Theses and Dissertations (Companion Animal Clinical Studies)

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The effect of equine maternal appeasing pheromone on heart rate variability and behavioural parameters in mares during a fear-inducing event
Simao, Chiraag (University of Pretoria, 2025)
The effect of equinBackground Fear related stress in horses is a common feature of routine management and clinical procedures that can elicit marked behavioural and physiological responses. Equine appeasing pheromone (EAP) has been proposed as a non-invasive intervention to mitigate stress responses, yet evidence for its effects on cardiac autonomic regulation during fear-inducing events remains limited. Aim The current study aimed to evaluate the effects of EAP on heart rate variability (HRV) and behavioural responses in mares exposed to a controlled fear-inducing protocol that included different fear-eliciting stimuli (FES) typical of a clinical setting. Methodology Thirty adult mares (11.8 ± 2.9 years, range 7-20 years) were exposed to six sequential experimental phases comprising baseline (Ph1), post-application rest allowing mares free movement (Ph2), rest during restraint (Ph3), fear exposure during restraint (Ph4), rest during restraint after fear exposure (Ph5), and recovery allowing free movement (Ph6). Fear exposure protocol included three specific FES namely removal of a herd mate, clipper noise (2 meters away from the mare subject) and application of tick grease under the mare’s tail, done sequentially within one minute of each other. Each mare received EAP and placebo treatments in separate trial periods, in a cross-over manner, 14 days apart. Heart rate and behaviour were recorded for each mare during each trial period using electrocardiograph (ECG) and video recordings. Cardiac autonomic activity was assessed using HRV derived from the ECG. Behaviour was scored as interval of occurrence (frequency) and duration recorded manually by the researcher. Treatment-, phase-, and treatment-by-phase comparisons were performed on the dataset for HRV and behaviour parameters. Heart rate variability (HRV) variables with a correction factor <5% were analysed in R (v4.2.1) using mixed models, with treatment, phase, and treatment-by-phase as fixed effects, and mare and crossover period as random effects. Model assumptions were checked (with Box–Cox transformation applied where necessary), and significant effects were explored using Tukey-adjusted multiple comparisons (α = 0.05). Behavioural outcomes were analysed using regression models matched to data type (logistic for binary presence/absence, Poisson or negative binomial for frequencies, and GLM for durations), with mare and crossover period included as random effects. Where behaviours were too infrequent for meaningful quantitative analysis, they were summarised descriptively as counts and percentages, and carryover was assessed via the treatment sequence effect; significant effects were followed by Tukey-adjusted post hoc comparisons (α = 0.05). Results HRV parameters Significant overall difference (p = 0.0011) between treatments (EAP vs. placebo), averaged across all phases was detected in normalized high frequency (HF norm) expressed in normalised units (n.u.). Significantly lower (p = 0.0368) HF norm (mean ± SD = 28.17 ± 15.44 n.u.) was found on placebo treatment during Ph6, compared to EAP treatment (32.98 ± 12.69n.u.), despite a significantly higher (p = 0.0054) HF norm on placebo treatment (54.67 ± 25.09 n.u.) versus EAP (32.47 ± 10.41 n.u.) during Ph2. Low frequency to high frequency ratio (LF/HF) and normalised low frequency (LF norm) were also found to be significantly (p=0.0017, and p = 0.0135, respectively) lower on the placebo treatment during Ph2. This pattern suggests difference in cardiac autonomic balance between the treatments prior to restraint which reversed during recovery. Notably, PNS-specific parameters followed a similar pattern in both groups, indicating that the observed effects likely reflect changes in overall autonomic balance rather that treatment-specific increase in pure PNS activity. Additionally, placebo treatment exhibited significant differences in cardiac autonomic balance parameters, LF/HF (p=0.0071), HF norm (p = < 0.0001), and LF norm (p = 0.0255) between phases of the trial where LF/HF differed between Ph2 and Phases 4,5 and 6, and between Ph3 and Phases 4 and 6. Similarly, both HF norm and LF norm differed between Ph2 and each subsequent phase (Ph3, Ph4, Ph5, and Ph6). HF norm further differed between Ph3 and Phases 4 and 6. While on EAP less changes in these parameters were detected between phases with significant difference (p = 0.0071) found in LF/HF between Ph3 and Ph4. Regarding behaviour, EAP demonstrated significantly (p = 0.0078) more movement across all post-treatment phases (16.70 ± 3.24%) and a significantly (p = 0.0207) higher proportion during restraint phases (Ph3, 4, and 5) (23.50 ± 4.59%). Additionally, significantly greater (p = 0.0139) head-up-and-down behaviour was observed throughout the experiment (32.60 ± 4.08%) and more alert posturing during restraint phases (41.20 ± 5.33%; p = 0.0360) compared to the placebo treatment. Conclusions EAP was associated with increased behavioural engagement during restraint and fear exposure, alongside less inter-phase differences in cardiac autonomic balance parameters compared to placebo treatment. This suggests that EAP affects how mares physiologically and behaviourally experience and recover from fear-inducing events.
