The infection results from the cytomegalovirus, an ether-sensitive, deoxyribonucleic acid virus belonging to the herpes family. CMV has been found in the saliva, urine, semen, breast milk, feces, blood, and vaginal and cervical secretions of infected people.

Transmission occurs through direct contact with secretions and excretions, through blood transfusions, through the placenta, and through transplanted organs (patients who receive organs from a CMV-seropositive donor run a 90% chance of contracting the infection). CMV in cervical secretions can infect a sexual partner or an infant during passage through the birth canal. CMV is reaching epidemic proportions in female prostitutes and sexually active homosexual
males as CMV antibody titers in these groups approach 100%.

The disease probably spreads through the body in lymphocytes or mononuclear cells to the lungs, liver, GI tract, eyes, and central nervous system, where it often produces inflammatory reactions.

Immunosuppressed patients, such as those with acquired immunodeficiency syndrome, may develop opportunistic infections, such as pneumonia, hepatitis, ulceration of the GI tract, retinitis, and encephalopathy.

There are predominantly three clinical syndromes for CMV: acute acquired CMV infection, CMV in immunocompromised hosts, and perinatal. The adult patient’s history may reveal an immunosuppressive condition. He may complain of mild, nonspecific clinical symptoms, such as fatigue, myalgia, and headache, or he may have no symptoms.