Theses and Dissertations (University of Pretoria)

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Exposure of wild carnivores to rabies and Mokola viruses in provincial and private game reserves in Mpumalanga province
Letsholo, Samantha Laone (University of Pretoria, 2014-03)
Rabies, a disease caused by members of the genus Lyssavirus, family Rhabdoviridae is a significant veterinary and public health threat globally including South Africa. This fatal but preventable zoonotic disease causes encephalitis in all warm-blooded vertebrates including humans. At least 50 000 human fatalities and 5 million rabies exposures occur annually. However, in developing countries where both domestic (urban type) and wild (sylvatic type) rabies cycles are common and transmission occurs readily across species barriers, the disease has proven difficult to eradicate. In South Africa, the main maintenance host species include the domestic dog, Canis lupus familiaris, in Limpopo province, Mpumalanga, Eastern Cape and coastal KwaZulu/Natal provinces, and wildlife host species including the black-backed jackal, Canis mesomelas, the bat-eared fox, Otocyon megalotis, (both maintain the canid rabies biotype) and the yellow mongoose, Cynictis penicillata, that maintains the mongoose rabies biotype. There are currently 12 Lyssavirus species worldwide. In South Africa, Lagos bat virus and Duvenhage virus are rarely diagnosed in terrestrial animals and are generally associated with fruit-eating (Epomophorus wahlbergi) and insect-eating (Minopterus schreibersii) bats respectively. To date, Mokola virus (MOKV) and Ikoma virus (IKOV) are the only lyssaviruses that have not been recovered from bat species. Between 1928 and 2006, rabies was diagnosed in 4952 wildlife species in South Africa, the majority of which were mongoose species, especially Cynictis penicillata, followed by the bat eared fox, Otocyon megalotis, and the black-backed jackal, Canis mesomelas. Only one case of rabies was diagnosed in lions over the same period and no cases of Mokola virus infections have been documented in South African wildlife thus far. This project was undertaken to determine the prevalence of neutralising antibodies to RABV and MOKV, the latter a rabies-related virus, in serum samples originating from lions in private and provincial game reserves adjacent to the Mnisi communal area in Mpumalanga province and in the greater Kruger National Park. The expected benefits of the study include the evaluation of exposure of lions to RABV and MOKV in the above-mentioned region of South Africa, further improving the understanding of the epidemiology of the disease in a human/domestic animal/wildlife interface. Stored lion serum samples from the University of Pretoria, Department of Veterinary Tropical Diseases (n=140) and the Agricultural Research Council-Ondesterpoort Veterinary Institute (ARC-OVI), OIE Rabies Laboratory (n=20) and sera from other carnivores from the ARC-OVI (n=5) were tested for antibodies to classical rabies virus and Mokola virus using the fluorescent antibody virus neutralization test. All 165 sera were collected from private and provincial game reserves in Mpumalanga province between the years 1995 and 2012. The cut-off point for both RABV and MOKV serum samples was determined as 0.5 IU/ml and 0.95 IU/ml respectively. Any serum sample with a titre less than 0.5 IU/ml was regarded as negative, while any serum sample with a titre equal to or above 0.5 IU/ml was regarded as positive for RABV. Any serum sample with a titre less than an equivalent of log100.95 dilution was regarded as negative, while any serum sample with a titre equal to or above log100.95 dilution was regarded as positive for MOKV. Lion sera collected between 1995 and 2000 (n=140) had a 2.1% prevalence of RABV neutralizing antibodies and a 0.7% prevalence of MOKV antibodies. Sera collected from lions between 2010 and 2012 (n=20) had a 65.0% prevalence of RABV antibodies and a 26.3% prevalence of MOKV antibodies. Due to the uncertain vaccination status of samples collected between 2010 and 2012 and the significant differences in prevalence between the lion serum collected between 1995 and 2000 and between 2010 and 2012, the two groups of lions were treated as two separate populations. Other carnivores (n=5) had a prevalence of RABV neutralising antibodies of 40.0% and a prevalence of MOKV neutralising antibodies of 25.0%. When calculating the difference of proportions for the prevalences of the antibodies of the two lyssaviruses within each population, the prevalences were not significantly different. The results of the study suggest that lions in Kruger National Park have been exposed to RABV (2.1%) and or possibly another lyssavirus related to MOKV at low frequencies between 1995 and 2000. The sample sizes of the lions from other game reserves and other carnivores were too small to make a valid conclusion thus larger sample population sizes must be considered for future studies in these areas. Since the neutralising antibody prevalences in the Kruger National Park lions were not significantly different for both viruses, it can be concluded that if a lion presents with clinical signs of rabies, the disease is just as likely to be caused by RABV as MOKV.
Cardiac troponin I immunoassay validation, reference interval determination and serum cardiac troponin I changes in translocated southern-central black rhinoceros (Diceros bicornis minor) and southern white rhinoceros (Ceratotherium simum simum)
Rautenbach, Yolandi (University of Pretoria, 2024-10)
The abundance and range of occurrence of the two rhinoceros species in sub-Saharan Africa, the southern-central black (Diceros bicornis minor) and southern white (Ceratotherium simum simum) rhinoceros, have decreased dramatically. Common threats to rhinoceros conservation include poaching, habitat fragmentation and loss,international trade in illegal rhinoceros products, and reduced financial resources due to global financial recessions and pandemics. Translocation of wildlife species is a commonly used tool for the conservation of threatened and endangered animals, with a focus on restoring and enhancing populations. It plays an integral part in national and international conservation plans for African rhinoceros. Chemical immobilisation is often used during translocation, with etorphine forming the basis of most drug combinations used. Ensuring animal welfare during wildlife transport is critical and dehydration, electrolyte imbalances, a negative energy balance, muscle damage, protein catabolism, stress-induced immunomodulation, and oxidative stress are the main pathophysiological findings reported in rhinoceros translocated over long distances. Investigation into possible cardiomyopathy in transported rhinoceros has been hampered by the lack of validated immunoassays to measure serum biomarkers, specifically cardiac troponin I (cTnI), in rhinoceros. The broad objectives of this study were therefore to 1) sequence the cTnI gene in both rhinoceros species, to obtain the inferred amino acid sequences from the messenger ribonucleic acid (mRNA) transcript sequences, and assess the potential a^inity of several commercial cTnI immunoassays for detecting cTnI in African rhinoceros; 2) validate two point-of-care (POC) cTnI immunoassays for use in African rhinoceros; 3) to generate cTnI reference intervals (RIs) on the high-sensitivity (hs)-cTnI immunoassay in both rhinoceros species and apply subset partitioning in white rhinoceros that were chased by helicopter during capture versus those