Cytomegalovirus (CMV) is a virus of the herpesvirus family, and is extremely common worldwide. CMV usually lies dormant within its host for life, but may be reactivated if the infected person’s immune system becomes weaker. The host may also be re-infected with a different strain of the virus.
It is estimated that between 40% and 80% of the population in industrialized countries and almost the entire population in developing countries will become infected with CMV sometime in their life. The infection usually evolves without symptoms and becomes latent. In Italy, about 70%-80% of the adult population are positive for CMV antibodies.
A good immune system is able to keep the infection under control, but immunocompromised individuals (i.e. people with immune defects or HIV, organ or marrow transplant recipients, cancer patients undergoing chemotherapy) and children under two years of age may develop serious complications, mainly affecting the eyes, lungs, liver, oesophagus, stomach, bowel and central nervous system.
The most important aspect is congenital infection. Infection with CMV during pregnancy may, if passed on to the unborn baby, cause permanent, and sometimes severe, damage.