Cytomegalovirus

Cytomegalovirus (CMV) is a very common virus. In most cases, its presence causes few or no symptoms at all. In people with weakened immune systems, however, it may cause severe illness. In fetuses, it may cause brain damage or birth defects.

What Is Cytomegalovirus (CMV)?

Cytomegalovirus (sy-to-MEG-a-lo-vy-rus) is a very common virus, with close to 85 percent of the U.S. population carrying antibodies to it, according to the U.S. National Institutes of Health. That means most Americans have been exposed to this virus. CMV may be present in urine, saliva, blood, breast milk, or semen. CMV can remain in the body for a long time without causing symptoms of illness, and most people who carry the virus probably picked it up during childhood.

Groups at risk for health problems

CMV infections can cause serious problems for people with immune disorders or weakened immune systems, such as people having organ transplants or cancer chemotherapy, or people with AIDS. About 40 percent of HIV and AIDS patients develop CMV retinitis (re-ti-NY-tis), an eye disease that can cause blindness. The virus also can be dangerous to fetuses, if transmitted during pregnancy, or to babies after birth if transmitted from the mother's milk. People who need blood transfusions or bone marrow transplantation also are at risk for CMV infection, and blood and bone marrow must be screened for the virus before use. The same blood screening is done for newborn infants who have a low weight at birth.

What Happens When People Have CMV Infections?

Symptoms

Newborn infants who survive a prenatal infection from cytomegalovirus may not weigh very much at birth. The infant may have fever and may appear yellowish, which indicates the child may have jaundice (a sign of liver disease). This infection can be very serious for an infant because it can cause many complications and disabilities. In older children and adults, CMV usually does not cause symptoms. When it does, symptoms may vary from mild to serious, and include fever lasting from one to two weeks, an illness that seems like mononucleosis, hepatitis, and sometimes a rash.

Diagnosis

Cytomegalovirus is diagnosed by isolating CMV antibodies from urine, blood, or tissues. CMV can remain in the body for months or years after initial infection, however, so the presence of the antibodies indicates only that the person has been infected at some point in the past. The doctor usually interprets the lab findings as part of an overall examination, review of symptoms, and complete medical history.

Treatment

Cytomegalovirus infections are treated with antiviral drugs. When illnesses are acute (severe), treatment may require intravenous (through a vein) injections for up to two weeks. People with CMV retinitis must remain on antiviral drugs for their lifetime.

Prevention

Many people acquire CMV during childhood by sharing toys or by touching the mouth with unwashed hands. Frequent handwashing by children and by adults can help reduce transmission.