Systemic amyloid A amyloidosis secondary to chronic enteritis in a captive little owl (Athenenoctua)

A male little owl (Athene noctua), approximately 2 years old, collapsed and subsequently died. Grossly, there was hepatomegaly with minimal chalky white lesions on the serosal surface of the liver. The serosal surface of the intestines was also tan to chalky white. Histologically, amorphous eosinophilic material was deposited in the vascular walls and interstitium of many organs, including endoneurial microvessels and perivascular interstitium. These deposits were consistent with amyloid and positive for anti-serum amyloid A (SAA) antibody on immunohistochemical labelling. On mass spectrometry-based proteomic analysis, high levels of SAA were detected. This report provides descriptive details of the histopathological and immunohistochemical findings and mass spectrometry-based proteomic analysis and genetic analysis of systemic amyloidosis with deposition in the peripheral nervous system in a little owl.