that were captured in a boma and therefore not chased; and 4) investigate the serum cTnI changes in long-distance translocated rhinoceros and in rhinoceros chemically immobilised with di^erent drug protocols during capture. Best practice guidelines for method validation, quality control (QC) and RI generation as published by the American Society for Veterinary Clinical Pathology were followed. Expert consensus recommendations on the clinical laboratory practice for hs-cTnI assays as advised by the International Federation of Clinical Chemistry Task Force on Clinical Applications of Biomarkers (IFCC TF-CB) were also complied with. The mRNA cTnI transcript sequences were obtained by RNA extraction from myocardium of deceased rhinoceros followed by primer design, complementary deoxyribonucleic acid (cDNA) synthesis using reverse transcription polymerase chain reaction, and Sanger sequencing. The percentage identity between black and white rhinoceros cDNA nucleotide sequences was 99%, while inferred amino acid sequences were identical. There were five amino acid di^erences between humans and rhinoceros in the epitope binding sites of immunoassay antibodies and five assays contained antibodies against epitopes that were not conserved. Nevertheless, only one assay was deemed unlikely to cross-react with rhinoceros cTnI and five assays were found to be suitable for further investigation into cTnI measurement in African rhinoceros. The Siemens Stratus CS Acute Care troponin I cTnI and Siemens Atellica VTLi hs-cTnI were the two POC cTnI immunoassays selected for analytical method validation. Validation experiments included precision studies, reportable range, haemoglobin interference studies, recovery studies, and detection limit studies with results assessed against two total allowable error (TEa) performance goals, namely 30% and 70%. Imprecision was acceptable and met low cTnI concentration performance goals. Thereportable ranges were similar to the manufacturer’s specifications. For the Stratus CS, high haemoglobin concentrations in white rhinoceros resulted in bias. The QC validation results showed that a simple 13s QC rule using two levels of QC material and a TEa of 70% could be used in both analysers, except at very low cTnI concentrations in the Atellica VTLi. This study showed that both cTnI POC analysers are suitable for use in African rhinoceros and analytical performance goals for low cTnI concentrations in hs-cTnI assays were met. To allow for the identification of cardiomyocyte injury in African rhinoceros, RIs were established for both species of rhinoceros using the validated hs-cTnI assay. Reference intervals were generated from 62 and 87 apparently healthy, free-living immobilised black and white rhinoceros, respectively. Additionally, the 99th percentile upper reference limits were also determined. Of interest is that subclass partitioning was valid for white rhinoceros based on whether they were immobilised in a boma or chased by a helicopter before being immobilised. Although chemical capture and translocation (involving capture and long-distance transport) in African rhinoceros are essential components of conservation strategies aimed at improving the conservation status of the species, several adverse pathophysiological e^ects, specifically hypoxaemia, acidosis and muscle damage, are associated with these processes which negatively impact rhinoceros’ welfare. Serum cTnI concentration was measured using the Atellica VTLI hs-cTnI assay on stored serum samples collected during four long-distance translocation studies in black and white rhinoceros and in one chemical immobilisation study in white rhinoceros. Measurement of serum cTnI concentration in rhinoceros translocated over long distances showed significantly increased cTnI concentrations during transportation and at release when compared to concentrations at capture. The degree of cTnI increase was more significant in cohorts chased and darted from helicopters. Concurrent skeletal and cardiac muscle damage was demonstrated in transported black and white rhinoceros, indicative of capture myopathy (CM) in these animals. Furthermore, hypoxaemia, acidosis and a negative energy balance were correlated with elevated cTnI concentrations, highlighting specific areas in procedures involving chemical immobilisation, capture, and transport that need to be addressed to mitigate these adverse effects. The results of this study will allow wildlife veterinarians involved in African rhinoceros conservation procedures, and in the treatment of injured animals, to assess if cardiomyocyte damage is present. This assessment will allow for cardioprotective adjustments to be implemented in these procedures, resulting in improved animal welfare. Demonstration of concurrent elevated skeletal and cardiac muscle biomarkers in translocated rhinoceros will assist wildlife veterinarians in identifying animals at risk of developing CM that should be kept in confinement (boma) at the receiving end of the journey for monitoring and reduction in stress before release.
Endocrine responses to snouted cobra (Naja annulifera) and African puffadder (Bitis arietans) envenomation in dogs
Fourie-Viljoen, Noeline (University of Pretoria, 2025-01)
The Hypothalamic-Pituitary-Adrenal (HPA) and Hypothalamic-Pituitary-Thyroidal (HPT) axes are pivotal in the pursuit of homeostasis in critical illness. The goal of this study was to investigate the host endocrine response in the snake-envenomed canine patient. This prospective study included 17 client-owned dogs naturally envenomed by either a snouted cobra (Naja annulifera) (n=9) or a puffadder (Bitis arietans) (n=8), that presented within 6 hours of envenomation. The dogs were further subdivided clinically into a neurological (n=5) and nonneurological group (n=4). Serum samples were collected at admission, and thereafter at 12-, 24-, and 36-hours post envenomation. At each time point, the serum total thyroxine (TT4), thyrotropin (TSH), C-reactive Protein (CRP) and cortisol concentrations were measured. Compared to control dogs, the median serum TT4 concentrations of all the snake-envenomed dogs were significantly lower at all time points (P<0.05). The non-neurological cobra subgroup recovered to serum TT4 concentrations comparable to that of the controls within 24 hours of envenomation, while the puffadder and neurological cobra subgroup serum TT4 concentration remained significantly suppressed until 36 hours post envenomation. Serum TT4 concentration was negatively correlated with serum CRP concentration (P<0.05, ρ=-0.326)). The differences in TSH between groups failed to reach significance. The total serum cortisol concentrations of all envenomed dogs were highest at admission, but only the neurological cobra subgroup had a significantly higher concentration at admission compared to the controls. The neurological cobra subgroup had the highest peak in serum CRP concentration, but the correlation between total serum cortisol and CRP concentrations failed to reach significance. Puffadder and snouted cobra envenomation is associated with significant suppression of serum TT4 concentrations that is correlated with the severity of the host inflammatory response. The only significant increase in total serum cortisol concentration was observed in the neurological snouted cobra envenomed subgroup at admission. This study provides novel insights into the temporal endocrine perturbations in Puffadder and snouted cobra envenomation, and the relation thereof to the degree of the host inflammatory response.