Cardiomyocyte damage in dogs with Babesia rossi infection and its association with anaemia, inflammation, endocrine dysfunction and microthrombi formation
Burger, Nina (University of Pretoria, 2026-02-04)
Background: Cardiac involvement in canine Babesia rossi infection is recognised, but the mechanisms of cardiomyocyte damage remain unclear. While increased serum cardiac troponin I (cTnI) concentrations have been reported, the contributions of anaemia, systemic inflammation, endocrine dysfunction, and microthrombi require further investigation. Objectives: This study aimed to evaluate the presence and severity of cardiomyocyte injury in B. rossi-infected dogs, and to assess its association with anaemia, inflammatory and endocrine responses, coagulation abnormalities, and clinical outcome. Methods: A retrospective analysis was conducted on 94 dogs with confirmed B. rossi infection and 13 healthy control dogs. Serum cTnI concentrations were correlated with haematocrit (HCT), inflammatory- (e.g. CRP, IL-2, IL-6, IL-8, IL-10, IL-18, GM-CSF, MCP-1), endocrine- (e.g. cortisol, total T4, TSH), and coagulation variables (e.g. PT, aPTT, fibrinogen, D-dimer, antithrombin (AT), and coagulation factors II, V, VII, IX, X, XI). Dogs were categorised by disease severity and outcome. Statistical analyses included Kruskal–Wallis, Mann–Whitney U, and Spearman’s rank correlation. Results: Cardiac troponin I concentrations were significantly increased in Babesia-infected dogs compared to controls, with highest concentrations in complicated cases and non-survivors. The HCT was significantly decreased in all infected subgroups, with a weak negative correlation between cTnI and HCT. Inflammatory markers (i.e. CRP, SAA, IL-10, MCP-1) were significantly increased, with IL-6 and MCP-1 higher in non-survivors, though all correlations with cTnI were weak. Total T4 was significantly decreased in all infected groups, with moderate negative correlations with cTnI. Cortisol concentrations were significantly increased in complicated and non-survivor groups, showing strong positive correlations with cTnI. No significant differences were observed for TSH. Coagulation abnormalities included thrombocytopenia, prolonged PT and aPTT, and decreased activities for FII, FVII, FX, FXI, and AT. Cardiac troponin I showed moderate to strong positive correlations with PT, aPTT, and D-dimer, and moderate to strong negative correlations with FII, FV, FVII, FX, and AT. Conclusion: Cardiomyocyte damage in canine babesiosis is more severe in dogs with the complicated form of the disease and non-survivors, and is associated with thyroid dysfunction, hypercortisolaemia, and hypercoagulability (i.e. microthrombi formation).
