Written by the Fiveable Content Team • Last updated August 2025
Written by the Fiveable Content Team • Last updated August 2025
Definition
Mononucleosis, often called 'mono' or the 'kissing disease,' is an infectious illness caused by the Epstein-Barr virus (EBV). It primarily spreads through saliva and can cause fever, sore throat, swollen lymph nodes, and fatigue.