Mono- Refers to a group of symptoms usually caused by the Epstein-Barr virus. Symptoms include fever, sore throat, fatigue, muscle weakness, etc.. There is no specific treatment but they are only used to calm down the symptoms. For example a doctor might prescribe corticosteroid medication for throat and tonsil to stop swelling. Mono is almost impossible to prevent but your body builds immunity to it by age 35. Up to 90% of American adults get mono by age 40.