Thesis (Ph.D.)--Murdoch University, 2003. / Thesis submitted to the Division of Health Sciences. Bibliography: leaves 164-198.

Sinonasal and dental diseases can be a serious disorder in horses due to the persistence of the former and the common extension of the latter to the supporting bones of the skull. The diagnosis of equine sinonasal and dental disease can be challenging due to the complexity of these and adjacent anatomical structures, and therefore the use of advanced imaging, including computed tomography (CT) has greatly increased recently. A major aim of this study was to improve the morphological characterization of the sinuses and cheek teeth in normal horses of different ages. These studies defined the volumes of the 7 different sinus compartments; showed that the volume of the different compartments increase with age; that in contrast to accepted findings, the Triadan 09 alveoli is located in the caudal maxillary sinus (CMS) in 13% of the youngest group and the Triadan 10 alveoli is fully within the rostral maxillary sinus (RMS) in 53% of cases. The infraorbital canal was found to be susceptible to apical infection-related damage in horses < 2 years of age (< 2 y.o.) due to the intimate relationship of this canal and the medial aspect of the maxillary cheek teeth alveoli. The mean positions of the clinical crowns and apices of the maxillary Triadan 11s were 2.48 cm (adjusted 5.2% of head height) and 2.83 cm (adjusted 6.2% of head height) more rostral, respectively in horses >16 y.o. compared to horses < 6 y.o., consistent with rostral dental drift. Measurements of dental drift could provide further objective radiographic guidelines on ageing horses by dental imaging and also help our understanding of the aetiopathogenesis of cheek teeth diastemata. This study also found that the reserve crown length decreased from a mean of 4.7 cm (adjusted 19.7% of head height) in the youngest (< 6y.o.) group of horses to a mean of 2.9 cm (adjusted 10.5% of head height) in the oldest group (>15y.o.), with the 06s and 09s having the shortest reserve crowns. These data are useful reference information for clinicians and radiologists in the diagnosis and treatment of equine sinonasal and dental disease. Morphological characterization of the ventral and dorsal conchal bullae in horses of different age using CT described the age-related difference in sizes of these structures (smaller in younger horses). In the ventral conchal bulla, this reduction in volume was probably related to protrusion of the large dental alveoli in young horses into the nasal cavity and bulla. Bullae linear measurements and volumes were also associated with head size. The anatomical position of both bullae was associated with specific maxillary cheek teeth, thus increasing the diagnostic value of conventional radiography in the investigation of bulla disease and providing landmarks for the surgical treatment of this disorder. Skull shape analyzed with the use of Procrustes statistical analysis showed landmark variability between different age groups and in particular, high landmark variability between young (< 5y.o.) and old (>16y.o.) horses and less landmark variability between adult (6-15y.o.) and old horses. Future studies could investigate changes in the equine skull in relation to genotype to characterize breed-related diseases affecting teeth and sinonasal compartments. In the second part of the study, 32 infected maxillary cheek teeth extracted from clinical cases were evaluated grossly and histologically and these pathological results were compared to the pre-extraction radiographic and CT imaging findings. This study showed a high sensitivity (97%) of CT in detecting changes in teeth affected by apical infection. In the third part of the study, 30 cheek teeth assessed as being abnormal based on oral, radiographic and CT examinations were extracted along with their alveoli from 27 cadaver heads. Gross and histological examination findings from these teeth and alveoli were compared to the pre-extraction imaging findings, again showed high sensitivity (96.4%) of CT in diagnosing cheek teeth apical infection. Additionally, CT showed a high correlation