Researchers from Arizona State University and Banner Alzheimer’s Institute have identified a connection between a chronic intestinal infection caused by the cytomegalovirus, a common herpes virus, and the development of Alzheimer’s disease. The study suggests that in some individuals, the virus can remain active in the gut and travel to the brain via the vagus nerve, potentially altering the immune system and contributing to Alzheimer’s. While this virus is widespread, it is only present in a subset of people, prompting researchers to develop a blood test for active infections and explore antiviral treatments for Alzheimer’s.