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Topic:Equine Health
Equine health encompasses the study and management of diseases, disorders, and overall well-being of horses. It involves understanding various physiological systems, preventive care, and treatment strategies to maintain optimal health in equine populations. Common areas of focus include nutrition, infectious diseases, orthopedic conditions, and reproductive health. Research in equine health aims to advance knowledge on diagnostic methods, therapeutic interventions, and management practices that improve horse welfare and performance. This page collects peer-reviewed research studies and scholarly articles that explore the diverse aspects of equine health, offering insights into current findings and advancements in the field.
West Nile virus surveillance in Connecticut in 2000: an intense epizootic without high risk for severe human disease. In 1999, Connecticut was one of three states in which West Nile (WN) virus actively circulated prior to its recognition. In 2000, prospective surveillance was established, including monitoring bird deaths, testing dead crows, trapping and testing mosquitoes, testing horses and hospitalized humans with neurologic illness, and conducting a human seroprevalence survey. WN virus was first detected in a dead crow found on July 5 in Fairfield County. Ultimately, 1,095 dead crows, 14 mosquito pools, 7 horses, and one mildly symptomatic person were documented with WN virus infection. None of 86 hospit...
Activities of enzymes related to the malate-aspartate shuttle in the blood cells of thoroughbred horses undergoing training exercise. The activities of the enzymes related to the malate-aspartate shuttle, which convert cytosolic NADH into mitochondrial NADH, were measured in red and white blood cells from thoroughbred horses undergoing continuous training (race horses) and compared with those in blood cells from riding horses. The activities of malate dehydrogenase (MDH), a rate-limiting enzyme for the malate-aspartate shuttle, were significantly elevated in the white blood cells (WBC) from race horses compared with those from riding horses. There were no significant differences in the activities of the enzymes in the red bl...
West Nile encephalitis: an emerging disease in the United States.
Clinical infectious diseases : an official publication of the Infectious Diseases Society of America
In 1999, an epidemic of West Nile virus (WNV) encephalitis occurred in New York City (NYC) and 2 surrounding New York counties. Simultaneously, an epizootic among American crows and other bird species occurred in 4 states. Indigenous transmission of WNV had never been documented in the western hemisphere until this epidemic. In 2000, the epizootic expanded to 12 states and the District of Columbia, and the epidemic continued in NYC, 5 New Jersey counties, and 1 Connecticut county. In addition to these outbreaks, several large epidemics of WNV have occurred in other regions of the world where t... West Nile outbreak in horses in southern France, 2000: the return after 35 years. On September 6, 2000, two cases of equine encephalitis caused by West Nile (WN) virus were reported in southern France (Hérault Province), near Camargue National Park, where a WN outbreak occurred in 1962. Through November 30, 76 cases were laboratory confirmed among 131 equines with neurologic disorders. The last confirmed case was on November 3, 2000. All but three cases were located in a region nicknamed "la petite Camargue," which has several large marshes, numerous colonies of migratory and resident birds, and large mosquito populations. No human case has been confirmed among clinically ...
Influence of plasma proteins on erythrocyte aggregation in three mammalian species. The aggregation capacity of human erythrocytes lies between that of the non-aggregating bovine erythrocytes and the remarkably aggregating equine ones. As the ability to aggregate is attributed to cell factors and the composition of the plasma proteins, the role that plasma proteins play in the aggregation process in these three species was studied. Washed erythrocytes were suspended in phosphate-buffered saline (PBS; pH 7.4, 300 mOsm/L) plus polyvinylpyrrolidone (PVP) in a suitable concentration to obtain an average intensity of aggregation (control media). The superimposed effect of replacin...
Equine monocytic Ehrlichiosis (Potomac horse fever) in horses in Uruguay and southern Brazil. A disease named locally as churrío or churrido equino (i.e., equine scours) has occurred for at least 100 years in Uruguay and southern Brazil in farms along both shores of the Merín lake. This report describes cases of churrido equino and provides serologic, pathologic, and DNA-based evidence indicating that the disease is in fact equine monocytic ehrlichiosis (Potomac horse fever). Results of an epidemiological investigation conducted on an endemic farm are also presented. Clinical signs in 12 horses were fever, depression, diarrhea, dehydration, and sometimes colic and distal hind limb ed...
