Mononucleosis

Mononucleosis is an infection caused by a herpes virus known as the Epstein-Barr virus, or EBV.

What is going on in the body?

Most people are exposed to EBV during childhood. Like other herpes viruses, it stays quiet in the body long after symptoms go away. It can be reactivated later in life. Often this happens when the immune system has been weakened by disease, cancer treatment, or an organ or bone marrow transplant.

What are the causes and risks of the infection?

Mononucleosis is caused by EVB. The virus may stay quiet in the body long after it is acquired. People with weakened immune systems are at risk for severe disease. This group includes individuals with cancer or immunodeficiency disorders.

EBV is spread primarily through saliva. It is nicknamed the kissing disease. Less commonly, it can be spread via blood transfusion. EBV lives in the person's mouth and throat for years after initial infection. Shedding of EBV by healthy individuals, through contact with salvia, accounts for most of the spread to uninfected people.

What are the signs and symptoms of the infection?

Young children exposed to EBV generally have no symptoms. At times, they may have vague symptoms, similar to many other childhood illnesses. When teens or young adults acquire EBV, though, mononucleosis can occur. Following are some of the common symptoms of mononucleosis:

EBV may cause enlargement of the liver or the spleen. If this occurs, the person may have abdominal pain or fullness.

How is the infection diagnosed?

Diagnosis of mononucleosis begins with a medical history and physical exam. An antibody titer test can detect antibodies produced by the body to fight EBV. Many people, though, have such antibodies without any symptoms.

What can be done to prevent the infection?

EBV is prevalent throughout the world. In the United States, 95% of the adults between 35 and 40 years of age have acquired EBV. The best way to prevent mononucleosis is to limit sharing of drinks, lipsticks, and other sources of saliva.

What are the long-term effects of the infection?

When a person has had mononucleosis, EBV may recur later in life. The EBV virus has been associated with Burkitt's lymphoma, an uncommon blood cancer. It has also been associated with nasopharyngeal cancer, a cancer that occurs in the back of the throat area. However, EBV is not the only cause of these cancers. It is extremely rare for people infected with EBV to ever develop either of these cancers. Other more common complications of EBV are as follows:

What are the risks to others?

EBV is spread through contact with the saliva of the infected person.

What are the treatments for the infection?

Otherwise healthy people are not treated for mononucleosis unless complications occur. Rest is important during the early stage of the infection. Strenuous exercise or contact sports should be avoided during this time to prevent rupture of the spleen. Oral corticosteroids, such as prednisone, are sometimes used to treat very large lymph nodes or tonsils. Antiviral agents like acyclovir may sometimes be used in complicated cases.

What are the side effects of the treatments?

Corticosteroids may cause bleeding, increased risk for infection, and bone thinning.

What happens after treatment for the infection?

Symptoms of mononucleosis can last for weeks but usually resolve. However, EBV is sometimes fatal in people with weakened immune systems.

How is the infection monitored?

Most cases resolve by themselves. Any new or worsening symptoms should be reported to the healthcare provider.

Author:Danielle Zerr, MD
Date Written:
Editor:Ballenberg, Sally, BS
Edit Date:07/31/01
Reviewer:Adam Brochert, MD
Date Reviewed:06/27/01