This collection of one book chapter and 12 peer reviewed scientific papers comprises of 7 chapters. The first chapter starts with a 2008 review article as an introduction. This was a comprehensive review of Spirocerca lupi with an extensive section on diagnostic imaging, which included the value of computed tomography. The second publication in the first chapter deals with our first paper in 2001 which described in detail the radiographic characteristics of the spondylitis reactions as well as the oesophageal masses, which could be typical or atypical. Aortic aneurysm formation as well as aortic mineralisation visibility was also reported on. Additionally, the value of computed tomography (CT) in spirocercosis was elucidated for the first time. This is the first S. lupi article to extensively describe the imaging findings from a radiological viewpoint and to combine these with the clinical findings. To date this paper is still regularly referenced. The second chapter emphasizes the value of a variety of radiographic techniques, including pneumoesophagography, to optimize the diagnosis of spirocercosis as a primary imaging modality. Radiography remains the cheapest and most readily accessible diagnostic imaging technique and as such making the correct technical decisions, as proven in these 3 papers, optimizes diagnostic capabilities in a cost‐effective way for the first time. The third chapter examines the value of CT and alternative imaging techniques in S. lupi associated disorders to diagnose spirocercosis and its complications. These include the limited value of ultrasonography and the very important role CT, as well as CT angiography, has to play. Computed tomography was shown to play a major role in detecting aortic changes, in decision‐making for surgical removal of neoplastic oesophageal masses, as well as in detecting and determining the extent of secondary changes associated with spirocercosis. The value of CT, first described by us in 2001, is amplified in these publications and has become an essential imaging tool to manage this disease. Magnetic resonance imaging is not available at the Onderstepoort Veterinary Academic Hospital and as such was not addressed in this dissertation. However, its primary use in spirocercosis is in diagnosing aberrant larval migration to the vertebral canal. The fourth chapter discusses the perplexing matter of malignant transformation of the S. lupi associated benign oesophageal nodule and how to diagnose it. This is an on‐going investigation in our department, but this chapter contains the first publication that linked diagnostic imaging findings with clinical parameters in an attempt to determine if malignant transformation of the nodule had taken place. The latter is vitally important in determining prognosis and treatment. Once malignancy is present, metastatic spread can take place to many parts of the body. Two case reports are presented with hitherto undescribed metastatic spread to the central nervous system from the primary oesophageal neoplasm. The fifth chapter looks at the pathomechanisms of spondylitis formation in spirocercosis by means of a radiological‐pathological investigation. This is the first in‐depth veterinary investigation on how vertebral new bone formation takes place and whether inflammation plays a role. The sixth chapter, consisting of a review paper published in 2010, brought together more recent thoughts on some of the dilemmas still facing clinicians in the diagnosis and treatment of spirocercosis. The final chapter concludes with a discussion of the most appropriate imaging procedures to use in diagnosing spirocercosis and its complications. Additionally challenges remaining and future research directions are considered. / Thesis (DVSc)--University of Pretoria, 2013. / gm2013 / Companion Animal Clinical Studies / unrestricted

Spirocerca lupi (S. lupi) is a nematode that infects the dog’s oesophagus resulting in an inflammatory fibroblastic nodule that progresses to a sarcoma in approximately 25% of cases. Inflammation, coagulation and cancer are exquisitely intertwined and inflammatory changes are known to lead to coagulation abnormalities. The nature and degree of haemostatic alterations in canine spirocercosis are unknown. Evidence of inflammation in dogs with clinical spirocercosis is provided by pyrexia, leucocytosis, increased serum interleukin 8 and C-reactive protein as well as severe inflammatory infiltrates on histopathology of nodules. This study aimed to determine if haemostatic abnormalities exist in canine spirocercosis, and hypothesised that the severity of abnormalities could be used to differentiate non-neoplastic from neoplastic spirocercosis. Thirty-nine client-owned S. lupi-infected dogs and 15 healthy age- and sex-matched control dogs were included in this study. Blood samples were collected at the time of diagnosis. A complete blood count, prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen concentration, antithrombin (AT) activity, D-dimer concentration and thromboelastography (TEG) analysis were performed. Hypercoagulability was based on the maximum amplitude (MA) value derived from TEG. Inflammatory parameters were also determined and included C-reactive protein (CRP) and fibrinogen concentrations. The S lupi-infected dogs were divided into a non-neoplastic group (n=24) and a neoplastic group (n=15). Data were compared using the Kruskal-Wallis Test and Dunn’s multiple comparisons applied post-hoc. Correlation was determined using Spearman’s correlation. Hypercoagulabilty was found in the neoplastic and non-neoplastic spirocercosis cases. In addition, the neoplastic group was significantly more hypercoagulable than the non-neoplastic group, and the non-neoplastic group