DefinitionCytomegalovirus (CMV) is a member of a group of herpes-type viruses that can cause disease in different parts of the body in people. This article discusses CMV in people with weakened immune systems.Alternative NamesCytomegalovirus - immunocompromised hostCauses, incidence, and risk factorsMost humans are exposed to CMV in their lifetime, but typically only individuals with weakened immune systems become ill from CMV infection. Usually, CMV produces no symptoms. However, serious CMV infections can occur in people with weakened immune systems due to AIDS, organ transplants, bone marrow transplant, chemotherapy, or medicines that suppress the immune system.A CMV infection may affect different parts of the body. Infections include:CMV esophagitis(infection of the esophagus)CMV gastr