Faculty of Veterinary Science
Department of Companion Animal Clinical Studies
Selected Highlights from Research Findings
Horses performing strenuous exercise frequently develop Exercise-Induced Pulmonary Haemorrhage (EIPH). Intrapulmonary blood accumulation causes small airway inflammation and may impair gaseous exchange. Bronchoconstriction may develop secondary to the bronchiolitis leading to increased pulmonary resistance and exacerbation of EIPH. The researchers recently demonstrated that racehorses have increased prevalence and severity of EIPH at sea level compared to high altitude. Intra-pulmonary pro-inflammatory cytokines may modulate pulmonary inflammation and enter the venous bloodstream. Our aim was to identify venous inflammation by measuring cytokine mRNA expression in racehorses with EIPH in South Africa, a racing jurisdiction that does not permit race day administration of furosemide, and in which horses race at both sea level and at high altitude. A prospective, cross-sectional study of pre-enrolled Thoroughbred racehorses competing in flat races at high altitude (1,450m above sea level) and at sea level was performed between 1 August and 19 November 2005. After tracheobronchoscopy was performed within 120 minutes post-race, the presence and severity of EIPH was graded (0 to 4) and venous blood collected from 10 horses in each grade classification at both altitude and sea level. Blood collection was repeated 72h later. Following RNA isolation and cDNA synthesis by reverse transcriptase, real-time PCR was used to detect equine cytokine-specific mRNA for IL-1, 6 & 10, INF-?, and TNF-a. Data was normalized to the RQ of the grade 0 EIPH samples. Data was analyzed using Spearman’s test, ANOVA and Holm-Sidak t-test for multiple comparisons. P <0 .05 was considered significant. Compared to racing at altitude, horses racing at sea level had increased pro-inflammatory cytokine expression (p < 0.001), especially horses with a grade 3 vs. 2 and 0 EIPH (p < 0.05). Racehorses at sea level with a grade 4 vs. 0, 1 and 2 EIPH expressed increased IL-6 (p < 0.05) while greater IL-10 expression was present in horses with grade 3 vs. 0 and 2 EIPH (p < 0.05). Overall, there was greater expression of IL-6 (p = 0.046) and TNF-a (p = 0.005) at sea level which increased with increasing severity of EIPH. We conclude that racing at sea level seems to be associated with increased inflammatory cytokine mRNA production in venous blood as compared with high altitude.
Contact person: Dr MN Saulez.
The research team studied 15 llamas and 34 alpacas between three weeks and 18 years old with faecal oocysts or intestinal coccidial stages morphologically consistent with Eimeria macusaniensis. They found that many severely affected camelids had signs of lethargy, weight loss, decreased appetite, and diarrhea. Camelids with clinical infection also commonly had evidence of circulatory shock, fat mobilization, and protein loss. Non-surviving camelids also had evidence of shock, edema, bile stasis, renal insufficiency, hepatic lipidosis, muscle damage, relative haemoconcentration, and sepsis. Postmortem examination frequently revealed complete, segmental replacement of the mucosa of the distal portion of the jejunum
with coccidial meronts and gamonts. For 17 of 42 camelids, results of initial faecal examinations for E. macusaniensis were negative. Most camelids admitted alive were treated with amprolium hydrochloride, plasma and various supportive treatments. Fifteen of the 30 treated camelids died or were euthanized. Findings suggest that E. macusaniensis may be an important gastrointestinal tract pathogen in camelids of all ages. Clinical signs were frequently non-specific and were often evident before results of faecal examinations for the parasite were positive. As with other coccidia, severity of disease was probably related to ingested dose, host immunity, and other factors. The clinical and herd relevance of positive faecal examination results must be determined.
Contact person: Dr MN Saulez.
Veterinary internists need to prognosticate patients quickly and accurately in a neonatal intensive care unit (NICU). This may depend on laboratory data collected on admission, the cost of hospitalisation, length of stay (LOS) and mortality rate experienced in the NICU. Therefore, a research team conducted a retrospective study of 62 equine neonates admitted to a NICU of a private equine referral hospital to determine the prognostic value of venous clinicopathological data collected on admission before therapy, the cost of hospitalisation, LOS and mortality rate. The WBC count, total CO2 (TCO2) and alkaline phosphatase (ALP) were significantly higher (P = 0.05) and anion gap lower in survivors compared with non survivors. A logistic regression model that included WBC count, haematocrit, albumin/globulin ratio, ALP,TCO2, potassium, sodium and lactate, was able to correctly predict mortality in 84 % of cases. Only the anion gap proved to be an independent predictor of neonatal mortality in this study. In the study population, the overall mortality rate was 34 % with greatest mortality rates reported in the first 48 hours and again on Day 6 of hospitalisation. Amongst the various clinical diagnoses, mortality was highest in foals after forced extraction during correction of dystocia. Median cost per day was higher for non survivors while total cost was higher in survivors.
Contact person: Dr MN Saulez.
Spirocerca lupi is a nematode of worldwide distribution, but it is most commonly found in tropical and subtropical areas with an increasing incidence in South Africa. Dogs are the definitive hosts and become infected by ingesting dung beetles which contain the larvae. After ingestion the larvae are liberated in the stomach and migrate via the aorta to the oesophagus where they form nodules. The latter may undergo neoplastic transformation. The typical clinical signs include regurgitation, vomiting, dysphagia and weight loss together with non-specific signs such as pyrexia. Acute death may also occur due to aortic rupture. The department has published research on aberrant migration of the larvae resulting in neurological disease as well as aortic thrombosis leading to embolism of the hind legs. A recent international congress presentation looked at clinicopathological differences between dogs with benign and malignant spirocercosis-induced oesophageal nodules which showed that hypertrophic osteopathy was only associated with malignant transformation of the Spirocerca-induced oesophageal lesion. This may provide a clue as to the pathogenesis of the malignant transformation. A commissioned review article was published under the authorship of a multidisciplinary faculty team. A long term prospective study has just been launched by our department in co-operation with other departments to gain a better understanding of this debilitating and common disease. Research will concentrate on improving diagnostic methods such as diagnostic imaging and faecal examinations, gaining a greater understanding of the pathophysiology of the disease, control mechanisms as well as determining the factors involved in why nodules become neoplastic. The latter may have applications in generating a greater understanding of oesophageal neoplasia in other species and in man.
Contact person: Prof RM Kirberger.
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