Cytomegalovirus (CMV) Infection: Symptoms, Effects & Treatment
Cytomegalovirus (CMV) is a virus that can be transmitted to a developing child before birth. CMV infection is usually harmless and rarely causes illness. For most healthy people who acquire CMV after birth, there are few symptoms and no long-term health consequences. Once a person becomes infected, the virus remains alive, but usually dormant within that person’s body for life.
There are two different types of infection: primary CMV and recurrent CMV infection. Primary infection can cause more serious problems in pregnancy than recurrent infection can. However, if a person’s immune system is seriously weakened in any way, the virus can become active and cause CMV disease. For the majority of people who have CMV infection, it is not a serious problem.
To learn more in-depth about the effects of congenital CMV (when a baby contracts CMV before birth) and how it may present in an infant, please visit our article on Congenital CMV.
What are the symptoms of CMV?
Most children and adults who are infected with CMV do not develop symptoms. However, some people may experience the following symptoms:
- Swollen glands
- Muscle aches
- Loss of appetite
- Stiff joints
What are the characteristics of CMV?
CMV is a member of the herpes virus group that is characterized by the ability to remain dormant within the body over a long period. Infectious CMV may be shed in bodily fluids (urine, saliva, blood, tears, semen, and breast milk) intermittently without any detectable signs or symptoms.
How common is CMV?
- By 40 years of age, over half of all adults have been infected with CMV.
- Is more widespread in developing countries and in areas of lower socioeconomic conditions.
Is higher among the following risk groups:
- babies in utero (most common virus with which children are born in the USA)
- people who work with children
- immunocompromised persons, such as organ transplant recipients and persons infected with human immunodeficiency virus (HIV)
How is CMV spread?
Transmission of CMV occurs from person to person and is not associated with food, water, or animals. CMV is not highly contagious but has been shown to spread in households and among young children in daycare centers.
For young children and families to avoid CMV and other viruses, this is why hand washing and avoiding touching the face (specifically the mouth, eyes, and nose) is important. The virus, if passed onto a hand, may not enter the body, but if this hand touches the mouth, eyes, or nose, it is able to enter the body.
CMV is spread through close, intimate contact with a person excreting the virus in their saliva, urine, breast milk, or other bodily fluids. This means that anything from sharing a drink or utensil (saliva) to sexual contact/intercourse (bodily fluids such as cervical mucus or ejaculate fluid) could pass the virus.
How is CMV diagnosed?
Most CMV infections are rarely diagnosed because the virus usually produces few if any, symptoms. However, people who have had CMV develop antibodies to the virus which remain in their body for the rest of their life. A blood sample can test for the CMV antibody, followed by another blood sample within two weeks.
The virus can also be cultured from specimens obtained from urine, throat swabs, and tissue samples. Laboratory tests to culture the virus are expensive and not widely available.
If a pregnant woman is diagnosed with the CMV infection, there are a few ways that the fetus can be checked for infection. Amniocentesis can be done to check fetal fluids or blood for signs of infection. However, amniocentesis also brings with it the risk of allowing the virus to pass from the mother to baby if it had not already. Speak with your healthcare provider about the associated risks of amniocentesis.
Symptoms that could signify possible infection include low amniotic fluid levels, intrauterine growth restriction, and enlarged tissues in the brain. Once the baby is born, testing can be done by saliva, urine, or blood.
What is the treatment for CMV?
Although vaccines for CMV are still in the research and developmental stages, there are some treatment options. One study revealed that hyperimmune globulin, when given to pregnant women with CMV, may help prevent the fetus from contracting the infection.
Although there is currently no medication that can fully prevent symptoms and long-term effects of CMV in infants, antiviral medications, including Ganciclovir and Valganciclovir, may be used to treat some aspects of congenital CMV.
These medications may even foster brain development and prevent hearing loss. If you have CMV during pregnancy or your infant has congenital CMV, consult your doctor about your treatment options.
To learn more about birth defects that may come about from a CMV infection in utero, see our Congenital CMV article.
How can CMV be prevented?
