Opportunistic protozoan parasitic infections of gastrointestinal tract

Opportunistic infections of the gastrointestinal tract have played a critical role in determining symptomatic illness in immunocompromised individuals. Protozoan parasites that cause mild or self-limited disease in immunocompetent individuals can cause protracted and severe diarrhoea in immunocompromised patients. Among the protozoans that cause intestinal infections in the immunocompromised, cryptosporidium species, Isospora and microsporidia are the most common organism encountered. In addition, infections due to Entamoeba histolytica, Cyclospora cayatenensis and Giardia are also seen. Treatment of these infections is available for Isospora, some microsporidia, E. histolytica, Cyclospora and Giardia, In addition, it has been shown recently that antiretroviral therapy can resolve diarrhoea due to Cryptosporidium and microsporidia