Histologic abnormalities were confined to the liver, which contained numerous coalescing foci of necrosis and inflammation with myriads of long, slender gram negative rods. The histologic changes and bacterial morphology were compatible with a diagnosis of Tyzzer's disease. Avian, Brown-throated conure, Aratinga pertinax , Tyzzer's disease, hepatitis Introduction Tyzzer's disease is a systemic bacterial infection first described in mice in 1917 by Tyzzer, who named the causative agent Bacillus piliformis .
Histologic lesions are most common in the liver and intestine.
The disease usually affects young animals and presents as an acute, rapidly fatal disorder. 1 Tyzzer's disease has been reported in a wide range of wild, domestic, and laboratory mammalian species 2-7 but it appears to be rare in birds. No clinical abnormalities were apparent in the other 29 birds in the collection. Necropsy examination revealed only a very enlarged, mottled liver. Sections of liver, lung, kidney, pancreas, heart, and spleen were fixed in formalin and submitted for histologic examination.