An in vitro investigation of the immunomodulatory effects of a traditional polyherbal traditional medicine product
Moloti, Tebatso Martin (University of Pretoria, 2018)
In South Africa, human immunodeficiency virus (HIV) remains one of the major public health concerns. HIV is a highly infectious lentivirus which causes a progressive degeneration of the immune system. When not treated, it leads to the development of acquired immunodeficiency syndrome (AIDS). AIDS is an immunosuppressive disease that results in opportunistic infections that can lead to death. Antiretroviral therapy (ART) is the most common and widely used treatment. Despite the availability of ART, HIV prevalence is on the rise. This has led to a surge in traditional herbal preparations that are purported as immune boosters for treatment in HIV patients. It is known that many patients switch from using ART to traditional herbal medicine due to side effects associated with ART. In South Africa and on the African continent, traditional medicine is not used only as an alternative and supplementary medicine, but also as a primary source of health care due to its ease of accessibility, affordability and also as it forms part of traditional and cultural practices. Safety and efficacy of many traditional medicines is not yet established and the pharmacological properties of the latter are based on anecdotal evidence with no scientific evidence. Prijap Health is a herbal traditional medicine preparation that is sold as an immune booster for immunocompromised patients. Prijap Health traditional herbal medicine is comprised of the following plants: Acorus calamus, Aloe arborescens, Artemisia afra, Drimia robusta, Elephantorrhiza elephantina, Erythrina lysistemon, Persea americana, Senecio serratuloides and Xysmalobium undulatum. It is claimed to have anti-viral, antioxidant, anti-inflammatory, blood cleansing and appetising properties. It is currently traded in select stores across South Africa. The aim of this study was to investigate the immune modulating properties of Prijap Health herbal concoction and the individual plant species that comprise the concoction. Water was used as a solvent to prepare plant extracts mimicking the traditional healer’s preparation technique. Phytochemical analysis was carried out using thin layer chromatography (TLC) and ultra-high-performance liquid chromatography coupled with mass spectrometry (UPLC-MS). Cytotoxicity of the extracts was evaluated by the sulphorhodamine B (SRB) protein staining assay using differentiated human acute leukaemia monocytic (THP-1) and human histiocytic lymphoma (U937) cell lines after incubation for 72 h. The free-radical scavenging activity of the extracts was evaluated against the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2, 2’-azinobis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radicals to determine the antioxidant potential. Evaluation of prostaglandin E2 concentration in phorbol-12-myristate 13-acetate (PMA)-differentiated and lipopolysaccharide (LPS)-activated THP-1 and U937 was conducted using enzyme-linked immunosorbent assay (ELISA). Determination of Th1/Th2/Th17 (IL-2, IL-4, IL-6, IL-10, TNF-α, IFN-ᵞ and IL-17A) and human inflammatory (IL-8, IL-1β, IL-6, IL-10, TNF-α and IL-12p70) cytokines concentrations was done using BD cytometric bead array (CBA) kits. The TLC revealed the presence of flavonoids in the extracts of A. afra, E. elephantina, P. americana and S. serratuloides. Sterols were detected in the extracts of A. arborescens, E. elephantina, P. americana, X. undulatum. Saponins were present in the extracts of A. afra, A. calamus, D. robusta, E. elephantina and P. americana. Alkaloids were not detected in any of the extracts. Phytochemical markers were identified in the plant extracts using UPLC-MS. These include uzarin (X. undulatum), β-asarone (A. calamus), catechin (P. americana), (-)-epicatechin (E. elephantina), rutin (A. afra), D-saccharic acid (D. robusta), 3-caffeoylquinic acid (S. serratuloides) and aloesin (A. arborescens). From the SRB assay, it was evident that the hot water extracts of A. afra, A. arborescens, A. calamus, E. elephantina, E. lysistemon, P. americana and S. serratuloides had no cytotoxic effects in both cell lines at the highest concentration tested (IC50>100 µg/mL). The THP-1 cells were found to be more sensitive and indicated lower cell viability than the U937 cells. The D. robusta, X. undulatum extracts and Prijap Health traditional herbal medicine displayed a potential for toxicity in the THP-1 cell line with IC50 = 39.29±1.76, 76.05±1.21 and 74.52±1.31 µg/mL, respectively. The DPPH and ABTS radical scavenging activity was most potent for the E. elephantina extract (DPPH scavenging EC50= 6.98±1.04 µg/mL; ABTS scavenging EC50= 2.45±1.05 µg/mL) and was found to be comparable to that of Trolox, the positive control (DPPH EC50 = 7.39±1.04 µg/mL; ABTS EC50 = 1.79±1.04 µg/mL). Prijap Health traditional herbal medicine showed greater antioxidant activity than all the individual plant extracts with the exception of E. elephantina. Curcumin (positive control), Prijap, D. robusta and X. undulatum extracts decreased the extracellular and intracellular PGE2 concentration in THP-1 cells, but not in U937 cells. Cytokine concentration determination by flow cytometry revealed that curcumin (positive control), A. calamus, Prijap Health traditional herbal medicine, and E. elephantina significantly (p<0.05) reduced IL-1β concentration. Curcumin, A. calamus and Prijap significantly (p<0.05) reduced TNF-α concentration. E. elephantina, A. arborescens and P. americana increased IL-10 concentration whereas curcumin, A. afra and Prijap significantly (p<0.05) reduced IFN-ᵞ concentration in both THP-1 and U937 cells. These findings suggest that the above-mentioned extracts and Prijap Health traditional herbal medicine have the potential to be used as anti-inflammatory agents. In conclusion, the results of the present study provide evidence of the antioxidant, anti-inflammatory, immune modulatory potential as well as safety of use of Prijap Health traditional herbal medicine. With this said, E. elephantina as a single plant showed to contain better activity than Prijap Health traditional herbal medicine concoction. Further studies in drug-herb interaction and antiviral properties should be conducted to investigate all the pharmacological properties of Prijap Health traditional herbal medicine.
Vegetative propagation of Pelargonium sidoides D.C. (Rabassam) using leaf-bud cuttings
Pholo, Mafamo Samuel (University of Pretoria, 2019-02)
Pelagonium sidoides (Rabassam) is an herbaceous plant of the Geraniaceae family used throughout history as a medicine for the people of South Africa which has and recently also been exported to other parts of the world. A number of studies have shown that the plant extracts have anti-microbial, anti-viral and immune boosting properties. Consequently, it has been harvested in the wild for these properties, exposing the species to possible extinction. This scenario can be addressed by artificially mass propagating and producing the species to satisfy demand. One method of propagating the plant is to use leaf-bud cuttings. Unfortunately, vegetative propagation of the species using leaf-bud cuttings is not documented. This study was therefore conducted to investigate the influence of rooting medium (sand and sand + coir), rooting hormone (0.1% indole-butyric acid (IBA), planting depth (1.5 and 3 cm) and season (summer, autumn, winter and spring) on rooting success of leaf-bud cuttings as well as impacts of these treatments on the survival and morphological characteristics of subsequent transplants. The experiments were conducted on a mist bed in a greenhouse located at the Experimental Farm of the University of Pretoria (25o45’S, 28o16’E). A 23 factorial experiment laid out in a randomized complete block design (RCBD) with 3 replicates was carried out. Root length, root number, planting depth, growth media and hormone application, were assessed by destructive sampling at 5 to 25 days after planting (DAP). Results of the study demonstrated that sand medium, compared to a mixture of sand + coir medium, resulted in higher rooting percentage and more roots. However, sand + coir medium produced longer roots on the cuttings. Planting depth of 3 cm resulted in higher rooting percentage and better establishment of cuttings as compared to a depth of 1.5 cm. Application of the rooting hormone 0.1% IBA improved the number of roots but not rooting percentage nor root length. Rooting of cuttings was improved when propagated in autumn (longer roots) and spring (higher number of roots) than in summer or winter. After one month transplanting of cuttings, significant differences (P < 0.05) were noted in survival percentage due to the media initially used. Cuttings initially propagated on sand showed a higher survival percentage (78.6%) and had a higher number of roots, which were longer, compared to cuttings initially propagated in a medium of sand + coir (61.2%). Cuttings initially propagated in sand and treated with hormone had significantly more roots after transplanting. Application of hormone also improved root and shoot length of transplants. Based on observations, cuttings taken from younger mother stock plants had a higher chance of survival than cuttings taken from mature stock plants. In general, leaf-bud cuttings of P. sidoides can be artificially propagated without rooting hormone but the success rate will be low. The ideal regime is to propagate cuttings treated with IBA in a sand medium.
