Canadian journal of comparative medicine and veterinary science最新文献

Six strains of African swine fever (ASF) virus were propagated in culture of primary pig kidney (PK) cells. The course of virus growth was followed by means of the fluorescent antibody staining technique. All 6 strains multiplied in the cultures, and 5 of these eventually showed cytopathic effects leading to cell death. Three of the strains were tested for pathogenicity in pigs at various passage levels. Each showed evidence of modification in virulence after a relatively few passages in PK cells. In one case modified virus produced resistance to challenge with homologous virulent virus. All strains rendered the PK cultures capable of hemadsorption of pig erythrocytes.

Five antigenic types of enteric viruses from swine in the Toronto area were characterized as members of the enterovirus subdivision of the picornavirus group. The criteria used in the characterization of these viruses were those established by the International Enterovirus Study Group.

A successful method for low temperature preservation of bull semen was modified for use with boar semen. Observations were made on the effects of varying cooling rate, equilibration time, freezing rate, glycerol concentration, method of glycerol addition, packaging containers, extender pH and tonicity. Observations indicate that boar semen should be cooled and frozen at a slower rate than bull semen. Within the ranges or methods examined, the other factors had little effect on recovery of motility after freezing.

The successful propagation of porcine cytomegalic inclusion disease virus (inclusion-body rhinitis virus) in primary pig lung cell cultures is reported. CID virus was carried through five passages in cell cultures with cytopathic affects appearing from 11 to 18 days post-inoculation. Four pigs inoculated with infected cell culture fluids from the second cell culture passage remained clinically normal. Two, however, had typical inclusion bodies in the glands of the nasal mucosa when examined three weeks post-inoculation. The progressive cytopathic effect produced and the inclusion bodies formed by this strain of porcine CIDV are described. These inclusion bodies appeared to be similar to those formed by cell culture-propagated cytomegaloviruses of man, mouse and guinea pig.

Isolation of IgG-slow by anion exchange chromatography is described. The turnover of IgG-I(131) has been studied in 10 cows, 5 of which were hyperimmunoglobulinemic, i. e. with serum immunoglobulin levels above 3.0gm/100 ml. These hyperimmunoglobulinemias were caused mainly by pyogenic infections. When these cows were compared with 5 normoimmunoglobulinemic cows the salient turnover data were, high fractional turnover rates, short plasma half lives, low Ev:Iv ratios and extended plasma volumes (table I). The results are discussed in relation to similar findings in other animal species and man. Possible mechanisms of the observed hypercatabolism are outlined.

Alkaline phosphatase activity was recorded in forty ejaculates of the sperm rich fraction of boar semen as 9,790 +/- 5,250 Klein-Babson-Read units per 100 ml. of seminal plasma. Acid phosphatase activity in the same ejaculates was 681 +/- 304 Babson-Read units per 100 ml. of seminal plasma. No alkaline phosphatase activity was detected in the seminal plasma of vasectomized boars. The pH of the sperm rich fractions was 7.69 +/- 0.33 and the osmotic pressure was 313.56 +/- 7.98 milliosmols.

A number of enteric viruses isolated from swine in the Connaught Medical Research Laboratories and the Mimico Reformatory herds were grouped serologically and compared with previously described porcine enteroviruses. Four of five antigenic types defined were related to other porcine enteroviruses. The fifth was unrelated to any viruses with which it was compared in this study.

Formalized African horse-sickness (AHS) type 9 virus cultivated in monkey kidney stable (MS) cell cultures was experimentally used for immunizing horses. Inactivated vaccines prepared either from viscerotropic or neurotropic type 9 AHS virus produced antibodies in vaccinated horses. Immunity developed in all horses vaccinated with various amounts of the vaccine, and protected them from infection, when challenged 5 weeks after vaccination.