Cytomegalovirus Colitis in a Patient With Ulcerative Colitis on Vedolizumab Monotherapy.

Cytomegalovirus (CMV) is a human herpes-type virus with variable clinical manifestations. Infections in immunocompetent patients are usually asymptomatic or mild, and severe infections are generally seen in immunosuppressed individuals. CMV colitis is not uncommon in patients with ulcerative colitis (UC) and is mostly associated with the use of steroids, immunomodulators like azathioprine, and biologics like infliximab, which have systemic immunosuppressive effects.