Investigation of alternative molecular approaches for enhanced traceability of illegally traded Temminck's Ground Pangolins (Smutsia temminckii)
Heighton, Sean Paul (University of Pretoria, 2018-12)
Conservation regulatory bodies created to limit the overexploitation of wildlife are reliant on regulatory adherence. This over-reliance on regulation means that complementary approaches to assist with enforcement are often required. Wildlife forensics is one such approach that can be used to address the illegal trade in wildlife and pangolins in particular. With estimates from the legal trade being that over one million pangolins were trafficked in a ten-year period, it is clear that alternative approaches to curb illegal trade, which represents >98% of pangolin trade, are needed. Geographic traceability uses a range of markers and georeferenced samples for tracking the origins of trafficked pangolins and their derivatives. In this study, the applicability of two molecular profiling approaches (stable isotopes and host microbes) were evaluated for their traceability potential, for three pangolin populations sampled from two sites in the Kalahari (xeric savanna) and one site in the Lowveld (mesic savanna). The feasibility of carbon and nitrogen stable isotope traceability using pangolin scales was evaluated through mass spectrometry (Chapter 2). Results revealed that intra-scale and inter-individual variation are important considerations for traceability, whilst inter-scale variation and scale harvesting methods (boiling or direct flaming of carcasses) are not. Given the high levels of intra-scale variation, development of a time and cost-effective sampling protocol suitable for forensic investigations was attempted. It was found that the use of duplicate samples of homogenised scales provides an averaged effect on scale variability. However, scale tips are comparatively isotopically enriched and should be taken into consideration during forensic analyses. Although preliminary results indicate that geographic separation based on isotopic ratios between Lowveld and Kalahari regions may be possible, geographic partitioning through use of stable isotopes could not be conclusively demonstrated due to the small sample size. Baseline estimates of microbial diversity were established using two metagenomics approaches (cloning versus next generation sequencing (NGS)) targeting the 16S rRNA gene of bacteria and two taxonomic assignment methods (phylogeny testing versus a heuristic search tool; Chapter 3). These differed significantly with respect to microbial community composition with results suggesting that phylogeny testing in combination with NGS holds potential for pangolin traceability. Although whole microbial communities differed by 70.3% between the two Kalahari sites, constraints with respect to the number of localities sampled and the number of cloning colonies characterised are duly noted. The results also revealed that Clostridium sordellii and genospecies C. novyi sensu lato appear to be key site-specific taxa for presence/absence and topotype traceability methods, respectively.Using a primer-set developed to target the phylogenetically-informative phospholipase C gene, the potential health risks and geographic traceability efficacy of the C. novyi sensu lato pathogenic genospecies group was investigated (Chapter 4). Although the prevalence was moderate at 17.65% and thus not feasible for traceability purposes, the potential public and animal health risks that the genospecies group poses, particularly for the illicit trade of pangolins, is of concern. Expanded studies using high throughput metagenomics and additional stable isotopes hold promise for enhanced traceability of illegally traded pangolins, particularly when used together.
Unravelling the role of Aurora kinases in cell cycle regulation of malaria parasites
Abrie, Clarissa (University of Pretoria, 2018-11)
The P. falciparum parasite’s life cycle, and implied cell cycle, is strictly controlled allowing the parasite to rapidly develop during the intraerythrocytic stages alternating DNA synthesis and mitosis during endocyclic schizogony. This results in asynchronous nuclear divisions to form multinucleated schizonts during mitosis. However, mitotic nuclear division in P. falciparum parasites remain poorly understood. Several mitotic kinases of the P. falciparum kinome, such as aurora related kinases (ARKs), have been suggested to be cell cycle regulators. The PfARKs are essential for intraerythrocytic stages of the Plasmodium parasite of which PfARK-1 are highly conserved and associated with spindle pole bodies (SPB) during schizogony. The role of PfARK associated with SPB in cell cycle regulation of P. falciparum parasites has been understudied, despite the close link to centrosome and bipolar microtubule dynamics, chromosome segregation and cytokinesis of Aurora kinases in various other organisms. Knowledge gaps regarding the parasite’s cell cycle regulatory mechanisms is mostly due to the complexity associated with cell cycle compartment synchronisation of the parasite under in vitro conditions. In this dissertation, an innovative approach is used for cell cycle compartmentalisation of parasites as a tool to interrogate the importance of PfARK in cell cycle regulation during the intraerythrocytic stages of the parasite through hesperadin-induced PfARK inhibition. Collectively, this dissertation provides extensive insight to PfARK cell cycle regulation during parasite asynchronous nuclear division associated with M-phase progression, chromosomal segregation and spindle formation. The data demonstrate that novel cell cycle regulatory mechanisms of mitotic kinases, such as PfARKs and their involved pathways, serve as attractive future drug targets in Plasmodium parasites.
Detection and characterisation of mycoplasmas in women visiting an antenatal or reproductive biology clinic
Duba, Thabang Confidence (University of Pretoria, 2019-02)
Genital mycoplasmas are opportunistic bacteria that are associated with undesirable gynaecologic and reproductive events. These bacteria are characterised by their small size, lack of cell wall, extremely fastidious in vitro environmental requirements, and tendency to form centred colonies on solid media. Ureaplasmas and M. hominis are considered opportunistic pathogens because they can be isolated from the lower urogenital tract of healthy women as well as from individuals with disease. The commercial Mycofast Revolution assay permits the phenotypic detection and identification of genital mycoplasmas. This assay allows for antimicrobial susceptibility testing with specific minimum inhibitory concentrations (MICs) as defined by the 2011 Clinical and Laboratory Standards Institute (CLSI) guidelines. The antibiotics that are tested include clindamycin, erythromycin, levofloxacin, moxifloxacin, and tetracycline (CLSI, 2011). The aim of this study was to detect genital mycoplasmas as well as their antimicrobial susceptibility profiles in women visiting an antenatal and the reproductive biology clinic of a tertiary academic hospital in Pretoria, South Africa. Methods: Women who attended either the antenatal or the reproductive biology clinic at an academic hospital in Pretoria, Gauteng South Africa, who met the inclusion criteria, were approached to participate in this study. Four self-collected vaginal swabs were obtained from each participant visiting the clinics who gave signed informed consent. The first swab was used to inoculate A7 Mycoplasma agar plates for culturing genital mycoplasmas. The second swab was used to perform Nugent scoring for diagnosing bacterial vaginosis. The third swab was used to inoculate the Mycofast Revolution assay for the identification, enumeration and antimicrobial susceptibility profiles of genital mycoplasmas and the fourth swab was used for a molecular conventional PCR assay for the detection of genital mycoplasmas. Results: Hundred and six participants who either attended the antenatal (55) or reproductive biology clinic (51) at an academic hospital in Pretoria, Gauteng South Africa were recruited.In the reproductive biology clinic, 53% (27/51) of cultures were positive for Ureaplasma spp., and 18% (9/51) for M. hominis. Ureaplasma spp. resistant to tetracycline in the antenatal and the reproductive biology clinics were 51% (18/35) and 52% (14/27) respectively. Bacterial vaginosis was diagnosed using the Nugent scoring system and 20% (11/55) of the participants were BV positive in the antenatal clinic and 20% (10/51) in the reproductive biology clinic. The Mycofast Revolution assay detected genital mycoplasmas in 67% (37/55) of samples at the antenatal clinic and 57% (29/51) in the reproductive biology clinic. In the antenatal clinic, 64% (35/55) of cultures were positive for Ureaplasma spp., and 27% (15/55) for M. hominis. The overall prevalence of M. genitalium, M. hominis, U. parvum and U. urealyticum in both clinics combined detected using conventional multiplex PCR assay was 1% (1/106), 5% (5/106),19% (20/106) and 4% (4/106) respectively. Mycoplasma hominis resistance to tetracycline in the antenatal and the reproductive biology clinics was 56% (5/9) and 51% (18/35) respectively. Conclusion: This study has shown that the infection rate of genital mycoplasmas was higher among pregnant women. In order to prevent complications in pregnant women, the foetus and the neonate, routine screening for the presence of genital mycoplasmas is strongly recommended. This study has shown that the Mycofast Revolution assay could be considered as a cost-effective alternative to conventional culture methods for the rapid detection of genital mycoplasmas as well as antibiotic resistance.
