Electron microscopic studies on the interaction between normal mice peritoneal phagocytes and Treponema hyodysenteriae, Treponema innocens and Bacteroides vulgatus.

One hundred and twenty female mice (CF1 strain) were divided into three groups of 40. The first group was injected intraperitoneally with broth cultures of Treponema hyodysenteriae. The second group was injected with a combination of T. hyodysenteriae and Bacteroides vulgatus. The third group was injected with Treponema innocens. Peritoneal wash from four mice of each group was collected at eight time intervals postinjection, then prepared for and examined by light and electron microscopy. Peritoneal wash from one mouse at each time interval was prepared for microbiological examination. Treponema hyodysenteriae produced peritoneal macrophage aggregation, transient neutrophilia and macrophage cytolysis. Cytolysis was characterized by rarefaction of the cytoplasm, vesiculation of the endoplasmic reticulum, mild swelling of the mitochondria and disruption of the nuclear and ctyoplasmic membranes. The combination of T. hyodysenteriae and B. vulgatus produced macrophage aggregation and marked neutrophil necrosis. Peritoneal macrophages phagocytized more T. hyodysenteriae than B. vulgatus during early postinjection intervals. Treponema innocens failed to produce cytotoxicity of peritoneal macrophages but did produce macrophage aggregation and transient neutrophilia. Treponema hyodysenteriae and T. innocens did not multiply in the mice peritoneal cavity and were reisolated up to 16 hours postinjection. Bacteroides vulgatus was reisolated up to 24 hours postinjection.     

Swine dysentery: studies of gnotobiotic pigs inoculated with Treponema hyodysenteriae, Bacteroides vulgatus, and Fusobacterium necrophorum

Transmission experiments were carried out in gnotobiotic pigs to determine whether lesions typical of swine dysentery could be produced by oral inoculation of Treponema hyodysenteriae in combination with Bacteroides vulgatus or Fusobacterium necrophorum, or both. Each of the organisms had been isolated from swine with early lesions of the disease. Lesions were not found in 6 pigs inoculated with T hyodysenteriae alone, in 4 pigs given F necrophorum and T hyodysenteriae, or in 4 pigs given B vulgatus and F necrophorum. Lesions typical of swine dysentery developed in 8 pigs given B vulgatus, F necrophorum, and T hyodysenteriae as well as in 3 of 4 pigs given B vulgatus and T hyodysenteriae. In both of these groups, the inoculated bacteria were recovered from the colon, and T hyodysenteriae was demonstrated in the colonic crypts, epithelium, and lamina propria. The pathogenicity of the T hyodysenteriae was shown by the development of characteristic signs and lesions of swine dysentery in 12 of 14 naturally farrowed pigs inoculated with T hyodysenteriae alone.     

Immunochemical studies on a Brucella ovis specific protein antigen

A Brucella ovis surface protein antigen (P-II), obtained by gel filtration with Sepharose 4B of a hot saline extract was characterized. The analysis of P-II over gradient sodium dodecylsulfate electrophoresis yielded an 18.5 and a 20 kDa band. In a radioimmunoprecipitation assay using P-II labeled with 125I, the antigen reacted specifically only with sera from rams experimentally infected with a naturally occurring rough strain of B. ovis and did not react with sera from rams experimentally infected with other smooth Brucella strains (B. abortus and B. melitensis).     

Workshop studies with monoclonal antibodies identifying a novel porcine differentiation antigen, SWC9

Two monoclonal antibodies (mAb) within cluster M4 of the myeloid section of the Second International Swine CD Workshop, C4 (No. 144) and PM18-7 (No. 192), showed reactivity with thymocytes and among cells of myelomonocytic origin with mature macrophages but not with monocytes and granulocytes. Both mAb recognize a protein showing two bands of 205 kDa and 130 kDa under both reducing and non-reducing conditions. Although epitope mapping with these mAb could not be performed, this cluster received the SWC9 designation.     

A history of the Pathological Division of the Bureau of Animal Industry, United States Department of Agriculture, between 1891-1921

As part of a continuing historical study of the evolution of the discipline of veterinary pathology in North America, this paper relates the role played by the Pathological Division of the Bureau of Animal Industry (BAI), formerly a unit of the United States Department of Agriculture. The work of this division of the BAI during its first three decades is examined with respect to its leadership, activities and attainments, and these are compared with similar activities in veterinary colleges and state experiment stations in the United States and in foreign veterinary colleges and research establishments. The Pathological Division devoted a good deal of its efforts to the production of biologic prophylactic products, with resounding success in controlling blackleg and other diseases. Its other activities were in laboratory diagnostic work and in research into animal diseases. The picture that emerges in those spheres is of an organizational unit that despite its name, made little use of the approaches and methods of pathology, but rather availed itself of the tools of microbiology whether or not these were appropriate. In so doing, it lagged considerably behind the comparable institutions both in the United States and abroad.     

Effect of levamisole on the clinical and immunologic responses to oral vaccine of Treponema hyodysenteriae

Conventionally raised crossbred Hampshire pigs were vaccinated orally with attenuated Treponema hyodysenteriae in combination with an anthelmintic, levamisole or dichlorvos. Pigs in group I (n = 9) were treated with levamisole and vaccinated with attenuated T hyodysenteriae and those in group II (n = 9) were treated with levamisole and permitted to commingle (contact exposure) with group I. Pigs in group III (n = 9) were vaccinated in a similar manner and were treated with dichlorvos. Pigs in group IV (n = 9) were treated with dichlorvos and permitted to commingle with group III. Control pigs (group V; n = 9) were not given any anthelmintic, nor were they vaccinated; they were housed separately. During the 8-week interval between vaccination and challenge inoculation, 4 total days and 8 total days of diarrhea were observed in pigs in groups I and II, respectively. Likewise, 5 total days and 10 total days of diarrhea were seen in groups III and IV, respectively. In all groups, the pigs tended to shed the organism in their feces after they were vaccinated or challenge inoculated, as determined by a fluorescent antibody technique (FAT) and culture procedure (CP). Overall mean shedding patterns of 5.5% and 24.5% identified by CP and FAT, respectively, were seen in the 2 levamisole-treated groups (I and II). In contrast, mean shedding patterns of 4% and 18% of the isolation attempts were detected by CP and FAT, respectively, in the 2 dichlorvos-treated groups. Diarrhea and shedding of T hyodysenteriae in the controls (group V) did not occur.(ABSTRACT TRUNCATED AT 250 WORDS)