Sequence conservation and antigenic variation of the structural proteins of equine rhinitis A virus. The nucleotide and deduced amino acid sequences of the P1 region of the genomes of 10 independent equine rhinitis A virus (ERAV) isolates were determined and found to be very closely related. A panel of seven monoclonal antibodies to the prototype virus ERAV.393/76 that bound to nonneutralization epitopes conserved among all 10 isolates was raised. In serum neutralization assays, rabbit polyclonal sera and sera from naturally and experimentally infected horses reacted in a consistent and discriminating manner with the 10 isolates, which indicated the existence of variation in the neutralizatio...
Influence of epidermal growth factor on mammalian oocyte maturation via tyrosine-kinase pathway. Epidermal growth factor (EGF) has been reported to promote different functions in mammalian ovaries, including oocyte maturation. The aim of the present study was to establish: that EGF influences oocyte maturation in ovine and equine, that a tyrosine kinase-dependent intracellular mechanism mediates EGF effect and, that EGF-R receptor is detectable in ovarian follicles by immunohistochemistry methods. Selected ovine and equine oocytes were aspirated from 2-5 mm (ovine) or 25 mm (equine) follicles and cultured in TCM 199 for 22 (ovine) or 36 hours (equine). They are then subjected to culture w...
Suppression of mosquito (Diptera: Culicidae) and black fly (Diptera: Simuliidae) blood feeding from Hereford cattle and ponies treated with permethrin. The blood feeding of mosquitoes and black flies from Hereford cattle and ponies treated with commercial formulations of permethrin was evaluated using an animal enclosure trap sample system that allowed comparison of insect blood-feeding levels between treated and nontreated animals. Blood feeding of both Aedes dorsalis Meigen and A. melanimon Dyar from heifers treated with pour-on concentrate and whole body spray treatments was reduced significantly by 79-88% at 4 d posttreatment, with apparent but not significant reductions of 61-68% at 11 d posttreatment. Simulium bivittatum Malloch and S. ...
The use of a neutralizing monoclonal antibody to detect infections of equine herpesvirus type 2 (EHV-2). A blocking enzyme-linked immunosorbent assay (ELISA) was developed to detect antibodies to equine herpesvirus 2 in serum samples of horses. By measuring the binding to a single epitope, this blocking ELISA gives a good picture of the antibody status in the animal. The test is based on a monoclonal antibody with neutralizing activity and had a sensitivity of 94% and a specificity of 100%. Antibodies due to newly acquired infection in foals were successfully detected with this blocking ELISA.
Influence of epidermal growth factor on mammalian oocyte maturation via tyrosine-kinase pathway. Epidermal growth factor (EGF) has been reported to promote different functions in mammalian ovaries, including oocyte maturation. The aim of the present study was to establish: that EGF influences oocyte maturation in ovine and equine, that a tyrosine kinase-dependent intracellular mechanism mediates EGF effect and, that EGF-R receptor is detectable in ovarian follicles by immunohistochemistry methods. Selected ovine and equine oocytes were aspirated from 2-5 mm (ovine) or 25 mm (equine) follicles and cultured in TCM 199 for 22 (ovine) or 36 hours (equine). They are then subjected to culture w...
Mapping the sequences that mediate interaction of the equine herpesvirus 1 immediate-early protein and human TFIIB. The sole immediate-early (IE) gene of equine herpesvirus 1 encodes a 1,487-amino-acid (aa) regulatory phosphoprotein that independently activates expression of early viral genes. Coimmunoprecipitation assays demonstrated that the IE protein physically interacts with the general transcription factor TFIIB. Using a variety of protein-binding assays that employed a panel of IE truncation and deletion mutants expressed as in vitro-synthesized or glutathione S-transferase fusion proteins, we mapped a TFIIB-binding domain to aa 407 to 757 of the IE protein. IE mutants carrying internal deletions of ...
Idiopathic systemic granulomatous disease and macrophage expression of PTHrP in a miniature pony. Idiopathic systemic granulomatous disease, which has been reported in horses, cattle and human beings, is characterized by perivascular granulomatous and lymphoplasmacytic inflammation in many organ systems. Diagnosis is based on the exclusion of possible viral, fungal or bacterial causes. The disease was identified in a miniature pony with widespread lymphoplasmacytic and granulomatous inflammation, special staining techniques having revealed no evidence of any aetiological agent. Skin lesions, which were severe, consisted of hyperkeratosis and serocellular crust formation, with inflammatory ...
