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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.
Correlation between colic and antibody levels against Anoplocephala perfoliata in horses in The Netherlands. The importance of Anoplocephala perfoliata in horses with colic was studied in 139 horses referred for colic and 139 control horses with no signs of colic for at least three years. The serodiagnostic method of Proudman and Trees, which measures the level of A. perfoliata antibody, was used to detect A. perfoliata infection. Thirty-two horses were examined at necropsy, to determine whether the presence of A. perfoliata in the ileocaecal region was associated with the A. perfoliata antibody level. The mean A. perfoliata antibody level was significantly higher in horses with colic than in horses ...
Evidence-based literature pertaining to thyroid dysfunction and Cushing’s syndrome in the horse. The evidence-based literature pertaining to thyroid dysfunction and Cushing's syndrome is discussed in this article. Summaries of and recommendations for the treatment of these conditions are made. There is a need for reliable diagnostic tests for these conditions in horses.
Preliminary anatomic investigation of three approaches to the equine cranium and brain for limited craniectomy procedures. To describe surgical approaches to the equine cranium and brain for limited craniectomy. Methods: Descriptive anatomic study. Methods: Equine cadavers (n=7). Methods: Head and neck sections from cadavers were used to establish techniques for exposing areas of the equine brain. Three basic approaches were used: rostrotentorial, suboccipital, and transfrontal. Techniques were adapted from small animal descriptions and modified to account for anatomic differences. Results: Descriptions of the rostrotentorial, suboccipital, and transfrontal approaches to the equine cranium and brain were defined. ...
Dental benign cementomas in three horses. Cementoma is a very rare odontogenic neoplasm of mesenchymal origin. Clinically, in 3 horses, multiple bony enlargements of the upper and lower jaw extending into the oral cavity were observed. Radiographically, multiple, well-circumscribed, radiopaque masses surrounding the roots of the upper and lower incisors or an upper premolar tooth were present. Due to malocclusion and local pain, single teeth were extracted in each case. Grossly, a hard grayish-white mass surrounding the root of the incisors and the premolars was identified. Histopathologically, the tumors consisted of excessive deposi...
Salinomycin toxicosis in horses. A 4-month-old American Paint filly was evaluated because of sudden onset of ataxia that progressed to recumbency. Five additional horses from the same and neighboring premises developed signs of poor performance, generalized weakness, ataxia, and recumbency; 2 of those horses were also evaluated. A new batch of a commercial feed supplement had been introduced to the horses' diet on each farm within the preceding 3 days. Results: Other than recumbency, findings of physical and neurologic examinations of the foal were unremarkable. The other 2 horses had generalized weakness and mild ataxia, and...
Electrosurgery as the sole means of haemostasis during the laparoscopic removal of pathologically enlarged ovaries in mares: a report of 55 cases. There is little published clinical evidence on the use of a laparoscopic approach for the removal of pathologically enlarged ovaries in standing mares. Objective: To show the orders of success and complication rates that can be expected if pathologically enlarged ovaries are removed from standing, sedated mares under laparoscopic guidance using only electrosurgical means of haemostasis. Methods: A retrospective analysis was made of 55 mares in which the removal of an enlarged ovary was attempted by applying a standard laparoscopic procedure for routine ovariectomy in standing mares including a...
Multiple masses in a horse’s tongue resulting from an atypical perineurial cell proliferative disorder. A 5-year-old National Show horse mare presented with a soft mass on the left dorsolateral aspect of the tongue. Over the next 2 years, the mare developed numerous, similar, coalescing masses that extended along the left dorsolateral aspect to the tip of the tongue. Microscopically, the bases for these masses were slender, fusiform, mesenchymal cells that formed compact whorls around myelinated and unmyelinated nerves. These cells were labeled by antibodies directed against vimentin but not by S-100. Ultrastructurally, multiple, concentrically arranged, long, slender cell processes, with discon...
Equine stomach worm, Drashia megastoma (Spirurida: Habronematidae): first SEM report. Drashia megastoma (Spirurida: Habronematidae) occurs in nodules in the stomach wall and rarely free in the stomach of the horse, mule and zebra throughout the world. D. megastoma develops in the housefly Musca domestica and causes gastric haemorrhage or even perforation of the stomach. Larvae of this nematode may be found in the lung, skin and eye of the host. Scanning electron microscopy (SEM) was used to study the surface ultrastructure of adult worms of this nematode. In both sexes, the head end was separated from the rest of the body by a constriction. The stoma was infundibuliform with a ...
Intra-abdominal adhesions in horses: a retrospective evaluation of repeat laparotomy in 99 horses with acute gastrointestinal disease. The objectives of this study were (1) to determine the prevalence of pathological abdominal adhesion formation following exploratory laparotomy; (2) to establish the site of adhesion formation and its relationship to the initial lesion; (3) to ascertain whether the development of intra-abdominal adhesions decreases long-term survival and (4) to identify risk factors for adhesion formation. Of 1014 horses treated surgically for acute gastrointestinal disease, 113 (10.1%) were subjected to repeat laparotomy, with surgical records available for 99 of these cases. Pathological adhesions were the m...
