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.
Disseminated intravascular coagulation in six horses. Disseminated intravascular coagulation (DIC) was diagnosed as a secondary disease in 6 horses. Four horses had localized and/or systemic sepsis, one horse had disseminated neoplasia, and one had idiopathic ulcerative enteropathy. The diagnosis of DIC was based on the finding of at least 3 of 4 abnormalities: thrombocytopenia, prolonged prothrombin time, prolonged activated partial thromboplastin time, and a high concentration of fibrinolytic degradation products. The most common clinical signs other than those attributable to the primary disease process were abnormal hemorrhage (4 hours) and v...
SEM study of Strongylus vulgaris larva-induced arteritis in the pony. This paper describes the histological and scanning electron microscopical examinations of the right colic artery of eight ponies. Lesions all had large thrombi surrounding a larva or larvae, with arterial wall thickening. Endothelial shape change, degeneration and loss were present. Fibrin-platelet red blood cell aggregates were present on endothelial surfaces as well as on the surface of thrombi. Damage to the intima appeared to produce the conditions for progressive thrombus formation.
Renal papillary necrosis in horses after phenylbutazone and water deprivation. Acute renal papillary necrosis occurred in five horses given normal therapeutic doses of phenylbutazone and deprived of water for 36 to 48 hours prior to euthanasia. Five horses given phenylbutazone alone and four horses subjected to water deprivation alone did not develop papillary necrosis. Urinalyses were normal prior to water deprivation, and also after water deprivation in the horses that did not receive phenylbutazone, but the water-deprived, phenylbutazone-treated horses had many red blood cells, transitional epithelial cells, and large numbers of oxalate crystals in their urine. Ulcera...
Ultrastructure of the equine hoof wall secondary epidermal lamellae. The ultrastructure of cells of the secondary epidermal lamellae from the hoof wall of 8 adult horses was described. Stages of progressive keratinization were not observed in this cell population. The morphologic features of cells of the secondary epidermal lamellae indicated that these lamellae were composed of nonmobile populations of cells and that primary epidermal lamellae moved past the secondary lamellae by breaking of the desmosomes connecting these 2 cell populations. Seemingly, debris present in the intercellular space between primary and secondary lamellae was a by-product of this re...
Traumatic patella fractures in the horse. Six cases of patella fractures are reported. Three horses presented an avulsion fracture of the medial patellar angle. For a precise diagnosis of this fracture a radiographic skyline view was indispensable; lateral views were not diagnostic. One of these horses recovered after three months' rest but radiographically the fracture remained visible. One horse with a comminuted fracture recovered after five months' rest. A case with a contaminated longitudinal patella fracture was destroyed. The sixth horse had a chip fracture of the dorsomedial part of the patella. The outcome of this case is unk...
The pathology of experimental Corynebacterium equi infection in foals following intrabronchial challenge. Six foals were inoculated intrabronchially with a suspension of Corynebacterium equi. Six weeks before this challenge, three foals were vaccinated with a C. equi bacterin. Three foals were unvaccinated controls. All foals developed a severe bronchopneumonia in the inoculated lung, indicating that vaccination was not protective. Three foals (two vaccinated, one control) were killed eight to nine days after infection. One control died on day 9 with lesions of disseminated intravascular coagulation. The remaining two foals (one vaccinated, one control) were killed on day 17. C. equi was cultured ...
Fecal leukocytes and epithelial cells in horses with diarrhea. Fecal samples from 74 horses with diarrhea were examined microscopically for leukocytes and epithelial cells. The diarrhea was categorized as either acute (less than two weeks) or chronic, Salmonella positive or negative, and mild or severe (based on the fecal consistency). A large number of fecal leukocytes was strongly suggestive of salmonellosis; however, approximately 1/3 of the horses with Salmonella-negative diarrhea also shed fecal leukocytes. Fecal leukocytes were more common in horses with acute and/or severe diarrhea regardless of cause. Numbers of fecal colonic mucosal epithelial ce...
Malignant melanomas in farm animals. Malignant melanomas in 5 horses, 1 calf, 1 cow and 2 pigs were described. The disease, in white or gray horses, was tegumentally located and generalized in the organs of the abdominal cavity. Microscopically, dendritic and fusiform pigment cells and multinucleated cells were identified. In the hypophysis there microcysts and in one case a hypophyseal adenoma were encountered. Electronmicroscopically, differentiated melanophores and melanophages were also found. The mature melanosomes were intensely black and the elementary granules concentrically and lamellarly arranged. In cattle, the general...
Fatal acorn poisoning in a horse: pathologic findings and diagnostic considerations. Acorn poisoning was diagnosed in an 11-year-old Quarter Horse with signs of severe colic, tachycardia, hyperpnea, abdominal borborygmus, rectal tenesmus, and hemorrhagic diarrhea. The diagnosis was based on history and predisposing factors, clinical signs, laboratory data, acorn husks in the feces, the urinary gallic acid equivalent concentration, and necropsy findings. The most striking pathologic changes were gastrointestinal and mesenteric edema, ulcerative enterocolitis, and nephrosis.
An in vitro study on joint fitting and cartilage thickness in the radiocarpal joint of foals. The change in the degree of fitting of the opposing articular cartilage surfaces of the radiocarpal joint of foals was studied in vitro using a pneumatic loading device. The thickness of the articular cartilage of the distal radius was examined using radiographic and histological techniques. The thickest cartilage corresponded with the approximate centre of the contact area of the opposing articular surface. The variations in articular cartilage contact area and thickness are discussed.
A study on the possible role of chymotrypsin in the aetiology of equine chronic obstructive pulmonary disease (COPD). The chymotrypsin activity of seven batches of Micropolyspora faeni and of five batches of Aspergillus fumigatus culture extracts, prepared for inhalation challenge in horses, was assayed and was found to range between 0.29 and 1.45 units/mg protein and 0.02 and 0.20 units/mg protein respectively. Horses affected with chronic obstructive pulmonary disease (COPD) were challenged with two batches of each antigen which had different chymotrypsin activities and no significant correlations were found between the degree of response to challenge and the chymotrypsin activity of the antigens. Inhalatio...
Experimental Streptococcus equi infection in the horse: correlation with in vivo and in vitro immune responses. Fourteen young outbred horses, divided into 2 groups on the basis of 18- or 24-hour skin-test reactions to Streptococcus equi, were inoculated nasopharyngeally with virulent S equi. Animals (n = 6, group I) with evidence of previous exposure to S equi (positive dermal response and existing serum antibodies), with one exception, developed minimal or no signs of disease after inoculation. In contrast, S equi skin-test negative and seronegative horses (n = 8, group II) developed predictable and severe clinical signs of infection after their inoculation, including shedding of the organism from nas...
A reagin-like antibody in horse serum. II. Anti-human IgE induced reversed cutaneous anaphylaxis-like responses in horse skin. Fc specific anti-human IgE serum induced prolonged reversed cutaneous anaphylaxis (RCA)-like reactions in horse skin. Morphologically and histologically, these reactions resembled passively induced late cutaneous anaphylaxis responses in human skin, but differed from reversed passive Arthus responses induced in horse skin using anti-horse IgG serum. The induction of RCA-like responses in horse skin by anti-human IgE indicates shared Fc antigenic determinants on human IgE and a horse homocytotropic or reagin-like antibody.