Infectious Diseases A to Z – Infectious Mononucleosis (mono)

With this new column, Elite Healthcare will compile an index of various infectious diseases, with occasional highlights of emerging conditions.

Infectious mononucleosis (mono)

General definition and information:

Frequently referred to as “mono,” infectious mononucleosis is a contagious disease that is most commonly caused by the Epstein-Barr virus (EBV; human herpesvirus 4), a member of the herpes virus family that typically spreads through bodily fluids. Also caused by other viruses, including HIV and hepatitis, mononucleosis is common among teenagers and young adults, especially college students, and most people will become infected with EBV at some point in their lives, according to the Centers for Disease Control and Prevention (CDC), which reports that at least one in four teenagers and young adults who become infected with EBV will develop infectious mononucleosis.

Also known medically as glandular fever and socially as the “kissing disease,” mononucleosis is characterized by swollen lymph glands, fever, sore throat, and extreme fatigue. Other symptoms include fever, headache, body aches and rash, the condition can be more serious in older adults and can also cause an enlarged spleen and/or swollen liver, though these are not considered to be common, according to the CDC. Complications of mono may also include kidney inflammation, hemolytic anemia, inflammation of the heart muscle, heart rhythm problems, and obstruction of the upper airways. Additionally, EBV infection itself can affect the brain, spinal cord, and nerves, and can cause conditions such as viral meningitis, encephalitis, swelling of the eye nerve, facial and body paralysis, Guillain-Barré syndrome, and sleep disorders. Laboratory tests are not typically needed for diagnosis but may be needed to identify the cause of illness in people who do not have a typical case of infectious mononucleosis, according to the CDC. Diagnosis may be challenging, due to symptoms that are similar among other conditions.1 Most people who become infected with mono will only have it once, although it can reactivate and people with weakened immune systems are more likely to develop symptoms if the EBV does reactivate. EBV infection can also affect a person’s blood and bone marrow and can cause the body to produce an excessive number of white blood cells. EBV can weaken the immune system and impact the body’s ability to fight infection, according to the CDC. Examples of conditions that patients may be more susceptible to include neutropenia, hemophagocytic syndrome, acquired hypogammaglobulinemia, X-linked lymphoproliferative disease, pneumonia, interstitial lung disease, pancreatitis, myocarditis, oral cavity-oral hairy leukoplakia, and cancers, according to the CDC.

Causes & Modes of Transmission:

Often spread through contact with infected saliva, hence the “kissing disease” reference, the infection can also be spread through exposure to blood and semen during sexual contact, blood transfusions, and organ transplantations. Most people who get sick will improve in 2-4 weeks, however, some people may feel fatigued for several more weeks, according to the CDC. Symptoms can also last for more than six months. The incubation period is 4-8 weeks.

Treatment Strategies:

Symptom relief can be managed by encouraging patients to drink plenty of fluids, eat a healthy diet, get plenty of rest, and follow instructions for over-the-counter medications used to treat pain and fever. Gargling with salt water several times per day can also be suggested to reduce pain related to sore throat (one-half teaspoon of salt in 8 oz of warm water). Health officials remind providers that patients who are infected with mononucleosis should not be prescribed penicillin antibiotics such as ampicillin or amoxicillin unless an additional infection such as strep throat accompanies the condition.2 Use of a penicillin antibiotic when mono is present may result in a rash (that does not necessarily signal an allergy).2 Based on symptom severity, healthcare providers may recommend treatment of specific organ systems affected by infectious mononucleosis, according to the CDC. Healthcare providers are also warned that patients who have been diagnosed with mono should be instructed to avoid contact sports until they have fully recovered due to the potential of spleen enlargement with the condition and potential subsequent rupture.

In cases where the condition lingers for many months, emotional support may assist in the recovery process. School students may require special considerations to keep up with their work in light of missed classes and other activities.2 Although it is not suggested that patients infected with mono be quarantined,2 because many people will already be immune to EBV after being exposed to the virus as children, patients should still be told that the expectation will be for them to stay at home until they are recovered.

Prevention Parameters:

There is no vaccine that protects against infectious mononucleosis. Avoiding kissing and the sharing of drinks, food, and toothbrushes or other personal items with someone who has been infected with mono can also reduce the risk of exposure and transmission.


  1. Hurt C, Tammaro D. Diagnostic Evaluation of mononucleosis-like illnesses. Am J Med. 2007;120(10):911.e1-e8.
  2. Mononucleosis. Mayo Clinic. 2018. Accessed online:

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