A syndrome associated with growth depression and amyloid arthropathy in layers: a preliminary report.

In heavy breed layers a new syndrome was encountered, associated with impaired growth. The disease developed from 5 to 6 weeks onwards. Morbidity in most flocks was 1 to 4%, but in some cases up to 20%. The affected birds were smaller in size, made a peeping sound like that of younger chickens, and showed a characteristic stiff gait. The stifle and hock joints were swollen. At necropsy 12 out of 66 affected birds (18%) had bronze-coloured livers and 23 out of 66 (35%) had orange-coloured joint deposits. Histology indicated that these birds appeared to have amyloidosis. The amyloid was found to react positively with anti-duck and anti-bovine amyloid protein A antisera on PAP-staining, indicating it to be of the reactive type. The cause of the syndrome is unknown. A possible association with infectious agents (Streptococcus faecalis and reovirus) is discussed.