An overview of parasitic infections of the gastro-intestinal tract in developed countries affecting immunocompromised individuals.

In both developed and developing countries, parasitic infections continue to be a frequent cause of mortality and morbidity. Due to the globalization of the world, doctors must be fully prepared to deal with a plethora of parasitic infections. More commonly the gastrointestinal (GI) tract is infected and in developed countries protozoans are more likely to be the cause of infection compared to helminths. These GI protozoa are progressively becoming recognized as important pathogens in patients that are immunocompromised. The number of immunocompromised patients is increasing and therefore the likelihood of similar infections will also increase. This paper aims to highlight the key GI parasites affecting immunocompromised individuals in developed countries, discussing diagnosis, treatment options and also prevention. Cryptosporidium parvum may be the most common GI parasite found in the immunocompromised host closely followed by Cyclospora, however, Giardia duodenalis is the most common GI parasite found in developed countries. The pathogenesis of parasitic infection is not clear, poorly understood and diagnostic testing remains difficult with management continuing to be a challenge.