Intestinal microsporidiosis with Septata intestinalis in a patient with AIDS—response to albendazole

Microsporidiosis is a common finding in HIV-infected patients who have diarrhoea. The species most commonly causing gastrointestinal disease is Enterocytozoon bieneusi. Recently Septata intestinalis has been described as a cause of diarrhoea and disseminated infection in patients with AIDS. A 44-year-old homosexual man with severe immunodeficiency (CD4 cell count 40/μl) had a history of watery diarrhoea for 2 weeks. Microsporidian spores measuring 1·2 to 1·5 × 2·5 to 3·0 μm were found in stool samples. Electron microscopy of duodenal biopsies confirmed the diagnosis of intestinal microsporidiosis and showed parasitophorous vacuoles with the typical ultrastructure of S. intestinalis. The patient was treated with albendazole (400 mg twice daily) and became asymptomatic within 4 days. No spores could be detected in stool samples after a treatment period of 14 days. About 25 infections with S. intestinalis have been reported to date, and the case presented here is the first in a German patient.