Polyserositis and Meningitis Associated with Escherichia coli Infection of Piglets

Two piglets which had a history of anorexia and weakness were examined pre and postmortem. Other piglets in the same herd had died within 24 hours of the onset of similar signs. The two piglets examined had a fibrinous polyserositis. Grossly, the pleura, peritoneum and joints were affected and an acute meningitis was noted on microscopic examination of the brains. Pure cultures of Escherichia coli were recovered from all but one of the organs and exudates cultured.     

The relationship between insulin-like growth factor-1, growth hormone, thyroid hormones and insulin in chickens selected for growth

The concentrations of circulating insulin-like growth factor I, growth hormone, insulin and thyroid hormones were measured in broilers selected for an increase in growth, broilers in which selection pressure was relaxed and in White Leghorns. Growth hormone levels increased in all lines between 3 and 4 weeks of age followed by a decline to adult levels. The lines with the slowest rate of growth had the highest growth hormone concentrations. Insulin-like growth factor I concentrations increased significantly in all three lines of birds during the 10 weeks of study and was significantly correlated with the increase in body weight. There were no consistent differences in plasma IGF-1 levels between the lines. Thyroxine levels increased consistently throughout the study but the levels of triiodothyronine decreased between 5 and 6 weeks of age in all lines. There were no consistent changes in plasma insulin levels. The highest rate of growth in these animals is accompanied by an increase in growth hormone concentration followed by an increase in plasma IGF-1. However, despite differences in plasma growth hormone, plasma concentrations of IGF-1 are not different between lines and are not related to between line differences in growth rate.     

The kinetics of mononuclear phagocytes in normal calves given Corynebacterium parvum.

Two groups of calves, three in each group, were used to determine the kinetics of mononuclear phagocytes in normal calves and in calves given Corynebacterium parvum intravenously, using tritiated thymidine as an in vivo deoxyribonucleic acid label. In normal calves, the mean production time of labelled monocytes in the bone marrow was 36.4 +/- 2.04 hours. The turnover rate of labelled monocytes from the bone marrow into the peripheral blood was 5.4 +/- 0.3% per hour and the disappearance rate of labelled monocytes from the circulation was 0.9 +/- 0.3%. The half lives of labelled blood monocytes were 22.5 hours for cells with 16-30 grains and 19.5 hours for cells with 31-50 grains. Alveolar macrophages were derived from peripheral blood monocytes. In calves given C. parvum, the production time, turnover rate and half lives of labelled monocytes did not differ significantly (p greater than 0.05) from the values in normal calves.     

Pulmonary lesions induced by Pasteurella hemolytica in cattle.

Twelve four month old calves were inoculated intratracheally with a large dose of Pasteurella hemolytica and the lungs examined 18 hours, three days and seven days later. The gross and microscopic lesions were graded in each calf. The most extensive gross lesions were present at three days and were characteristic of a fibrinous pneumonia. Discrete areas of coagulation necrosis were present at three days and granulation tissue had formed around these by seven days. Characteristic swirly dark cells accumulated in alveoli and alveolar ducts and were observed from three days onwards. The gross and microscopic lesions were similar to those seen in field cases of pneumonic pasteurellosis.     

Pasteurella haemolytica cytotoxin: production by recognized serotypes and neutralization by type-specific rabbit antisera

A sterile culture supernatant from each of the 12 recognized serotypes of Pasteurella haemolytica was toxic to bovine alveolar macrophages when assayed by 51Cr release. Types appeared to differ in their ability to liberate cytotoxin, although this may have reflected strain variation rather than serotype-related differences. Toxicity was partially neutralized by type-specific rabbit antisera, with neutralization of the homologous toxin being more effective than that of the heterologous serotype.     

Immune response of pigs to parenteral vaccination with an aromatic-dependent mutant of Salmonella typhimurium.

Cellular and humoral immune responses to parenteral vaccination with an aromatic-defined (aroA) Salmonella typhimurium and to oral challenge with the S. typhimurium parent strain were examined in pigs. The effectiveness of aroA S. typhimurium vaccination for prevention of clinical disease following challenge was also evaluated. A split litter model was utilized and analysis of variance was by least squares. The statistical model accounted for the effects of vaccination and litter. Parenteral vaccination of pigs with the aroA mutant induced a significant O-polysaccharide (O-ps) specific lymphocyte blastogenic response as well as a significant antibody response to O-ps, lipopolysaccharide and killed bacteria. The aroA strain was avirulent in pigs, was not shed in the feces and significantly reduced the severity of diarrhea following oral challenge.     

Sequential titration of bovine lung and serum antibodies after parenteral or pulmonary inoculation with Pasteurella haemolytica

Calves were vaccinated by intrabronchial or subcutaneous injection of formalinized Pasteurella haemolytica. Antibody in serum, nasal washings, and bronchoalveolar washings was titrated sequentially before and after calves were vaccinated and then challenge exposed with live homologous bacteria. Bronchoalveolar washings were collected by fiberoptics bronchoscopy, and antibody was titrated by indirect (antiglobulin) bacterial agglutination. Responsiveness to vaccination was related in initial serum antibody concentrations. Calves with serum antibody titers of 1:20 or more were nonresponsive, whereas with few exceptions, calves having titers of less than 1:20 responded to vaccination. Results indicated that serum and lung antibody were induced by subcutaneous or by intrabronchial inoculation of formalinized P haemolytica. By either route of immunization, serum antibody was more persistent than was lung antibody, and pulmonary challenge exposure with live P haemolytica did not alter existing titers.     

Bovine Vibriosis: The Distribution and Specificity of Antibodies Induced by Vaccination and Infection and the Immunofluorescent Localization of the Organism in infected Heifers

Two groups of three Holstein heifers were immunized respectively with Vibrio fetus venerealis and Vibrio fetus intestinalis incorporated in Freund's complete adjuvant. Both serum and vaginal mucus agglutination titers increased following immunization. Vaginal mucus samples were more frequently positive when the homologous cells were used as antigen in the agglutination test.

Ten non-immunized heifers were inoculated with another strain of V. fetus venerealis and slaughtered at periods of 30 to 40 and 60 to 70 days post-inoculation (DPI). Agglutinating antibodies were present in the vaginal mucus of some infected individuals by five weeks post-inoculation. In the course of the experiment 11 vaginal mucus samples were obtained which agglutinated heated cells of the infecting strain; one aggglutinated whole cells. Precipitins toward homologous antigens could not be demonstrated in vaginal mucus but four of six samples tested precipitated a heat stable extract from an intestinal strain of the same O-serotype. Bacterial antigen was detected by immunofluorescence on the surface, as well as within and beneath the epithelium at all levels of the reproductive tract regardless of time of slaughter. Lesions in infected animals consisted of focal and diffuse lymphocytosis, plasmacytosis, and epithelial vacuolation. Diffuse neutrophilic infiltration of the oviducts was observed.

Agglutinins appeared in the serum of each of nine heifers immunized with whole cells of same venereal strain. Group mean serum titers for whole and heated cells were 1/28,000 and 1/1,300 respectively. Vaginal mucus samples agglutinated whole cells in 48% of tests while 6.3% reacted with heated cells. Serum, but not vaginal mucus, of immunized animals precipitated soluble antigens of the immunizing strain. The immunizing strain of V. fetus did not infect the reproductive tract of any of six immunized heifers upon challenge.