Mononucleosis (Mono) Symptoms

Mononucleosis, often called “mono” or the “kissing disease,” is usually caused by the Epstein–Barr virus (EBV). It spreads through saliva and close contact. Mono is most common among teens and young adults. Symptoms may include extreme fatigue, fever, sore throat, swollen lymph nodes, enlarged tonsils, headache, and sometimes an enlarged spleen or liver.

• Cause: Epstein–Barr virus (less commonly cytomegalovirus or other viruses).
• Risk factors:

Adolescents and young adults, especially those in high school or college

Close personal contact (kissing, sharing drinks or utensils)

Weakened immune system

Living in close quarters (dormitories, military housing)

See a doctor if you have persistent fever, severe sore throat, difficulty swallowing, swollen lymph nodes, or prolonged fatigue. Urgent medical attention is needed if you develop severe abdominal pain (possible ruptured spleen), breathing difficulty, or yellowing of the skin/eyes (jaundice).