with histology in detecting dental infection related alveolar bone changes including alveolar bone lysis, sclerosis and bone thickening. This aspect of the study was also the second largest pathological study of equine apical infection published to date and thus has also improved our understanding of the pathogenesis of this disorder. In conclusion, CT was shown to be an excellent imaging modality for improving the morphological characterization of the sinuses and teeth in normal horses of different ages, and thus also improving the value of this modality in diagnosis and treatment of disease affecting sinonasal and dental structures. This study also objectively showed the high sensitivity of CT in detecting cheek teeth apical infection in horses as compared to radiography, including by assessment of alveolar bone changes. Overall, the results of this project improve morphological knowledge of the equine skull and teeth and will have direct clinical benefits by improving the diagnosis and thus the treatment of equine sinonasal and dental disease.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / The necropsy reports of 335 horses necropsied at the LPV-UFSM between 1968-2007 were reviewed in order to determine the necropsy findings related with cause of death or reason for euthanasia. The distribution of these findings by organ system were as follows: digestive (79/335 [23.6%]), striated muscle and skeleton (47/335 [14.0%]), nervous (37/335 [11.0%]), respiratory (35/335 [10.4%]), integument (31/335 [9.3%]), hematopoietic (24/335 [7.2%]), cardiovascular (13/335 [3.9%]), reproductive (12/335 [3.5%]), urinary (7/335 [2.1%]), and endocrine (3/335 [0.9%]). The cause of death was not possible to be determined in 47 (14.0%) necropsied horses. Displacements of the intestines (17/79 [21.5%]) were the main findings in digestive system, followed by obstruction and impactation (14/79 [17.7%]). Torsion were the type of displacement more frequently observed in the intestines (14/17 [82.4%]). Among those the more prevalent affected the small intestine (7/14 [50%]). Most horses dying from fractured bones were 1-5-year-old. The most prevalent diseases in the nervous system were leukoencephalomalacia and trypanosomiasis, whereas respiratory depression due to anesthesia was the leading cause of death related to the respiratory system. Equine infectious anemia was the most diagnosed infectious disease and the main reason leading to euthanasia. / Os protocolos de necropsia de 335 eqüinos necropsiados no LPV-UFSM entre 1968-2007 foram revisados com o objetivo de determinar os achados de necropsia relacionados com a causa da morte ou razão de eutanásia. A distribuição desses achados de acordo com os sistemas afetados foi a seguinte: digestivo (79/335 [23,6%]), músculo-esquelético (47/335 ([14,0%]), nervoso (37/335 [11,0%]), respiratório (35/335 [10,4%]), tegumentar (31/335 [9,3%]), hematopoético (24/335 [7,2%]), cardiovascular (13/335 [3,9%]), reprodutor (12/335 [3,5%]), urinário (7/335 [2,1%]) e endócrino (3/335 [0,9%]). Não foi possível determinar a causa da morte em 47 (14,0%) eqüinos necropsiados. As principais afecções do sistema digestivo foram as alterações na posição dos intestinos (17/79 [21,5%]), seguidas pelas obstruções e impactações (14/79 [17,7%]). As torções foram as principais alterações da posição dos intestinos (14/17 [82,4%]). Dentre as torções, as mais prevalentes foram as localizadas no intestino delgado (7/14 [50%]). A maioria dos eqüinos que morreram em razão de fratura óssea tinham idades entre 1-5 anos. As duas doenças mais freqüentemente diagnosticadas no sistema nervoso foram leucoencefalomalacia e tripanossomíase. Depressão respiratória causada por anestesia foi a principal causa de morte relacionada com o sistema respiratório. A anemia infecciosa eqüina foi a doença infecciosa mais diagnosticada e a principal razão para eutanásia observada neste estudo.