Infectious diseases


Infectious diseases
portrait of José Antonio Zumalacárregui Ph.D.
Written by

José Antonio Zumalacárregui Ph.D.
Medically reviewed by our Medical staff

Last update: 13-10-2021

How else can it be called?

  • Mono

  • Kissing disease

  • Glandular fever

  • ICD-10: B27

What is mononucleosis?

Mononucleosis is an acute viral infection caused by the Epstein-Barr virus. The disease has a typical clinical triad of fever, pharyngitis, and lymphadenopathy (swollen lymph nodes).

Mononucleosis is a benign contagious disease with a good prognosis. Nevertheless, fatigue, one of the main symptoms, may last for months.

What is the cause of mononucleosis?

Mononucleosis is a viral disease commonly caused by the Epstein-Barr virus (EBV). EBV, also called herpesvirus 4, is a member of the herpesvirus family.

Sometimes, it may be caused by Cytomegalovirus and other types of virus, but it is not common.

How is it transmitted?

The virus usually spreads through saliva, which is why it is known as the "kissing disease". It is transmitted through virus-infected saliva by coughing, sneezing, kissing as well as sharing cups, drinking glasses or eating utensils.

It usually appears as an outbreak that simultaneously affects numerous people, but it may also appear in isolated cases.

Contrary to popular belief, it is not a very contagious disease.

It mainly affects children, adolescents, and young adults between 15 and 35 years old. The disease affects both genders equally.

It is estimated that 90% of adults have had contact with the virus to a greater or lesser extent. The typical age of infection is between puberty and adolescence, although younger children can be also affected.

What are the main symptoms of mononucleosis?

The incubation period of the disease is between 4 and 7 weeks. After this period, the first symptoms appear.

People with mononucleosis generally have the following symptoms:

  • Fatigue.
  • Asthenia (weakness).
  • Fever.
  • Pharyngitis or sore throat.
  • Loss of appetite.
  • Muscle pain.
  • Painful swallowing.
  • Adenopathies (swollen lymph nodes) mainly in the neck and armpits.
  • Splenomegaly (enlarged spleen), seen in 50% of cases.

Initially, symptoms are associated with the inflammation of the lymph nodes and the possible enlargement of the spleen, such as fever, headache and sore throat.

Later, other symptoms may appear such as:

  • Nausea
  • Jaundice (yellowing of the skin)
  • Watery eyes
  • Shortness of breath
  • Palpitations
  • Occasionally skin rash, especially if the disease is treated with penicillin (although the rash may not always be related to penicillin allergy).

How can it be detected?

A blood test may be performed to check for the presence of the virus in the blood (serology). Additionally, a pharyngeal smear may also be performed to rule out streptococcal pharyngitis (which is often associated with mono).

The definitive diagnosis is made by the detection of antibodies in the serology test. If there is presence of anti-VCA IgM, the disease is considered to be in the acute phase; after the acute infection, there will be anti-VCA IgG antibodies.

There are also some rapid test available, such as the monospot test or Paul-Bunnell test, for a quick screening. Rapid test sensitivity (how well a test can identify true positives) is in the range of 70 to 90%.

What is the recommended treatment?

Because no medicine can cure the Epstein-Barr virus the recommended treatment is palliative. Palliative care includes rest for a few weeks, proper hydration and antipyretics.

General recommendations are:

  • Bed rest at the beginning of the disease. Later on, rest at home is recommended for at least 2 or 3 weeks.
  • Increase fluid intake (drinking water and fruit juices) to prevent dehydration.
  • For the fever, it is recommended to take ibuprofen or acetaminophen, and gargling with salt water is helpful for the sore throat. It is not recommended to administer Aspirin®, especially in children, to avoid Reye's syndrome, a serious illness aggravated by aspirin.
  • When there is strep throat associated, an antibiotic is prescribed.

If severe acute pain appears in the upper left quadrant of the abdomen, the patient should look for immediate medical care due to a possible ruptured spleen. If this possibility is confirmed, the patient must undergo immediate surgery to remove the spleen.

What is the prognosis of the disease?

Mononucleosis is a benign disease. Only in very rare cases is it associated with heart or brain complications (less than 1% of cases).

High fever may be present. Fever usually peak in the afternoon or evening, with temperatures close to 39.5 ° C (103 º Fahrenheit).

Most people get better within 2 to 4 weeks. Fatigue is usually present during the first 2 or 3 weeks. When fever and fatigue (the so-called typhoid form of the disease) predominate, the evolution will be slower.

The general symptoms of infectious mononucleosis, such as tiredness, headache, fatigue, loss of appetite, etc., can last from 2 to 3 months, especially in older people. This is common and it is not a sign of future complications.

Medically reviewed by our Medical staff on 13-10-2021


  • Principles and Practice of Clinical Virology. 5th edition. Arie J. Zuckerman, Jangu E. Banatvala, John R. Pattison, Paul D. Griffiths, Barry D. Schoub. 2004. ISBN 0-470-84338-1. Pag 130.
  • Diagnostic pathology of Infectious Disease. 2nd edition. Richard L. Kradin. 2018. ISBN: 978-0-323-44585-6. Pag 323.
  • Epstein Barr Virus. Methods and Protocols. Janos Minarovits, Hans Helmut Niller. 2017. ISBN 978-1-4939-6653-0.

Show more

Rating Overview

Share your thoughts about this content

E-mail (Optional):
Add a review