In two studies in the journal Alzheimer's & Dementia, researchers at Umea University determined the association between the herpes virus and Alzheimer's may be due to a weakened immune system among seniors, which creates opportunities for the virus to spread further to the brain.  There it can start the process which results in Alzheimer's disease.
 

"Our results clearly show that there is a link between infections of herpes simplex virus and the risk of developing Alzheimer's disease. This also means that we have new opportunities to develop treatment forms to stop the disease," said Hugo Lövheim, associate professor at the Department of Community Medicine and Rehabilitation, Geriatric Medicine.  
 

The findings are based on two large studies involving nearly 4,000 seniors who were tracked for about a decade. Both studies determined herpes infection doubled the risk of developing Alzheimer's disease.
 

"Something which makes this hypothesis very interesting is that now herpes infection can in principle be treated with antiviral agents. Therefore within a few years we hope to be able to start studies in which we will also try treating patients to prevent the development of Alzheimer's disease," said Lövheim.
 

Alzheimer's disease is the most common form of dementia, striking about five million Americans.