What is mononucleosis?

Mononucleosis, or mono, is a contagious viral infection caused by the Epstein-Barr virus (EBV) that is frequently referred to as kissing disease or glandular fever.

There are more than 3 million cases of mono diagnosed in the United States each year.

Common related conditions
Strep Throat Common Cold (Upper Respiratory Infection) Tonsillitis

Causes of mono

Mono is most often caused by the Epstein-Barr Virus (EBV), which lives in the salivary glands. Though it is mostly dormant, it can be activated in some people and become contagious, spreading through saliva or mucus from:

  • Coughing or sneezing
  • Sharing food, drinks or utensils
  • Kissing

Risk factors for mono

Risk factors for mono include:

  • Age — those who are 15-25 are at higher risk for mono, especially if they are in close contact with large numbers of people, such as on a high school or college campus.
  • Weakened immune system — people who can’t fight infection may be more likely to get mono or develop more severe symptoms.

Symptoms of mono

Symptoms of mono typically don’t show until 4-6 weeks after infection.

Mono typically starts with a sudden burst of symptoms including:

  • Fatigue
  • Fever
  • Swollen lymph nodes in the neck or armpit
  • Sore throat
  • Headache or muscle aches
  • Swollen tonsils

Initial symptoms are followed by a prolonged period of post-viral fatigue.

Diagnosis of mono

Mononucleosis is diagnosed in a physical exam by a primary care provider who will ask you about symptoms and possible exposure to the disease.

The following tests may be ordered to confirm a mono diagnosis:

  • Complete blood count (CBC) — identifies possible changes in blood cell count, often used to rule out other illnesses
  • Mononucleosis spot test (Monospot) — checks for the presence of EBV antigens in the blood

Treatments for mono

Most cases of mono will clear without treatment. Antibiotics are not effective on viral infections so the goal of treatment is symptom relief.

Mono symptoms can be treated with:

  • Pain reliever such as acetaminophen or ibuprofen
  • Hydration — including clear, warm fluids to soothe the throat
  • Rest — avoid intense physical activity

Recovery from mononucleosis

Most people recover from mono in two to six weeks. After symptoms are gone, you may still carry contagious antigens and spread mono for many months following the infection.

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