Cytomegalovirus (CMV) is a virus found around the world. It is related to the viruses that cause chickenpox and infectious mononucleosis (mono). Between 50 percent and 80 percent of adults in the United States have had a CMV infection by age 40. Once CMV is in a person's body, it stays there for life.
Most people with CMV don't get sick. But infection with the virus can be very serious in babies and people with weak immune systems. If a woman gets CMV when she is pregnant, she can pass it on to her baby. CMV does not harm most babies. But some develop lifelong disabilities.
CMV is spread through close contact with body fluids. You should use good hygiene, including proper hand washing, to avoid catching or spreading the virus. Most people with CMV don't require treatment. If you have a weakened immune system, your doctor may prescribe antiviral medicine.
Centers for Disease Control and Prevention