What is mononucleosis?

Infectious mononucleosis or "mono" is an illness caused by the Epstein-Barr virus (EBV). Symptoms of mono include persistent fatigue, sore throat, swollen lymph nodes, fever, and decreased appetite. Most people become infected with EBV at some point during their lives; the majority have developed immunity by age 35.

How do you get it?

Once infected the virus remains in the body for life and is intermittently shed in saliva of otherwise healthy people. Only about 5% of people who become ill have had recent contact with someone with the disease. The EBV is unstable and requires direct contact with someone's contaminated saliva. Usually it is transmitted through kissing or sharing drinks. The time between infection and development of mono symptoms is 30-50 days.

How will I feel?

The usual presentation is persistent fatigue for several days followed by fever, sore throat and swollen lymph nodes. The throat symptoms can be severe and resemble strep throat. Mononucleosis can affect any part of the lymph system which includes the liver and spleen. Abdominal pain, nausea and vomiting, and jaundice are less common symptoms.

How is it diagnosed?

People that have symptoms of mono and are ill enough to seek medical care often have their blood tested to confirm the diagnosis. Laboratory findings include alterations in the type and appearance of white blood cells, and in the 2nd-3rd week specific antibodies for mono can be detected (the mono-spot test).

What can be done for it?

There is no specific therapy for this viral disease and treatment is mainly supportive with bedrest, fluids and pain relievers. Sometimes narcotic pain relievers are needed or steroids to control tonsillar swelling. Enlargement of the spleen occurs in about 50% of cases and peaks during the 2nd to 3rd week. This is a concern for people with active lifestyles. Contact sports, strenuous exercise and heavy lifting should be avoided for about 2 months after onset of the illness.

How long will I be sick?

The duration and severity of the illness is variable, but in 50% of cases people return to school and work within two weeks. Full resolution of the fatigue may take several more weeks.