Researchers have discovered a link between a chronic gut infection caused by a common virus and the development of Alzheimer's disease in some people. Most people encounter cytomegalovirus (CMV) during childhood, and after the initial infection the virus remains in the body for life, usually dormant.

Scientists from the University of Pittsburgh have discovered a surprising connection between Alzheimer's disease and the herpes simplex virus type 1 (HSV-1). Their study suggests that viral infections may play a role in the development of this condition.