Application of in situ viral nucleic acid hybridization to the study of Aujeszky\u27s disease (pseudorabies) in calves

摘要

This thesis is presented in the alternate format and it is composed of three interrelated but independent manuscripts;The first manuscript, titled \u22Pseudorabies in cattle: a review,\u22 is a critical rather than a historical review of much of the literature available on the subject. It focuses on the problem from the perspective of pathogenetic mechanisms, highlights opportunities for further research, raises questions about accepted views, and suggests that recently developed techniques may prove useful in gaining new insights about this particular infectious process;The second manuscript is titled \u22Comparative usefulness of tissue fixatives for in situ viral nucleic acid hybridization.\u22 It deals with the student\u27s efforts to adapt one of the newer research techniques for its use in pseudorabies-infected cattle tissues. The work was actually carried out with mice in order to limit expenses and conserve resources. It established that the available hybridization probes could detect the nucleic acids of pseudorabies virus effectively and specifically. In addition, the paper offers a detailed account of the various fixatives tested for degree of usefulness and compatibility with in situ hybridization. A modification of Carnoy\u27s fluid (MOCA) was devised and found to be well-suited for fixation of bulky cattle tissues;The third manuscript is titled \u22Reproducibility of in situ hybridization when applied to MOCA and formalin-fixed pseudorabies-infected cattle tissues.\u22 It documents the reproducibility of in situ hybridization as well as its degree of correspondence to quantitative virus isolation when it was applied to a wide range of MOCA-fixed, pseudorabies-infected bovine tissues. In addition, the paper offers the results of a limited retroactive study carried out with 7 year old formalin-fixed infected neural bovine tissues. Reliable specific in situ hybridization occurred in MOCA-fixed neural tissues, but suspicious, seemingly false positive reactions were not uncommon in other tissues, particularly those rich in lymphocytes and macrophages. A strong hybridization signal was present in the formalin-fixed material despite its age, so that type of material is suitable for retrospective studies.