Farmer's risk perception, and seroprevalence and associated risk factors of Toxoplasma gondii in small ruminants and backyard chickens in selected districts of West Gojjam Zone, Northwest Ethiopia
Mebratie, Yechale Teshome (University of Pretoria, 2024-10)
Toxoplasmosis, caused by an intracellular protozoan parasite T. gondii, is a widespread and neglected zoonotic disease with significant health and economic impacts that affects nearly one-third of the global human population. A cross-sectional survey and questionnaire study was conducted from May 2023 to December 2023 to estimate the seroprevalence of T. gondii infection in small ruminants and backyard chickens in Bahir Dar Zuria and Sekella Districts, Northwest Ethiopia. The study aimed to identify risk factors and assess risk perceptions of the farmers’ towards the disease. Furthermore, animal owners were provided with a structured questionnaire to collect data on household demographics and animal management practices, and checklists were employed to record individual animal level factors along with the collection of serum samples. Simple random sampling technique was employed to select small ruminants and backyard chickens from the study population. A total of 541 serum samples from small ruminants and backyard chickens were tested for antibodies against T. gondii using a commercially available latex agglutination test kit. One hundred and ninety one samples tested positive for the presence of T. gondii antibodies, resulting in an overall animal-level seroprevalence of 35.31% (95% CI= 0.314 - 0.395). The prevalence of T. gondii varied significantly between the two districts (OR = 2.78, 95%CI = 1.893 - 4.072 and P = 0.000). The prevalence of T. gondii infection was found to be significantly influenced by management practices (OR=2.85; 95%CI: 1.532- 5.308, P= 0.001), with extensively managed small ruminants being three times more likely to be affected by T. gondii compared to semi-intensively managed small ruminants. Compared to exotic chicken breeds, the local breed of backyard chickens were four times more likely to acquire a T. gondii infection (OR= 4.61, 95%CI: 1.951 -10.869, P= 0.000). Backyard chickens were two times more likely at risk of acquiring a T. gondii infection (OR= 2.035; 95%CI: 1.389 - 2.979, P = 0.000) when compared to small ruminants. Small ruminants and backyard chickens in close contact with cats were found to have significantly higher risks of acquiring a T. gondii infection compared to those with limited or no cat exposure. In conclusion, the findings of this study indicate a high prevalence of T. gondii in the animals sampled in the current study sites. Furthermore, multiple risk factors influencing the prevalence of T. gondii infection were investigated. The increased prevalence and poor awareness of the disease among the participants could have a significant impact on the health of people and other animals in the study areas, highlighting the necessity for evidence-based integrated strategies and promotion of behaviour change to control and prevent T. gondii infection in both humans and other animals in the West Gojjam Zone, Ethiopia.
Neutrophil gelatinase-associated lipocalin and symmetric dimethylarginine concentrations in dogs with carcinoma and sarcoma
Rixon, Anouska Jade Rixon (University of Pretoria, 2024-11)
Although neutrophil gelatinase-associated lipocalin (NGAL) and symmetric dimethylarginine (SDMA) are considered sensitive biomarkers of kidney injury and function, respectively, their specificity is affected by extra-renal factors. The extra-renal effect of tumours on biomarker concentrations is yet to be fully elucidated despite their association with tumourigenesis. Due to the lack of renal histopathology in previous studies, it remains unclear if tumours or concomitant kidney disease is responsible for the appreciable increases in serum and urinary NGAL and SDMA concentrations reported in various cancers in both humans and dogs. This study aimed to determine the extra-renal effect of tumours on serum and urine NGAL and SDMA concentrations in dogs with carcinoma or sarcoma without significant kidney disease. Additionally, this study aimed to evaluate the association between biomarker concentrations and tumour type, as well as metastasis. If biomarker concentrations were found to be increased in tumour-bearing dogs, the potential contribution of tumour-associated systemic inflammation on NGAL concentrations would also be investigated. Concentrations of serum NGAL (sNGAL), SDMA, urinary NGAL (uNGAL) and uNGAL-to-creatinine ratio (uNGAL/Cr) were measured on stored samples from a previous prospective study. Patient clinicopathological and histopathology records were reviewed and those with renal azotaemia or moderate-severe histopathological renal changes were classified as having significant kidney disease. Biomarker concentrations were compared between tumour-bearing dogs without significant kidney disease and healthy age-controlled dogs. Additionally, comparisons between dogs with carcinoma and sarcoma; and dogs with and without metastasis; as well as correlations between urinary and serum NGAL and acute phase protein (APP) concentrations were analyzed. Twenty-one dogs with carcinoma, 18 dogs with sarcoma and 20 healthy age-controlled dogs were included. Tumour-bearing dogs without significant kidney disease had significantly increased uNGAL/Cr (P < .001), but not sNGAL, compared to healthy controls. Although median SDMA concentrations did not significantly differ between groups, increased concentrations were found in 32% and 20% of dogs with carcinoma and sarcoma, respectively. Additionally, no differences between dogs with carcinoma or sarcoma or those with and without metastasis were found. Urinary NGAL concentrations were moderately correlated with sNGAL concentrations, with moderate to no correlations shown with APPs, respectively. In conclusion, this study found that tumour presence, but not metastasis, effects uNGAL/Cr and SDMA concentrations in dogs with carcinoma and sarcoma. uNGAL should therefore not be used, and SDMA used with caution, as renal biomarkers in dogs with carcinoma and sarcoma. Additionally, the disproportionate increase in urinary, as compared to serum, NGAL concentrations in this cohort of dogs with carcinoma and sarcoma is suggestive of a potential glomerulopathy and increased glomerular permselectivity secondary to tumour presence.
Disposable diaper use and perception of health and environmental risks in a rural community from Bushbuckridge, South Africa
Lowe, Amy L (University of Pretoria, 2024-10)
Littering of disposable diapers is a problem with One Health implications and has been identified as an issue within the Mnisi community, a rural area within Bushbuckridge, South Africa. Several environmental and public health related concerns arise from this, including contamination of waterways used by animals and people with human waste, scavenging by domestic and wild animals, and the aesthetic impact on the environment. The aim of this study was to gain an understanding of the use and sanitation practices associated with disposable diapers, with the ultimate goal of identifying possible community-led initiatives and solutions which can be used for training and education. Focus group discussions were conducted within the community which included a participatory mapping exercise used to map general diaper disposal sites. Focus group data was analyzed according to three themes: decisions and factors around diaper use and disposal, perceptions of impact and health risk of diaper use for people and animals, and barriers and solutions for proper disposal. Most participants used disposable diapers and disposed of them within the environment because they lacked access to municipal waste collection. Regarding decisions around diaper use, common factors discussed were convenience, social perception and beliefs, cost, water access, and diaper disposal logistics. Convenience and societal perception and beliefs were determined as key factors behind diapering choices, and both a gender and a generational divide was revealed. Participants express general understanding of negative impacts associated with diaper disposal, but knowledge gaps exist, notably regarding water pollution and pathogen spread, that could be a focus of educational campaigns. Regarding solutions, participants proposed the provision of a central collection point as well a return to reusable diapers, each of which has its own considerations and hurdles. Any interventions should retain the perceived convenience factor of disposable diapers and be implemented on a community rather than individual basis. Solutions should be multifaceted, involve opportunities for community collaboration amongst all ages and genders, and should also engage local leadership. Focus groups should be considered as the first steps towards continued discussions amongst stakeholders.