Diagnostic and prognostic utility of serum amyloid A for systemic inflammatory response syndrome and sepsis in feline patients at the Onderstepoort Veterinary Academic Hospital, South Africa
Seedat, Muhammad (University of Pretoria, 2025)
Serum amyloid A (SAA) is a major positive acute phase protein in cats and is commonly used for the early detection of inflammation. A newer immunoturbidimetric assay, namely the VET-SAA assay (Eiken), has been developed and validated for SAA measurement with an improved sensitivity and diagnostic performance but has yet to be validated and investigated in the Onderstepoort Veterinary Academic Hospital (OVAH) feline population. Systemic inflammatory response syndrome (SIRS) is a clinical state of widespread inflammation, and its identification has shown some prognostic benefits in other species. The aim of this study was to explore the diagnostic and prognostic utility of SAA, measured by the VET-SAA assay, in cats with SIRS and sepsis. A partial VET-SAA assay method validation study was conducted using stored serum samples, where an imprecision, linearity, and detection limit verification experiment was performed. An overlap study investigating SAA in cats with SIRS was subsequently conducted using stored serum samples from cats presented to the OVAH. Cats were classified into three groups: healthy, non-SIRS disease (NSD), and SIRS. The SIRS group was subclassified into those with and without sepsis. Measurement of SAA was performed on serum from admission and, if available, follow-up visits. Concentrations of SAA were compared between groups using non-parametric tests with significance set at p < 0.05. The short- and long-term imprecision experiments showed acceptable repeatability and reproducibility. The detection limit verification yielded the following: LoD was 1.4 mg/L and LoQ was 1.5 mg/L. A total of 118 cats were included in the final study population. This included 21 healthy cats, 74 cats with NSD, and 23 cats with SIRS. Of the SIRS cats, 12/23 (52%) had sepsis, while 11/23 (48%) did not. A significant difference in SAA concentrations was found between healthy, NSD, and SIRS cats (p<0.05). However, no significant difference was found between SIRS cats with sepsis compared to those cats without sepsis, p=0.6889. Following Receiver operator characteristic (ROC) curve analysis, an SAA cutoff of 81.0 mg/L had a 90.5% specificity (95% CI: 82.8-95.6%), but a poor sensitivity of 30.4% (95% CI: 13.2-52.9%) for the detection of SIRS. An SAA cutoff of 1.5 mg/L had a 91.3% sensitivity (95% CI:72.0-98.9%), but a poor specificity of 31.6% (95% CI: 22.4-41.9%) for SIRS detection. There was no significant difference in admission SAA found between survivors (median 27.8 mg/L; 1.5-266.0 mg/L) and non-survivors (median 14.8 mg/L; 1.6-1786 mg/L), p=0.698. There was no significant difference in the change in SAA over the first two measurements between survivors and non-survivors. The VET-SAA assay is a validated and reliable method of SAA measurement which performs similarly to previous SAA assays. Serum amyloid A is increased in cats with SIRS and sepsis compared to cats without SIRS, but a fairly high cutoff of >81.0 mg/L is needed for adequate specificity for the diagnosis of SIRS. In contrast with other studies, SAA was not found to be different between cats with or without sepsis, nor was there a difference in SAA in cats with SIRS between survivors and non-survivors, in the OVAH feline hospital population. Further prospective studies are warranted to refine the diagnostic and prognostic potential of SAA for systemic inflammation in cats.
Analytical and overlap performance of an automated serum amyloid A assay in free-living and managed lions (Panthera leo) in South Africa
Morris, Tessa L. (University of Pretoria, 2025)
Analytical and overlap performance of an automated serum amyloid A assay in free-living and managed lions (Panthera leo) in South Africa. Serum amyloid A (SAA) is a biomarker of inflammation in both domestic and free-living mammals and may have utility as an objective measure of health and indicator of inflammation in lions. The aim of this study was to validate the Eiken VET-SAA immunoturbidometric assay for use in lions, determine reference intervals (RI), investigate changes in SAA concentrations in various diseases, and establish a diagnostic cut-off for the detection of systemic inflammation in lions. Analytical validation experiments included linearity, intra- and inter-assay imprecision, recovery, limit of quantification (LoQ), interference and quality control validation, using stored serum samples from free-living and managed lions. Reference intervals were established using the non-parametric method from 66 apparently healthy lions, which included 54 free-living and 12 managed lions. One hundred and twenty-nine diseased lions, including 52 free-living and 77 managed lions, were categorised as having either non-inflammatory or 13 inflammatory disease. Serum amyloid A in the healthy and two disease groups was compared with the Kruskal-Wallis and post-hoc Conover tests (P <0.05 significant). Diagnostic accuracy was investigated using Receiver Operator Characteristic (ROC) curve analysis. A diagnostic cut-off for the detection of inflammatory disease was calculated using Youden’s index. Serum amyloid A in 38 tuberculosis (TB) test-positive lions and 17 healthy TB test-negative lions was compared using the Mann-Whitney test. The VET-SAA assay was validated in lions. The assay was linear over a range of 2.1-178.5 mg/L, short- and long-term imprecision ranged from 2.0-9.4%, LoQ was 2.1 mg/L, recovery was 88.7%. Severe haemolysis or lipaemia did not cause significant interference. The reference interval was 2.1-20.7 mg/L. Significant differences were found between the SAA concentrations in the inflammatory disease group and both the healthy and non-inflammatory disease groups but there was some overlap, with good diagnostic accuracy for the discrimination of healthy/ non-inflammatory disease versus lions suffering from inflammatory disease (ROC area under curve 0.87). There was no significant difference found between the healthy and non-inflammatory disease group. The SAA at Youden’s index was 18.2 mg/L with a sensitivity of 80% and a specificity of 87.9%. There was no significant difference found between the TB test-positive group and the healthy TB test-negative group. In conclusion, the Eiken VET-SAA assay has adequate precision and accuracy for the measurement of SAA in lions. Reference intervals were generated and SAA demonstrated good diagnostic accuracy and performance for the detection of inflammation in free-living and managed lions. Serum amyloid A should be further investigated in specific diseases of clinical and conservation importance, to determine its potential use during health screening and as an indicator of inflammatory disease.
