Cytomegalovirus (CMV) is a common virus. While often harmless, it can pose health challenges for specific populations. Understanding CMV is important due to its widespread nature and potential complications.
Understanding Cytomegalovirus
Cytomegalovirus (CMV) is a member of the herpes virus family. Like other herpesviruses, CMV establishes a lifelong presence, remaining dormant after initial infection. It can reactivate later, particularly if the immune system weakens.
CMV is common worldwide, with high seroprevalence. In the United States, over half of adults have been infected with CMV by age 40. Many acquire the virus in childhood; nearly one in three U.S. children are infected by age five.
How CMV Spreads
CMV primarily spreads through direct contact with infected bodily fluids. These include saliva, urine, blood, tears, semen, breast milk, and vaginal fluids. Transmission often occurs through close, prolonged contact.
Transmission commonly occurs through sharing food/drinks, kissing, or contact with young children’s saliva or urine. Sexual contact is another route. CMV can also transmit from a pregnant individual to their baby during pregnancy, birth, or through breast milk, known as congenital transmission. Organ transplants and blood transfusions are other pathways.
Signs of CMV Infection
CMV symptoms vary significantly depending on immune status. In healthy individuals, CMV often causes no noticeable symptoms; when they do appear, they are typically mild and may resemble mononucleosis, including fatigue, fever, muscle aches, sore throat, and swollen glands. A skin rash or malaise may occur. Less commonly, an enlarged spleen or inflamed liver can develop.
For individuals with weakened immune systems, such as transplant recipients, chemotherapy patients, or those with HIV/AIDS, CMV can cause severe, life-threatening illness. Symptoms in this group are often organ-specific and can include pneumonia, retinitis leading to vision loss, or gastrointestinal issues like colitis or esophagitis. Brain inflammation (encephalitis) and bone marrow suppression are possible complications.
Congenital CMV (infection before or during birth) can lead to serious health problems. While many babies show no symptoms at birth, some may have signs like a rash, jaundice, low birth weight, an enlarged liver or spleen, or microcephaly. Long-term complications, such as hearing loss, can develop later. Other problems include developmental delays, vision problems, seizures, and lack of coordination.
Diagnosis and Management
Diagnosing CMV infection often involves laboratory tests that detect the virus or the body’s immune response. Blood tests can detect antibodies (indicating past or current infection) or viral DNA. Urine tests and tissue biopsies may also be used, particularly when specific organ involvement is suspected. Diagnosis often depends on symptoms and risk factors.
For most healthy individuals, no specific treatment is necessary, as the immune system typically controls the virus. Over-the-counter medications can manage flu-like symptoms. However, for immunocompromised individuals or babies born with symptomatic congenital CMV, antiviral medications may be prescribed.
Antiviral drugs reduce the virus’s ability to replicate, mitigating symptoms and preventing complications. These treatments are not a cure, as CMV remains in the body for life. The aim is to manage active infection and minimize damage, especially for vital organs or infants with congenital CMV.
Reducing Your Risk
Minimizing CMV risk involves good hygiene. Frequent handwashing is important, especially after contact with bodily fluids like those from young children. Young children can shed the virus in their saliva and urine for extended periods, even without symptoms.
To further reduce transmission, avoid sharing food, drinks, or eating utensils. Pregnant individuals should take extra precautions to protect their developing baby from CMV. This includes avoiding kissing young children on the mouth and contact with their saliva and urine. While no approved CMV vaccine exists, several are in development to prevent congenital CMV and reduce the overall burden of infection.