What infectious agents are associated with acute and persistent diarrheal illness in HIV patients?
The degree of immune deficiency influences the differential diagnosis. Generally, the same pathogens as seen among immunocompetent community dwellers is seen among patients with HIV infection, but persistent and chronic presentations may be more common for these same organisms. In addition, symptoms suggestive of invasive disease may occur with infections caused by normally noninvasive pathogens. Highly active antiretroviral therapy and direct viral involvement by HIV may also be common contributors to diarrhea.
Among bacterial contributors, Salmonella (nontyphoidal bacteremia) is of particular concern and can be recurrent. Other contributors are Campylobacter and Shigella. Mycobacterium avium complex may be present even without significant diarrhea, and is often part of an overall wasting syndrome.
Parasite contributors are Cryptosporidium parvum , Microsporidium (a common cause of chronic diarrhea in HIV), Giardia lamblia, Entamoeba histolytica, Strongyloides stercoralis, Isospora belli, and Cyclospora cayetanensis.