Tissue diagnosis of intestinal microsporidiosis using a fluorescent stain with Uvitex 2B.

To detect intestinal microsporidiosis in paraffin wax embedded biopsy specimens using a fluorescence technique incorporating optical brighteners. Eight HIV infected patients with confirmed intestinal microsporidiosis (six with Enterocytozoon bieneusi, one with Encephalitozoon intestinalis and one with Encephalitozoon cuniculi infection) and 10 without infection were studied. Tissue sections of paraffin wax embedded duodenal biopsy specimens were stained with 1% Uvitex 2B, coded and analysed independently by two investigators. In all eight cases with confirmed intestinal microsporidian infection, spores could be detected easily in tissue sections using the fluorescence technique. Spores or other elements consistent with microsporidiosis were not found in the 10 patients without infection. Staining of tissue sections from paraffin wax embedded intestinal biopsy specimens with stains incorporating Uvitex 2B is a rapid and easy technique for the diagnosis of intestinal microsporidiosis.