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Topic:Disease Etiology
Disease etiology in horses refers to the study of the causes and development of diseases within equine populations. It encompasses various factors, including genetic predisposition, environmental influences, infectious agents, and nutritional imbalances, that contribute to the onset and progression of diseases in horses. Understanding disease etiology is essential for identifying risk factors and implementing preventative measures in equine health management. This topic includes research on pathogen-host interactions, the impact of management practices on disease incidence, and the role of genetic and environmental factors in disease susceptibility. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, contributing factors, and implications of disease etiology in horses.
Miscellaneous conditions of the equine foot. The etiology, clinical presentation, radiographic findings, diagnostic criteria, differential diagnoses, treatment, and prognosis are reviewed for several clinically important conditions of the equine foot. These include pedal osteitis, sheared heels, distal sesamoid bone (navicular) fractures, subchondral bone cyst of the distal phalanx, distal interphalangeal joint subluxation, congenital phalangeal hypoplasia, bipartite and tripartite distal sesamoid bones, keratoma, ossification of the cartilages of the distal phalanx (sidebones), necrosis of the cartilages of the distal phalanx (quittor),...
Basal and bile salt-stimulated bile flow and biliary lipid excretion in ponies. The role of bile salt in biliary lipid excretion was studied in 3 healthy ponies with chronic external biliary fistulas. After endogenous bile salt pool depletion, micelle-forming taurocholate or taurochenodeoxycholate was infused to replace excreted bile salt. Enterohepatic circulations were held open (total biliary diversion) throughout each study. Results indicated that biliary lipid excretion in ponies (113 +/- 21 nmol/min/kg of body weight) is approximately 10 times less than that reported in rodents. Although the lipid composition (4.4% cholesterol, 5.6% phospholipid, and 90% bile salt) ...
In vitro reactivity of digital arteries and veins to vasoconstrictive mediators in healthy horses and in horses with early laminitis. The in vitro reactivity of vasoconstrictive mediators that are implicated in acute laminitis was determined in palmar and plantar digital arteries and veins obtained from healthy horses and in palmar digital vessels of horses with early laminitis (Obel grade I). To obtain baseline reactivity data, 3 experiments were conducted, using healthy horses: (1) the reactivity of palmar and plantar digital arteries and veins to angiotensin II, norepinephrine, and 5-hydroxytryptamine (serotonin) were compared; (2) the direct effects of bacterial endotoxin on vascular reactivity were assessed; and (3) the...
Evaluation of total plasma bile acid concentrations for the diagnosis of hepatobiliary disease in horses. Plasma bile acid concentrations were measured in normal horses. There was no diurnal variation in values, and age and sex had no effect. There was no significant difference between serum and plasma bile acid concentrations in clinically normal horses. Plasma bile acids were stable on storage for one month at -20 degrees C. The total plasma bile acid concentrations together with total and direct bilirubin concentrations and plasma activities of aspartate aminotransferase, glutamate and iditol dehydrogenase were evaluated in horses with various types of hepatobiliary disease (hepatic necrosis, l...
Sustained supraventricular tachycardia in a horse. A case of sustained supraventricular tachycardia of unknown aetiology in a two-year-old Thoroughbred filly is reported. The cardiac dysrhythm was successfully treated by the oral administration of quinidine sulphate. Conversion of the dysrhythm to sinus rhythm occurred approximately 80 min after the initial dose of 5 g of quinidine sulphate. The horse returned to training approximately 2 months after treatment and has since successfully returned to racing.
Immunoglobulin lambda-light-chain-derived amyloidosis (A lambda) in two horses. Tumorous amyloid deposits in the nasal mucosa of two horses differed from generalized AA-amyloidosis with respect to clinical features, organ distribution, and resistance to KMnO4 treatment. Using a panel of antibodies directed against different human amyloid fibril proteins and employing the peroxidase-anti-peroxidase (PAP) technique, we showed the described equine amyloid to be A lambda-type, as demonstrated by immunohistochemical cross-reactivity. Consequently, we identified a second amyloid class in horses and showed that immunoglobulin light-chain-derived amyloid may also be present in an...
