INFECTIOUS MONONUCLEOSIS

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.

Infectious Mononucleosis: Words to Know

Herpes viruses:

A group of viruses that cause cold sores, chickenpox, shingles, and other diseases.

Reye's syndrome:

A very serious, rare disease, most common in children, believed to be caused by aspirin.

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 had organ transplants often have weakened immune systems. In such cases, serious complications may develop after a bout of mononucleosis.

CAUSES

The EBV that causes mononucleosis is related to the herpes viruses (see herpes infections entry). The herpes viruses are responsible for infectious diseases such as cold sores, chickenpox (see chickenpox entry), and shingles. Most people are exposed to EBV at some point in their lives. The virus is spread through contact with saliva from an infected person. It can be transferred by coughing, sneezing, kissing, or sharing of drinking glasses or eating utensils.

SYMPTOMS

The most prominent symptoms of mononucleosis are weakness and fatigue. Some other common symptoms include:

• Sore throat and/or swollen tonsils
• Fever and chills
• Nausea and vomiting
• Decreased appetite
• Swollen lymph nodes in the neck and armpits
• Headaches or joint pain
• Enlarged spleen
• Jaundice
• Skin rash

Serious complications of mononucleosis include an enlarged spleen or inflamed liver. In rare cases, the spleen may rupture (break open), producing sharp pains on the left side of the abdomen. This symptom calls for immediate medical attention. Other symptoms of a ruptured spleen include light-headedness, rapid heartbeat, and difficulty breathing. Other rare complications include damage to the heart, brain, or the body's red blood cells.

Symptoms usually do not appear until four to seven weeks after exposure to EBV. Even though symptoms have not appeared, an infected person is still contagious. That is, he or she can pass the disease on to another person. An infected person remains contagious for up to five months after symptoms have disappeared.

EBV is actually not very contagious. People can live in close contact with an infected person without catching the disease as long as they do not have direct contact with that person's saliva.

DIAGNOSIS

The symptoms of mononucleosis are similar to those of other diseases. If mononucleosis is suspected, a doctor may conduct a complete physical examination. The examination will usually include a test known as the "Monospot" antibody blood test. This test can pick out chemicals in a person's blood that the body has produced to fight off mononucleosis. Other blood tests are also available to confirm a diagnosis of mononucleosis.

TREATMENT

The most effective treatment for mononucleosis is rest because a person's body needs time to fight off the infection. Individuals with mild cases may not require bed rest, but they should restrict their physical activity. In any case, vigorous physical activity, such as athletics or heavy lifting, should be avoided. Such activities can cause the spleen to rupture, making the condition much more serious.

Treatments are available for the symptoms of mononucleosis. For example, drinking water and fruit juices can help relieve the sore throat and dehydration that often accompany mononucleosis. Gargling with salt water or taking throat lozenges may also relieve discomfort. Over-the-counter medications, such as acetaminophen (pronounced uh-see-tuh-MIN-uh-fuhn, trade name Tylenol) or ibuprofen (pronounced i-byoo-PRO-fuhn, trade name Advil), may relieve symptoms such as fever and headache. Aspirin should not be given to children because it may cause Reye's syndrome (see Reye's syndrome entry), a serious illness.

Antibiotics are not effective in curing mononucleosis. However, they may be helpful in treating some symptoms of the disease. For example, they may help relieve the discomfort of the sore throat that often occurs with mononucleosis. Cortisone can also be used to reduce swelling and inflammation in the throat and tonsils.

PROGNOSIS

Most people recover from mononucleosis in about two to three weeks. They are then able to resume their normal activities, especially if they rested during their illness. A patient may not feel completely recovered, however, for a period of up to three months after being cured.

One of the most common problems in treating mononucleosis is that people are eager to return to their usual activities too quickly. When that happens, the disease may return. Once the disease has completely run its course, a person cannot be reinfected.

PREVENTION

There is no guaranteed way to avoid becoming infected with EBV. However, some simple rules of good hygiene can reduce a person's chance of catching the disease. For example, one should avoid sharing utensils and drinking glasses with someone who has cold symptoms.

FOR MORE INFORMATION

Books

Silverstein, Alvin, Virginia Silverstein, and Robert Silverstein. Mononucleosis. Hillside, NJ: Enslow Publishers, 1994.

Smart, Paul. Everything You Need to Know About Mononucleosis. New York: Rosen Publishing Group, 1998.

Zonderman, Jon. Mononucleosis and Other Infectious Diseases. New York: Chelsea House Publishers, 1989.

Organizations

National Institute of Allergy and Infectious Diseases. Building 31, Room 7A-50, 31 Center Drive, MSC 2520, Bethesda, MD 20892–2520. http://www.niaid.nih.gov.