Inflammatory airway disease of horses. The purpose of this consensus statement is to provide a review of current knowledge and opinions concerning inflammatory airway disease (IAD) and to help practitioners differentiate IAD from heaves (or recurrent airway obstruction; RAO) and other inflammatory respiratory diseases of horses.
Kernicterus in a neonatal foal. A 5-day-old Thoroughbred foal was submitted to the necropsy service at the University of Kentucky Livestock Disease Diagnostic Center. The foal had a clinical history of seizure activity and severe icterus. A complete blood count and serum chemistry analysis indicated that the foal was anemic (hematocrit, 16%), hyperbilirubinemic (45 mg/dl), and hypoglycemic. At necropsy, all tissues were discolored various shades of yellow. Microscopically, there was degeneration and necrosis of cerebral neurons and cerebellar Purkinje cells; severe hepatocellular degeneration and necrosis; and deposition of ...
Effect of light exercise on valvular regurgitation in standardbred trotters. Although valvular regurgitation is diagnosed frequently by colour Doppler echocardiography in racehorses at rest, there is currently no information about the effect of exercise on valvular regurgitation. Objective: To investigate the effect of light exercise on valvular regurgitation in a population of trotters. Methods: Standardbred trotters (n = 73) were examined by resting auscultation and echocardiography, of which 50 fullfilled the criteria of the study. Of these, 4 had reduced performance according to the trainers and were not included in the statistical analyses. Horses that showed valv...
Defocused CO2 laser on equine skin: a histological examination. No studies have been published on effects of treatment with a defocused beam carbon dioxide (CO2) laser on equine skin histology. A better understanding of this will help to define how lasers should be used, in order to reduce potential side effects. Objective: To describe the acute effects of different doses of defocused CO2 laser, ranging from therapeutic to surgical levels, on equine skin. Methods: Defocused CO2 laser was administered to the skin in the hamstrings (91 J/cm2), fetlock (137 J/cm2) and loin (450 J/cm2) areas of 13 Standardbred horses. The acute effects on skin histology were e...
A case of multiple epitrichial sweat gland ductal carcinomas in a horse. This case report describes a rare epitrichial sweat gland ductal carcinoma in a 14-year-old horse and is the first report of multiple carcinomas of this type in horses. Although several tumours developed, mostly on the distal extremities, over a 2-year period, the horse remained otherwise healthy. Topical treatment with imiquimod was successful for many of them.
Ultrasonographic evaluation of the supraspinous ligament in a series of ridden and unridden horses and horses with unrelated back pathology. Injury to the supraspinous ligament (SSL) is reported to cause back pain in the horse. The diagnosis is based on clinical examination and confirmed by ultrasonographic examination. The ultrasonographic appearance of the supraspinous ligament has been well described, but there are few studies that correlate ultrasonographic findings with clinical pain and/or pathology. This preliminary study aims to test the hypothesis that unridden horses (n = 13) have a significantly reduced frequency of occurrence of ultrasonographic changes of the SSL consistent with a diagnosis of desmitis when compared to...
A subcutaneous mass on the neck of a horse. A 25-year-old Arabian gelding was presented for investigation of a subcutaneous neck mass. Fine-needle aspirates and impression smears revealed mast cells with widely varying degrees of cytoplasmic granulation and scattered eosinophils. Histopathology revealed a poorly circumscribed mass composed of sheets and bundles of mast cells with a large population of eosinophils. The mast cells were separated into numerous lobules by a heavy collagenous stroma, and multifocal collagen necrosis was present. Strong reactivity of the tumor cells for both Giemsa and toluidine blue stains confirmed the diag...
Muc5b and Muc5ac are the major oligomeric mucins in equine airway mucus. Horses frequently suffer from respiratory diseases, which, irrespective of etiology, are often associated with airway mucus accumulation. Studies on human airways have shown that the key structural components of the mucus layer are oligomeric mucins, which can undergo changes of expression and properties in disease. However, there is little information on these gel-forming glycoproteins in horse airways mucus. Therefore, the aims of this study were to isolate equine airways oligomeric mucins, characterize their macromolecular properties, and identify their gene products. To this end, pooled tr...
Cellular basis of chronic obstructive pulmonary disease in horses. Chronic obstructive pulmonary disease (COPD) is an inflammatory obstructive disease of the airways characterized with hypersensitivity of the airway tissues to various allergens, most commonly the fungi contained in the poor-quality hay and straw bedding-Saccharopolyspora rectivirgula, Aspergillus fumigatus, and Thermoactinomyces vulgaris. It is manifested clinically in middle-aged horses with recurrent episodes of dyspnea, chronic cough, and their reduced athletic and working capacity. Pulmonary emphysema and lack of pulmonary collapse are the most common gross lesion. Pathohistological findi...
