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What is congenital CMV?
By: Tina L. Konczol

CMV (cytomegalovirus) is a member of the Herpes group of viruses. It is a very common virus that infects people of all ages and in all parts of the world. CMV is spread by person-to-person contact with body fluids (urine, saliva, blood, tears, semen, breastmilk, etc.) from a person who is excreting the virus, from mother to fetus, or by blood transfusion or organ transplantation. CMV is very common among children, especially toddlers who attend group child care. Most people will catch the virus before they reach adulthood, but usually will be free of any signs or symptoms of infection. An infected person with no symptoms or knowledge of the infection could easily be unintentionally passing it to others. On occasion, a person can develop temporary symptoms that are similar to mononucleosis: fever, sore throat, fatigue and swollen glands. CMV infection is not a serious problem to the vast majority of people, but can harm some groups of people. CMV poses the greatest risk to developing fetuses. Other areas of concern are the risk of infection to people who work with infants and children and the risk of infection to the person whose natural immunity to infection is underdeveloped or supressed, such as newborns, organ transplant recipients, AIDS/HIV infected persons and chemotherapy patients. During an active infection, the virus is excreted in body fluids. During the primary CMV infection (the first time a person gets the virus) the body's immune system produces antibodies and immune cells. After recovery the virus itself remains in cells of the body in an inactive or latent state, but can be reactivated under certain conditions.

Congenital CMV (CMV that is passed from an infected mother to her fetus) can cause a wide range of disabilities in children whose mothers caught the virus for the first time during pregnancy, mostly due to abnormal development of the unborn child's central nervous system. These disabilities, ranging from mild to severe, include mental retardation, cerebral palsy, visual impairment, epilepsy and hearing loss. One out of a hundred infants are born with CMV infection. Most appear to be perfectly normal at birth, and only a small percentage of these infants will develop disabilities later on. Some infants do have apparent signs of CMV at birth, and these infants usually have more severe disabilities.

Researchers are currently trying to develop a vaccine for CMV, but since it is not available at the present time, knowing your CMV antibody status and preventing CMV are important. A person can have a simple laboratory test performed to determine if antibodies to CMV are present, indicating a past infection. If the test is positive, the results also may indicate if the virus is currently active. If a female that is contemplating pregnancy receives test results indicating a current primary infection she should be strongly advised to postpone pregnancy until the infection is inactive. The safest scenario for pregnancy is when the female receives test results indicating antibodies are present, but she is not currently infected. The risk to the fetus is extremely small if the mother's virus is not a primary infection or if the virus is not curently active because her existing antibodies should protect the fetus from CMV. If a person's test for antibodies is negative, they are susceptible to catching CMV, so simple hygienic precautions should be taken to reduce the chances of catching the virus. These precautions are extremely important for pregnant females or females planning pregnancy, especially if she has frequent contact with young children. These precautions are also important for her spouse or partner and other children she has frequent contact with since they could catch CMV and then transmit it to her. The simple hygienic precautions are:
1. Do not kiss young children on the mouth, cheek, or hands. Instead, kiss them on the forehead or top of the head, or give them a big, long hug.
2. Do not share food, drink, utensils, or toothbrushes, especially with young children.
3. Wash your hands after changing diapers or after contact with a child's saliva, or other body fluids.

These precautions should also be practiced with persons known to be shedding CMV or likely to be shedding CMV or other illnesses. Since other diseases and viruses can also cause similar damage to a developing fetus, pregnant females should avoid intimate contact with all ill persons.

Tina L. Konczol
Also credit to:
National Congenital CMV Disease Registry
Baylor College of Medicine
Houston, Texas