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.
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.
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.
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.
Long bone fractures in impala (Aepyceros melampus) : a classification 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.
Dental, oral and maxillofacial pathology in a wild serval (Leptailurus serval) population
Emslie, Roxanne (University of Pretoria, 2018-11)
Objective: Members of the family Felidae suffer from a wide range of dental, oral and maxillofacial conditions. These conditions can cause significant morbidity and mortality. However, no studies could be found investigating the dental, oral and maxillofacial pathology in serval (Leptailurus serval). Serval are frequently kept in captivity and occasionally as household pets. Having knowledge of the pathology affecting wild serval would greatly assist in improving preventative care practices and the welfare of serval in captivity. The objective of this study was therefore to describe the dental, oral and maxillofacial pathology of a wild serval population. Animals: Thirty wild serval, which occur naturally on the Sasol Synfuels Operations property in Secunda, Mpumalanga, South Africa; were examined for dental, oral and maxillofacial pathology. Methods: Detailed extraoral and intraoral examinations, as well as full-mouth dental radiographs, were performed on each anaesthetised serval. Results: Fourteen different conditions affecting the teeth were recorded, but no oral or maxillofacial pathology was found. The most common dental pathology observed was tooth wear affecting 67% of the serval examined. Dental fractures, including complicated crown fractures, uncomplicated crown fractures and root fractures, were diagnosed in 23% of the serval. The two canine teeth with complicated crown fractures also displayed grey discolouration clinically and periapical radiolucencies radiographically. Abnormal root morphology was apparent at the maxillary canines in 20% of cases. Supernumerary roots of maxillary third premolar teeth and supernumerary mandibular premolar teeth were noted in 17% and 10% of serval examined, respectively. Other dental abnormalities identified less frequently included rotated teeth, retained deciduous roots, enamel defects and tooth resorption. Conclusion: This study indicates that intraoral and extraoral examinations, as well as dental radiography, are important aspects of the clinical evaluation of wild felines. These findings are particularly interesting as the study population represents the highest density of serval ever recorded, with their habitat consisting primarily of disturbed wetland and grassland directly surrounding a highly active industrial site. This demonstrates that even the most unexpected sectors and opportunities can be used to advance conservation efforts and to provide knowledge to assist in improving the husbandry of captive wild animals.
