Mononucleosis, also known as mono, is a viral infection caused by the Epstein- Barr virus (EBV). It is often referred to as the "kissing disease" because it can be spread through saliva, leading to its association with kissing. The common symptoms of mono include fatigue, sore throat, fever, swollen lymph nodes, and swollen tonsils. It is most common in teenagers and young adults, and the symptoms typically appear four to six weeks after being infected with EBV. Rest and staying hydrated are key to recovery, and there is no specific vaccine for the prevention of infectious mononucleosis