Pathological and mycological characterization of pulmonary Aspergillus fumigatus infection producing gliotoxin in a captive African grey parrot (Psittacus erithacus)

Aspergillosis, the main causative agent of which is Aspergillus fumigatus, causes mortality in all types of birds. Gliotoxin (GT), one of the multiple virulence factors of A. fumigatus, has a variety of immunosuppressive effects. The corpse of an African grey parrot (Psittacus erithacus) was sent for necropsy and diagnostic rule-out. The lungs were enlarged, firm, and had dark-red coloration, on the parietal faces of both lungs, some semi-circular caseous necrosis areas were observed. The caudal thoracic and abdominal air sacs were thickened and contained a fibrin-heterophilic exudate. Histopathologically, a necrotic and granulomatous bronchopneumonia was observed with intralesional hyphae with characteristics compatible with Aspergillus sp. that were positive with Grocott´s staining. Fibrinous and heterophilic airsacculitis was found in the air sacs. A. fumigatus was isolated from lungs, characterized using serial microcultures, and confirmed using polymerase chain reaction. In addition, GT production was detected in vitro from the culture filtrate in which the isolate was grown; the organic extract was analysed via thin-layer chromatography. This is the first detection of GT in a case of pulmonary aspergillosis in a parrot, which could help to understand the pathogenesis of the disease in psittacines.