Scintigraphic evaluation of the proximal metacarpal and metatarsal regions of horses with proximal suspensory desmitis. The aim of the study was to characterize radiopharmaceutical uptake patterns in horses with clinical and ultrasonographic evidence of proximal suspensory desmitis. It was hypothesized that radiopharmaceutical uptake in the proximal palmar (plantar) aspect of the third metacarpal (metatarsal) bone would be greater in lame limbs of horses with proximal suspensory desmitis than in sound limbs and that there would be a positive correlation between the severity of ultrasonographic abnormalities and the degree of radiopharmaceutical uptake. Nuclear scintigraphic evaluation of the proximal metacarpal...
Morphological alterations in oxidative muscles and mitochondrial structure associated with equine atypical myopathy. There is a lack of well documented studies about muscular lesions in equine atypical myopathy (EAM). Objective: To characterise morphopathological changes of striated muscles and myocardium, to progress understanding of this disease. Methods: Thirty-two horses age 0.5-7 years kept on pasture were referred for a sudden ataxia/myoglobinuria syndrome. Clinical examination (stiffness, muscle pain, muscle fasciculations, abnormal gait, recumbency, myoglobinuria, tachycardia, sweating) and plasma CPK, LDH and AST levels were consistent with extensive myonecrosis and, together with anamnestic data, w...
Clinical and pathological findings in a HERDA-affected foal for 1.5 years of life. A Quarter horse filly bred from two horses affected with HERDA (hereditary equine regional dermal asthenia) was observed clinically and its skin histologically for the 1.5 years of its life. Severe signs of the disease did not manifest until 1.5 years of age, and were not temporally related to saddling. Histological comparison to an age-, breed- and sex-matched control did not show any consistent diagnostic features. Monitoring of the proband substantiated previous reports of (i) the autosomal recessive nature of the disease, (ii) mares affected with HERDA being able to foal without damage to ...
A case of equine motor neuron disease (EMND). We report a case of EMND in a heavy horse that was bred and trained in Hokkaido, Japan. Clinical symptoms included severe ataxia of all four limbs, tilted head, lethargy, and flaccid lips. Numerous axonal degenerations and swellings were observed in nuclei, mostly in the cerebellar dentate nucleus and the nucleus of the hypoglossal nerve, and in the ventral horn of the spinal cord. In the ventral horn of the spinal cord, neuronal degeneration, swelling, and/or necrosis were observed sporadically. The case was diagnosed as EMND from the clinical symptoms and pathological findings.
Plasma concentration of insulin-like growth factor I (IGF-I) in growing Ardenner horses suffering from juvenile digital degenerative osteoarthropathy. Degenerative osteoarthropathy resulting in a reduced active lifespan was observed in Ardenner horses. In the context of joint biology, insulin-like growth factor I (IGF-I) is a potential candidate to affect the anabolism of cartilage matrix molecules. A group of 30 Ardenner horses reared under standardized conditions from weaning were evaluated periodically from 15 to 28 months of age to detect the early manifestations of the disease. At the end of this period, horses were classified in two pathological groups related to the degree of interphalangeal degenerative osteoarthropathy based on clin...
Expression of cyclooxygenase-1 and -2 in naturally occurring squamous cell carcinomas in horses. To assess expression of cyclooxygenase (COX)-1 and -2 in naturally occurring squamous cell carcinomas (SCCs) and the analogous normal tissues in horses. Methods: Tissue samples collected from 3 conjunctival, 2 vulvar, 4 preputial, and 5 penile SCCs during surgical excision in 14 horses and from corresponding body regions (conjunctiva [n = 5 horses], vulva [2], prepuce [3], and penis [3]) in 5 horses euthanized for reasons unrelated to neoplasia. Methods: Tissue samples were snap frozen in liquid nitrogen and stored at -80 degrees C until analysis. Protein was extracted from the frozen tissues,...
Verminous encephalitis in a horse produced by nematodes in the family protostrongylidae. Parasitic granulomatous eosinophilic inflammation was observed in the central nervous system (CNS) of a 6-month-old Arabian colt from New York state. Inflammation was associated with eggs, larvae, and adult nematodes in the cerebellum. Nematodes had histological characteristics of the superfamily Metastrongyloidea. The presence of dorsal-spined larvae in the CNS was further indicative of infection with a nematode in the family Protostrongylidae. Infections were most compatible with Parelaphostrongylus tenuis but specific diagnosis was not possible. This is the first definitive report of a prot...
Evaluation of equine papillomas, aural plaques, and sarcoids for the presence of Equine papillomavirus DNA and Papillomavirus antigen. Immunohistochemical (IHC) testing and electron microscopy have implicated Papillomavirus (PV) as the etiologic agent for equine papillomas and aural plaques, but Equine papillomavirus (EPV) DNA has yet to be demonstrated in these lesions by polymerase chain reaction (PCR). The purpose of this study was to evaluate formalin-fixed, paraffin-embedded tissues from naturally occurring cases of equine papillomas, aural plaques, and sarcoids for the presence of EPV DNA by means of PCR and for the presence of PV antigen by means of IHC testing. We used EPV-specific primers that amplified a region of 3...
