Acute acquired cytomegalovirus infection

Alternative names
CMV Mononucleosis; Infectious mononucleosis (CMV); Cytomegalovirus (CMV)

Infectious mononucleosis is an acute viral infection that can cause high fever, sore throat, and swollen lymph glands, especially in the neck. Unlike the more common form of mononucleosis, caused by the Epstein-Barr virus, this type is caused by cytomegalovirus (CMV).

Causes, incidence, and risk factors

Infectious mononucleosis can be caused by several different viruses and a few types of bacteria. Less commonly, it is caused by parasites.

The most commmon causes are the Epstein-Barr virus (EBV) and cytomegalovirus (CMV), both members of the herpesvirus family. The symptoms of infection, including sore throat, occur less commonly with CMV than with EBV.

The infection is transmitted by saliva, sexual contact, respiratory droplets, and blood transfusions. While the peak incidence occurs in 15- to 17-year-olds, the infection may occur at any age, most often between the ages of 10 and 35.

Abnormal or atypical lymphocytes (white blood cells) are seen in the peripheral blood, and may persist for 2 to 8 weeks. Abnormalities of liver function are also characteristic. Risk factors other than age are not known. The vast majority of people are exposed to CMV early in life and do not realize it because they have no symptoms.


  • Fever  
  • Sore throat  
  • Enlarged lymph nodes, especially in the neck  
  • Malaise (vague ill feeling)  
  • Frequent tiredness or fatigue  
  • Loss of appetite  
  • Muscular aches or stiffness

Less common symptoms include:

  • Jaundice (yellow cast to skin)  
  • Headache  
  • Neck stiffness  
  • Sensitivity to light  
  • Cough  
  • Shortness of breath  
  • Chest pain  
  • Rapid heart rate  
  • Irregular heart rate  
  • Hives

Signs and tests
A physical examination reveals an enlarged liver or an enlarged spleen. The liver and spleen may be tender when they are gently pressed (palpated). There may be a skin rash.

  • A CMV ELISA antibody test may be positive and should increase in the few weeks after the disease ends.  
  • A monospot test may be negative in CMV mononucleosis.  
  • A CBC shows decreased platelet count and atypical lymphocytes.  
  • A chemistry panel shows abnormal liver enzyme results.

Most patients recover within 4 to 6 weeks without medication. There is no specific treatment available. Antiviral medications do not help. Rest is needed, sometimes for a month or longer to regain full activity levels. Relief of symptoms is provided with analgesics, and warm salt water gargles for sore throat.

Expectations (prognosis)
Fever usually resolves in 10 days, and swollen lymph glands and spleen return to normal in 4 weeks. Fatigue may linger for 2 to 3 months.


  • Secondary throat infection  
  • Rupture of spleen (rare)  
  • Neurologic complications (rare)

Calling your health care provider
Call for an appointment with your health care provider if symptoms indicate mononucleosis.

Go to the emergency room or call the local emergency number (such as 911) if sharp, sudden pain in left upper abdomen occurs. This could indicate a ruptured spleen, which requires emergency surgery.


Infectious mononucleosis can be contagious if the infected person comes in close or intimate contact with another person. Because the infection is probably spread by saliva or sexual contact, kissing and sexual contact with an infected person should be avoided.

However, the vast majority of people are exposed to CMV early in life without suffering any symptoms, so it is very difficult to control infection and spread of CMV.

Johns Hopkins patient information

Last revised:

Diseases and Conditions Center

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All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.