Thesis (Ph. D.)--University of Wisconsin--Madison, 1959. / Typescript. Abstracted in Dissertation abstracts, v. 20 (1959) no. 3, p. 851. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 39-43).

Six 3 to 4 weeks old, cesarian-derived lambs were inoculated with ovine an adenovirus isolate 475N. Inoculated lambs showed moderate clinical signs of respiratory distress, conjunctivitis, and loose feces during the 10-day observation period. Virus was detected from nasal and conjunctival swabs starting on postinoculation day (PID) 2. Virus was detected in the feces in a inconsistent fashion. At necropsy, virus was present in the lung, tonsils, and bronchial and mediastinal lymph nodes of lambs necropsied on PID 5 and 7. Tissue samples from gastrointestinal tract and kidney were negative for the virus. Presence of virus in the feces was believed to be from replication in tonsillar tissue. At necropsy, lambs showed signs of pneumonia and numerous intranuclear inclusion bodies were detected in affected lung tissue. Virus neutralizing antibodies appeared at low levels in serum on PID 6 and reached higher levels by PID 10. Six ovine adenovirus prototype species, three uncharacterized ovine and bovine adenoviruses isolates and two uncharacterized llama adenoviruses isolates were digested with four different restriction enzymes. Digested viral DNA was separated in 0.7% agarose gels. The enzymes Barn HI, Eco RI, Hind III, and Pst I digested viral DNA and produced 2-10 bands. The profile of the band distribution permitted the differentiation of the viruses under study. However, further studies using multiple isolates of each species are required to determine if this procedure will efficiently distinguish different species of ruminant adenoviruses. Ten adenoviruses from sheep (including the six prototype species), one from bovine and one from llama were studied by virus neutralization test to determine their degree of antigenic similarities. Reciprocal virus neutralization tests were performed and the degree of antigenic similarities, i.e., strain differentiation was determined by criteria established by the International Committee for the Nomenclature of Viruses. Isolates 32CN (a bovine adenovirus) and 475N (an ovine adenovirus) were antigenically identical and not neutralized by any of the prototype species antiserum. They are candidates for a new species of ruminant adenoviruses. Ovine adenovirus isolate 47F was shown to be a member of OAV-5 species while the llama adenovirus strain represents a newly recognized species for this animal. / Graduation date: 1996

A cohort study was conducted in order to measure the effect of the chronic indurative lymphocytic mastitis caused by the South African strain ofMaedi visna virus (SA-OMVV) on the pre-weaning growth of lambs born of naturally infected and uninfected ewes kept under similar conditions. 50 naturally infected ewes and 40 controls from an MVV-free source were purchased and kept separately. All ewes were of the same breed - the Dorper¬and 3 to 4 years old. From the adaptation period, through mating, pregnancy and lactation periods they were monitored for MVV antibodies and managed under similar conditions. The lambs were weighed at birth and thereafter every two weeks until the age of 90 days, when they were weaned. The ewes were slaughtered, their udders examined histologically and the lesions were assessed by counting typical lymphocytic follicles. Although the observed values indicated a correlation between the number of follicles in the udder and the reduction in the growth rate of the lambs, this was not statistically significant. Similarly, despite higher counts of lymphoid follicles in the udder of sero-positive ewes as compared to sero-negatives and the observed lower ewe productivity indexes (EPI) in infected ewes, no statistically significant differences were found in the EPI of ewes in different follicle categories. The present study was a first attempt to evaluate the effect of the SA-OMVV infection on sheep productivity in South Africa. / Dissertation (MSc)--University of Pretoria, 2000. / Production Animal Studies / Unrestricted

Bluetongue virus belongs to the Orbivirus genus from the Reoviridae family. It infects predominantly domestic and wild ruminants and is economically significant worldwide. Bluetongue virus VP7 forms the intercepting layer between the outer capsid (VP2 and VP5) and VP3 which surrounds the genomic material. BL21(DE3), NiCo21(DE3), C43(DE3) pLysS and KRX Escherichia coli cells were transformed with a pET28a plasmid with the cDNA sequence encoding Bluetongue virus VP7. Expression of Bluetongue virus VP7 was tested at post induction temperatures between 16˚C and 37 ˚C, at inducer concentrations between 0.1 mM and 1.0 mM isopropyl-β-D-thiogalactopyranoside in BL21(DE3), NiCo21(DE3) and C43(DE3) pLysS cells and 0.05 % and 0.15 % rhamnose for KRX cells, in two types of growth media (LB and 2xYT) and post-induction growth times between two and 16 hours. Under all conditions tested; Bluetongue virus VP7 expression was found to be predominantly in the insoluble fraction (pellet). BL21(DE3) and NiCo21(DE3) cells were chosen and grown for five hours post induction, induced with 0.1 mM isopropyl-β-D-thiogalactopyranoside and grown at a post-induction temperature of 37 ˚C. Bluetongue virus VP7 in bacterial cell inclusion bodies was solubilised using urea and a freeze-thaw step. Solubilisation was tested with urea concentrations between 2 M and 8 M, with solubilisation efficiency not increasing past 5 M urea. Solubilized Bluetongue virus VP7 was purified using nickel-affinity chromatography. Purified Bluetongue virus VP7 was then probed with far-UV circular dichroism and intrinsic fluorescence in several buffer conditions including different urea and guanidinium chloride concentrations as well as in the presence of glycerol and sodium chloride. Guanidinium chloride was able to cause Bluetongue virus VP7 unfolding, and the unfolding transition had 94 % and 89 % reversibility at 218 nm and 222 nm respectively. Bluetongue virus VP7 was shown to contain a native-like structure in 20 % glycerol and in up to 8 M urea and was found to be stable till at least 55 ˚C, even in the presence of 5 M urea. Glycerol and sodium chloride influenced the conformation of the protein resulting in different unfolding transitions. Thermal unfolding of Bluetongue virus VP7 was found to be irreversible. / Life and Consumer Sciences / M. Sc. (Life Sciences)