Infectious mononucleosis is caused by the Epstein-Barr virus, and is spread by close personal contact. Since kissing allows the virus to pass from one person to another, the illness has been nicknamed "the kissing disease." However, most younger children contract the disease by putting their hands, contaminated with the virus from other children, into their mouths, or by playing with a toy, previously touched by another child with mono.

The incubation period (the time between exposure to the virus and the outbreak of symptoms) is 1-2 months, averaging six weeks. The symptoms unfold slowly and the illness may takes days to even weeks to develop, making the diagnosis difficult. After feeling "out of sorts" for a few days, the child with mono might experience headaches, fever, muscle aches, abdominal pain and tonsillitis, with the characteristic extreme fatigue coming not far behind. The lymph glands in the neck and armpits swell and become tender, and loss of appetite usually develops. In about 50% of children with mono, the spleen-an internal abdominal organ located below the left diaphragm, becomes enlarged, causing soreness in the upper abdomen.The virus can also affect the liver, producing a mild case of hepatitis and yellow jaundice.

Because these same symptoms occur in many other diseases, the diagnosis can be tricky. Mono is frequently confused with strep throat, the "flu", hepatitis, and even German measles. The illness is confirmed by having the typical symptoms and a positive blood test showing antibodies against the Epstein-Barr virus. These studies may have to be repeated, because the test frequently is frequently negative in its early stages of the illness and only converts to being positive later. In addition, a blood count shows a large number of unusually shaped white blood cells with one nucleus (mononuclear), thus the term mononucleosis.

Unfortunately, there is no treatment for mononucleosis. Antibiotics, used to treat bacterial infections, have no effect on this viral disorder. The illness takes about one to four weeks to run its course, though fatigue may persist for two months or more in some children. Severe complications from infectious mononucleosis are fortunately rare. The sore throat can be intense at times and many children have trouble eating and drinking. To help soothe the throat, children should drink plenty of cold liquids and use throat spray. Since swollen tonsils can make foods hard to swallow, a soft diet is best for a while. Acetaminophen may also help ease the throat pain and any headache. While antibiotics have no effect on infectious mononucleosis, they are sometimes used to treat secondary bacterial infections that can develop with the mononucleosis. Hospitalization is rarely necessary unless the child is having trouble breathing or is unable to take adequate amounts of fluids and becomes dehydrated.

Bed rest is usually not required and forcing the child to stay in bed does not speed recovery. Most children are so tired that they voluntarily reduce their activity to a level they are comfortable with, taking it easy for as long as the weakness and tiredness persist. However, contact sports and other strenuous activities should be avoided for at least six to eight weeks or until the spleen returns to normal size.

Despite its reputation, infectious mononucleosis is not highly contagious, and there is no need to isolate the affected child or adolescent. Family members and roommates do not readily contract the illness , but that’s because they are already immune. Children with mono can have visitors and eat with the family, but separation of drinking and eating utensils ( for example, avoid drinking from the same glass) is usually all that is necessary. Common sense would indicate people with infectious mononucleosis should avoid kissing until recovery is complete. A child with infectious mononucleosis is most contagious when they have the upper respiratory symptoms (during the first 7-10 days) , but it is not known for sure exactly how long they can spread the virus. Once a child or adult has been infected they become immune to further infections from the Epstein-Barr virus. While no vaccine is available to prevent mono, researchers are optimistic that one can soon be developed.

Most parents equate infectious mononucleosis with the prolonged illness seen primarily in adolescents and college students. What they do not realize is that the Epstein-Barr virus is commonly acquired at an early age in nursery schools, day care centers, or from friends and relatives. Therefore, one of their children’s many past colds could have been infectious mononucleosis, and they are probably already immune to the "kissing disease."

see also:

Infectious Mononucleosis: Information for Parents

Infectious Mononucleosis: Information for Teenagers

As a reminder, this information should not be relied on as medical advice and is not intended to replace the advice of your child’s pediatrician. Please read our full disclaimer.