The present study was conducted to investigate the Bordetella bronchiseptica infection in Youngnam swine herds during the period of August 1986 to July 1987 and some properties of the organisms isolated from these Korean swine. B. bronchiseptica was recovered from 25 of 70 (35.7%) growing pigs of 4 to 10 weeks of age and from 12 of 13 (92.3%) herds. From 115 slaughter pigs, 58(50.4%) pigs were culture positive and the pigs from 13 of 14 (92.9%) herds were found to be infected with B. bronchiseptica. The majority of biochemical and cultural properties of B. bronchiseptica isolated from Korean swine were identical to those of the standard strain employed and some 97.6% of the isolates showed the characters of phase I organism on primary isolation.

Rabbits were given T-2 mycotoxin orally at 0, 0.25, 0.5, and 0.75 mg/kg of body weight/day for 21 days. Only rabbits in the 0.75 mg/kg/day group (4 of 5 rabbits) died. Alveolar macrophages were harvested on day 22 and used for in vitro phagocytosis of killed Aspergillus fumigatus conidia. Cultures included sera from untreated rabbits or rabbits treated with T-2. Phagocytosis was significantly (P < 0.01) reduced in cultures that used serum from rabbits treated with 0.5 mg of T-2kg/day and alveolar macrophages from untreated rabbits or rabbits treated with T-2. There was little reduction in phagocytosis when alveolar macrophages from rabbits treated with T-2 and normal serum were used. Ingestion of 0.5 mg of T-2 toxin/kg/day significantly (P < 0.05) reduced weight gain, serum alkaline phosphatase activity, serum sorbitol dehydrogenase activity, and serum bacteriostasis. Similar changes were found in the 0.75 mg/kg/day group, as well as a significant (P < 0.05) reduction in PCV, total WBC, and differential leukocyte counts. Neutrophil counts decreased, but not significantly (0.05 < P < 0.10). Significant changes were not detected in alanine transaminase activity, aspartate transaminase activity, blood urea nitrogen concentration, or complement hemolytic activity. Histopathologic changes consisting of centrilobular hepatocellular swelling, mild portal and periportal fibrosis and lymphocyte necrosis within secondary lymphoid tissues developed in most rabbits treated with T-2. Thymic atrophy, bile duct reduplication, and lymphocyte depletion of secondary lymphoid tissues developed in the group given 0.75 mg/kg/day. Severity of lymphoid depletion in secondary lymphoid tissues was greatest in the appendix and decreased in the following order: appendix > sacculus rotundus > ileal Peyer patches > lymph nodes and spleen. In this study, we provide additional data showing that, at these oral doses of T-2 toxin, rabbits could be immunosuppressed, as evidenced by reduced alveolar macrophage phagocytosis and histopathologic changes in lymphoid tissues. Also, these doses caused reductions in weight gain, certain hematologic factors, and serum alkaline phosphatase and sorbitol dehydrogenase activities.

Holstein cow 1 was examined because of skin fragility and delayed healing of skin wounds, which were markedly exacerbated around the time of parturition. A skin biopsy sample was obtained, and light microscopy revealed irregular deposition of thin collagen fibers in a dermal matrix. Although diffuse inflammation did not occur, the number of plump fibroblasts was increased. Electron microscopy revealed poor construction of collagen fibrils in the dermal matrix. Biochemical analysis of the dermis revealed a normal amount of collagen and uronic acid, but sodium dodecyl sulfate-polyacrylamide gel electrophoresis reveled an increased proportion of soluble alpha-, beta-, and gamma-collagen chains of normal molecular weights. Neither procollagen nor its intermediates devoid of amino- or carboxy-terminal extension peptide were observed. Dermal collagen from cow 1 was more soluble in a neutral salt solvent, 0.5M acetic acid, and the acid containing pepsin than was dermal collagen from healthy cow 2. The peptic digestion profile of dermis from cow 1 revealed a lowered degree of intermolecular cross-linking and destabilization of helical structure in the dermis collagen. The extrahelical peptic cleavage of collagen before cyanogen bromide digestion resulted in release of more fragments derived from carboxy-terminal part of alpha1 chains in dermis of cow 1 than in dermis of healthy cow 2.