Describing blood acid-base response in dogs with acute haemorrhagic diarrhoea syndrome using three different methods
Michaletos, Anthea Francis (University of Pretoria, 2025-09)
Objective: To describe blood acid-base response in dogs with acute haemorrhagic diarrhoea syndrome (AHDS) using three different methods of analysis. Hypothesis: Dogs with AHDS have increased unmeasured strong anions compared to healthy dogs. Design: Prospective, observational study. Setting: Private referral hospital. Animals: A total of 20 dogs used in two groups as follows: 10 healthy age-, weight- and breed-matched dogs and 10 dogs with AHDS. Interventions: Blood that was collected from healthy dogs were used to establish an expected normal range (minimum and maximum limits of the ranges were calculated as mean ± 2 standard deviations). Jugular venous blood, AHDS index scores (0 – 3: insignificant disease; 4 – 5: mild AHDS; 6 – 8: moderate AHDS; 9 – 18: severe AHDS) and intravenous fluid infusion volumes (mL/kg) were collected at presentation (0H) and then at set hour-intervals post presentation (4H, 8H, 12H, 16H, 20H, 24H, 36H, 48H and 60H). Blood was analysed to measure or calculate acid-base variables used in three different methods of analysis: 1) traditional, 2) Stewart theory, and 3) semi-quantitative theory approaches. Longitudinal data were compared using a general lineal mixed model with post-hoc comparisons using Dunnett's method (control variable: values at 0H) and significance was P < 0.05 and data were reported as median (minimum – maximum). Measurements and main results: The pH, at 0H, was 7.31 (7.22 – 7.49) and classified as acidaemic with a wide anion gap of 24.6 (13.1 – 27.6) mmol/L because of a raised venous carbon dioxide tension [48 (26 – 51) mmHg], negative base excess of extracellular fluid [-5.4((-8.0) – (-2.4)) mmol/L] and acidaemic lactate effect [-3.5 ((-5.4) – (-1.2)) mmol/L]. The pH normalised by 4H (P < 0.0001) in response to fluid administration where 37 (29 – 63) mL/kg was given over the 4-hour period. Whereas the AHDS clinical index score was classified as ‘insignificant disease’ by 48H. The pH remained within normal reference intervals until 60H and fluid rates were 3 mL/kg/hour from 8H onwards. The bicarbonate and haemoglobin buffer systems played a role in blood acid-base homeostasis. Conclusions: The acidaemia at presentation in dogs with AHDS was related to hypovolaemia and all derangements were corrected by fluid resuscitation. All three methods of analysis were useful in interpreting the complex interplay between acidifying and alkalinising effects and blood buffers.
Disposable diaper use and perception of health and environmental risks in a rural community from Bushbuckridge, South Africa
Lowe, Army L. (University of Pretoria, 2024-10)
Littering of disposable diapers is a problem with One Health implications and has been identified as an issue within the Mnisi community, a rural area within Bushbuckridge, South Africa. Several environmental and public health related concerns arise from this, including contamination of waterways used by animals and people with human waste, scavenging by domestic and wild animals, and the aesthetic impact on the environment. The aim of this study was to gain an understanding of the use and sanitation practices associated with disposable diapers, with the ultimate goal of identifying possible community-led initiatives and solutions which can be used for training and education. Focus group discussions were conducted within the community which included a participatory mapping exercise used to map general diaper disposal sites. Focus group data was analyzed according to three themes: decisions and factors around diaper use and disposal, perceptions of impact and health risk of diaper use for people and animals, and barriers and solutions for proper disposal. Most participants used disposable diapers and disposed of them within the environment because they lacked access to municipal waste collection. Regarding decisions around diaper use, common factors discussed were convenience, social perception and beliefs, cost, water access, and diaper disposal logistics. Convenience and societal perception and beliefs were determined as key factors behind diapering choices, and both a gender and a generational divide was revealed. Participants express general understanding of negative impacts associated with diaper disposal, but knowledge gaps exist, notably regarding water pollution and pathogen spread, that could be a focus of educational campaigns. Regarding solutions, participants proposed the provision of a central collection point as well a return to reusable diapers, each of which has its own considerations and hurdles. Any interventions should retain the perceived convenience factor of disposable diapers and be implemented on a community rather than individual basis. Solutions should be multifaceted, involve opportunities for community collaboration amongst all ages and genders, and should also engage local leadership. Focus groups should be considered as the first steps towards continued discussions amongst stakeholders.
Toxoplasma gondii infection in impala (Aepyceros melampus) from the Timbavati abattoir
Rabe, Shanzelle (University of Pretoria, 2024-10)
Toxoplasma gondii (T. gondii) is a protozoon parasite with a worldwide distribution that infects mainly domestic and wild felids, with virtually all mammal and avian species acting as intermediate hosts. Clinical manifestation known as toxoplasmosis causes encephalitis as well as infertility, abortion or the birth of offspring with central nervous system abnormalities. The feline definitive host ingests the parasite when consuming intermediate hosts with tissue cysts containing T. gondii bradyzoites. Considering the possible presence of the parasite in production and wildlife species, the consumption of undercooked game meat by people, should be regulated because of the potential risk of T. gondii transmission to humans. In this study the prevalence of infection and the tissue cyst predilection sites was determined through serological and molecular assays performed on impala antelope (Aepyceros melampus) samples collected from the Timbavati abattoir, located within the Timbavati Private Nature Reserve (TPNR), on the western boundary of the Kruger National Park (KNP). Impala samples (n = 138) were collected within the TPNR over six months. Serum was used in two serological assays, the Modified Agglutination Test (MAT) and the Latex Agglutination Test (LAT), for assessing the seroprevalence. An optimised in-house sodium acetate method was used to extract DNA from the triceps brachii, cardiac muscle, tongue, diaphragm, spleen, liver, and brain samples, followed by quantitative polymerase chain reaction (qPCR) to amplify an 81-bp fragment of the Repeat element 529-bp sequence to confirm the presence of T. gondii DNA. Due to the limited research on T. gondii in wildlife species in Africa, in terms of both clinical significance and the interface between humans and wildlife in the rural setting, the main focus of the current study was to determine whether the rural communities in and around the Mnisi area are at risk of contracting T. gondii by consuming game meat, and to determine if specific organs/tissues were more prone to containing T. gondii cysts than others. Based on a seroprevalence of 8.70% (MAT) and 13.77% (LAT) in impala in the Mnisi area, the risk of infection via environmental (faecal) contamination is quite low, but still noteworthy. In both assays the two strong positive impala individuals were F18 and F29. When comparing the results between MAT and LAT using the McNemar’s test and Kappa statistics, the LAT yielded a higher seroprevalence, alluding to the possibility of it being the less specific test of the two, however the MAT is more subjective in terms of interpretation of the results. When evaluating the presence of T. gondii DNA using qPCR, 7.25% of individual impala contained T. gondii DNA in at least one of the seven tissues that were sampled, and of these the only samples to have Ct values consistently below 35 were F18 (brain) and F29 (tongue). The presence of DNA within specific tissues (tongue, heart, brain, triceps brachii, and diaphragm) correlates directly with the risk of infection via ingestion of tissue cysts. Undercooked game meat is often sold to nature reserves as biltong or carpaccio, but is most often consumed locally by the population around Timbavati. A lack of resources in the rural community often leads to ingestion of raw or undercooked game meat, and therefore poses a significant risk of contracting toxoplasmosis. Since treatment of T. gondii using drugs such as sulphadiazine, pyrimethamine, clindamycin, or toltrazuril is challenging in people, a better understanding of the prevalence of this parasite within the wildlife population can lead to advances in prevention of disease in and around the Mnisi community. Furthermore, investigating the different strains of T. gondii circulating in wildlife species might shed some light on its genetic diversity within the South African population, and will also help to assess the clinical importance of this disease.
