About Cytomegalovirus

Infection with cytomegalovirus (CMV), a member of the herpes virus family, is very common. Between 50% and 85% of people in the United States have had a CMV infection by the time they are 40 years old, according to the Centers for Disease Control and Prevention (CDC).

Kids typically become infected in early childhood, especially those in childcare and preschool settings. CMV infections are rarely serious in otherwise healthy kids and adults; they usually cause only mild symptoms, if any. When symptoms do appear, they're similar to those seen in mononucleosis ("mono") and only last a few weeks.

CMV is mainly a problem for certain high-risk groups, including:

• unborn babies whose mothers become infected with CMV during the pregnancy
• children or adults whose immune systems have been weakened by disease or drug treatment, such as organ transplant recipients or people infected with HIV

Once a person has had a CMV infection, the virus usually lies dormant (or inactive) in the body, but it can be reactivated. The virus is more likely to be reactivated — and cause serious illness — in people who have weakened immune systems due to illness.

Symptoms

The symptoms of a CMV infection vary depending upon the age and health of the person who is infected, and how the infection occurred.

Infants who are infected before birth usually show no symptoms of a CMV infection after they are born, although some of these infants can develop hearing, vision, neurological, and developmental problems over time. In a few cases, there are symptoms at birth, which can include premature delivery, being small for gestational age, jaundice, enlarged liver and spleen, microcephaly (small head), seizures, rash, and feeding difficulties. These infants are also at high risk for developing hearing, vision, neurological, and developmental problems.

Newborns can also contract CMV infection during or soon after birth by passing through the birth canal of an infected mother, consuming breast milk from a mother with the virus, or receiving a transfusion of blood donated by a person infected with CMV. Most of these infants show no symptoms of CMV infection; however, a few may develop pneumonia or other symptoms.

Premature and ill full-term infants who are infected soon after birth are also at risk for neurological and developmental problems over time.