Cytomegalovirus (pronounced sy-toe-MEG-a-low-vy-rus), or CMV, is a common virus that infects people of all ages. In the United States, nearly one in three children are already infected with CMV by age five. Over half of adults by age 40 have been infected with CMV. Once CMV is in a person’s body, it stays there for life and can reactivate. A person can also be re-infected with a different strain (variety) of the virus.
Most people infected with CMV show no signs or symptoms. That’s because a healthy person’s immune system usually keeps the virus from causing illness. However, CMV infection can cause serious health problems for people with weakened immune systems and for unborn babies (congenital CMV).
Most people with CMV infection have no symptoms and aren’t aware that they have been infected. In some cases, infection in healthy people can cause mild illness that may include:
- Sore throat
- Swollen glands
People with weakened immune systems who get CMV can have more serious symptoms affecting the eyes, lungs, liver, esophagus, stomach, and intestines. Babies born with CMV can have brain, liver, spleen, lung, and growth problems. The most common health problem in babies born with congenital CMV infection is hearing loss, which may be detected soon after birth or may develop later in childhood.
People with CMV may pass the virus in body fluids, such as saliva, urine, blood, tears, semen, and breast milk. CMV is spread from an infected person in the following ways:
- From direct contact with saliva or urine, especially from babies and young children
- Through sexual contact
- From breast milk to nursing infants
- Through transplanted organs and blood transfusions
A woman who is infected with CMV can pass the virus to her developing baby during pregnancy. Women may be able to lessen their risk of getting CMV by reducing contact with saliva and urine from babies and young children. The saliva and urine of children with CMV have high amounts of the virus. A pregnant woman can avoid getting a child’s saliva in her mouth by, for example, not sharing food, utensils, or cups with a child. Also, she should wash her hands after changing diapers. These cannot eliminate her risk of getting CMV, but may lessen the chances of getting it.
Healthcare providers should follow standard precautions. For more recommendations in healthcare settings, see the Guide to Infection Prevention for Outpatient Settings.
Blood tests can be used to diagnose CMV infection in adults who have symptoms. However, blood is not the best fluid to test newborns with suspected CMV infection. Tests of saliva or urine are preferred for newborns.
Healthy people who are infected with CMV usually do not require medical treatment. Medications are available to treat CMV infection in people who have weakened immune systems and babies with signs of congenital CMV.