhaki, from the University of Manchester, worked with scientists from Oxford’s Institute of Population Ageing and Tufts University in the US on the study, published in the Journal of Alzheimer’s Disease.

She said: ‘This striking result appears to confirm that, in humans, infections such as VZV can cause an increase in inflammation in the brain, which can reactivate dormant HSV-1.

‘The damage in the brain by repeated infections over a lifetime would lead eventually to the development of Alzheimer’s disease or dementia.’