Publication Abstract

The Luna stain, an improved special stain for detection of microsporidian spores in histological sections

T.S. Peterson, J.M. Spitsbergen, S.W. Feist* and M.L. Kent

Microsporidia in histological sections are most often diagnosed by observing spores in host tissues. Spores are easy to identify when they occur in large aggregates or xenomas when sections are stained with hematoxylin and eosin (H&E). However, individual spores are not frequently detected in host tissues with conventional H&E staining, particularly if spores are scattered within the tissues, areas of inflammation or small spores in nuclei (i.e., Nucleospora salmonis).   Hence, a variety of selective stains that enhance visualization of spores are recommended.   We discovered that the Luna stain, used to highlight eosinophils, red blood cells and chitin in arthropods, also stains spores of Pseudoloma neurophilia. We compared this stain to the Gram, Fite’s acid fast, Giemsa, and H&E stains on eight other aquatic microsporidian organisms that were readily available in our two laboratories: Loma salmonae, Glugea anomala, Pleistophora hyphessobryconis, Pleistophora vermiformis, Glugea sp., Steinhausia mytilovum, cf. Endoreticulatus eriocheir). Based on tinctorial properties and background staining, the Luna stain performed better for detection of 7 of the 9 microsporidia (Gram stain was superior for the two microsporidia from invertebrates, Steinhausia mytilovum and  E. eriocheir).

Reference:

T.S. Peterson, J.M. Spitsbergen, S.W. Feist* and M.L. Kent (2011)The Luna stain, an improved special stain for detection of microsporidian spores in histological sections. Diseases of Aquatic Organisms 95:175-180.