Myopathy in the nyala.

Between January 1973 and June 1981, a total of 21 nyalas (Tragelaphus angasi) died with clinical and/or pathologic evidence of myopathy. The main clinical signs were stiffness, inability to rise, and failure to suckle in newborn fawns. Death usually occurred without premonitory signs of disease. Gross lesions were characterized by white or pale patches of skeletal or cardiac muscle. Histologically, acute degeneration or necrosis and mineralization were commonly observed in skeletal muscle. Acute necrosis of the myocardium with or without arteriolar fibrinoid necrosis was usually found in juvenile animals. Interstitial fibrosis of the myocardium with arteriosclerosis was commonly observed in adults. The plasma alpha tocopherol values of 3 affected nyalas ranged from 0.03 to 0.08 mg/dl (mean, 0.05 mg/dl). Unaffected nyalas from the same herd had a range of 0.09 to 0.24 mg/dl (mean, 0.13 mg/dl), which is low enough to be considered clinically deficient. The blood selenium values of the affected nyalas and other nyalas from the same herd ranged from 0.30 to 0.33 ppm (mean, 0.32 ppm), and were considered normal.