Mononucleosis

PDF of the Mononucleosis Fact Sheet

What is Mono (Mononucleosis)?

This page was reviewed or revised on Thursday, August 13, 2009.

Mono is a viral infection that causes tiredness, fever, sore throat, swollen glands and may cause the liver or spleen to become bigger than normal or abnormal liver and spleen function. Mono in children and young adults is usually mild and hard to identify. Signs usually vanish within a few weeks. Adults or those with weak immune systems may take months to regain their strength and energy level. Mono is detected by a blood test or by symptoms.

Because mono can cause the liver or spleen to become bigger than normal, you should not take part in contact sports until the doctors gives you the okay.

How is Mono Spread?

Mono is passed from one person to another through contact with nose and throat discharge, mainly saliva. Wet kissing assists the spread among young adults. Though rare, mono may also be spread by a blood transfusion. It takes about 4 to 6 weeks after contact for signs to appear. Once a person is infected, they can pass the infection to others for up to a year or longer. As many as 20% of those infected will not show symptoms but still have the virus in their saliva.

What Can I Do To Protect Myself?

Sorry to say, there is no cure for Mono. Time and getting as much rest as possible is the best treatment. Slowly increase normal activities when you feel able or allowed by your doctor. It is important that you take safety measures to avoid becoming infected or passing the infection on to others.

The best way to protect against Mono is to avoid contact with the saliva from another person.

This means: 

• Avoid wet kissing where there is an exchange of saliva
• No contact sports
• Do not share drinks out of the same glass, can or bottle.
• Do not share eating utensils
• Do not take bites from someone else's food
• Do not share cigarettes
• Wash hands before eating and after using the washroom
• Do not handle any articles that may be infected with nose and throat fluids. Dispose of tissues in the garbage and wash hands after use.