Infectious Mononucleosis, often called "mono," is a viral infection primarily caused by the Epstein-Barr virus (EBV). It is commonly spread through saliva, which is why it’s sometimes referred to as the "kissing disease." Symptoms typically include extreme fatigue, sore throat, fever, and swollen lymph nodes. Mono is most common in teenagers and young adults, but anyone can get it. Diagnosis usually involves a physical exam and blood tests to check for specific antibodies. While there is no specific treatment, rest, hydration, and over-the-counter pain relievers can help manage symptoms. Most people recover fully within a few weeks to months.