Cytomegalovirus (CMV) is present worldwide, and infections are very common. In the third world, CMV infection occurs at or near the time of birth, while in more developed countries, infection is slightly delayed and occurs throughout infancy, childhood, and through adolescence.

CMV is transmitted in situations of close interpersonal contact. The virus has been isolated in nearly all organs and body fluids in the human body. By adulthood, up to 80% have anti-CMV antibodies, which signifies prior infection.

CMV infection in normal people usually produces no symptoms. However, a flu-like syndrome can occur. In rare instances, more severe CMV infection, involving the GI tract, has been reported in people with normal immunity.

Patients with CMV colitis manifest symptoms, such as fever, bloody diarrhea, and abdominal pain. When CMV colitis occurs in patients with normal immune systems, they typically have other serious medical problems, such as severe trauma, renal failure, or severe infection.

A special category of patients who have inflammatory bowel disease, such as Crohn's Disease and ulcerative colitis, can suffer from gastrointestinal CMV infections. In fact, a small number of patients who have undergone colectomy for ulcerative colitis have been found to have symptomatic CMV infections in their remaining intestine.

Symptomatic CMV infections of the GI tract are more common in persons with impaired immune systems, and in these patients serious infections can occur.

People at risk include those with AIDS, recipients of organ transplants (overall incidence between 2-16%) or bone marrow transplants (overall incidence between 32-52%), and people receiving chemotherapy or other immunosuppressive treatments. Immunocompromised people who develop CMV gastroenteritis and colitis can have severe illness.

GASTROINTESTINAL CMV INFECTION
Gastrointestinal CMV disease may be localized or widespread. Ulcers can occur in the esophagus, stomach, small intestine, or colon. Additionally, overt gastritis (inflammation of the stomach) and colitis (inflammation of the colon) can also be seen.

Typically, ulcerations in the upper GI tract (esophagus, stomach) are associated with symptoms of nausea and vomiting, pain on swallowing (odynophagia), difficulty swallowing (dysphagia), or abdominal pain.

When the intestines are involved, the ulcerations may cause abdominal pain, diarrhea, or bloody stools. More severe infections can result in gastrointestinal bleeding or perforation (a hole through the wall of the infected organ).