Mononucleosis (Mono) Prevention, Diagnosis

The virus that causes mono (Epstein-Barr virus) is not spread as easily as most people think. If you follow these tips, you can reduce the chance of spreading or catching mono.

Mononucleosis is caused by the Epstein-Barr virus, a member of the herpes virus family. The disease develops if the virus is encountered for the first time at an age when the response of the body’s immune system is most vigorous (that is, during adolescence and early adult life). The peak incidence of the illness occurs around the ages of 15 and 17.

Mononucleosis spreads by contact with moisture from the mouth and throat of a person who is infected with the virus.

Complications are rare and hospitalization is seldom required when they do occur. The most common complication is dehydration from not drinking enough fluids. Breathing may be obstructed by enlarged tonsils, adenoids and other lymph tissue in the back of the throat. On rare occasions, the enlarged spleen will rupture if the abdomen is hit or strained.

Additionally, the person may develop hepatitis (inflammation of the liver), pericarditis (inflammation of the sac surrounding the heart), myocarditis (inflammation of the heart muscle), encephalitis (inflammation of the brain) or hemolytic anemia (destruction of the red blood cells).


The diagnosis is often obvious from the symptoms and examination of a blood smear, which shows many atypical lymphocytes (white blood cells).There are two general types of blood tests for mono.

The first is called a monospot test (or a spot test). Monospot relies on clumping of horse red blood cells by mononucleosis antibodies presumed to be in a person’s serum. The other test is called the heterophil antibodies test. This test looks for antibodies (proteins produced by the immune system to counter the virus) that possess the unique ability to cause clumping of red cells taken from sheep’s blood.

A physical examination sometimes reveals an enlarged liver and/or enlarged spleen, or the liver and spleen may simply be tender when gently pressed.

Defensive Measures:

There is no vaccine for Epstien-Barr Virus. There are steps to prevent mono:

  • Wash hands frequently.
  • Avoid close contact with those who have mono.
  • Do not let your child share cups, bowls, glasses, or utensils with someone who is infected.
  • Never allow your child to share a toothbrush.
  • Use disposable paper cups and paper towels in the bathroom.
  • Do not share toys, teething rings, or similar items.
  • Frequently wash and sterilize pacifiers and bottles.
  • Disinfect shared surfaces, such as tabletops, kitchen counters, and play equipment.
  • Make it clear, especially to teenagers, that kissing a person infected with mono is off-limits.