What Is It?
Cytomegalovirus (CMV) is a virus related to the herpes virus. It is so common that almost all adults in developing countries and 50% to 85% of adults in the United States have been infected.
Usually CMV is a mild disease that does not cause any serious problems in healthy children and adults. Most people get flu-like symptoms or an illness similar to mononucleosis, if they develop symptoms at all.