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.
Pathologic changes and pathogenesis of Parascaris equorum infection in parasite-free pony foals. Parasite-free pony foals (n = 10) were infected orally with 1000,000 Parascaris equorum embryonated eggs. One pony foal each was euthanatized on days 1, 3, 5, 7, 11, 16, 23, 27, 42, or 80 after infection. Foals infected for more than 7 days showed signs of coughing, anorexia, rough coat, and weight loss. Cellular changes in the blood were mild anemia, marked eosinophilia, and leukopenia. Gross postmortem lesions included hemorrhage, edema, and white-to-yellow necrotic foci (0.5 to 1.00 mm) in lungs, liver, and bronchial and hepatic lymph nodes. Microscopically, the liver was hemorrhagic and ha...
Characterization of haemolytic streptococci isolated from horses and cattle. No abstract available
Cardiopathological observations on histopathogenesis of wandering pacemaker in horses. Histopathololgical observations were performed on the heart and cardiac nervous system of 5 horses affected with wandering pacemaker. The histopathological lesions common to all the animals were as follows: (1) Focal fibrosis in the atrial myocardium just beneath the subendocardium and/or in the endo- and subendocardium, and existence of atrial Purkinje-like fibers within the fibrotic lesions, (2) Microvascular altetation, characterized by edematous-loosening and/or fibrous swelling of the walls of the small and minute arteries, in both the atria, (3) Edema in the intracadiac nerves of both th...
Gastrict carcinoma with pseudohyperparathyroidism in a horse. Pseudohyperparathyroidism was diagnosed in a mature stallion presented for anorexia, weight loss, pollakiuria and constipation. Laboratory findings included hypercalcemia, hypophosphatemia, anemia and isosthenuria. Thoracocentesis indicated an exfoliating squamous cell carcinoma. At necropsy, a squamous cell carcinoma of the stomach with metastases to the abdominal and thoracic cavities was diagnosed. No osseous metastases were found. No gross or microscopic renal lesions were noted. Bone tissue showed arrested resorption, and the parathyroid gland was atrophic.
Neurologic signs and neuropathology associated with a case of equine infectious anemia. Neurologic signs and neuropathologic lesions associated with a case of equine infectious anemia in a 7 year old Quarter-horse mare were studied. Clinical signs included depression, disorientation, circling, knuckling at the fetlock and hypermetria. The neuropathologic lesions were characterized by a granulomatous ependymitis, subependymal encephalitis, choroiditis and hydrocephalus. These lesions were associated with signs of neurologic dysfunction which were the cause of the prominent clinical features.
Changes in the sustentaculum tali associated with distension of the tarsal sheath (thoroughpin). Results of the clinical and radiographic examination of 8 lame horses with tarsal sheath distension are described. In chronic cases pathological exostoses were identified radiographically in the sustentaculum tali and were demonstrated at post mortem in 4 of the horses which were destroyed. The prognosis and the feasibility of treatment are discussed in the light of these changes and the associated damage found at post mortem in the deep flexor tendon and its sheath. Trauma to the hock was known to have occurred in half the cases and was suspected in the others.
Tricuspid atresia in a foal. An Arabian crossbred foal was examined because of a suspected congenital cardiac anomaly. There was a grade V/V crescendo-decresendo holosystolic murmur and thrill in the left 4th intercostal space. The foal was slightly cyanotic and polycythemic. Electrocardiography suggested left ventricular hypertrophy. Angiography and cardiac and vascular pressure recordings led to a diagnosis of pulmonic stenosis. The foal died after cardiac bypass and corrective surgery. Postmortem examination revealed an enlarged right atrium, atresia of the tricuspid orifice, a large, fenestrated patent foramen ovale, ...
Clinical signs and chemical confirmation of 4-aminopyridine poisoning in horses. 4-Aminopyridine poisoning in horses was diagnosed. Specific methods, utilizing thin-layer and high-performance liquid chromatography, were developed for determining the compound in stomach contents and corn bait. The lethal dose was estimated at 2 to 3 mg/kg of body weight.
Scanning electron microscopy of Gasterophilus intestinalis lesions of the equine stomach. The lesions caused by larvae of Gasterophilus intestinalis in the cardiac region of the equine stomach were funnel-shaped ulcers surrounded by a rim of hyperplastic epithelial cells. Bacteria were commonly seen on the rim of epithelial cells, at the base of some ulcers, and within the cavities produced by the hooks of the larvae. Cellular debris and mucus were within the ulcer.
Chronic enteritis associated with the malabsorption and protein-losing enteropathy in the horse. Chronic granulomatous enteritis associated with weight loss and hypoproteinemia was identified in 2 horses. Both horses continued to have normally formed feces. Malabsorption of carbohydrate and lipid, with concomitant gastrointestinal protein loss was demonstrated in 1 case. One horse was treated symptomatically and gained 108 kg. In both cases, principal gastrointestinal lesions were partial to total villus atrophy and transmural mononuclear leukocytosis, with lymphocytes and histiocytes predominating. The cause of the condition was not identified in either case.
