Cytomegalovirus (CMV) is a common virus that is part of the herpes family of viruses.
How CMV is spread
CMV is spread through bodily fluids. These include:
- saliva
- semen
- blood
- urine
- vaginal fluids
- breast milk
Close physical contact
A CMV infection can be spread through close physical contact. For example, the infection can be present in small droplets of saliva that are transmitted from one person to another when an infected person coughs or sneezes.
You can also get the CMV virus by touching surfaces that have been infected with contaminated saliva or urine, and then touching the inside of your nose or mouth. CMV can also be spread during sexual intercourse.
Most CMV infections occur in early childhood. The infection can spread rapidly in places where young children spend a lot of time in close contact with each other, such as day care centres and nurseries. However, by the time a child is old enough to attend, their immune system (the body’s natural defence against infection and illness) should be strong enough to deal with an infection.
If you experience any symptoms of a CMV infection, they should pass quickly and the virus will then remain inactive in your body’s cells for the rest of your life.
Reoccurring CMV
CMV will only become a problem if your immune system becomes severely weakened, leading to the virus "waking up" and re-infecting your body’s organs.
Your immune system may become weakened if you:
CMV and breastfeeding
CMV can be passed from a mother to her child through breast milk. However, the benefits of breastfeeding your baby far outweigh any risk from CMV.
The one exception is if a child is born prematurely. The immune system of premature babies is often not strong enough to deal with a CMV infection. If your baby is born prematurely, your treatment team will advise you about the best way to feed your baby.
Congenital CMV
Congenital CMV is when an unborn baby develops a CMV infection from its mother.
Most cases of congenital CMV develop when a pregnant woman is infected by the CMV virus for the first time during, or shortly before, pregnancy. In about 4 out of 10 cases, the baby will be infected as well.
In some cases, a previously inactive CMV infection can reoccur during pregnancy as a result of the mother having a weakened immune system. The mother could also be re-infected with another strain of the CMV virus. If this happens, the CMV virus can be passed from the mother to her unborn baby.
In most cases where CMV is passed from a mother to her unborn baby, the virus does not cause any damage to the baby. However, if a large amount of the virus is spread to the baby, it can interfere with the baby’s normal development, resulting in symptoms and associated disabilities of congenital CMV. See Cytomegalovirus - symptoms for more information.