Comparison of haematology and specific serum biochemistry variables between anaesthetised non- injured and injured southern white rhinoceros (Ceratotherium simum simum)
du Preez, Jacques Pieter (University of Pretoria, 2018-10)
N/A
Dental and maxillofacial anamalies and pathologies in southwestern black rhinoceros (Diceros bicornis bicornis) skulls from Etosha National Park, Namibia
Set, Eggyda Paul Shatunga (University of Pretoria, 2025-09)
This study examined the dental and maxillofacial pathology and anomalies of the south-western black rhinoceros from the Etosha National Park in Namibia. In general, rhinoceros tend to suffer from a wide range of dental and maxillofacial conditions. These conditions could cause significant morbidity and/or mortality which may affect the quality of life in the rhinoceros. No studies could be found investigating the dental and maxillofacial anomalies or pathology of this species. A total of 106 skulls were collected in Etosha National Park. Complete skulls (both maxilla and mandible present) were examined for dental and maxillofacial anomalies and pathologies. Dental pathologies such as fractures, periodontitis, abnormal attrition or abrasion were identified. The right mandibular first premolar tooth was the most commonly absent tooth. The most common reason for absent teeth recorded was congenital absence 12% (346/2 968) and post-mortem/ artefactual tooth loss was 6 % (177/2 968) of the total number of teeth. Artefactual or postmortem tooth fractures were present in all skulls and in 98% (2 360/2 391) of the teeth evaluated. Crown root fractures affected 1.5 % (37/2 391), complicated crown fractures affected 0.1 % (3/2 391) and one tooth had a complicated crown root fracture (0.04%). Periodontitis (all stages) was more evident in the XVI age class and periodontitis stage 2 was present in 21% (493/2 391) of the teeth evaluated. Periodontitis stage 3 was present in 6 % (135/2 391) of the teeth evaluated while 3 % (81/2 391) of the teeth evaluated were of periodontitis stage 4. Osteomyelitis, degenerative joint disease and tumors were also associated with severe periodontal disease. Vestigial incisor teeth or empty alveoli were present in 16% (17/106) of the skulls examined (Fig. 4.4). These vestigial incisor teeth or empty alveoli was present in the maxilla 47% (8/17) and in the mandible 54% (9/17). The left mandible had the highest number of vestigial incisor teeth or empty alveoli 52% (9/17) and the right mandible had 47% (8/17) vestigial incisor teeth present. Temporomandibular joint abnormalities were either present as anomalies or pathological lesions in 43.4% (46/106) of the skulls. Of these abnormalities 43.5% (20/46) were bilateral and 56.5% (26/46) unilateral. The anomalies 34% (37/206) included sagittal ridges which were lateral 69%, medial 26% or centrally located was 5 %. In conclusion, periodontitis was most prevalent in older south-western black rhinoceros than younger or juvenile south-western rhinoceros. In most skulls periodontitis was associated with food trapped in between tooth and tooth fracture leading to accumulation of bacteria in dental space. This study indicates that periodontitis and temporomandibular joint pathologies increase with an increasing age of the rhinoceros.
Prevalence of elodontomas in Cape ground squirrels (Geosciurus inauris) and other rodents in South Africa
Norval, Quintin (University of Pretoria, 2025-05)
Rodents, the most abundant mammalian order, are being increasingly kept as pets, which necessitates a deeper understanding of their health issues. One such issue is elodontomas, dental overgrowths that can obstruct rodent nasal passages, causing respiratory distress. The cause of elodontomas remains largely unclear, with hypotheses centred on captivity-related factors. To this end, this study investigates the potential aetiology of elodontomas in rodents. The work consists of three different studies. Firstly, the radiographic interpretation of the normal anatomy of rodent heads is described. Utilising the unique anatomical landmarks of rodent skulls, the normal anatomy can be differentiated to diagnose potential pathology, such as elodontomas. Secondly, a retrospective analysis of museum specimens from various South African rodent species was conducted to assess the prevalence of elodontomas in wild populations. The findings align with the existing notion that elodontomas are rare in wild rodents. Finally, a study examined 50 semi-wild and 50 wild Cape ground squirrels (Geosciurus inauris) for the presence of elodontomas. The complete absence of elodontomas in these free-ranging animals strengthens the link between elodontoma development and captive environments, suggesting a potential role of husbandry practices in this pathology. This research emphasises the importance of proper husbandry for pet rodents and highlights the need for further investigation into the specific captive factors that contribute to elodontoma formation.
