Epstein-Barr virus (EBV) is a ubiquitous human herpesvirus. Infection with EBV is common, worldwide in distribution, and largely subclinical in early childhood. EBV has been established as the causative agent of heterophile-positive mononucleosis, which occurs most frequently in late adolescence or early adulthood. In addition, seroepidemologic data have suggested that EBV also plays an etiological role in African Burkitt’s lymphoma and nasopharyngeal carcinoma.