Cytomegalovirus (sye-tuh-MEH-guh-lo-vy-rus), or CMV infection, is very common and usually causes no symptoms. It poses little risk for healthy people, but it can lead to serious illness in people with weak immune systems.
CMV is part of the herpesvirus (her-peez-VY-rus) family, which also includes the viruses that cause herpes * , chickenpox, and mononucleosis * . As with other members of the herpesvirus family, once CMV enters a person's body, it remains there for the person's whole life. CMV infection can cause flulike symptoms when a person is first infected, but many people have no symptoms at all. The virus usually becomes dormant after it enters the body, meaning that it remains hidden and does not cause symptoms of illness. The virus can emerge at a later time, however, and produce illness in people with weakened immune systems, such as people who have cancer or AIDS or those who have received organ or bone marrow * transplants. CMV is a risk for pregnant women because of the danger that it can be transmitted to their babies. CMV is the most common viral infection for infants born in the United States, about 30,000 cases each year, and more than 5,000 children per year suffer permanent problems. The disease is the leading cause of intellectual disability and hearing defects in newborns in the United States as a result of congenital (kon-JEH-nih-tul) infection, that is, infection that is present at birth.
CMV is contagious and can spread through bodily fluids, including blood, saliva, semen * , breast milk, tears, and urine * . The virus can be transmitted by sexual contact, by close person-to-person contact, or from mother to baby during pregnancy, birth, or breastfeeding. It often spreads among children in day care or preschool or among family members. In the United States, as many as three of every five adults have been infected with CMV by the time they reach age 40. CMV infects people all over the world and is even more widespread in developing countries and among those with poor living conditions.
Most people who have been infected with CMV never show symptoms. In some people, the virus causes mild symptoms that mimic the flu or infectious mononucleosis, such as fever, chills, body aches, headache, swollen lymph nodes * , sore throat, and fatigue. Newborns who contract CMV infection in the womb may be born with jaundice * , microcephaly * , signs of brain damage, and a serious inflammation of the eyes known as retinitis * . Others seem healthy when they are born but later have growth problems and signs of hearing loss or intellectual disability.
Most cases of CMV infection are never diagnosed because they produce few or no symptoms. When doctors do suspect CMV, they often base the diagnosis on symptoms, physical examination, and blood tests for antibodies * * . Sometimes blood tests show evidence of past infection with CMV but do not indicate active infection. A test known as the polymerase (pahLIM-er-ace) chain reaction, or PCR, can test specifically for active CMV infection by finding traces of DNA from the virus in body fluids. People with healthy immune systems who contract CMV infection usually do not require medical treatment. When people with weakened immune systems develop CMV infection, doctors often prescribe medication made to fight viruses. These antiviral medicines may need to be given by injection, and patients sometimes have to take them for months or even years. Symptoms of initial CMV infection usually last two to three weeks in healthy people. After that, the virus remains in the body for life. Flare-ups of illness from CMV in healthy people are rare and typically occur when the immune system has been stressed by fighting another illness.
CMV infection can cause more severe illnesses, such as pneumonia * and retinitis, in people with weakened immune systems. Left untreated, retinitis can lead to blindness. CMV also can cause severe inflammation of the esophagus and colon, leading to difficulty in swallowing, long-lasting diarrhea, and weight loss. It also can affect the brain or nerves. Infants born with CMV infection may have jaundice, poor growth, problems with vision and hearing, and other disabilities, including slow development and intellectual disability.
The best way to help prevent the spread of CMV is to wash hands regularly, especially after changing diapers or touching bodily fluids. Doctors advise women who are pregnant and people who work in child care to be particularly careful. Patients scheduled to have organ or bone marrow transplants typically receive medication before the operation to prevent CMV disease from developing, as the transplant process weakens their immune systems.
See also AIDS and HIV Infection • Blindness • Congenital Infections • Hepatitis • Immune Deficiencies • Jaundice • Mononucleosis, Infectious • Pneumonia • Pregnancy • Viral Infections
Solana, R., et al. CMV and Immunosenescence: From Basics to Clinics. Oak Ridge, TN: Scitech, 2015.
MedlinePlus. “Acute Cytomegalovirus (CMV) Infection.” U.S. National Library of Medicine. http://www.nlm.nih.gov/medlineplus/ency/article/000568.htm (accessed December 1, 2015).
Centers for Disease Control and Prevention. 1600 Clifton Rd., Atlanta, GA 30333. Toll-free: 800-311-3435. Website: http://www.cdc.gov (accessed December 1, 2015).
National Institute of Allergy and Infectious Diseases. Office of Communications and Public Liaison, 6610 Rockledge Dr., MSC 6612, Bethesda, MD 20892-66123. Toll-free: 866-284-4107. Website: http://www.niaid.nih.gov (accessed December 1, 2015).
Stop CMV: The CMV Action Network. PO Box 62214, Sunnyvale, CA 94088. Telephone: 209-712-9929. Website: http://www.stopcmv.org (accessed December 1, 2015.).
* herpes (HER-peez) is a viral infection that can produce painful, recurring skin blisters around the mouth or the genitals, and sometimes symptoms of infection elsewhere in the body.
* mononucleosis (mah-no-nuklee-O-sis) is an infectious illness caused by a virus with symptoms that typically include fever, sore throat, swollen glands, and tiredness.
* bone marrow is the soft tissue inside bones where blood cells are made.
* semen (SEE-men) is the sperm-containing whitish fluid produced by the male reproductive tract.
* urine is the liquid waste material secreted by the kidneys and removed from the body through the urinary tract.
* lymph nodes (LIMF) are small, bean-shaped masses of tissue containing immune system cells that fight harmful microorganisms. Lymph nodes may swell during infections.
* jaundice (JON-dis) is a yellowing of the skin, and sometimes the whites of the eyes, caused by a buildup in the body of bilirubin, a chemical produced in and released by the liver. An increase in bilirubin may indicate disease of the liver or certain blood disorders.
* microcephaly (my-kro-SEH-fahlee) is the condition of having an abnormally small head, which typically results from having an underdeveloped or malformed brain.
* retinitis (reh-tin-EYE-tis) is an inflammation of the retina, the nerve-rich membrane at the back of the eye on which visual images form.
* antibodies (AN-tih-bah-deez) are protein molecules produced by the body's immune system to help fight specific infections caused by microorganisms, such as bacteria and viruses.
* Epstein-Barr virus (EP-stine-BAHR VI-rus) is a common virus that causes infectious mononucleosis.
* pneumonia (nu-MO-nyah) is inflammation of the lungs.