Note: This message is displayed if (1) your browser is not standards-compliant or (2) you have you disabled CSS. Read our Policies for more information.
Mononucleosis (or mono) is an infection caused by the Epstein-Barr virus (EBV). Most children are exposed to EBV, which is a common virus. Infants and young children who are infected usually have very mild or no symptoms at all. Teenagers and young adults who become infected are more likely develop a full-blown, classic case of mononucleosis.
Mononucleosis is spread by direct contact with the saliva of an infected person. It can be spread by kissing, coughing or sneezing, or any contact with the saliva of someone infected with EBV. People with infectious mononucleosis may be able to spread infection to others for weeks. It is not normally spread through the air or through blood exposure.
Adolescents and young adults are at higher risk for classic or full-blown mononucleosis than children and older adults. Persons who have contact with the saliva of an infected person are at risk for developing mono if they have not been previously exposed and infected.
Typical symptoms of mononucleosis are:
Other symptoms may include headache, sore muscles, abdominal pain, skin rash, loss of appetite, and night sweats. Persons with mononucleosis are usually very tired and weak for several weeks, and may have an enlarged liver or spleen.
There is no specific treatment for infectious mononucleosis, other than treating the symptoms. Some practical ways to help with symptoms include:
Symptoms usually go away in 2-4 weeks, but an enlarged spleen and lymph nodes can last longer. Doctors usually recommend that persons with mono avoid sports activities for at least one month because an enlarged spleen can easily rupture.
There are very few prevention measures that can be used to stop the spread of mononucleosis. If you are infected, you can help reduce the spread of EBV to others by not kissing them or sharing food or drinking and eating utensils for several days after the fever has gone (and longer if possible). Good hygiene and frequent hand-washing are important factors in preventing the spread of most infectious diseases. Currently, there is no vaccine available to prevent mononucleosis.
All information presented is intended for public use. For more information, please refer to the CDC Web site at:
or the Mayo Clinic Website at:
This page was last reviewed September 22, 2008