(HealthDay News) -- Mononucleosis, commonly known as mono, is a virus that often affects teens. Flu-like symptoms usually appear four to seven weeks after infection, which often stems from close, personal contact.

The Nemours Foundation says if you have these symptoms, you should see a doctor:

• Constant fatigue.
• Abdominal pain.
• Fever.
• Sore throat.
• Loss of appetite.
• Skin rash.

There is no cure for mono, but the illness usually ebbs in three to four weeks. Patients should get plenty of rest and try to eat a well-balanced diet.