Encephalitozoon pogonae–Associated Systemic Vasculitis in a Central Bearded Dragon (Pogona vitticeps)

What is your diagnosis? A blood film and saliva direct smear from two inland bearded dragons (Pogona vitticeps)

“…Microsporidia are obligate intracellular atypical fungi which can infect a wide variety of animal hosts, including humans. [2][3][4][5] Rare reports of microsporidial infections exist in various reptile species, including lizards, tuatara, snakes, and crocodiles. 6 Phylogenetic data first obtained in 2013 led to the establishment of the species Encephalitozoon pogonae in 2016 as the only known etiologic agent of microsporidiosis in bearded dragons.…”

“…6 Infected bearded dragons, often subadults and adults, typically develop multifocal and multisystemic distributions of granulomatous to necrogranulomatous inflammation with surrounding lymphoid infiltrates. [2][3][4][5][6][7] Hematology data have not been reported in prior publications; however, there are multiple reports of vascular tropism, which may explain the novel finding of microsporidial organisms in the peripheral blood of Case 1. 4,7 On histopathologic review of granulomatous foci, microsporidial organisms can be recognized as 1-3 μm, refractile, intrahistiocytic oblong spores within a parasitophorous vacuole in which all stages develop.…”

“…[2][3][4][5][6][7] Hematology data have not been reported in prior publications; however, there are multiple reports of vascular tropism, which may explain the novel finding of microsporidial organisms in the peripheral blood of Case 1. 4,7 On histopathologic review of granulomatous foci, microsporidial organisms can be recognized as 1-3 μm, refractile, intrahistiocytic oblong spores within a parasitophorous vacuole in which all stages develop. [3][4][5][6][7] In the two present cases, presumptive parasitophorous vacuoles were discernible in Case 1 and may have been absent in Case 2 due to slide preparation artifact.…”

“…4,7 On histopathologic review of granulomatous foci, microsporidial organisms can be recognized as 1-3 μm, refractile, intrahistiocytic oblong spores within a parasitophorous vacuole in which all stages develop. [3][4][5][6][7] In the two present cases, presumptive parasitophorous vacuoles were discernible in Case 1 and may have been absent in Case 2 due to slide preparation artifact. The organisms typically stain Gram-positive, with variably positive staining for PAS, Giemsa, silver, and acid-fast stains.…”

“…The organisms typically stain Gram-positive, with variably positive staining for PAS, Giemsa, silver, and acid-fast stains. [3][4][5][6][7] On transmission electron microscopy, E. pogonae spores have a thin outer exospore, thick inner endospore, 3-6 polar filament coils, a mushroom-shaped polar disk, and a polar sac within approximately half of the volume of the lamellar polaroplast. [5][6][7] Definitive diagnosis is obtained via PCR of affected tissues.…”