A new study revealed that people with Alzheimer's disease had higher levels of certain kinds of herpes virus in their brains. Roughly 90 percent of the U.S. population has the specific strains of herpes that this study links to Alzheimers. However, medical experts say there is no need to worry, as herpes has not been found to cause Alzheimer's.Though scientists haven't pinpointed the exact cause of Alzheimer's disease, they know that genetics, lifestyle and environmental factors all play a role. And now, they also know that certain strains of the herpes virus might have something to do with it.In a study funded by the National Institute of Health and published in the journal Neuron, researchers found that people with Alzheimer's disease had higher levels of herpes strains 6A and 7. These aren't the strains that cause genital herpes or cold sores; they're responsible for a common childhood virus called roseola.The study authors hope their research could someday help determine who's at risk for Alzheimer's disease— as well as lead the way for new treatments.Alzheimer's disease — a form of dementia — causes people to lose their ability to remember, think, and reason, which makes it hard to perform even routine activities. Alzheimer's disease is the sixth-leading cause of death in the United States, and the NIH will spend more than a billion dollars on research this year in the hope of learning more about the debilitating disease. Diving into the researchScientists at Icahn School of Medicine at Mount Sinai in New York City; and Arizona State University, in Phoenix, Arizona; studied brain tissue from 622 people who showed signs of Alzheimer's disease and 322 who didn't. They were hoping to find existing medications that could be viable treatments for Alzheimer's patients, CNN reported. Instead, their research led them to discover that levels of those specific herpes strains were twice as high in the brains affected by Alzheimer's disease compared to those without it.This new study reignites an old theory that viral infections could have long-term impacts on brain functions. "The hypothesis that viruses play a part in brain disease is not new, but this is the first study to provide strong evidence based on unbiased approaches and large data sets that lends support to this line of inquiry," National Institute of Aging Director Richard J. Hodes, M.D., said in a statement. "This research reinforces the complexity of Alzheimer's disease."Geneticist Joel Dudley, of Icahn School of Medicine, and study co-author told STAT his research is stronger than prior studies linking viruses to Alzheimer's disease. Unlike past studies, Dudley's research found that viruses somehow transfer their genes into the brain cells of people with Alzheimer's disease. He theorizes that the virus' genes somehow activate other genes linked to an increased risk of the disease.Should you be worried about the discovery?Short answer: no. About 80-90 percent of people have one of these herpes strains, meaning more people would develop Alzheimer's if the virus could truly cause the form of dementia. The paper does not show causation — only a link between the herpes strains and the presence of Alzheimer's disease. Instead, the team believes the study offers new areas for scientists to explore when developing Alzheimer's treatments. "While these findings do potentially open the door for new treatment options to explore in a disease where we've had hundreds of failed trials, they don't change anything that we know about the risk and susceptibility of Alzheimer's disease or our ability to treat it today," Gandy told CNN.While there's no way to prevent Alzheimer's disease, medical experts recommend staying active and maintaining a healthy weight, low blood pressure and low cholesterol to lower your risk.