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A common virus may slink into the brain through the nose. After setting up shop in people’s nasal mucus, human herpesvirus-6 may travel along olfactory cells right into the brain, researchers report online the week of August 8 in the Proceedings of the National Academy of Sciences.

Most people’s first bout with HHV-6 comes at a tender age: It causes the common childhood infection roseola, marked by a chest rash and a high fever. “Everyone is exposed to this,” says study coauthor Steven Jacobson of the National Institute of Neurological Disorders and Stroke in Bethesda, Md. “You have it. I have it.”