Laboratory Diagnosis of Microsporidia

The Microsporidia are a phylum containing over 1200 species. Since the mid-1980s, these organisms have been increasingly identified as agents of human disease in patients with HIV infection. Detection of microsporidia can also be done by histologic examination of tissue specimens fixed by formalin or by electron microscopy of tissues fixed with glutaraldehyde. The staining techniques include chromotrope stains, Gram or Giemsa stain, and fluorescein-tagged antisera. Nucleic acid-based detection methods utilize synthetic DNA molecules that are specific and complementary to a sequence in the DNA of the pathogen. Antigen-based detection methods such as the immunofluorescence assays (IFA), enzyme-linked immunosorbent assay (ELISA), and Western blot (WB) use antibodies from experimentally immunized animals to recognize characteristic pathogen-specific antigens. Antibody-based detection method is used as a supplement to conventional histological techniques. Detailed histopathology of human microsporidiosis has mostly been performed in patients with immune deficiencies.