Endothelial damage and cellular apoptosis in horses experimentally infected with African horse sickness virus
Schonken, Emma (University of Pretoria, 2024-12)
African horse sickness (AHS) is an infectious, non-contagious vector-borne viral disease caused by the African horse sickness virus (AHSV), a non-enveloped, double-stranded RNA Orbivirus belonging to the Sedoreoviridae family (1). Primarily transmitted by Culicoides midges, AHSV infection results in a mortality rate exceeding 90% in susceptible equine populations (2,3). The disease manifests in four clinical forms: pulmonary (“dunkop”), cardiac (“dikkop”), fever, and mixed form, with severity depending on factors such as viral virulence and host immune status (3,4). Clinical signs of severe AHS infection are consistent with vasculitis, characterized by oedema in the supraorbital fossae, ocular conjunctiva, and intermandibular spaces, as well as pulmonary oedema. Hydropericardium and petechial haemorrhages are also commonly observed during clinical examination and necropsy (5). These clinical manifestations suggest significant vascular endothelial damage as a key aspect of AHS pathogenesis. The endothelium, comprising the inner lining of blood vessels, forms a semi-permeable membrane between blood and surrounding tissues. On its luminal surface lies the glycocalyx, a gel-like layer composed of membrane-attached proteoglycans, glycosaminoglycan chains, and glycoproteins. This structure plays a crucial role in maintaining vascular homeostasis, regulating vascular permeability, and exerting anti-coagulant and anti-adhesive effects (6–8). Syndecan-1 (SYND1), a heparan sulphate proteoglycan expressed on endothelial cells, is a key component of the glycocalyx. When endothelial damage occurs, plasma concentrations of SYND1 increase, as reported in human trauma patients, making it a potential biomarker for endothelial injury (9,10). The shedding of glycocalyx components into the circulation may correlate with disease severity in various conditions characterized by endothelial damage. Previous studies have demonstrated AHSV tropism for the heart, lung, and spleen, with the virus successfully identified in these organs using immunohistochemistry (IHC) (11,12). Microscopic evaluation of endothelial cells in these tissues from horses infected with AHSV have reported ultrastructural changes suggestive of apoptosis, as well as loss of intercellular junction integrity, presence of cytoplasmic projections, and nuclear condensation (13). Given the hallmark finding of vascular permeability and tissue oedema in AHSV-infected horses, this study aimed to quantify the extent of endothelial damage using SYND1 concentrations in the blood as a biomarker and to correlate the severity of endothelial damage with apoptosis observed in endothelial cells, using IHC, of horses infected with AHSV. This study retrospectively evaluated stored plasma and tissue samples (spleen, heart, lung) from four Boerperd mix horses that were experimentally infected with AHSV. Syndecan-1 plasma concentrations in horses experimentally infected with AHSV showed no significant change over the course of infection (Skillings-Mack test = 13.516; P = 0.077). Immunohistochemical analysis showed positive staining for AHSV viral protein 7 (VP7) and non-structural protein 4 (NS4) antigens in endothelial cells and some mononuclear cells in spleen, lung, and heart tissues of infected horses. Tissue from control horses were negative for both antigens. Immunolabeling for caspase-3, a marker for cellular apoptosis, in the spleen of AHSV-infected horses showed a marked increase in positive cells (186.0 to 262.4 cells/image) compared to controls (1.0 to 25.0 cells/image). Similarly, in lung tissue, AHSV-positive horses exhibited higher caspase-3 positive cell counts (11.6 to 75.4 cells/image) than controls (0.4 to 7.4 cells/image). However, cardiac tissue showed no significant difference in caspase-3 labelling between infected and control horses. Immunohistochemistry for leucocyte markers in infected horses demonstrated strong labelling for ionized calcium-binding adapter molecule 1 (IBA-1), a marker for mononuclear cells, within splenic lymphoid tissue and lung parenchyma. T lymphocytes observed in splenic periarteriolar lymphoid sheaths and peribronchiolar interstitium stained positive for cluster of differentiation 3 (CD3). CD20-positive B lymphocytes were extensively labelled throughout splenic lymphoid follicles. These findings suggest that AHSV infection does not result in direct damage to endothelial cells; instead, it induces a significant apoptotic response in the spleen and lungs of infected horses, but not in the heart, and is associated with notable changes in mononuclear leucocyte distribution and viability in affected tissues.
