Researchers have discovered links between viruses in the brain and Alzheimer’s disease, The Guardian reports. Tests on nearly 1,000 subjects have found that two strains of herpes were more prevalent in brains of those with early-stage Alzheimer’s than in control subjects. Whether or not the virus is contributing to the disease remains unclear. Scientists are divided over whether the virus can actually trigger the disease or if those on a path to Alzheimer’s are simply more prone to infection. When the scientists started their study, they were searching for genes that were unusually active in the brains of people with early stages Alzheimer’s, not the presence of viruses. Lead author of the study, Ben Readhead, assistant professor at Arizona State University-Banner Neurodegenerative Disease Research Center, told The Guardian, “We didn’t go looking for viruses, but viruses sort of screamed out at us.” But don’t panic. The viruses found in the study were not the ones that cause cold sores, but rather more common strains that most people already carry without experiencing symptoms.