Equine zygomycosis caused by Conidiobolus lamprauges. A 15-year-old Arabian mare from southern Louisiana with a 2-month history of periodic epistaxis and severe weight loss had a large, fibrosing, granulomatous mass containing numerous nodules ("kunkers") projecting dorsally into the nasopharynx, and was euthanized at the owner's request. In addition to these kunkers, the mass contained a single trematode tentatively identified as Fasciola hepatica. Several kunkers were removed, washed thoroughly in sterile water and embedded in nutrient agars; the fungus that grew out of them was identified as Conidiobolus lamprauges Drechsler (Entomophthorales:...
An intersex horse with X chromosome trisomy. An X-trisomy has been detected in an intersexuality Spanish-bred horse by using G- and C-banding methods. The external characteristics and the behavioural and physiological irregularities of the horse are described. This is the first time that an association between an X-trisomy and a case of intersexuality has been reported in any domestic animal.
Etiologic agents, incidence, and improved diagnostic methods of cantharidin toxicosis in horses. In addition to the 3-striped blister beetles (Epicauta temexa and E occidentalis), other sources of equine cantharidin toxicosis were identified at the Texas Veterinary Medical Diagnostic Laboratory and included E albida and E attrivittata and the previously incriminated E pardalis and E pennsylvanica. Improved methods for diagnosing cantharidin or blister beetle toxicosis involve partial purification of urine and gastric content extracts, using silica cartridges, followed by analysis, using capillary gas chromatography/mass spectrometry. During a 26-month period, 53 episodes of cantharidin to...
Hepatotoxicity and renal toxicity in rats of corn samples associated with field cases of equine leukoencephalomalacia. Currently there is no convenient bioassay to determine the potential toxicity of corn naturally contaminated with Fusarium moniliforme. A short-term bioassay would be useful for future investigations aimed at isolating as yet unidentified toxins produced by this fungus. Two groups of five male Sprague-Dawley rats were each fed one of two F. moniliforme contaminated corn samples, designated CS-1 and CS-2, that were associated with separate field cases of equine leukoencephalomalacia (ELEM). A control group, also consisting of five male rats, was fed uncontaminated seed corn. All animals survive...
Echinococcus granulosus: a comparison of free amino acid concentration in hydatid fluid from primary and secondary cysts and host plasma. A total of 28 components were detected in the free amino acid (FAA) pool of hydatid fluid from primary and secondary equine cysts, secondary ovine cysts and host plasma. Examination of data from equine cysts revealed that the majority of FAAs were present in significantly greater concentrations in secondary cysts, glycine being over 30 times more concentrated. Values for total carbohydrates and glucose did not, however, differ significantly and total protein content was greater in primary cysts. Comparison of the (FAA) pool of secondary equine and ovine cysts revealed strain variation. It was ...
Studies on serum selenium and tocopherol in white muscle disease of foal. In order to clarify the cause of white muscle disease (W.M.D.) in foals, tocopherol and selenium concentrations in serum and glutathione peroxidase activities in blood were measured. Examination was made on the samples from horses affected with W.M.D., the foal kept with them in the same stable, the foals kept in the stables without affected foals, and respective mares. The heavy-breed horses in Fukuoka prefecture and Tokachi district were also examined for comparison. Serum tocopherol levels of these foals were normal because after intake of colostrum. Mares of affected foals showed lower toc...
The epidemiology of Echinococcus granulosus in Great Britain. V. The status of subspecies of Echinococcus granulosus in Great Britain. Twenty-five years ago Williams and Sweatman suggested that in Great Britain there are two subspecies of Echinococcus granulosus--E. granulosus granulosus and E. granulosus equinus. Echinococcus granulosus granulosus does not mature either in foxes or in horses: E. granulosus equinus will mature in either. The prepatent period of E. granulosus granulosus in the definitive host is about 42 days while that of E. granulosus equinus is about 70 days. Each subspecies has a characteristic morphology. More recently, in the course of seven experiments, dogs, red foxes (Vulpes vulpes crucigera), arctic ...