Neutrophil Myeloperoxidase Index in Dogs with Babesiosis
Celliers, Anri (University of Pretoria, 2018-08)
Babesiosis caused by the more virulent tick-borne haemoprotozoan, Babesia rossi, results in a marked systemic inflammatory host response in dogs. Neutrophils are part of the innate immune system and myeloperoxidase is the predominant component of the neutrophil lysosomal protein in azurophilic granules. This enzyme plays a crucial role in the process of destruction of microbes by neutrophils. Neutrophil myeloperoxidase index (MPXI) is a reflection of the intracellular myeloperoxidase content in circulating neutrophils. The aims of this study were to: (a) compare MPXI in dogs with babesiosis with healthy control dogs, using the ADVIA 2120; (b) compare MPXI in dogs that died from babesiosis with dogs that survived and controls; and (c) correlate the MPXI results with (i) total band and segmented neutrophil count and (ii) various cytokine concentrations. Data for 140 dogs, naturally infected with B. rossi, and 20 healthy control dogs were retrospectively evaluated. Approval was obtained from the University of Pretoria’s Animal Ethics committee, as well as the Faculty Research Committee. Owner consent was obtained for enrolment of each case. MPXI was generated on an automated cell counter, ADVIA2120, and various cytokine concentrations, including interleukin-2 (IL-2), IL-6, IL-8, IL-10, IL-18, granulocyte-macrophage colony stimulating factor (GM-CSF) and monocyte chemoattractant protein-1 (MCP-1), were determined using a canine-specific multiplex immunoassay (MILLIPLEX MAP Canine Cytokine/Chemokine Magnetic Bead Panel CCYTO-90K-07, Millipore, Billerica, USA). The mortality rate of the Babesia-infected dogs was 11% (15/140). MPXI was significantly higher in the Babesia-infected dogs (P = 0.033), as well as the Babesia-infected nonsurvivors (P = 0.011), compared to the controls. For the Babesia-infected group a significant positive correlation was found between MPXI and IL-10 (r = 0.211, P = 0.039), and a significant negative correlation between MPXI and IL-8 (r = -0.350, P < 0.001). For the dogs that died, significant positive correlations were found between MPXI and IL-2 (r =0.616, P = 0.033), IL-6 (r = 0.615, P = 0033), IL-18 (r = 0.613, P = 0.034), GM-CSF (r =0.630, P = 0.028) and MCP-1 (r = 0.713, P = 0.009). In dogs that survived, a significant negative correlation was found between MPXI and IL-8 (r = -0.363, P = 0.001). The higher MPXI value in Babesia-infected dogs and especially Babesia-infected nonsurvivors, in conjunction with cytokines, could indicate an increased inflammatory response, as is expected in B. rossi-infections. The potential of MPXI as a novel marker of inflammation and prognosis in Babesia rossi-infected dogs, warrants further exploration.
Expression analysis of selected maize primary metabolism genes in response to Cercospora zeina inoculation in the glasshouse
Mlunjwa, Zimbili Ethel. (University of Pretoria, 2018-09)
Maize is one of the most important grain crops in Africa especially in Southern and sub-Saharan Africa. This crop contributes not only to food security but also to the economy. However, there are factors that affect the development of maize including diseases, which pose as threats to food security. Grey leaf spot (GLS), a foliar disease of maize, is caused by Cercospora zeina, an economically important ascomycete worldwide. It causes over 65% yield losses, thereby being a great threat to food security. This disease was first reported in KwaZulu-Natal province, a GLS hot spot in South Africa in 1988. Strategies such as crop rotation, conventional tillage and fungicides are widely used to manage the progression of GLS. However, these strategies are labour-intensive and expensive for farmers. An alternative cost-effective method is the utilization of host resistance. To better understand the mechanism of host resistance, two primary metabolism genes, isocitrate lyase (ICL) and malate synthase (MS), involved in the glyoxylate pathway, were previously shown to be highly induced by the fungus in a field RNAseq study. This research was aimed at elucidating expression of these two primary metabolism genes. Glasshouse trials were conducted by inoculating the maize genotypes B73 (susceptible) and B73-QTL (resistant) with C. zeina. Genomic DNA was extracted and the fungal CTB7 gene region amplified to confirm that the infection was due to C. zeina. RNA was also extracted, and reverse transcribed to copy DNA (cDNA). The quality of RNA was confirmed by performing a reverse transcriptase PCR (RT-PCR) with banana actin primers as a positive control. Primer pairs flanking an intron in the ICL and MS genes were successfully designed to specifically amplify their respective cDNA. To further confirm these results, the amplified gene products were sequenced using Sanger sequencing platform and thereafter aligned to respective reference genes obtained from NCBI. Overall, ICL and MS genes were successfully amplified from the infected maize genotypes. The ICL amplification needs further optimisation as the bands were not intense to continue with expression analysis. The expression of the two MS transcripts increased at the different progression stages indicated that the glyoxylate pathway plays a role in fungal pathogenicity.
Long bone fractures i n impala (Aepyceros melampus) : a classifica tion system and review of 55 cases
van Heerden, Frans G. (University of Pretoria, 2019-01)
Aim and objective:To introduce and apply a modified-Unger fracture classification in impala, determine the long bone fracture distribution based on 58 long bone fractures, and report the fracture fixation methods used to treat some of the fractures studied. Study design : Retrospective descriptive radiographic study. Sample population: Fifty eight long bone fractures in 55 impala. Materials and methods: This radiographic study evaluated 122 radiographs of 58 long bone fractures in 55 impala. The Unger fracture classification was modified and fracture illustrations for the metacarpal and metatarsal bones added. Each fracture was classified and assigned a four symbol alpha-numeric code using this classification. The long bone fracture distribution, patient signalment, skeletal maturity, fracture associated soft tissue changes, presence of fissure lines, periosteal reaction, fracture displacement, cause of the fracture and treatment were recorded. Results :The overall fracture distribution based on location, found tibial (n=17) fractures to be the most common. Seventy eight percent of the cases had fractures in the diaphysis. The fracture distribution based on complexity was 46% simple, 28% wedge and 26% multi-fragmentary fractures and based on severity was 36% severity 1, 36% severity 2 and 28% severity 3. Fifty seven percent of the fractures affected rams and 43% ewes, with 68% of all cases being skeletally immature. Fifty three percent of cases had open fractures and fissure lines were detected in 34% of fractures. Eighty two percent of all cases had no periosteal reaction associated with the fracture. The average displacement in a cranio-caudal direction was 18 mm, medio-lateral 16 mm and proximo-distal 32 mm. The cause in the majority of fractures was unknown, with some fractures caused by an immobilization dart (n=6). Most patients were treated with external fixation (n=18) only, followed by internal fixation (n=6) or a combination of internal and external fixation methods (n=4). Conclusion :The modified-Unger fracture classification was applicable in classifying 58 long bone fractures in impala, and facilitated determining the long bone fracture distribution. This classification, the determined fracture distribution and the reported fracture fixation methods, should provide a foundation for further advances in veterinary and comparative ungulate, and particularly antelope, orthopaedics and traumatology.
