Epstein-Barr virus (EBV) is a ubiquitous herpesvirus that primarily infects humans and is best known for causing infectious mononucleosis, but it is also associated with several types of cancer, including Burkitt's lymphoma and nasopharyngeal carcinoma. EBV is transmitted through bodily fluids, especially saliva, and most people become infected with it at some point in their lives, often without significant symptoms.