Common Herpes Virus Could Cause 50 Percent of Alzheimer's Disease Cases, Expert Says

A study published in Frontiers in Aging Neuroscience suggests the common herpes virus could be the cause of at least half of the cases of Alzheimer's, reports Newsweek . University of Manchester Professor Ruth Itzhaki reviewed several studies, including three based this year on the National Health Insurance Research Database in Taiwan. Two of them investigated varicella zoster virus (VZV) and its relationship to cognitive decline, while the third focused on herpes. Itzhaki cited the third study for targeting correlations between herpes and Alzheimer's in 8,362 participants who were at least 50 years old in the year 2000, and the incidence of Alzheimer's in this cohort was compared with 25,086 subjects matching their age and gender who were herpes-free. Those infected with HSV and VZV were more likely to develop senile dementia, but Itzhaki noted antiviral treatments appeared to spur a "dramatic decrease" in the number of subjects who later developed dementia. Slightly more than 5 percent of the group that took anti-herpes medication developed dementia in the following decade, versus more than 28 percent of those who did not take the medication. "Viral DNA is located very specifically within plaques in postmortem brain tissue from people with Alzheimer's," Itzhaki said. "The main proteins of both plaques and tangles accumulate also in HSV1-infected cell cultures — and antiviral drugs can prevent this."