Systemic amyloidosis in laying Japanese quail

Systemic amyloidosis was seen in laying Japanese quail in a flock of a farm rearing 95,000 birds. The clinical signs included decreased egg production, anorexia, white diarrhea, and subcutaneous abscesses of the head. Histologically, amyloid deposited predominantly in the spleen and liver. In addition, there were lesser degrees of amyloidosis in other organs (pancreas, kidney, heart, lung, gastrointestinal tract). Amyloid stained positively with Congo red and thioflavin T. Immunohistochemically, amyloid substance stained positively against amyloid A protein, but not with amyloid protein derived from light chains of immunoglobulins, transthyretin of familiar amyloid polyneuropathy, amyloid protein of dermal amyloidosis, nor amyloid P component. Ultrastructurally, amyloid substance consisted of many nonbranching amyloid fibrils about 10 nm in diameter.