was significantly more hypercoagulable than the control group. The median fibrinogen concentration was significantly higher in the neoplastic group compared to the non-neoplastic group, but there was no significant difference between the non-neoplastic and control group. The median CRP concentration was significantly higher in the neoplastic group compared to the non-neoplastic group, with no significant difference between the non-neoplastic and control group. Compared to the control group the median AT activity was significantly decreased in both the non-neoplastic and neoplastic groups. No significant difference was found between the infected groups. Across the non-neoplastic and neoplastic groups, MA showed positive linear correlation with CRP and fibrinogen. The study showed that spirocercosis is associated with a hypercoagulable state that becomes progressively more severe with neoplastic transformation. Overlap did exist between the median MA values of the non-neoplastic and neoplastic groups, but an MA of >76 mm provided a specificity of 96% and sensitivity of 73% for the differentiation of disease state. Thromboelastography might therefore be used as an adjunctive assay to support the suspicion of neoplastic transformation of the oesophageal nodule as well as to determine the overall haemostatic status of the patient. The MA correlated positively with the indicators of inflammation (CRP&fibrinogen) supporting the hypothesis that an inflammatory state induced by the S. lupi nodule is at least partly responsible for the hypercoagulability. The link between inflammation, coagulation and neoplastic transformation in spirocercosis warrants further investigation to elucidate the exact factors resulting in the hypercoagulable state, whether clinically relevant complications develop and whether or not specific therapy should be instituted to prevent thrombotic sequelae. / Dissertation (MMedVet)--University of Pretoria, 2012. / Companion Animal Clinical Studies / unrestricted

Spirocercosis is a canine disease caused by the nematode parasite Spirocerca lupi (Rudolphi, 1809) (Spirurida: Spirocercidae) and is a potentially fatal condition in domestic dogs (Canis familiaris). The larval life cycle of this parasite involves intermediate and paratenic (transport) hosts. Various species of coprophagous dung beetles (Scarabaeidae: Scarabaeinae) serve as the principle intermediate hosts. Despite extraordinary advances in biomedical research, it is unlikely that these alone will alleviate the burden of this parasitic disease in dogs. Recently, there has been growing concern over the upsurge in incidence and reported cases of spirocercosis in domestic dogs in South Africa. There is a plethora of literature on the clinical, diagnostic and epidemiological aspects of this disease in dogs, yet no study has aimed at fully understanding the dynamic interactions between the various hosts and S. lupi, governed by the consequences of their behaviour under different and ever-changing environmental conditions. It is most likely that the impact of this disease is accentuated by constant changes in human demographics and behaviour. Studies on spirocercosis in dogs have considered the consumption of the various paratenic hosts or the deliberate ingestion of dung beetles to be the main cause of the transmission of S. lupi to dogs. However this study suggests that the coprohagous behaviour of dogs and the subsequent accidental ingestion of coprophagous dung beetles in or on faeces are mainly responsible for the transmission of this parasitic nematode to dogs. Changes in urban land use and subsequent changes along urban-rural gradients influence the nature of biological interactions partly due to changes in species assemblage structure and composition. Such alterations in assemblage structure of species pose a particular risk to altered rates of parasitism and disease transmission. It is concluded that these changes in landscape use coupled to altered dung beetle species assemblage structure have influenced the pattern of events observed in this host – parasite relationship. Furthermore, the social organization of domestic dogs (pets versus feral animals) and the availability of exposed excrement as a direct or indirect consequence of human behaviour played a pivotal role in the rate these parasites are transmitted to dogs. / Thesis (PhD)--University of Pretoria, 2012. / Zoology and Entomology / unrestricted

A variety of faecal examination methods have shown variable sensitivity in identifying larvated Spirocerca lupi (S. lupi) eggs. The purpose of this study was to determine which faecal examination method, including a novel modified centrifugal flotation method, was most sensitive in the diagnosis of spirocercosis. Faeces were collected from 33 dogs diagnosed with spirocercosis by oesophageal endoscopy at the Onderstepoort Veterinary Academic Hospital between 2008 and 2009. If the first evaluation was negative, a second faecal sample was evaluated 24-48 h later. Ten faecal examinations using 1 g aliquots of faeces were performed per sample. Four faecal examination methods were evaluated; direct faecal examination using saline, direct faecal flotation, a modified faecal centrifugal flotation and a laboratory performed faecal sedimentation/flotation. The direct and modified centrifugal flotation methods were each performed using four faecal flotation solutions; NaNO3 (Specific gravity (SG) 1.22), MgSO4 (SG 1.29), ZnSO4 (SG 1.30) and saturated sugar (SG 1.27). The sedimentation/flotation method utilized MgSO4 (SG 1.29). The modified centrifugal flotation method required centrifugation (1400 G) of a prepared faecal suspension (1 g faeces suspended in 5 ml of flotation solution) after which 0.1 ml of