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Equine sarcoid is a locally aggressive cutaneous neoplasm, described and characterized as a clinical entity by Jackson in 1936. The neoplasm has a worldwide distribution and affects several equine species. It is believed that the cause of sarcoid is this infection by bovine papillomavirus 1 or 2. The combination of certain factors, including cutaneous trauma, genetic predisposition and viral exposure, seem to be involved in the development of the lesions. Sarcoid have no seasonality, no predilection by color or type hair and is considered the most common skin tumor of horses. Due to the lack of data which could characterize this tumor under the sphere of influence of the Laboratório de Patologia Veterinária (LPV) of the Universidade Federal de Santa Maria (UFSM), this dissertation determines the epidemiological aspects and the anatomic distribution of the different clinical forms of equine sarcoid in the state of Rio Grande do Sul. The files of histopathological exams carried out by the Laboratório de Patologia Veterinária of the Universidade Federal de Santa Maria (LPV-UFSM), between January 2000 and March 2010, were reviewed in search of cases of equine sarcoid. Forty cases were selected to determine epidemiological aspects and the anatomical distribution of the various clinical forms of these neoplasms in horses from Rio Grande do Sul. Out of the cases in which the ages were registered in the histopathological reports, 73,0% (27/37) were 1-5 years-old horses. Multiple sarcoids were observed in most of the affected horses (29/40 [72,5%]). The fibroblastic was the most observed clinical form and it occurred in 42,2% (27/64) of the cases. In more than half of the cases (22/40 [55,0%]), sarcoids had a multifocal distribution. Twenty two (55%) out of the 40 horses evaluated had the tumors in the limbs. / O sarcoide equino é um neoplasma cutâneo, localmente agressivo e foi descrito e caracterizado como uma entidade clínica por Jackson em 1936. Tem distribuição mundial e afeta várias espécies equídeas. Acredita-se que a causa seja a infecção pelo papilomavírus bovino tipo 1 ou 2. A combinação de alguns fatores, incluindo trauma cutâneo, predisposição genética e exposição ao vírus, parecem estar envolvidas no aparecimento das lesões. Não tem predileção por cor ou tipo da pelagem ou da pele e nem por estação do ano. O sarcoide é considerado o tumor mais comum de pele dos equinos. Devido a escassez de dados que caracterizam esse tumor na região de abrangência do Laboratório de Patologia Veterinária (LPV) da Universidade Federal de Santa Maria (UFSM), essa dissertação determina os aspectos epidemiológicos e a distribuição anatômica das diferentes formas clínicas do sarcoide no Rio Grande do Sul. Foram revisados todos os protocolos de exames histopatológicos, arquivados no LPV-UFSM, realizados entre janeiro de 2000 e março de 2010, na busca de casos de sarcoide equino. Quarenta casos foram selecionados com o objetivo de determinar os aspectos epidemiológicos e a distribuição anatômica das diferentes formas clínicas deste tumor em equinos no Rio Grande do Sul. Dos casos que tiveram suas idades anotadas nos protocolos, 73,0% (27/37) eram de equinos entre 1 e 5 anos de idade. Múltiplos sarcoides foram observados na maioria dos equinos afetados (29/40 [72,5%]). A forma clínica mais observada foi a fibroblástica, que ocorreu em 42,2% (27/64) dos casos. Em mais da metade dos casos (22/40 [55,0%]), os sarcoides tinham distribuição multifocal. Equinos que apresentavam tumores nos membros totalizaram 22 dos 40 (55%) casos analisados.

Cases of trypanosomiasis by Trypanosoma evansi were diagnosed in horses in the state of Rio Grande do Sul, Brazil, between 2003 and 2006. In one stud farm (Farm A) with 125 horses, 53 died. Additionally, around 80 mares were sent to Farm A to be bred. Of those, 66 became ill and 56 died after being returned to their farms of origin. Twenty three horses clinically affected by the disease were observed. Clinical signs included loss of weight (despite voracious appetite), lethargy, incoordination and instability of hindlimbs, atrophy of the large muscles of the hindlimbs, muscle weakness and paleness of mucosae. Specimens of T. evansi were detected in the blood drawn from four affected horses. Normocytic normochromic anemia with PCVs ranging from 15 to 31%, leucocytosis due to lymphocytosis associated to large atypical lymphocytes