Cold Sores Linked to Alzheimer's Disease

Cold sores might be linked to Alzheimer's disease, a new study suggests.

The same herpes simplex virus type 1 (HSV1) that causes cold sores on the lips, mouth, or gums can contribute to dementia, according to a study published in the March 31 issue of the journal PLoS ONE.

"Herpes infects mucous membranes, such as the lip or eye, and generates viral particles," lead author Dr. Elaine Bearer, a pathology professor at the University of New Mexico School of Medicine, said in a written statement released in conjunction with the study. "These viral particles burst out of the cells of the mucous membrane and enter sensory nerve cells where they travel inside the nerve toward the brain."

In the study, researchers tagged herpes virus particles with a green fluorescent protein. The saw the proteins leave the mucous membranes and enter nerve cells that could travel to the brain and affect plaques that cause dementia.

"Clinicians have seen a link between HSV1 infection and Alzheimer's disease in patients, so we wanted to investigate what might be going on in the body that would account for this," he says. "What we were able to see in the lab strongly suggests a causal link between HSV1 and Alzheimer's."