Cytomegalovirus (CMV) is a widespread virus that many individuals acquire, often without realizing it. Belonging to the herpesvirus family, CMV can remain dormant in the body and reactivate later. Understanding CMV is important due to its diverse transmission routes and potential impact on specific populations.
How CMV Spreads
CMV transmission primarily occurs through close, prolonged contact with infected bodily fluids. These fluids can include saliva, urine, blood, tears, semen, vaginal fluids, and breast milk. The virus does not typically spread through casual contact, such as brief touching or sharing the same air.
While sexual contact is a possible route, CMV is not exclusively classified as a sexually transmitted infection. It can be transmitted through semen and vaginal fluids. However, direct contact with saliva and urine, particularly from young children, represents a common mode of spread. Children, especially those in daycare settings, frequently shed the virus through these fluids.
Transmission from a pregnant individual to their child can occur in several ways. The virus can pass through the placenta to the fetus before birth, leading to what is known as congenital CMV. Additionally, a baby can acquire the virus during childbirth or through breastfeeding. Beyond these routes, CMV can also be transmitted through organ transplantation or blood transfusions.
Common Symptoms and Risk Factors
Most healthy individuals who contract CMV experience no symptoms. When symptoms do appear, they are usually mild and resemble common illnesses like the flu or mononucleosis, including fever, fatigue, a sore throat, and swollen glands.
Certain populations face a higher risk of developing more severe symptoms or complications from CMV. Individuals with weakened immune systems, such as those with HIV/AIDS or organ transplant recipients, are particularly susceptible. In these cases, CMV can lead to serious conditions affecting various organs, including vision loss due to inflammation of the retina, digestive issues, lung infections, or brain inflammation.
Newborns are another group at risk, particularly if they acquire CMV before birth. Approximately 1 in 200 babies in the United States are born with congenital CMV. While most infants show no symptoms at birth, some may exhibit signs such as low birth weight, jaundice, a rash, an enlarged liver or spleen, or a small head size. The most common long-term complication is hearing loss, which can manifest months or even years after birth, with developmental delays and vision problems also potential effects. Pregnant individuals are also a risk group, as a first infection during pregnancy can transmit the virus to the fetus.
Preventing Transmission and Complications
Reducing the risk of CMV transmission involves practicing consistent hygiene. Frequent handwashing with soap and water is an effective measure, especially after contact with saliva or urine, such as when changing diapers or assisting young children. It is also advisable to avoid sharing food, drinks, eating utensils, or pacifiers. Avoiding kissing young children directly on the mouth can further lower the risk of saliva-borne transmission.
While not the primary mode of transmission, practicing safer sex, including condom use, can help reduce the sexual spread of CMV. Pregnant individuals should be particularly diligent with hygiene practices, minimizing direct exposure to children’s saliva and urine. For most healthy adults, CMV infections typically resolve without specific medical intervention. However, for individuals with compromised immune systems or newborns with symptomatic congenital CMV, antiviral medications, such as ganciclovir or valganciclovir, may be prescribed to manage the infection or reduce the severity of potential complications like hearing loss.