Common injury may trigger Alzheimer’s disease by awakening hidden virus, study warns

Inflammation in the brain can reawaken dormant viruses, which may lead to the onset of neurodegenerative disease, a new study finds.

New research has shown for the first time that repeated head injuries – a known risk factor for Alzheimer’s disease – may reactivate a common virus that can lie dormant in human cells for a lifetime.

According to Alzheimer’s Research UK, almost half of dementia cases worldwide could be prevented or delayed. Without severe head injuries, there would be three fewer cases of dementia for every 100 people who develop it now.

Published in the journal Science Signaling, the study suggests that the herpes simplex virus 1 (HSV-1), or the so-called cold sore virus, which is found in over 80% of people, may connect the dots between head trauma and brain disease.

"We thought, what would happen if we subjected the brain tissue model to a physical disruption, something akin to a concussion?” asked Dana Cairns, research associate in the Department of Biomedical Engineering at Tufts University and lead author of the study. “Would HSV-1 wake up and start the process of neurodegeneration?"

In earlier studies, Cairns had noted that activation of HSV-1 from its dormant state triggers the signature symptoms of Alzheimer's disease in lab models of brain tissue.

Researchers from Oxford’s Institute of Population Ageing and the University of Manchester, and Tufts University then set out to reconstruct the environment of the brain in a lab model to better understand how concussions may set off the first stages of virus reactivation and neurodegeneration.

Under lab conditions, researchers created a brain-like tissue using neural stem cells, enclosed it in a cylinder and gave it a sudden jolt to mimic a