Histology of the female reproductive tract of the cheetah (Acinonyx jubatus)
Penfold, Miles J. (University of Pretoria, 2018-11)
Cheetahs are listed as vulnerable by the IUCN (International Union for Conservation of Nature) with their total worldwide population estimated at 6674 individuals. Ongoing habitat destruction, fragmentation, human animal conflict and predation threaten the survival of the wild cheetah population. Zoos and wildlife parks are tasked with maintaining a genetically healthy population as insurance against catastrophic extinctions. In contrast to reproduction in the wild, reproductive success in captivity has been poor, with only a handful of facilities achieving reasonable success. Much research has been done to try identify why. Both husbandry and spermatic factors have been investigated. Recently the focus has shifted to investigating the role of uterine health in reproductive success. Since the identification of pathology in any organ or system is made with reference to the normal, it was decided to investigate and document the normal histology of the female cheetah reproductive tract. Six captive female cheetah uteri, obtained from post-mortems after elective euthanasia of cheetahs aged 7-10.5 years, and one uterus, from a 3 year-old cheetah that died acutely, were sectioned and processed by routine histological methods. Histological sections were stained with haematoxylin and eosin and studied and photographed with an Olympus BX63 light microscope using bright field illumination and fitted with an Olympus DP72 digital camera. Very early signs of cystic endometrial hyperplasia were identified in 4 of the 7 uteri. These sections were disregarded and only sections with no pathological changes were included in the histological atlas. The histology of the female reproductive tract of the cheetah generally resembled that of the domestic dog, cat and African lioness. In the cheetah the suspensory ligament mostly branched in the region of the tubal pole of the ovary with the branch running in the mesosalpinx to join the tip of the uterine horn. The reproductive ligaments were comprised predominantly of smooth muscle, which was very well developed and supported the entire length of the uterus up to the cervix, similar to the African lioness. Cyst-like structures were found in the region of the UTJ. The uterine tube opened into the uterine lumen from a microscopic, well-defined papilla. The papillary glands were morphologically distinct to the uterine glands. The cyst like structures appeared to be dilations of the papillary glands, potentially acting as a storage cistern. The cyst-like structures are of importance to pathologists examining uterine sections in the UTJ region as they could easily be confused with cystic endometrial hyperplasia. It is therefore advised that sections for histopathology of the uterus of the cheetah be taken at least 5 mm distal to the UTJ to preclude accidental inclusion of these cyst-like structures. The Tunica muscularis of infundibulum to the ampulla, before increasing in thickness in the isthmus. The uterus and uterine glands were lined by a low cuboidal to cuboidal epithelium which contrasts with the dog and lioness. No ciliated cells were present in the uterus. The cervix displayed very few tertiary folds, no mucigenous nor goblet cells which is similar to the lioness but contrasts to the dog. The cervix contained no elastic fibres. Further research needs to be done to document the histology of the vestibule and clitoris as well as to determine the presence or absence of striated muscle in the distal two thirds of the round ligament as described in the lioness. The function of the papillary glands and significance of their cyst like appearance also needs to be further investigated.
A comparison of perceptions of the tuberculin skin test and an incentive postmortem-based surveillance system in the Mnisi community, Mpumalanga, South Africa
Marange, Rudo (University of Pretoria, 2018-10)
Tuberculosis (TB) is a global health concern. Mycobacterium bovis (M. bovis) and Mycobacterium tuberculosis (M. tuberculosis) are the most common causes of TB in animals and humans respectively. As part of TB control strategies most governments have instituted test and slaughter policies to eradicate bovine TB (bTB). While this has been met with some success, innovative and effective strategies to control TB are needed. We evaluated the postmortem surveillance (PMS) system as an alternative to the tuberculin skin test (TST) and found it to be a potentially cheaper and effective surveillance method. The level of TB awareness in the Mnisi community was also evaluated. Tuberculosis awareness by the community is also an effective way of TB control as education empowers people to make informed choices with regards to mitigating TB risk factors in their daily lives.
Vaccination of on-farm cattle against heartwater : safety and efficacy of Ehrlichia ruminantium (Welgevonden) vaccine
Marumo, Ratselane Daniel (University of Pretoria, 2018)
Ehrlichia ruminantium (Rickettsiales, Rickettsiaceae) is the causative agent of heartwater disease transmitted to cattle, sheep, goats and wild ruminants e.g. springbok by Amblyomma hebraeum in South Africa (SA). The current live blood vaccine (Ball 3) used in SA has limitations; it does not show efficacy against most field strains, it is virulent and concurrent treatment with antibiotic is necessary and it is produced in life animals which hinders its quality control. Second generation vaccines have not yet been developed to commercial stages. Previous experiments using an attenuated E. ruminantium (Welgevonden) tissue culture experimental vaccine in Merino sheep, Boer goats and Angora goats, administered through intramuscular (I/M) and intravenous (I/V) routes, without the use of antibiotic, showed promising results in terms of safety and efficacy. The objective of the current study was to test the safety and efficacy of this attenuated tissue culture vaccine in cattle, administered by the I/M route. One sheep injected with 10 ml of the virulent Welgevonden heartwater strain was used to infect Amblyomma hebraeum nymphs. Twenty (8-24 months old) male Friesian Holstein cattle obtained from a heartwater and vector free area were used; ten were vaccinated with the attenuated Welgevonden tissue culture isolate intramuscularly and ten were untreated controls. The vaccine was prepared and inoculated with an estimated concentration of 1.11 X 10⁶ E. ruminantium organisms in 2 ml. Tick challenge of both cattle groups was performed with 17 infected A. hebraeum (7 males/10 females) 35 days following vaccination. Cattle were screened serologically by the indirect fluorescent antibody test (IFAT) and by molecular tools using pCS20 quantitative real-time TaqMan (qPCR) before and after vaccination and challenge. Cattle were weighed before vaccination, during vaccination reactions and tick challenge (Days 0-77). Animals were monitored for clinical signs of heartwater disease and treated according to a score sheet when appropriate. Samples of ticks that dropped from infected sheep on different days were highly infected (103) with E. ruminantium (Welgevonden) organisms as tested using qPCR and deemed suitable for animal challenge. The group of cattle (n=10) which were vaccinated intramuscularly, showed no clinical or local vaccine related reactions and no treatment was required. The vaccinated group was challenged 35 days post vaccination together with the untreated controls (n=10). The mean number of engorged female ticks that dropped from the vaccinated (n=7.7) and unvaccinated (n=8.3) groups showed no statistical difference. The vaccinated group did not show any clinical reactions, while 8/10 of the unvaccinated controls developed severe reactions and received treatment while one animal was euthanized following the score sheet. There was a statistical significant mean difference (p-value = 0.0003) in the final weight gain/loss between the vaccinated (mean 5.6 + 2.84 Kg) and unvaccinated (mean -0.33 + 2.78 Kg) groups. On Day 37 after tick challenge, 100% of the vaccinated and 80% of the unvaccinated cattle showed sero-conversion (1/180) in the IFAT. The results of the study have demonstrated the safety and efficacy of the attenuated E. ruminantium (Welgevonden) experimental vaccine against homologous challenge in cattle as judged by the severe clinical reactions in the unvaccinated group. The vaccinated group also had a gain in mean body weight compared to the unvaccinated group after challenge.

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