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About Epstein-Barr virus


What is Epstein-Barr virus?

The Epstein-Barr virus is the germ that causes “mono,” or mononucleosis (say “mah-no-new-klee-OH-sis”). You might hear mono called the “kissing disease.” This is because it often spreads through saliva (spit). Doctors and nurses sometimes call the Epstein-Barr virus “EBV.”

Most people get EBV when they are children. The virus lives inside them but does not make them sick. But cancer, cancer treatment, and other diseases can weaken the body’s infection-fighting system. This system is called the “immune system.” If your child has a weak immune system, EBV can cause serious illness.

What are the symptoms of EBV?

EBV often causes no symptoms in babies and young children. If your child takes an antibiotic called ampicillin, they might get a rash. This could mean EBV is present.

When EBV causes “mono”

The symptoms of “mono,” or mononucleosis, include:

  • Fever
  • Sore throat
  • Swollen glands – Mostly in the neck, and
  • Feeling extremely tired

Your child’s liver and spleen might be larger than normal. A doctor or nurse can check for this. A blood test can show signs of EBV infection in the blood.

When EBV causes serious illness

If your child is a St. Jude patient, their immune system is probably weaker than normal. So EBV infection can be very serious. It can cause severe and even life-threatening problems with the heart, lungs, brain, bone marrow, and blood. EBV can also cause cancer in some people.

How does EBV spread?

EBV spreads from one (1) person to another. It usually spreads through saliva (spit). A person who has “mono” can spread it by:

  • Kissing another person,
  • Sharing eating utensils, such as a spoon, fork, or plate,
  • Drinking out of the same glass, can, or bottle, or
  • Sharing someone’s toothbrush.

If your child has a weak immune system, they should not share eating or drinking items or toothbrushes. Ask your child’s doctor or nurse if your child has a weak immune system.

Should my child be tested for EBV?

Maybe. If your child has a weak immune system, the doctor can do a blood test for signs of EBV. These signs do not mean your child will get sick, but doctors will know EBV is present. Your child’s doctor might watch for signs that EBV will cause illness if your child has certain treatments, such as a stem cell transplant.

If your child with a healthy immune system could have mono, the doctor can examine them to find out. Your child might also have a blood test.

How do I keep EBV from spreading?

  • Wash your hands often. Read “Do you know … Clean hands.”
  • Wear gloves when you touch body fluids, such as urine, vomit, or saliva.
  • Do not give blood if you recently had mono.

Your child does not need to be isolated if a blood test shows EBV is present in their blood.

How do doctors treat EBV?

There is no specific treatment. Doctors treat people with EBV infection with:

  • Rest
  • Plenty of fluids, such as water, juice, Gatorade, and tea, and
  • Medicines to treat fever and discomfort, such as acetaminophen.

If your child develops a serious illness because of EBV infection, doctors will treat that illness. For example, if your child gets pneumonia or heart problems, doctors will treat them.


If you have questions about Epstein-Barr virus, mono, or your child’s immune system, talk to your child’s doctor or nurse.


This document is not intended to take the place of the care and attention of your personal physician or other professional medical services. Our aim is to promote active participation in your care and treatment by providing information and education. Questions about individual health concerns or specific treatment options should be discussed with your physician.

St. Jude complies with health care-related federal civil rights laws and does not discriminate on the basis of race, color, national origin, age, disability, or sex.

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