Mononucleosis, commonly known as the 'kissing disease,' is a widespread viral infection typically caused by the Epstein-Barr virus (EBV). Besides EBV, some other viruses can also lead to the disease. The infection is transmitted through saliva, particularly via close contact such as kissing or sharing food/drinks.

Symptoms of the disease usually include fever, severe sore throat, swollen lymph nodes in the neck, armpits, and groin, tonsillitis, extreme fatigue, skin rashes, headaches, and sometimes an enlarged spleen.

Treatment is generally symptomatic, supported by ample rest, adequate fluid intake, and over-the-counter pain relievers or fever reducers to alleviate pain and fever. In cases of an enlarged spleen, it is crucial to avoid physical activities.