Infectious mononucleosis, often called mono, is a viral infection that is most common in teens and young adults.
Mono is spread by close contact, such as kissing, with infected people
Symptoms include a very sore throat, extreme tiredness, and swollen lymph nodes in your neck
People with mono usually feel better after about 2 weeks, but some people may feel very tired for weeks or even months
Acetaminophen or ibuprofen lowers fever and lessens pain
Mono is caused by the Epstein-Barr virus, a type of herpesvirus. Infection with Epstein-Barr virus (EBV) is common, but not everyone who gets it gets mono. Many people with EBV infection have no symptoms or very mild symptoms.
Symptoms of mono include:
Extreme tiredness—this is usually most severe during the first 2 to 3 weeks
Fever, up to about 103° F (39.4° C)
Very sore throat—there may be pus at the back of your throat
Swollen lymph nodes, especially in your neck (lymph nodes are tiny, bean-shaped parts of your immune system that help fight off infections)
You can have mono without having all of these symptoms.
About half of people with mono have a swollen spleen. Your spleen is an organ in the left side of your belly just below your ribcage. It's about the size of a fist. The spleen makes blood cells that help your immune system and also gets rid of blood cells that are old or abnormal. A spleen is more likely to burst if your belly is injured while your spleen is swollen.
If mono is very severe, it can cause low blood count and problems with your liver, heart, and nerves.
There are no medicines to cure mono. Antiviral drugs don't help. Doctors will:
After 2 weeks, as you start to feel better, you can be more active—just don’t lift anything heavy or play contact sports (like football) until your doctor tells you that your spleen is back to its normal size.