People who have the herpes virus could be at a higher risk of developing Alzheimer's disease, according to research.
Re-activation and growth of the herpes simplex virus type 1 (HSV1) plays a part in the cognitive decline seen in Alzheimer's disease, according to the study published in journal PLoS ONE.
Lead researcher Elaine Bearer explained that herpes infects mucous membranes such as the lip or eye and produces viral particles, which then enter sensory nerve cells where they travel towards the brain.
"We now can see this cellular transportation system and watch how the newly formed virus engages cellular APP [amyloid precursor protein] on its journey out of the cell," she added.
This comes after the discovery of four new genes that increase the individual's predisposition to Alzheimer's disease.
Researchers from the Mount Sinai School of Medicine analysed more than 11,000 people with Alzheimer's, along with almost the same number of older people with no symptoms of dementia to identify the genes.