Cytomegalovirus

Cytomegalovirus (say: "si-toe-meg-ah-low-vi-russ"), or CMV, is a very common virus. People are usually infected by the time they are 2 years old or during their teenage years and carry the virus for life (usually in a dormant or inactive state). The majority of adults carry the virus by the time they are 40 years of age. Many people are infected with CMV and don't even know it because the virus rarely causes symptoms. CMV usually does not cause long-term problems. However, CMV can cause problems in people who have weak immune systems (from diseases such as HIV and from organ transplants) and in a newborn if the mother gets the infection during pregnancy.

CMV gets into body fluids, such as saliva, blood, urine, semen and breast milk. A person is able to transmit (or "shed") the virus to others only when it is active in his or her system (not dormant). It can be spread from one person to another through sexual contact and contact with blood and other body fluids. CMV can rarely be transmitted by blood transfusion or organ transplantation.

In child care centers, as many as 70 percent of children age 1 to 3 can shed the virus. Careful, frequent hand washing with soap and water may help prevent the spread of CMV.

Usually, there are no symptoms or only mild symptoms. A few people will have symptoms that are similar to mononucleosis (such as a sore throat, swollen glands, fever, headache and tiredness).

People who have weakened immune systems because they have human immunodeficiency virus (HIV) or because they received an organ transplant may have severe symptoms, such as blindness, pneumonia, diarrhea, bleeding ulcers in the esophagus (windpipe) or intestines and inflammation of the brain (encephalitis).

If a pregnant woman transmits CMV to her unborn baby, miscarriage, stillbirth or death of the newborn may occur. Newborns who survive are at an increased risk for hearing loss and mental retardation. However, only 3 percent (3 babies out of every 100) of newborns who are infected with CMV during pregnancy experience problems from the virus. Most are born healthy, or with only mild CMV symptoms.

Because CMV usually doesn't cause symptoms, your doctor may not know that you have CMV. If you do have symptoms, your doctor may test your blood to check for CMV. If you have HIV and CMV, your doctor may recommend that you visit an eye doctor to find out whether the virus has infected your eyes. People who have HIV should be sure to let their doctor know if they are having any painless blurring of their vision, "floaters" only in one eye, light flashes or areas of blindness. They should also let their doctors know if they are experiencing frequent shortness of breath with flu-like symptoms.

For otherwise healthy people, CMV usually doesn't require treatment. If your immune system is weakened, your doctor may use one of several different medicines to treat CMV infection. However, because CMV is a virus, regular antibiotics won't work against it. Antiviral drugs are usually prescribed, which slows the virus down (but cannot cure CMV).

If you are pregnant, your doctor may want to test you for CMV to determine if there is a risk for your unborn baby. If you do carry the virus, your doctor may suggest a test called amniocentesis, which collects a sample of the amniotic fluid for testing. It can help determine whether your unborn baby has CMV.

If you are pregnant and your baby has CMV, you doctor will likely check your baby once he or she is born for any problems or birth defects so they can be treated early. Treatable symptoms in newborns include pneumonia, hearing loss and inflammation of the eye.