Viruses that hide in the brain might influence Alzheimer’s disease. That is what researchers said in a new study that is expected to restart debate about what causes the brain-wasting disease. However, the findings do not prove viruses cause Alzheimer’s. They also do not suggest that it can be passed from one person to another. A team led by researchers at New York’s Mount Sinai Health System found that some viruses affect genes involved in Alzheimer’s. Among those genes are two very common herpes viruses. The idea that infections earlier in life might somehow begin the process of getting Alzheimer’s years later has been discussed for years. But the theory that Alzheimer’s starts from sticky plaques that clog the brain has had more support. The study released Thursday has some specialists saying it is time to look more closely at viruses.