Stain techniques for detection of Encephalitozoon cuniculi in tissue sections

In this study, it was investigated different staining techniques applied to histological sections for identification of Encephalitozoon cuniculi. It was used liver fragments from Balb-c mice immunosuppressed with cyclophosphamide and inoculated with spores of Encephalitozoon cuniculi. The histological paraffin embedded sections were stained with hematoxylin-eosin (H-E), modified trichrome, Gram-Chromotrope, Giemsa, Brown-Hopps, PAS, Ziehl-Neelsen, and Grocott and also by the technique of calcofluor. Toluidine blue-fuchsin and toluidine blue stainings were used for the cuts embedded in plastic resin. Gram-Chromotrope, Brown-Hopps and Ziehl-Neelsen staining techniques permitted the best visualization of the spores for the diagnosis of E. cuniculi in histological paraffin embedded sections, since they allowed the clear differentiation of the spores among other tissue structures. In tissues embedded in plastic resin, toluidine blue-fuchsin and toluidine blue stainings also facilitate the finding of the agent. On the other hand, the trichrome technique showed great variability on results, therefore, allowing the identification of the parasite in tissue. The other techniques, H-E, calcofluor, Grocott, Giemsa and PAS did not permited the easy identification of the E. cuniculi spores.