Microsporidiosis in AIDS

Microsporidiosis is caused by an obligate intracellular protozoan and is usually seen in the setting of AIDS. The causative agent is Enterocytozoon bieneusi which is best seen by electron microscopy. Giemsa and other special stains may also be helpful in its recognition. Jejunum usually shows the highest parasite burden. The organism causes minimal morphologic changes in the affected portion of the gut.