Intestinal microsporidiosis in a German patient with AIDS.

Since intestinal microsporidiosis might be of importance in the pathogenesis of gastrointestinal symptoms in patients infected with HIV, we examined duodenal biopsies of HIV-infected patients by electron microscopy. Enterocytozoon bieneusi infection of the small intestine was found in one of 23 patients studied, which gives a 95% confidence interval for the prevalence rate between 0.1% and 22%. The infected patient was a 24-year-old homosexual male with AIDS who underwent upper endoscopy because of acute epigastric pain, nausea, and vomiting. These symptoms were obviously due to mesenterial Kaposi's sarcoma obstructing the duodenal passage, as was later revealed at autopsy. However, microsporidiosis might have caused the patient's eight-month history of diarrhea and weight loss, since infected cells showed signs of degeneration, and no other pathogens were ever detected in stool or biopsy. Our finding of Enterocytozoon bieneusi infection in a German AIDS patient supports the concept of a worldwide distribution of this parasite; further studies are needed to define its exact prevalence in HIV-infected patients and its pathogenic relevance.