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Topic:Pathology
Pathology in horses involves the study of diseases and abnormalities affecting equine health, encompassing a range of conditions that can impact various systems within the horse's body. This field examines the causes, mechanisms, and effects of diseases, as well as the structural and functional changes they induce in equine tissues and organs. Common pathological conditions in horses include laminitis, colic, equine infectious anemia, and respiratory disorders. Understanding these diseases involves evaluating clinical signs, diagnostic methods, and treatment options. This page compiles peer-reviewed research studies and scholarly articles that explore the etiology, pathogenesis, and clinical implications of pathological conditions in horses.
Murine infection model for contagious equine metritis: a new venereal disease of horses. An infection model in laboratory mice for studying the bacterium (proposed name Haemophilus equigenitalis) causing contagious equine metritis is described. Small porous chambers were implanted subcutaneously into mice and after 1 to 3 weeks were inoculated with H equigenitalis. Infections that persisted for > 30 days were established by direct transfer of infective chamber fluid or by injection of laboratory-grown cultures. Immunization of mice with formaldehyde-treated cells induced significant, strain-related immunity to infection and did not appear to require complement as a protection medi...
Lameness caused by inflammation in the distal hock. Since horses ridden at a gallop have a high incidence of bone spavin, and harness horses (Standardbred pacers and trotters) have a different
syndrome, they will be discussed separately. Osteoarthritis (bone spavin) apparently is caused by impact and compression on the distal tarsal
bones, which occurs most forcefully at the gallop (canter). Shear stresses, which occur in the joint between these bones, are most severe at the trot
or pace, and probably cause the usual cunean-tarsitis problem in
Standardbreds. Obviously some of each force occurs at each gait.
Cell morphology and collagen types in equine tendon scar. The histological appearance of cells and tissues in the reparative scar tissue which forms in the equine superficial flexor tendon following partial rupture was compared to that of normal tendon. The repair fibroblasts were found to be larger and more basophilic than the tenocytes of normal tendon, to have large vesicular nuclei and to resemble the 'myofibroblasts' described in scar tissue elsewhere. The cell to matrix ratio in scarred zones of tendon was found to be increased and the concentration of collagen in these areas was less than in normal tendon. However, the scar tissue collagen was...
Granulomatous enteritis in a young standardbred mare. Granulomatous enteritis was diagnosed in a 4-year-old Standarbred mare suffering from chronic weight loss, depression, dependent oedema but not diarrhoea. There was hypoproteinaemia (hypoalbuminaemia), lymphocytopaenia and neglibible carbohydrate absorption from the small intestine. Pathological changes in almost the entire small intestine included proprial infiltration resulting in partial villous atrophy, and granuloma formation beneath the muscularis which was most severe in the ileum. Slight infiltration occurred in the stomach and the colon. The cells were predominantly lymphocytes and hi...
Squamous cell carcinoma of the equine stomach. Summary Both clinical and pathological features of seven horses suffering from a squamous cell carcinoma of the stomach are presented. The main complaints in the horses, aged six years or more, were loss both of weight and of condition. Metastases had often developed. The diagnostic difficulties and possibilities are discussed.
Histiolymphocytic lymphosarcoma in the subcutis of two horses. Two aged mares with histiolymphocytic lymphosarcoma had multiple rapidly proliferating tumours in the subcutis. Consistent haematological changes were absent. One mare had lymph node involvement but no neoplastic lesions in the viscera. Microbiological examination of tumour tissue showed coryneform bacteria; there was no evidence of C-type or lytic viruses or of reverse transcriptase. Prominent intramitochondrial crystalline inclusions were in histiocytic tumour cells.
Mucosal alterations in experimentally induced small intestinal strangulation obstruction in ponies. Small intestinal strangulation obstruction (ISO) was produced in seven ponies (under pentobarbital-anesthesia) by arteriovenous ligation. Positive-pressure ventilation with room air was used to maintain arterial PCO2 at the initiation of the ISO. Biopsy materials obtained from affected intestines at various times were evaluated, using histopathologic examination and scanning electron microscopy. Mucosal and villus degeneration was graded 0 to V and compared with intestinal gross color, motility, and wall thickness. The mucosa at the tip of the villus was the first to be affected. Degeneration ...