Campylobacteriosis in an aborted equine fetus. Abortion caused by Campylobacter fetus subsp fetus was diagnosed in a 7-month-old equine fetus. The fetus was small for its gestational age. Macroscopically, the proximal portion of the small intestine was hemorrhagic and its wall was thick. Histologically, the Brunner glands were distended with neutrophils, and the submucosa was thick, owing to fluid accumulation and/or cellular infiltrates. Curved bacteria were observed in the Brunner glands and intestinal glands. Campylobacter fetus subsp fetus was isolated from stomach contents, liver, and lungs, and was detected by dark-field microscopic ...
Caecal intussusceptions in horses and the significance of Anoplocephala perfoliata. A caecocaecal intussusception in a pony and a caecocolic intussusception in a horse, both infected with Anoplocephala perfoliata, are described and the relevance of tapeworms in such intestinal disease of horses is reviewed.
Animal virus infections that defy vaccination: equine infectious anemia, caprine arthritis-encephalitis, maedi-visna, and feline infectious peritonitis. Lentiviruses are associated with persistent infection and chronic
disease in three major species of livestock—horses, sheep, and goats.
Another lentivirus named bovine immunodeficiency virus (BIV) recently has been described (Gonda et al., 1987). It is a Visna-like virus that was originally isolated over a decade ago from cattle with
persistent lymphocytosis, lymphadenopathy, weakness, emaciation,
and central nervous system (CNS) lesions (Van der Maaten et al,
1972). There is very little information on the epidemiology, clinical
manifestations, or importance of bovine lentivirus infect...
Production of monoclonal antibodies against equine influenza: application to a comparative study of various strains of the virus. Monoclonal antibodies (Mo Abs) were prepared against influenza/A/equine/Prague/1/56 (H7N7) and influenza/A/equine/Miami/1/63 (H3N8) reference strains of equine influenza virus. These monoclonals were tested against the 2 reference strains, 8 field strains of equine influenza virus, 3 human influenza viruses possessing the H3 hemagglutinin, and one virus of human origin possessing the H1 hemagglutinin. Two antibodies were obtained in one fusion against the Prague/1/56 strain and reacted only with this strain. Four anti/A/equine/Miami/1/63 Mo Abs were obtained in one fusion. They differentiated ...
Plasma and liver copper values in horses with equine degenerative myeloencephalopathy. Equine degenerative myeloencephalopathy (EDM) is a common spinal cord disease in the horse. The etiology of EDM currently is unknown. In other species, there are similarities in the clinical signs and neuropathological changes observed in EDM and in copper deficiency. The objective of this study was to determine if horses affected with EDM had low levels of plasma or liver copper. Plasma copper values were determined in 25 EDM affected horses and 35 normal horses. Liver copper levels were determined on 13 EDM affected horses and 22 normal horses. Plasma and liver copper values were not signifi...
[Histochemical changes in skeletal muscles of racehorses susceptible to rhabdomyolysis after exertion. I. Early myopathological changes]. In this communication, the results of an enzyme histochemical study on m. gluteus medius of horses, sensitive to exertional myopathy, during attacks of rhabdomyolysis are presented. The activity and location of about 25 enzymes were examined. In the present report, the early metabolic changes are discussed. Within 6 min after an attack, some large rounded fibres (approximately 2%) were seen, which showed an intense red staining in the haematoxylin and eosin sections. These hypercontracted fibres showed an increase in activity of mitochondrial adenosine triphosphatase, indicating the presence o...
An aerogenic Pasteurella-like organism isolated from horses. Thirteen strains of a gram-negative, fermentative bacterium that produced gas from glucose were isolated from horses with a variety of clinical conditions. The morphological and biochemical characteristics of this bacterium are similar to those described for the family Pasteurellaceae. These strains appear to constitute a new taxon within the genus Pasteurella; however, the final taxonomic position of this group depends upon more detailed genetic studies. Case histories indicate that this bacterium may be a primary respiratory pathogen and may play a secondary role in various other disease con...