the supernatant was aspirated from the surface using an adjustable volume micropipette for microscopic examination. The 10 faecal examination tests were statistically analysed using the Friedman test (nonparametric equivalent of analysis of variance) p=0.000, z value = 0.05. The sensitivity of the tests ranged between 42 % and 67 %, with the NaNO3 solution showing the highest sensitivity in both the direct and modified centrifugal flotation methods. The modified NaNO3 centrifugal method ranked first with the highest mean egg cell count (45.24 ± 83). The modified centrifugal NaNO3 method was found to be superior (i.e. higher egg counts) and significantly different (p<0.001) compared with the routine saturated sugar, ZnSO4 and MgSO4 flotation methods. The direct flotation method/technique using NaNO3 flotation fluid was also superior and significantly different (p<0.001) when compared to the same technique using ZnSO4 or MgSO4 flotation fluids. Neoplastic transformation of oesophageal nodules was confirmed in 15 % (n=5) of dogs and a further 18 % (n=6) had both neoplastic and non-neoplastic oesophageal nodules. S. lupi eggs were demonstrated in 40 % of dogs with neoplastic nodules and in 72.9 % of dogs with non-neoplastic nodules. The mean egg count in the non-neoplastic group (61) was statistically greater (p=0.02) than that of the neoplastic group (1). The results show that faecal examination using the direct and modified centrifugal flotation methods with the NaNO3 flotation fluid are the most sensitive methods in the diagnosis of spirocercosis. The modified centrifugal flotation method using this solution has the highest mean egg count. The study also found that dogs with neoplastic nodules shed significantly fewer eggs than dogs with non-neoplastic nodules. Copyright / Dissertation (MMedVet)--University of Pretoria, 2011. / Companion Animal Clinical Studies / unrestricted

Spirocerca lupi is a nematode that infects the dog’s oesophagus and promotes the formation of an inflammatory fibroblastic nodule that progresses to sarcoma in approximately 25% of cases. Differentiating neoplastic from non-neoplastic cases ante-mortally is challenging and has major therapeutic and prognostic implications. More importantly, spirocercosis-associated oesophageal sarcoma is an excellent and under-utilized spontaneous model of parasite-associated malignancy and the pathogenesis of the neoplastic transformation is poorly understood. The current study objective was to investigate potential clinical, clinicopathological, radiological and tissue biomarkers for the malignant transformation and an attempt to use these biomarkers to gain a deeper understanding of the pathogenesis of the neoplastic transformation. Our central hypothesis was that the parasite produces excretory product(s) which diverts the immune response from a T helper 1 (Th1) to Th2 cell response, typical of many nematode infections, and further to an immunoregulatory (immunosuppressive), FoxP3+ regulatory T cell-predominated response which then facilitates neoplastic transformation. The following parameters were studied and compared between cases with non-neoplastic and neoplastic spirocercosis: clinical presentation, haematology, serum albumin and globulin, thoracic radiology, haematoxylin-eosin (H&E) histology, Immunohistochemistry for expression of vascular endothelial growth factor (VEGF)-A, fibroblast growth factor (FGF), platelet-derived growth factor (PDGF), MAC387 (myeloid cells), CD3 (T cells), Pax5 (B cells) and FoxP3 (T regulatory cells) and plasma cytokine concentrations including IL-2, IL-4, IL-6, IL-8, IL-10, IL-18, GM-CSF and MCP-1. Hypertrophic osteopathy showed 100% specificity for neoplastic transformation but relatively poor sensitivity (40%). Female gender, anaemia, leukocytosis, thrombocytosis, spondylitis and bronchial displacement were significantly more common in neoplastic cases, but appeared in non-neoplastic cases as well. The H&E study revealed 2 stages in the non-neoplastic nodules: early inflammation, characterized by fibrocytes and abundant collagen, and a pre-neoplastic stage, characterized by activated fibroblasts and reduced collagen. The neoplastic cases were all sarcomas, primarily osteosarcoma with very aggressive features comparable to other appendicular osteosarcoma in the dog. The inflammation in spirocercosis is characterized by pockets of pus (MAC387+ cells) surrounded by organized lymphoid foci (CD3+ and to a lesser degree Pax5+ cells). There was no evidence of a local accumulation of FoxP3+ cells, unlike many previous studies which have reported an increase in Foxp3+ T cells in both malignancies and parasite infections. Interleukin-8 plasma concentration was higher in the neoplastic group compared to the non-neoplastic and the control groups. Interleukin-18 concentration was higher in the non-neoplastic group followed by the control group and finally the neoplastic group. As with most similar studies, no ideal biomarker with high sensitivity and specificity was identified. However, if examined together, a panel of the biomarkers that were identified more commonly in the neoplastic cases should substantially increase the index of suspicion for neoplastic transformation in a diagnosed spirocercosis case. The inflammatory response showed features of increased myeloid (innate) response and lymphocytic response with pro-inflammatory cytokines. This was not our initial hypothesis and the question remains whether the response is secondary to the worm infection, or to a symbiotic bacterium that is carried by the worm. The role of such a reaction in neoplastic transformation remains to be elucidated. / Thesis (PhD)--University of Pretoria, 2012. / Companion Animal Clinical Studies / unrestricted