RESUMEN
BACKGROUND: Most of the latest clinical and epidemiologic studies indicate that microsporidiosis and above all Enterocytozoon bieneusi cause approximately 7-50% of otherwise unexplained diarrhea in HIV-infected patients. Four cases of intestinal microsporidiosis in AIDS-patients are reported. METHODS: Detection of spores of microsporidiosis in stool samples from HIV-infected patients was performed by the following techniques: 1) light microscopy, using Kokoskin's modification of the Weber trichrome stain; 2) electron microscopy, for confirmation (only available in one case), and 3) indirect immunofluorescence assay (IIF), performed on all positive samples. Rabbit polyclonal antibodies anti-Encephalitozoon cuniculi, anti-E. hellem and anti-E. (Septata) intestinalis were used to eliminate the possibilities of presence of microsporidiosis other than E. bieneusi. RESULTS: Detection of spores of microsporidiosis by trichrome stain was positive in all samples from the 4 patients. By elimination, IIF confirmed the presence of Enterocytozoon bieneusi in all 4 cases. E. bieneusi was identified by electron microscopy in the only case available. Three patients had CD4+ lymphocyte counts < 100 x 10(6)/l and one < 500 x 10(6)/l. All had AIDS and three of them were homosexual. Two patients remained positive for microsporidiosis for almost 5 months. CONCLUSIONS: Despite the very few cases described in Spain, these preliminary data lead us to believe that intestinal microsporidiosis should be considered as an possible cause of diarrhea in our country also, and mainly in acute immunodeficiency patients.