Epstein-Barr virus (EBV), computer illustration. EBV, also known as human herpes virus 4, is 1 of 8 herpes viruses that infects humans. It is best known as the cause of infectious mononucleosis (glandular fever), but is also associated with some forms of cancer, including Burkitt's lymphoma. In both infections, the virus infects one type of white blood cell, B lymphocytes. Infection with EBV is common and usually harmless; additional factors potentiate the development of more serious diseases.