The virus behind cold sores may be linked to Alzheimer's and the disease could be treatable with existing drugs, research has found.
Scientists at the University of Manchester found the virus, herpes simplex virus type 1 (HSV1), was a major cause of the protein plaques found in the brains of Alzheimer's sufferers.
Their research, published in the Journal of Pathology, suggests HSV1 could be a significant factor in developing the disease. They also claim it could be treated by antiviral agents already used to treat cold sores and other conditions caused by the herpes virus.
Their research found that the protein plaques in Alzheimer's disease sufferers' brains contained the DNA of the cold sore virus.
Professor Ruth Itzhaki, who led the research at the University of Manchester, said: "We suggest that HSV1 enters the brain in the elderly as their immune systems decline and then establishes a dormant infection.
"The ensuing active HSV1 infection causes severe damage in brain cells, most of which die and then disintegrate, thereby releasing amyloid aggregates which develop into amyloid plaques."