Advances in Diagnosis and Treatment of Cytomegalovirus Gastrointestinal Infection in Immunocompetent Adults

Cytomegalovirus (CMV), a kind of human herpes virus, is highly prevalent globally. It was believed that CMV posed a considerable risk only in newborns and immunocompromised individuals in the past, but there are increasing reports that CMV caused adverse outcomes in immunocompetent adults. The gastrointestinal canal (especially colon) is one of the usual sites of cytomegalovirus infection. Moreover, severe CMV gastrointestinal disease can lead to considerable mortality. Male, age ≥55 years, immunomodulatory comorbidities (such as kidney failure, pregnancy, diabetes mellitus, or non-hematological malignancies without treatment) and the need for surgical intervention are factors that are not favorable to survival. When patients have unfavorable risk factors for survival or serious complications, antiviral treatment should be administered. Targeted antiviral therapy with intravenous ganciclovir or valganciclovir was suitable for severe CMV disease in immunocompetent adults before the advent of new and safer anti-herpesvirus drugs. Although there are many simple ways to detect the presence of CMV, most of them cannot distinguish between latent infection and active disease, which makes clinical decision-making difficult. CMV gastrointestinal disease has no specific clinical and endoscopic manifestations, and the diagnosis is to a large extent dependent on histopathology and tissue CMV polymerase chain reaction technology. Quantitative testing of tissue CMV DNA is a useful diagnostic tool, but further research is needed to explain the quantitative value, such as obtaining a viral load cutoff to decide whether to apply antiviral therapy.