Graft versus host reactions in foals with combined immunodeficiency. Nine foals with combined immunodeficiency were given hepatic and thymus cells from 68- to 110-day-old (gestational age) fetuses or peripheral blood lymphocytes from nonrelated horses. Clinical signs and lesions consistent with graft vs host reaction were observed in eight of the foals. Diarrhea was observed in these 8 foals, and ulcerative dermatitis, stomatitis, or glossitis was detected in 6 of the 8 foals. Histopathologic changes consisting of necrosis and lymphocyte infiltration were observed in liver, skin, alimentary tract, and less frequently in lymphoid tissues. Changes in complete blo...
[Bacteriological studies of Haemophilus equigenitalis Taylor 1978, the causative organism of contagious equine metritis 1977 (author’s transl)]. The cultural, biochemical, antigenic and antibiotic susceptibility characteristics of 17 strains of Haemophilus equigenitalis, the causative organism of contagious equine metritis (CEM), were studied. Biochemical characteristics were investigated using both conventional method and the API ZYM system of enzyme detection. The biochemical profile of the H. equigenitalis strains was unique and differed from the other bacterial species studied under the same experimental conditions (H. influenzae and H. parainfluenzae, B. abortus and B. melitensis, P. multocida, A. calcoaceticus). The required X an...
Haematology as an aid to prognosis of chronic laminitis. A COMMON progression of chronic laminitis is ischaemic
necrosis with secondary infection a frequent complication.
For 6 years we have performed a complete blood count
(CBC) on all hospitalised horses (at the University of Missouri
Veterinary Hospital) every Monday, Wednesday and Friday.
Preliminary scrutiny of the results indicated that persistent
elevation of the total white blood cell count (WBC) and
neutrophilia was consistent with poor prognosis in horses
affected with laminitis. Because of these considerations we
decided to perform a retrospective examination of the blood
cell d...
The origin of nuclear bodies: a study of the undifferentiated epithelial cells of the equine small intestine. During an electron and light microscopic study of the equine intestinal epithelium, it was observed that some secretory granules of the undifferentiated crypt epithelium were incorporated into the nucleus during mitosis. A study was made of the chemical nature of the granules, using standard histochemical techniques: PAS-Alcian blue, Deamination-PAS, and Ninhydrin-Schiff reactions. The granules contained a neutral protein-polysaccharide complex with many terminal amino groups, possibly an antibody (IgA). The intranuclear granules underwent coalescence and degeneration during differentiation. T...
[13 Years of veterinary mycological routine diagnostics. Isolation of dermatophytes in the years 1965-1977]. Over a thirteen year period (1965 to 1977) a total of 4790 skin scrapings and hair samples of animals were examined mycologically. 887 strains of dermatophytes were isolated out of 885 of these samples (= 18,5%). Most frequently Trichophyton verrucosum was identified in samples from cattle, followed by Microsporum canis isolated from cats, dogs and zoo animals. T. mentagrophytes was mainly found on guinea pigs, chinchillas and dogs and T. equinum on horses. Although the total number of the samples examined within the last 8 years increased, the total of the dermatophytes isolated remained prop...
Persistent right aortic arch associated with a persistent left ductus arteriosus and an interventricular septal defect in a horse. In this article a description is given of the clinical and postmortem findings of a persistent right aortic arch in association with a persistent left ductus arteriosus and a ventricular septal defect in a horse.
Chronic phenylmercuric acetate toxicity in a horse. Phenylmercuric acetate (PMA) was administered orally to a horse over a period of 27 weeks (190 days) at a dose rate of 0.4 mg Hg/kg per day. The effects produced were consistent with those of chronic inorganic mercury intoxication. The clinical features included masseter muscle atrophy, difficulty in prehension and mastication, malodorous breath, reduced appetite and weight loss, and reflected significant pathological changes involving the buccal, mandibular and dental tissues. Renal dysfunction was evident terminally and there was degeration and necrosis of the proximal tubular epithelium. Ne...
Ossifying ameloblastoma in a horse. The features of an ossifying ameloblastoma in a 5-year-old gelding are described. The tumour developed in the angle of the right mandible and microscopically consisted of multiple follicles and islands of epithelial tissue adjacent to which were trabeculae of bone, osteoid and compact collagenous tissue.
Spontaneous fracture of the navicular bone in the horse. After a short review of previous literature about fractures of the navicular bone in horses, the symptoms and the pathological-anatomical changes of the condition are described. The most important clinical symptom is acute severe lameness without significant swellings, but with pronounced pain reaction to rotation of the coffin joint. After rest the lameness is reduced considerably, but without treatment it can persist for several years. Adherences between the deep flexor tendon and the site of the fracture and eventual damage to the coffin joint are considered to be the cause of the persistin...
