Case Report

Aspergillus Section Nigri-Associated Calcium Oxalate Crystals in an Eurasian Eagle Owl (Bubo bubo)

Figure 3

Eurasian eagle owl, air sac. (a),(b) The air sac wall was diffusely thickened by an exudate of fibrin, heterophils, and fewer macrophages with entrapped oxalate crystals. H&E stained section (a) with comparable view under polarized light (b). Polarized light with lower light intensity to better visualize the birefringent, entrapped oxalate crystals. Original objective 4x. (c) Oxalate crystals entrapped within the air sac wall (arrow). Crystals have the characteristic wheat sheaf and rosette arrangement for calcium oxalate. Original objective 20x.
(a)
(b)
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