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Cytomegalovirus (CMV) Infection


Kenneth M. Kaye

, MD, Harvard Medical School

Reviewed/Revised Sep 2021 | Modified Sep 2022
Topic Resources

Cytomegalovirus infection is a common herpesvirus infection with a wide range of symptoms: from no symptoms to fever and fatigue (resembling infectious mononucleosis) to severe symptoms involving the eyes, brain, or other internal organs.

CMV may cause symptoms soon after infection. Also, it remains dormant (inactive) in various tissues for life. Various stimuli can reactivate the dormant CMV, resulting in virus growth which can sometimes cause disease. The lungs, gastrointestinal tract, brain, spinal cord, or eyes may be infected.

Transmission of CMV

Infected people may shed cytomegalovirus in their urine or saliva intermittently. The virus is also excreted in mucus in the cervix (the lower part of the uterus), semen, stool, and breast milk. Thus, the virus is spread through sexual and nonsexual contact.

If a pregnant woman is infected, the fetus may acquire the infection during the pregnancy, or the baby may acquire the infection during delivery.

CMV infection may develop in people who receive a transfusion of infected blood or an infected organ transplant. People who have received an organ transplant Overview of Transplantation Transplantation is the removal of living, functioning cells, tissues, or organs from the body and then their transfer back into the same body or into a different body. The most common type of... read more are particularly susceptible to CMV infection because they are given drugs that suppress the immune system (immunosuppressants Suppression of the Immune System ) to prevent rejection of the transplant.

Symptoms of CMV Infection

Most people infected with cytomegalovirus have no symptoms.

A few infected people feel ill and have a fever.

Infection with CMV, like that with Epstein-Barr virus (EBV, a type 4 herpesvirus), can cause a type of infectious mononucleosis Infectious Mononucleosis Epstein-Barr virus causes a number of diseases, including infectious mononucleosis. The virus is spread through kissing. Symptoms vary, but the most common are extreme fatigue, fever, sore throat... read more Infectious Mononucleosis in adolescents and young adults. Both CMV and EBV mononucleosis cause fever and fatigue. But EBV also causes a severe sore throat. CMV does not.

An uninfected person who receives a transfusion of blood containing CMV and becomes infected can have a fever, and sometimes liver inflammation develops 2 to 4 weeks later.

If a pregnant woman transmits CMV to the fetus, the following may result:

In newborns, CMV infection may cause extensive damage to the liver or brain. Newborns who survive may have hearing loss and intellectual disability.

Diagnosis of CMV Infection

  • In newborns, urine culture

  • Blood tests

  • In people with a weakened immune system, often biopsy

Cytomegalovirus infection may not be recognized immediately. Diagnosis of CMV infection is often unnecessary in healthy adults and children because treatment is unnecessary. However, doctors consider the possibility of CMV infection in the following people:

Once CMV infection is suspected, a doctor conducts tests to detect the virus in body fluids or tissues.

In newborns, the diagnosis is usually made by sending a sample of urine to a laboratory to grow (culture) and identify the virus.

Blood tests that detect antibodies to CMV can confirm a new infection. (Antibodies Antibodies One of the body's lines of defense ( immune system) involves white blood cells (leukocytes) that travel through the bloodstream and into tissues, searching for and attacking microorganisms and... read more Antibodies are produced by the immune system to help defend the body against a particular attacker, such as CMV.) But these tests cannot confirm whether disease is present. For instance, disease can be caused by reactivation of the virus, as in people with a weakened immune system. In these people, a biopsy of affected tissues is often necessary to confirm CMV disease.

Blood tests to estimate how many viruses are present may also be done.

Treatment of CMV Infection

  • For CMV retinitis, antiviral drugs

  • For people with HIV/AIDS, drugs used to treat HIV infections

Mild cytomegalovirus infection is usually not treated. It subsides on its own.

When the infection threatens life or eyesight, an antiviral drug Antiviral drugs A virus is composed of nucleic acid, either DNA or RNA, surrounded by a protein coat. It requires a living cell in which to multiply. A viral infection can lead to a spectrum of symptoms from... read more (valganciclovir, ganciclovir, cidofovir, foscarnet, or a combination) may be given. These drugs may be given by mouth or by vein. When CMV retinitis is very severe, the drugs may also be injected directly into the eye. These drugs have serious side effects (see table Some Antiviral Drugs for Herpesvirus Infections Some Antiviral Drugs for Herpesvirus Infections Some Antiviral Drugs for Herpesvirus Infections ) and do not cure the infection. However, treatment slows the disease's progression and may preserve sight.

Antiviral drugs are used to treat other severe symptoms due to CMV but are less reliably effective than when used to treat retinitis.

If CMV infection occurs in people whose immune system is temporarily weakened or suppressed (by a disorder or drug), the infection usually subsides when the immune system recovers or the drug is stopped.

Drugs Mentioned In This Article

Generic Name Select Brand Names
Valcyte, Valcyte Powder
Cytovene, Vitrasert, Zirgan
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