Experimental ovine mastitis. A pathologic study

Strains of Staphylococcus aureus, Corynebacterium pyogenes, and Corynebacterium ovis isolated from naturally occurring, cases of ovine mastitis in Egypt were inoculated unilaterally via the teats into the mammary glands of 20 native-bred ewes, and the course and pathogenesis of the resulting changes were described.

One ewe of the group infected with S. aureus developed mastitis acuta gravis. The other ewes of this group had Galactophoritis et Mastitis catarrbalis chronica et acuta. The ewes infected with G. pyogenes or with mixed G. pyogenes and S. aureus developed Galactophoritis et Mastitis catarrbatis purulenta acuta et chronica. The ewes infected with C. ovis had Mastitis apostematosa chronica. The mastitis was unilateral in all animals.

Experimental bacillary hemoglobinuria. II. Pathogenesis of the hepatic lesion in the rabbit

Bacillary hemoglobinuria was expertmenially induced in rabbits by intravenous inoculation with Spores of Clostridium bemolyticum and subsequent hepatic biopsy. The biopsy wound disrupted the hepatic vasculature and damaged the adjacent parenchyma. This damage and the resulting hypoxia created conditions favorable for the germination of the inoculated spores. As the bacteria proliferated, their exotoxin lysed the hepatocytes and the erythrocytes in the immediate area. The bulk of the hepatic necrosis in bacillary hemoglobinuria was due to this exotoxin. Vascular thrombi caused by the exotoxic damage enhanced the development of the lesion.