Calcium and magnesium abnormalities in dogs with parvoviral enteritis
Mouton, Anneri (University of Pretoria, 2024-10)
Canine parvoviral enteritis (CPE) is a common cause of acute, life-threatening enteritis in young dogs. While gastrointestinal disturbances and immunosuppression are the most recognised sequelae of CPE, a less apparent systemic inflammatory response syndrome (SIRS) also develops in many dogs. Calcium and magnesium abnormalities are increasingly recognised in the critical care setting. Ionised hypocalcaemia (iHypoCa) is well documented among humans with sepsis, and it has been associated with an increased duration in hospital stay in dogs with CPE, as well as mortality in dogs evaluated in an emergency room or intensive care setting. Moreover, critical illness has been identified as the most common cause of iHypoCa in dogs. Hypomagnesaemia is a common occurrence in critically ill people and animals, but it has not been associated with outcome in dogs infected with CPE. A significant correlation has been found between serum calcium and magnesium concentrations in dogs with hypomagnesaemia. The objective of this study were a) to determine the association between the development of iHypoCa and total hypomagnesaemia, and sepsis, and b) to investigate whether ionised calcium (iCa) or total magnesium (tMg) is associated with mortality in dogs with CPE. Sixty-four client-owned dogs with CPE were enrolled in this prospective cohort study. Serum iCa and tMg were measured daily from admission until death or discharge. Fifteen healthy client-owned dogs were used as controls. Mean iCa concentrations of the CPE group on admission were significantly lower compared to the control group (1.35 mmol/L vs 1.52 mmol/L). Ionised calcium concentrations of non-survivors were significantly higher compared to survivors on day two, but not on any other days. Dogs that were hypercalcaemic on day two were also significantly more likely to die than normocalcaemic dogs after adjusting for multiple comparisons (OR = 10.7; 95% CI: 1.7-71). Ionised calcium was not associated with the development of sepsis on any day. In contrast, mean admission tMg concentrations of the CPE group were significantly higher compared to the control group (0.72 mmol/L vs 0.63 mmol/L). However, tMg concentrations were not significantly different between survivors and non-survivors, nor were they associated with the development of sepsis on any day. In summary, dogs with CPE had lower iCa and higher tMg compared to healthy dogs on admission, and the iCa concentrations of non-survivors were significantly higher on day two compared to survivors. Results of this study provide insight into calcium homeostasis in critically ill young dogs with CPE.
Prevalence of co-infection with Ehrlichia spp. or Theileria spp. in dogs naturally infected with babesiosis in the Eastern Cape
Cloete, Henry Pieter Pienaar (University of Pretoria, 2025)
This study describes the prevalence of Ehrlichia canis or Theileria equi co-infections in dogs that are naturally infected and clinically sick due to babesiosis. Canine babesiosis and ehrlichiosis are tick-borne diseases of great significance in South Africa. Theileriosis in dogs in South Africa is still poorly understood. Co-infection with multiple tick-borne pathogens has been documented and is perceived as a common occurrence in South Africa. The Mdantsane State Veterinary Clinic in Mdantsane, Eastern Cape Province, South Africa was used as the centre where sample collection took place. Limited data on the prevalence and distribution of tick-borne diseases in the Eastern Cape Province are available and thus this population of dogs can be viewed as a novel study population. The main objective of this study was to determine the prevalence of co-infections with E. canis or T.equi in dogs with babesiosis in the Eastern Cape province. Possible associations of population characteristics and haematological and biochemistry measures with a co-infection in these dogs were also investigated. The study population included 150 dogs naturally infected with babesiosis that presented to the Mdantsane State Veterinary Clinic between January 2021 and November 2021. Quantitative polymerase chain reaction was used to confirm the Babesia spp. that the dogs were infected with and to identify co-infections. Association with co-infection for the following parameters were evaluated: sex, breed, age, duration of sickness, leukocyte count, band neutrophil count, monocyte count, platelet count, absolute reticulocyte count, and serum globulin concentration. Positive and negative predictive values of monocytosis, leukopenia, band neutrophilia, thrombocytopenia, and on regenerative absolute reticulocyte count for co-infection were also calculated. Babesia rossi was identified in 149/150 samples and B. vogeli in only 1/150 samples. A co-infection prevalence of 2.0% (3/149; 95% confidence interval: 0.4–5.7) with B. rossi and E. canis was found. No other co-infections were reported. No investigated variables showed significant associations with coinfections. Monocytosis, in particular, was not associated with co-infection. Co-infection with other tick-borne pathogens in dogs with babesiosis is uncommon in the Eastern Cape province. These findings raise the possibility that B. rossi may have a protective effect against other tick-borne pathogens. It is advised that further testing, ideally with the use of polymerase chain reaction, be done when a co-infection is suspected to practice responsible antibiotic stewardship.
