The Epstein–Barr virus (EBV), also called human herpesvirus 4 (HHV-4), is one of eight known viruses in the herpes family, and is one of the most common viruses in humans. EBV infects B cells of the immune system and epithelial cells. Once EBV's initial lytic infection is brought under control, EBV latency persists in the individual's B cells for the rest of the individual's life.