Cytomegalovirus (CMV) is a common, usually mild, and often asymptomatic virus that can infect people of all ages. CMV is a part of the herpes family of viruses, and the severity and duration of the infection vary widely among individuals. When an infant is born with the virus, it is referred to as congenital cytomegalovirus. Congenital CMV has an estimated incidence rate of 1 in 200 live births. Of those infants born with congenital CMV, 1 in 5 will have long-term complications.
Once an individual is infected, CMV remains in the body permanently, either inactively or actively. An infected individual can be asymptomatic or symptomatic. CMV is not considered highly contagious; however, an infected individual can transmit the virus even if it is inactive or the individual is asymptomatic. CMV is transmitted through bodily fluids such as tears, saliva, blood, semen, cervical fluid, urine, and breast milk. CMV can cross the placenta during pregnancy, infecting the unborn baby. A mother can also transmit the virus during delivery as the infant passes through the birth canal.
Infants born with congenital CMV are at risk for brain, lung, liver, spleen, eye, and gastrointestinal complications. Infants may experience developmental and motor delays as well as vision loss. The most common complication caused by congenital CMV is hearing loss, which can be present at birth or occur later in childhood. Signs of congenital CMV range from mild to severe, including rashes, jaundice, low-birth weight, premature birth, lung issues, microcephaly, seizures, damage to the retina of the eye, and liver or spleen abnormalities.
CMV is diagnosed in adults through blood tests. However, when congenital CMV is suspected, saliva and urine tests performed within three weeks of delivery are the preferred and most accurate methods of testing newborns. Babies born with congenital CMV can be treated with medication, reducing the risk and severity of long-term complications; however, there is no medication or treatment that guarantees a child will not develop complications.