Viruses and Alzheimer's disease

This week's ALZForums newsletter highlighted an article connecting the herpes virus with AD.  The article reflects the results of a four-year "big data" study of available  information regarding what goes wrong in brains suffering AD.  It found evidence linking viral load (notably herpes) to the molecular, pathological, and clinical manifestations of dementia.  There was a connection between how many herpes viruses were present in the brain with the brain's dementia status.

But, the researchers who made this connection could not determine cause and effect.  Are the viruses driving the disease, or are they opportunistic, taking advantage of the weakened condition of the already diseased brain? 

A couple of points in the article:

• An association between AD and some viruses, especially herpes, has long been recognized.
• The different herpes viruses cause a variety of problems with the nervous system.
• The viruses may be driving the production of amyloid.
• People begin to accumulate these viruses at a young age, but they may only be activated at the time AD pathology begins.  Most people have them hiding in their brains.