Transmission of cytomegalovirus is often preventable because it is most often transmitted through infected bodily fluids that come in contact with hands and then are absorbed through the nose or mouth of a susceptible person.
People who interact with children should use safe hygiene practices including good hand washing and wearing gloves when changing diapers. Hand washing with soap and water is effective in preventing the spread of CMV.
Especially if you are pregnant, you want to avoid a new infection. Talk to your doctor about finding out if you have CMV through blood testing, and discuss your risk factors for contracting CMV if you do not have it already (it is less of a concern if it is dormant in your body).
If you do not have CMV, there are things you can do (or not do) to reduce the likelihood of contracting CMV:
- Do NOT share drinks or utensils with others
- Avoid new sexual partners (even kissing) especially if you don’t know their CMV status (or you know they have it)
- If you work with/have children, do NOT kiss them on the face, and make sure you wash your hands after touching them or changing diapers
- Wash your hands after using the restroom
- Keep children’s toys and counters/etc they touch cleaned regularly
- Wash your hands immediately after coming into contact with someone’s saliva or tears.
How does CMV affect pregnancy?
Pregnant women who are healthy are not at special risk for CMV infection. Pregnant women who are infected with CMV rarely have symptoms, but rather their developing baby may be at risk for congenital (meaning from birth) CMV disease.
The transmission rate from a pregnant woman who contracts CMV during pregnancy to the fetus is between 30-50% according to the Organization of Teratology Information Service (OTIS). Of those babies who become infected, only 10-15% show signs of congenital CMV after primary maternal infection. Congenital CMV affects about 0.2-2.5% of babies worldwide.
For a woman who has a recurrent CMV infection during pregnancy (meaning this is not a primary infection), the rate of newborn CMV infection is about 1%. Of these, only 1-10% of the babies born with CMV infection will have symptoms at birth. Another 10-15% may not show any symptoms at birth but may still have long-term effects such as hearing loss and learning disabilities.
The following potential problems can occur for infants who are infected from their mothers before birth (during pregnancy):
- Moderate enlargement of the liver and spleen, small red spots on the skin, problems with the eyes and seizures are potential complications.
- 85-95% will have no symptoms or complications at birth, and the majority will not develop problems later in life.
- 10-15% of those at birth with no symptoms will go on to develop varying degrees of hearing and mental or coordination problems.
When CMV is transmitted at the time of delivery from contact with genital secretions or later in infancy through breast milk, these infections usually result in few, if any, symptoms or complications.
What are some recommendations for pregnant women regarding CMV infection?
- Throughout your pregnancy practice good personal hygiene, including hand washing with soap and water.
- If you develop a mononucleosis-like illness, you should be checked for CMV infection.
- Refrain from sharing food, eating utensils and drinking utensils with anyone.
- Your doctor can test the CMV antibodies to determine if you have already had CMV infection.
- Breastfeeding benefits outweigh the minimal risk of transmitting CMV (but discuss with your doctor first).
What are some recommendations for individuals who care for infants and children regarding CMV infection?
Most healthy people working with infants and children are not at risk for CMV infection. However, women of child-bearing age who previously have not been infected with CMV still have a potential risk of passing CMV to their babies in utero. CMV is commonly transmitted among young children.
Since CMV is transmitted through contact with infected bodily fluids, including urine and saliva, child care providers (including daycare workers, special education teachers, and therapists) should be educated about CMV infection and practice preventive measures.
Susceptible non-pregnant women working with infants and children should not routinely be transferred to other work situations. Routine laboratory testing for the CMV antibody in female workers is not recommended, but it can be performed to determine their immunity status.
Compiled using information from the following sources:
1. National CMV Foundation.
2. Organization of Teratology Information Specialists (OTIS, 2017): Cytomegalovirus (CMV) Fact Sheet. Available through Mother To Baby.
3. Centers for Disease Control & Prevention: Cytomegalovirus (CMV) and Congenital CMV Infection.
3. Williams Obstetrics Twenty-Second Ed. Cunningham, F. Gary, et al, Ch. 58.