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What is infectious mononucleosis (Mono)?

Mono, sometimes called glandular fever or "the kissing disease" is usually caused by the Epstein-Barr virus (EBV), a member of the herpes virus family. Infection with this virus causes a sudden increase in mononuclear leukocytes.

It is common among teenagers and young adults, especially college students. At least one out of four teenagers and young adults who get infected with EBV will develop infectious mononucleosis.


It can take 4-6 weeks for symptoms of mono to appear after you have been infected. These symptoms may develop slowly and may include:

  • Extreme fatigue
  • Fever
  • Sore throat
  • Head and body aches
  • Swollen lymph nodes in the neck and armpits
  • Swollen liver or spleen (or both)
  • Rash

Most people get better in two to four weeks; however, some people may feel fatigued for several more weeks. Occasionally, the symptoms of infectious mononucleosis can last for six months or longer.

How is Mono Spread?

Mono is usually caused by the Epstein-Barr Virus (EBV), which is spread in body fluids. Saliva is the main mode of spreading Mono, which is why it is nicknamed the "kissing disease." Eating with the same utensils and drinking out of the same glass as someone who is infected may also spread the virus.


  • Do not kiss or share cups, utensils, toothbrushes, etc. with someone who is infected with mono
  • Frequent handwashing with soap and water


  • Healthcare providers may be able to diagnose mono based on your symptoms and physical exam alone
  • There are rapid mono tests that can be performed at an appointment, but they may be falsely negative if your symptoms have just started
  • The blood work of patients who have infectious mononucleosis due to EBV infection may show:
    • more white blood cells (lymphocytes) than normal
    • unusual looking white blood cells (atypical lymphocytes)
    • fewer than normal neutrophils or platelets
    • abnormal liver function

Mono and Sports

Mono can cause an enlarged liver and/or spleen. Someone who is hit in the stomach with an enlarged spleen has a much higher risk of the spleen rupturing and causing severe internal bleeding. Due to this, people who have mono and also play contact sports (e.g. football) will need to refrain from participating for 2-6 weeks, depending on what sport they play.


Mono is a viral illness, and so there is no medication that can cure it. Antibiotics will not help a person with mono. People with mono should rest as much as possible and drink fluids (especially water). Many symptoms are similar to the common cold and can be treated as such with over-the-counter medications.