Picture of Infectious Mononucleosis
Infectious mononucleosis, or "mono" as it is commonly referred to, is a viral illness that causes extreme fatigue, fever, muscle aches, swollen lymph nodes, and sore throat. It is sometimes called “the kissing disease” because it spreads easily through saliva. The Epstein-Barr virus (EBV) causes most cases of mono, although other viruses may cause the illness. Severe cases of mono may cause inflammation of the liver or spleen. If the spleen is enlarged, it is important to avoid vigorous physical activity and contact sports to reduce the risk of spleen rupture.
The illness is usually less severe when it occurs in childhood. It tends to be more severe in teens and young adults. Mono typically lasts for 2 to 4 weeks. Some individuals suffer from it for many months. Most adults have EBV antibodies in their blood indicating prior infection. Stress or depressed immunity may cause EBV reactivation.
Text Reference: "Epstein-Barr Virus and Infectious Mononucleosis." Centers for Disease Control and Prevention.