title: A retrospective study of the prevalence of calcium oxalate crystals in veterinary Aspergillus cases.
abstract: Fungi in the genus Aspergillus are some of the most common fungal pathogens in veterinary species, primarily affecting the respiratory tract. In both human and veterinary cases, calcium oxalate crystals have been documented in sites of Aspergillus infection. Cases in multiple species (16 birds, 15 horses, 5 dogs, 1 ox, and 1 dolphin) were identified that had either positive cultures for Aspergillus sp., or had conidiophores present that could be identified as belonging to the genus Aspergillus. Histologic slides were examined to confirm the presence of oxalate crystals and how often they were identified on the original report. Calcium oxalate deposition was detected in 14 of 38 cases examined, including A. fumigatus, A. versicolor, A. niger, and unspecified Aspergillus sp. infections. Calcium oxalate crystals were identified in 11 of 16 avian cases, as well as in 1 of 1 bovine, 1 of 15 equine, and 1 of 5 canine cases. Crystals were described in only 3 of the 14 original pathology reports of these cases, indicating that identification and reporting of crystals in histologic specimens could be improved. All the tissues with crystals were respiratory tissues with air interfaces, including nasal sinus, trachea, syrinx, lung, and air sac. In cases with crystals identified on H&E-stained sections, crystals were frequently not present or were fewer in number in tissue sections stained with Gomori methenamine silver and periodic acid-Schiff. Routine polarization of slides of fungal infections, especially in the respiratory tract, should be considered to check for calcium oxalate crystals.
authors.affiliation: Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, Gainesville, FL.
authors.forename: Courtney L
authors.initials: CL
authors.lastname: Payne
authors.affiliation: Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, Gainesville, FL.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Dark
authors.affiliation: Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, Gainesville, FL.
authors.forename: Julia A
authors.initials: JA
authors.lastname: Conway
authors.affiliation: Department of Infectious Diseases and Pathology, College of Veterinary Medicine, University of Florida, Gainesville, FL.
authors.forename: Lisa L
authors.initials: LL
authors.lastname: Farina
mesh_terms: D000818:Animals; D001228:Aspergillosis / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D001234:Aspergillus niger / Q000302:isolation & purification*; D001717:Birds; D002129:Calcium Oxalate / Q000032:analysis*; D002417:Cattle; D004285:Dogs; D004289:Dolphins; D006736:Horses; D008172:Lung Diseases, Fungal / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D015995:Prevalence; D012189:Retrospective Studies; D013194:Staining and Labeling / Q000662:veterinary
chemical_list: D002129:Calcium Oxalate
keywords: Aspergillus; birefringence; calcium oxalate; polarization microscopy