What is the most common cause of viral diarrhea in AIDS?
- CMV is one of the most common opportunistic infections in patients with AIDS, occurring late in the course of HIV infection when immunodeficiency is severe (CD4 lymphocyte count l < 100/mm 3 ).
- CMV has been identified in mucosal biopsy samples in as many as 45% of patients with AIDS and diarrhea, especially in those patients with negative stool studies. CMV causes both enteritis and colitis.
- A number of other viral pathogens—adenovirus, rotavirus, astrovirus, picobirnavirus, and coronavirus—have been reported to involve the GI tract in patients with AIDS, but their clinical importance remains to be determined.
- HSV can cause proctitis that mimics diarrhea because of the rectal mucous discharge.
- However, HSV does not cause enterocolitis because it invades the squamous mucosa, not the columnar epithelium, such as the one lining the colonic and small bowel mucosa.