A condition characterized by an increase in mononuclear white blood cells and swollen lymph nodes, which is usually caused by infection with the Epstein-Barr virus. The disease is infectious mononucleosis (MONDO_0005810). Also known as: Filatov's disease, Gammaherpesviral mononucleosis, Mono, Pfeiffer's disease, glandular fever, monocytic angina, mononucleosis.