was observed in several affected horses. High levels of antibodies against T. evansi were detected in the serum of fifteen horses. Ten horses presented encephalic neurological signs such as circling, ataxia, blindness, excitation, falls, listlessness, proprioception deficits and head tilt. One horse assumed a dog-seating position . Necropsy findings included muscle atrophy, enlargement and lymphoid hyperplasia of the spleen and lymphnodes. Seven out of the 9 necropsied horses with encephalic signs had asymmetrical gross lesions in the brain consisting of flattening of gyri and focal extensive areas of yellow discoloration and softening of white matter. Histologically, an overwhelming necrotizing anencephalitis was observed in all 9 horses with encephalic neurological signs. This panencephalitis was characterized by marked edema, demyelination and malacia, and perivascular infiltrates of up to 20 rows of mononuclear cells affecting mainly the white matter. Several plasma cells in the inflammatory infiltrate contained numerous eosinophilic globules (Mott cells) or homogenous bright-red material (flame cells) in their cytoplasm. Mild to moderate meningomyelitis and/or meningitis were observed in the spinal cord of 5 horses. Similar histological lesions were observed in the spinal cord of the horse with the dog-seating position . The brains of nine horses with the encephalic signs were submitted to immunohistochemistry stain by the streptavidin-biotin technique. In eight brains moderate to abundant specimens of T. evansi in the perivascular spaces and neuropile were marked by the specific antibody. / Casos de tripanossomíase por Trypanosoma evansi foram diagnosticados em eqüinos no Rio Grande do Sul entre 2003 e 2006. Em uma propriedade (Propriedade A) com 125 eqüinos, 53 morreram. A Propriedade A recebeu ao redor de 80 éguas de outras propriedades para cobertura. Dessas, 66 adoeceram e 56 morreram após voltarem para suas propriedades de origem. A doença clínica observada em 23 eqüinos caracterizava-se por emagrecimento (apesar de apetite voraz), letargia, incoordenação e instabilidade dos membros pélvicos, atrofia das grandes massas musculares dos membros pélvicos, fraqueza muscular e palidez das mucosas. Exemplares de T. evansi foram observados na corrente sangüínea de 4 eqüinos. Anemia normocítica normocrômica, com hematócritos que variavam de 15-31%, e leucocitose por linfocitose associada à presença de linfócitos atípicos foram observadas em vários eqüinos. Altos níveis de anticorpos contra T. evansi foram detectados em 15 eqüinos. Dez eqüinos desenvolveram um quadro neurológico encefálico caracterizado por andar em círculos, ataxia, cegueira, hiperexcitabilidade, quedas, embotamento, déficits proprioceptivos e desvio da cabeça. Um eqüino desenvolveu posição de cão sentado . Nas 15 necropsias, havia esplenomegalia, linfadenomegalia, hiperplasia linfóide no baço e linfonodo e atrofia das grandes massas musculares dos membros pélvicos. Sete dos nove eqüinos com um quadro neurológico encefálico que foram necropsiados apresentavam lesões encefálicas macroscópicas assimétricas que consistiam de achatamentos dos giros e áreas amarelas e amolecidas focalmente extensas na substância branca. Histologicamente, uma panencefalite necrosante avassaladora foi observada em todos os 9 eqüinos. Essa panencefalite era caracterizada por acentuado edema, desmielinização, malacia e infiltrado perivascular de até 20 fileiras de células mononucleares afetando principalmente a substância branca. Vários plasmócitos no infiltrado inflamatório continham numerosos glóbulos eosinofílicos (células de Mott) ou material vermelho-brilhante (células em flama) em seus citoplasmas. Meningomielite e/ou meningite leve ou moderada foram observadas na medula espinhal de 5 eqüinos. Lesões semelhantes foram observadas na medula espinhal do eqüino que desenvolveu posição de cão sentado . Os encéfalos de 9 eqüinos com quadro encefálico foram submetidos à técnica de imunoistoquímica estreptoavidina-biotina; em oito observou-se a marcação de números moderados ou elevados de espécimes de T. evansi pelo anticorpo específico nos espaços perivasculares e na neurópila.

