The Epstein-Barr virus (EBV) is a common virus that belongs to the herpesvirus family. It is best known for causing infectious mononucleosis, often referred to as "mono." Most people are infected with EBV at some point in their lives, usually during childhood or adolescence, and many do not show symptoms. Once infected, EBV remains dormant in the body and can reactivate later. It is also associated with certain cancers, such as Hodgkin lymphoma and nasopharyngeal carcinoma. Transmission typically occurs through saliva, which is why it is sometimes called the "kissing disease."