Definition

Infectious mononucleosis (pronounced MON-o-NOO-klee-O-siss) is a contagious (catching) illness caused by the Epstein-Barr virus (EBV). The virus most commonly infects the liver, lymph nodes, and mouth. Mononucleosis is usually not a serious disease. However, its major symptoms—fatigue and lack of energy—can linger for several months. Infectious mononucleosis is also known as "mono" or "the kissing disease."

Description

Anyone can have infectious mononucleosis. However, the disease is most common in young adults between the ages of fifteen and thirty-five. It is especially common among teenagers. The rate of mononucleosis among college students has been estimated at 15 percent. The disease is often not recognized when it occurs in young children.

In people who are otherwise healthy, mononucleosis usually lasts about four to six weeks. In people with weakened immune systems, the disease may last much longer. AIDS patients (see AIDS entry) and people who have...