Two oubreaks of poisoning by the mushroom Ramaria flavo-brunnescens are reported in cattle from two farms located in the municipalities of Santa Maria and São Gabriel, state of Rio Grande do Sul, Brazil during April-May 2005. Out of a total of 180 yearling calves that had access to a pasture with eucalyptus woods, 19 were affected and 10 died. The clinical courses were 8-15 days and clinical signs included depression, weight loss, dehydration, drooling, loosening and loss of the long hairs of the tip of the tail, smoothening of the dorsal surface of the tongue with occasional ulceration, loosening of the corneal encasement of horns, hard and ball-shaped feces covered with a film of mucous, hypopion, hyphema and corneal opacity. Two calves had leucocytosis due to mild regenerative left shift. Nine calves were necropsied. Necropsy findings confirmed the clinical observation and additionaly included fibrinonecrotic esophagitis, mainly in the distal third of the esophageal mucosa. Histopathological changes in the skin of the tail included orthokeratotic hyperkeratosis; hair folicles with irregular contours, and thickening of the tricolemmal keratin layer with occasional formation of keratin plugs, and degeneration and necrosis of the outer root sheath. At the laminar region of the hooves, there was hemorrhage, fibrin and neutrophilic infiltrate in the dermal laminae. hyperplasia of the top of epidermal laminae with irregular keratinization and retention of nuclei; several epidermal laminae were shortened and fused. In the mucosa of the tongue there was thinning of the covering epithelium, atrophy and loss of filiform papillae, multifocal areas of dyskeratosis, and spongiosis of the basal cell layer. In some parts the epithelium was lost and the surface consisted of granulation tissue and mixed inflammatory cell infiltrate. The esophageal mucosae of six calves had varying degree of epithelial necrosis and inflammation. The loss of the covering epithelium revealed an underneath area of granulation tissue with heavy inflammatory infiltrate composed predominantly of neutrophils and macrophages. In six calves there were focal symmetric bilateral areas of malacia observed at the level of obex in the medulla oblongata and affecting the white matter and parts of the dorsal nucleus of the vagus and of the hypoglossal nucleus. Ultrastructurally the keratinocytes of the dorsal epithelial surface of the tongue had decreased numbers of cytokeratin filament bundles. The epidemiology, clinical signs, pathology, and pathogenesis of poisoning by R. flavo-brunnescens in cattle are discussed. Additionally a case of R. flavo-brunnescens poisoning in a horse is described. / Dois surtos de intoxicação pelo cogumelo Ramaria flavo-brunnescens são relatados em bovinos de duas fazendas localizadas nos municípios de Santa Maria e São Gabriel, no Rio Grande do Sul, no período de abril-maio de 2005. De um total de 180 bovinos de sobreano que tiveram acesso a bosques de eucaliptos, 19 adoeceram e 10 morreram. A evolução clínica foi de 8-15 dias e os sinais clínicos incluíam depressão, perda de peso, desidratação, salivação excessiva, afrouxamento e perda dos pêlos longos da cauda, alisamento da superfície dorsal da língua com ocasional ulceração, afrouxamento do estojo córneo dos chifres, fezes em forma de cíbalos e recobertas por película de muco, hipópion, hifema e opacidade da córnea. Dois novilhos tinham leucocitose devido a leve desvio regenerativo à esquerda. Os achados de necropsia confirmaram as observações clínicas e adicionalmente incluíam esofagite fibrinonecrótica, principalmente no terço distal do esôfago. Alterações histopatológicas na pele da cauda incluíam hiperqueratose ortoqueratótica, folículos pilosos com contornos irregulares, espessamento da camada de queratina tricolemal e formação ocasional de tampões de queratina; degeneração e necrose da bainha radicular externa também era observada. Nos cascos havia hemorragia, fibrina e infiltrado neutrofílico nas lâminas dérmicas, hiperplasia do topo das lâminas epidérmicas com queratinização irregular e retenção dos núcleos; várias lâminas epidérmicas estavam encurtadas e fundidas. Na mucosa da língua o epitélio de revestimento estava adelgaçado, com atrofia e perda das papilas filiformes e havia áreas multifocais de disqueratose e espongiose das células da camada basal. Em algumas porções havia perda do epitélio e a superfície da língua era formada por tecido de granulação e infiltrado inflamatório misto. A mucosa esofágica de seis novilhos apresentava vários graus de necrose epitelial e inflamação. A perda do epitélio de revestimento revelava uma área subjacente de tecido de granulação com marcado infiltrado inflamatório predominantemente neutrofílico e macrofágico. Em seis novilhos, o bulbo, na altura do óbex, apresentava áreas focais bilaterais e simétricas de malacia que afetava a substância branca e partes do núcleo dorsal do vago e do núcleo hipoglosso. Ultra-estruturalmente, os queratinócitos do epitélio da superfície dorsal da língua apresentavam diminuição do número de feixes de filamentos de citoqueratina. São discutidos a epidemiologia, os sinais clínicos, a patologia e a patogênese da intoxicação por R. flavo-brunnescens em bovinos. Adicionalmente um caso de intoxicação por R. flavo-brunnescens é relatado em eqüino.