Doctoral Degrees (Molecular Biology and Human Genetics)
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Browsing Doctoral Degrees (Molecular Biology and Human Genetics) by Author "Bernitz, Netanya"
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- ItemNovel approaches to the diagnosis of Mycobacterium bovis infection in African buffaloes (Syncerus caffer)(Stellenbosch : Stellenbosch University, 2019-12) Bernitz, Netanya; Miller, Michele Anne; Parsons, Sven David Charles; Du Plessis, Nelita; Stellenbosch University. Faculty Medicine and Health Sciences. Dept. of Biomedical Sciences: Molecular Biology and Human GeneticsENGLISH ABSTRACT: Mycobacterium bovis(M. bovis) is the pathogen that causes bovine tuberculosis (bTB) in a wide range of host species including livestock and wildlife. Globally, the control of M. bovisinfection is hindered by the existence of wildlife maintenance hosts. In South Africa, African buffaloes (Syncerus caffer) are considered maintenance hosts of bTB, and therefore control in this species will facilitate control in other sympatric wildlife species and livestock. With the limited availability of diagnostic tools and their suboptimal test performancesto detectM. bovisinfection in buffaloes, it is imperative to develop novel approaches to improve the detection ofinfected buffaloes. In this study, the QuantiFERON®TB-Gold (QFT) system in combination with the cattletype®IFN-gamma ELISA, the QFT interferon gamma (IFN-γ)release assay (IGRA), was shown to have high specificity but poor sensitivity in detecting M. bovisinfection in buffaloes. The sensitivityof the QFT IGRA was improved by measuring the chemokineIFN-γ-inducible protein-10 (IP-10)in theQFTIP-10release assay (IPRA). When both cytokines IFN-γ and IP-10 were measured in parallel in the QFT system, sensitivity was further improved and the specificityof the individual assays were maintained. The concentrations of IFN-γ and IP-10 in QFT tubes were used to predictthe presence of macroscopic pathology in M. bovis-infected buffaloes. Lastly, the immunophenotyping of cattle whole blood identified cellular subsets of bovine leukocytes,however, the production of IP-10 in these cells wasnot confirmed. This study has demonstrated that the QFT system is a highly practical stimulation platform to detect M. bovisinfection in buffaloes with high specificity. The QFT system and novel cattletype®IFN-gammaELISA is anIGRA with high specificity that can be used to detect M. bovisinfection in buffalo populations. The cytokine IP-10 is a more sensitive biomarker than IFN-γ and when these two cytokines are measured in parallel in the QFT system, the detection of infected buffaloes is maximised, the specificityis high and the testing procedure is simplified. Finally, the magnitude of IP-10 and IFN-γ concentrations in QFT-processed whole blood can be usedas indicators of bTB pathology in M. bovis-infected buffaloes