Systemic microsporidiosis in inland bearded dragons (Pogona vitticeps)

One laboratory-hatched and -reared inland bearded dragon (Pogona vitticeps) (No. 1) and two privately owned inland bearded dragons (Nos. 2 and 3) died, showing nonspecific signs of illness. Light microscopic examination of hematoxylin and eosin-stained tissue sections from lizard No. 1 revealed severe hepatic necrosis with clusters of light basophilic intracytoplasmic microorganisms packing and distending hepatocytes and free in areas of necrosis. Similar microorganisms were within cytoplasmic vacuoles in distended renal epithelial cells, pulmonary epithelial cells, gastric mucosal epithelial cells, enterocytes, and capillary endothelial cells and ventricular ependymal cells in the brain. In lizard Nos. 2 and 3, microorganisms of similar appearance were in macrophages in granulomatous inflammation in the colon, adrenal glands, and ovaries. The microorganism was gram positive and acid fast and had a small polar granule that stained using the periodic acid-Schiff reaction. Electron microscopic examination of deparaffinized liver of lizard No. 1 revealed merogonic and sporogonic stages of a protozoan compatible with members of the phylum Microspora. This report provides the first description of microsporidiosis in bearded dragons and is only the second report of this infection in a lizard.