Chronic obstructive pulmonary disease (COPD): identification of affected horses. Mean normal values for PaO, and max A Ppl for horses were determined. Using 2 standard deviations below (Pa0,) and above (max A Ppl) the mean normal values as a guide, horses affected with COPD were satisfactorily distinguished from other horses in a series of 100 animals. The frequency of occurrence of 20 different clinical parameters in affected, not affected and possibly affected horses was examined statistically. Poor work performance and a history of previous febrile illness occurred more often in COPD horses than in others. The presence of a chronic cough, dyspnoea, double expiratory eff...
Horner’s syndrome in the horse: experimental induction and a case report. The findings in 6 experimental and 1 natural case of Horner's Syndrome (HS) are presented. The experimental cases were induced by unilateral surgical section of the cervical sympathetic trunk in the middle third of the neck. The naturally occurring case was seen in a 17 year old gelding with a mediastinal tumour. The signs of HS in these horses included ptosis, miosis, enophthalmos, hemilateral sweating and temperature increase of the face and cranial cervical region on the affected side. The intensity of these signs was variable between and within animals. Miosis, enophthalmos and temperature...
Black grain mycetoma (maduromycosis) in horses. Black grain mycetoma occurred in two horses, one a cross-bred pony and the other a Thoroughbred racehorse. Lesions were limited to wart-like growths in one case and a deep-seated girth gall in the other. In both cases the granules in the affected tissues were similar in pigmentation and structure to those produced by Curvularia geniculata in dogs. Since all the specimens were received in formalin, the causative fungus could not be isolated. These are the first cases of maduromycosis in animals to be recorded in South Africa.
Some unusual cases of abnormal respiratory noises in the horse. Any condition which leads to a diminution in the size or alteration of the shape of the lumen of the respiratory tract in the horse may result in the production of abnormal respiratory noises at exercise.
Plasma clearance of [51Cr] albumin into the intestinal tract of normal and chronically diarrheal horses. Five clinically normal, mature horses and 11 with chronic diarrhea were given 51Cr-tagged Cohn fraction V equine albumin intravenously. All urine and feces were collected separately, and blood for plasma analysis was taken periodically for 5 to 8 days after injection of the isotope. Plasma clearance of albumin into the intestinal tract of normal horses was calculated as 0.67 +/- 0.23 (SD) ml/kg of body weight/day, with 1.33 +/- 0.69% of the 51Cr dose appearing in the feces in 5 days. Of the 11 diarrheal horses, 8 had a plasma clearance of 0.49 +/- 0.21 ml/kg/day with 1.12 +/- 0.68% of the dose...
Syringomyelia in a thoroughbred foal. The report describes a case of myelodysplasia involing spinal cord segments C7 to T8 of a 5 month old part-Thoroughbred foal. There was a single extensive syringomyelic and hydromyelic cavity which extended from the seventh cervical segment (C7), to the seventh thoracic segment (T7), abnormal size and shape of central canal, and disorderly differentiation of the grey and white matter. The cause of the defect is unknown.
A correlation of the endoscopic and pathological changes in subclinical pathology of the horse’s larynx. The larynges of 6 horses were examined endoscopically and the findings correlated with the gross and histological appearance of the intrinsic laryngeal muscles and their nerve supply. In all cases it appeared that the balance between abductor and adductor muscle groups had been lost due to preferential atrophy of individual muscles or groups of muscles. The laryngeal abnormalities recorded were asymmetry of the larynx with asynchronous left sided abduction and fluttering or trembling of the left vocal cord and arytenoid cartilage. It is suggested that these changes represent the early signs of...
Phenylalanine inhibited p-nitrophenyl phosphatase activity in the serum as an indication of intestinal cellular disruption in the horse. Examination of tissues obtained from thoroughbred horses showed that the 'intestinal' phosphatase activity could be differentiated from other phosphatases by analysis at a pH of 9-5 and inhibition with 15 mM L-phenylalanine. A simple method for the measurement of 'intestinal' phosphatase in heparinised plasma or serum is described. Application of the technique to serum or plasma from normal and diseased horses indicates that the increase in the activity of 'intestinal' phosphatase is associated with cases showing clinical, biochemical and haematological evidence of intestinal damage.
Cell-mediated immune response in equine babesiosis. An intradermal skin test, to demonstrate a delayed cutaneous hypersensitivity reaction in Babesia equi infection in donkeys, was developed. A skin reaction to B. equi antigen was elicited in vaccinnated, infected and carrier intact and splenectomised donkeys. The histopathological examination of the skin biopsy revealed infiltration of mononuclear cells and accumulation of oedematous fluid in the deeper layers of the dermis. A leucocyte migration inhibition test was developed and its specificity as an in vitro measure of cell-mediated immunity to B. equi antigen was established. The results of...