Assessment of coxofemoral joint laxity in juvenile boerboel dogs using mobile phone goniometry
Triegaardt, Christiaan Francois (University of Pretoria, 2024-05-17)
BACKGROUND Canine hip dysplasia (CHD) is closely associated with hip joint laxity (HJL), which is considered as one of the primary precursors to coxofemoral degenerative joint disease. However, the relationship between HJL and hip joint range of motion remains underexplored. OBJECTIVES This study aimed to investigate a correlation between hip joint angles (rotation and abduction) and the laxity index (LI) measured by the Vezzoni Modified Badertscher Distension Device technique (VMBDD) in juvenile boerboels.  METHODS Hip joint angles were measured in 33 boerboels (aged 4-12 months) using mobile phone goniometer-based measurements by three independent examiners for abduction, internal, and external rotation. Stress view radiography with the VMBDD method assessed HJL, and LI's correlation with measured angles were examined. Inter-and-intra-operator variability of hip joint angles were also evaluated.  RESULTS No significant correlation was found between abduction or internal rotation angles and laxity. However, external rotation demonstrated a weak correlation with laxity (r=0.207, p=0.095). Weight had a significant negative correlation with laxity (r=-0.265, p=0.031). Intra-operator variability ranged from 2.2 to 5.9, with the highest variability noted with internal rotation (4.0 to 5.9). Inter-operator variability ranged from 4.4 to 11.4, with the greatest variability observed in internal and external rotation (11.4 and 10.9, respectively).  CONCLUSION Mobile phone goniometry appears unreliable for predicting joint laxity due to high inter- and intra-operator variability with poor repeatability.
Physiological variables for the objective detection of intraoperative nerve block failure in dogs
Basson, Pierre Etienne (University of Pretoria, 2023-08)
Objective To identify physiological variables that can be used to objectively detect intraoperative nociception to indicate peripheral nerve block failure. Study design A prospective blinded randomized clinical study. Animals A sample of 14 male (40.8 ± 12 kg; mean ± SD) and 16 female (34.3 ± 11.4 kg) client-owned dogs undergoing a stifle arthrotomy. Methods Dogs were randomly assigned to one of three treatment groups for psoas compartment and proximal sciatic nerve blocks (0.2 mL kg-1 per site): guided bupivacaine (GBB) or saline (GSB) blocks or blind bupivacaine block (BBB). Guided blocks were performed using ultrasound and nerve stimulation. Dogs were premedicated intramuscularly with 0.01 mg kg-1 medetomidine and 0.3 mg kg-1 morphine. General anaesthesia was induced with propofol (to effect to achieve tracheal intubation) and maintained with isoflurane in oxygen (targeted end-tidal concentration of 1.6%). The assigned investigator, based on randomisation, allotted a confidence score [1 (poor) to 4 (high)] that the block will be successful after administering the assigned nerve block treatment. The blinded investigator allotted a binomial subjective score of the nerve block outcome (“Yes”: response to surgical stimulation; “No”: no discernible response) at each time point. Receiver of operator characteristic curve analysis was used to compare actual values and change in values of physiological variables between GSB (Yes nociception) and GBB (No nociception) at the time of the arthrotomy. The Youden index and associated criterions for each physiological variable were used as an objective measure. Fishers exact t-test, McNemar's test and Cohens kappa statistical analysis were used to determine association, differences and inter-score reliability, respectively between the objective and subjective scoring for the BBB. The subjective score was compared to objective scores after being stratified into the assigned confidence scores using Kendall’s tau-b rank correlation coefficient. Results The cardiovascular variables had good discriminating ability in distinguishing a nociceptive response (p < 0.01). The Youden indexes for MAP and DAP had the best potential effectiveness in detecting a response to surgical stimulus. The highest sensitivity was that of delta MAP (100%). Good agreement was indicated between the subjective and objective scores with delta HR or SAP. The use of delta MAP (> 6 mmHg), delta SAP (> 10 mmHg), delta DAP (> 8 mmHg) had the best ability in indicating peripheral nerve block failure (p < 0.001). Conclusions and clinical relevance The use of delta MAP, delta SAP or delta DAP can be considered as objective measures to detect intraoperative peripheral nerve block failure in anaesthetised dogs undergoing stifle arthrotomy. The determination of criterion values for different populations and conditions will benefit future clinical trials.

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