Thesis (M.Sc.) (Microbiology)-University of Pretoria, 2005. / Abstract in English. Includes bibliography. Available on the internet via the World Wide Web.

No description available.

Thesis (MSc. (Paraclinical Sciences, Veterinary Science)--University of Pretoria, 2009. / Includes bibliographical references. Also available in print format.

Thesis (M.S.)--Ohio State University, 2005. / Includes bibliographical references (leaves 86-91). Available online via OhioLINK's ETD Center

No description available.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 67-76). Also available via the Internet.

Thesis (D. Phil. (Microbiology))--University of Pretoria, 2006. / Includes bibliographical references. Available on the Internet via the World Wide Web.

In response to an epidemic of rabies in the mid-Atlantic region, the Virginia Department of Health and the Consolidated Laboratory Services in 1982, redesigned their submission forms for animals being tested for rabies in an effort to elicit detailed information about the epidemiology of rabies in Virginia. The information collected from those submission forms was used in a mathematical model analysis of the epidemiology of raccoon rabies in Virginia for the years 1984 through 1987. Eleven explanatory variables and one response variable (positivity for rabies) were examined. The objective of this study was to develop a model, through logistic regression, that would explain the epidemiology of rabies in raccoons in Virginia, and determine the risk factors for prediction for positivity for rabies in raccoons in Virginia. This information would aid further surveillance efforts, preventive education programs, and in formulating future oral vaccination programs in raccoons. Multiway contingency tables were constructed (involving 2,3,4,5,and 6 way interactions), and log-linear models were fitted using an iterative fitting process to generate maximum likelihood estimates. The goodness of fit of each model was judged using the likelihood-ratio-chi-square p value (0.01). The backward stepwise model selection process was performed on logit models to find the best fitting model (0.01). The final model consisted of a combination of 17 four variable term models. Eight of the eleven explanatory variables remained important risk factors in the prediction of positivity for rabies in raccoons. To validate the model, it was applied to data collected in the years 1988 through July 1989. The model fit at the 0.01 level. Parameter estimates were calculated for each term in the model. All eight variables had main order effects (direct) on the response variable (positivity for rabies). Three second order effects were evident: age and season, behavior and season, and year and season. Future studies will involve applications of this model to other species to further explore the epidemiology of rabies, and to refine the model for practical applications. / Ph. D.

Rabies is a fatal but preventable neurotropic disease of potentially all mammals. The disease is caused by lyssaviruses. Rabies is recognized as the 10th most common lethal infectious disease in the world, rendering it one of the most feared zoonotic diseases known to man. Nevertheless, rabies can be prevented by application of pre- or post exposure treatments. Rabies vaccines have been available since the time of Pasteur, more that one hundred years ago. Since, vaccine research focused on the development of safer and more effective vaccines. Topics of current interest in the field of rabies vaccinology were addressed in this study. A primary concern regarding the disease is human mortalities, in the range of 60 000, reported every year. Most of these are linked to exposure to rabid dogs. In addition, a great number of post exposure treatments are administered each year at great costs. Despite availability of efficacious biologics, several factors influence the optimal use and accessibility of these agents in the countries of interest, with cost and availability being the major contributing factors. A proven approach is mass oral vaccination of target animals, such as dogs, which indirectly infers protection to susceptible hosts, including man. Currently available vaccines present several disadvantages of use though, including issues of safety or doubtful stability. Safer but effective alternative vaccines that could be used in oral baits would be valuable. Here the use of two candidate host restricted poxvirus vaccine vectors were explored, particularly also in regard to oral innocuity. The construction, convenient isolation and use of a recombinant Lumpy skin disease virus (Neethling strain) expressing rabies virus glycoprotein in a mouse model were investigated. In addition, a recombinant Modified Vaccinia virus Ankara expressing rabies virus glycoprotein was prepared and tested as a vaccine in mice, dogs and raccoons. In both cases it was clear that the severe attenuation of these viruses did affect the efficacy of the recombinant vaccines in the non-permissive hosts. With the recombinant MVA a clear dosage effect could be shown, and equivalent humoral responses could only be attained at much higher titers of vaccine virus as with replication competent counterparts. Secondly, the cross-protection of rabies vaccines across the spectrum of lyssaviruses was addressed. Lyssaviruses can be divided into two groups based on sequence analysis and pathogenesis. Viruses belonging to the so-called phylogroup II, are the Mokola, Lagos and West Caucasian Bat viruses. Classic rabies biologics fail to fully protect against the viruses attributed to a lack of cross-neutralization. Here, cross-protection and cross-reactive immune responses induced by recombinant vaccinia viruses expressing rabies, Mokola or West Caucasian Bat virus glycoproteins, in single or dual combinations, were investigated. As expected, there was a lack of cross-protection of rabies and Mokola glycoprotein vaccines. There was also a clear lack of cross-protection of West Caucasian Bat virus glycoprotein vaccine and rabies and Mokola viruses. The dual antigen expressing vaccines did not appear to offer any additional protective effect in the tested model. The Mokola virus glycoprotein vaccines induced neutralizing antibody responses that significantly cross-neutralized Lagos Bat virus. / Thesis (PhD (Microbiology))--University of Pretoria, 2006. / Microbiology and Plant Pathology / unrestricted