Disseminated metastatic intramedullary melanoma in an aged grey horse. A 12-year-old grey Warmblood stallion presented with fever of unknown origin, and anaemia. Five days later it had developed ataxia and become recumbent, and was humanely killed. At necropsy, malignant melanomas were identified in the perineal subcutis, spleen, and thoracic vertebral canal (T10-11). Populations of malignant melanoma cells were scattered throughout medullary cavities of the axial and appendicular skeleton, and were identified grossly as irregular areas of black to grey discoloration. To the authors' knowledge, this is the first report of disseminated intramedullary melanoma in a...
Evaluation of the effects of omeprazole on physiological indices of performance of horses during incremental treadmill exercise. Omeprazole is a proton-pump inhibitor recently approved in the United States for the treatment of gastric ulcer disease in horses. A study was designed to determine the effects of omeprazole treatment on the physiological indices of performance of horses during incremental treadmill exercise. In a crossover-design study carried out over 2 weeks, five horses completed standardized incremental exercise tests on a high-speed treadmill either with no treatment or treatment with omeprazole. No statistically significant effects of omeprazole were found on the mean maximum responses for specific oxyg...
Safety of an oral chondroprotective agent in horses. Six healthy, adult female horses were administered five times the minimum maintenance dose of an oral low-molecular-weight chondroitin sulfate, glucosamine HCl, and manganese ascorbate chondroprotective agent (Cosequin; Nutramax Laboratories, Inc., Edgewood, MD) daily for 35 days. Hematology, serum biochemistry, and synovial fluid parameters were assessed twice prior to administering the product and again at the end of the treatment period. Physical examinations performed daily throughout the study showed no abnormal clinical changes attributable to the product. All hematologic parameters meas...
Lymphocyte phenotype subsets in the cerebrospinal fluid of normal horses and horses with equine protozoal myeloencephalitis. The percentages of T-lymphocytes, lymphocyte subsets CD4+ and CD8+ T-cells, and lymphocyte adhesion molecule CD11a/CD18 were determined in the peripheral blood and cerebrospinal fluid (CSF) of seven normal horses and four horses with equine protozoal myeloencephalitis (EPM) using flow cytometry. There was a greater percentage of CD5+ cells in the CSF (79.0%) than in peripheral blood (67.0%), although this did not achieve statistical significance. Furthermore, the lymphocyte population in CSF comprises a significantly greater (P = .01) percentage of CD8+ T-cells, resulting in a decrease of the ...
Effect of two anaesthetic regimens on airway nitric oxide production in horses. There is evidence that halothane inhibits nitric oxide synthase in vitro, but the effect of intravenous anaesthetic agents is less clear. This study was undertaken to compare the rate of exhaled nitric oxide production (VNO) in spontaneously breathing horses anaesthetized with halothane or an intravenous regimen. Seven adult horses were studied twice in random order. After premedication with romifidine 100 microg kg(-1), anaesthesia was induced with ketamine 2.2 mg kg(-1) and maintained with halothane in oxygen (HA) or by an intravenous infusion of ketamine, guaiphenesin and romifidine (IV). I...
The effects of ph, osmolarity and urine contamination on equine spermatozoal motility. Urospermia has been reported as a cause of infertility in numerous species. The detrimental effects of urine on spermatozoa are due, at least in part, to changes in pH and osmolarity. Semen was collected and subjected to conditions of varying pH (Experiment 1), of varying osmolarity (Experiment 2), and various quantities and concentrations of urine (Experiment 3) and effects on motility were recorded. Finally, semen was contaminated with urine and then either of 2 semen extenders was added, with or without centrifugation, in an attempt to alleviate the detrimental effect of urine on motility (...
Effect of antioxidants on preservation of motility,viability and acrosomal integrity of equine spermatozoa during storage at 5 degrees C. Preservation of liquid semen at 5 degrees C is an important technique in the breeding management of horses. Oxidative damage to spermatozoa during storage is a potential cause of the decline in motility and fertility during hypothermic storage of liquid semen. The objective of this study was to evaluate the use of water-soluble and lipid-soluble antioxidants to improve the maintenance of motility of equine spermatozoa at 5 degrees C during storage for 72 to 96 h. In Experiment 1, the effect of addition of catalase on the maintenance of motility, viability and acrosomal integrity was determined...
Radiculomeningomyelitis due to Halicephalobus gingivalis in a horse. An adult horse was euthanatized following a clinical diagnosis of cauda equina neuritis. Significant gross postmortem and histopathologic findings were limited to the sacral spinal cord and cauda equina. The sacral spinal cord, meninges, and spinal nerve roots were expanded and partially effaced by sclerosing granulomatous inflammation with necrosis. The lesion contained numerous nematode larvae and fewer adults with a rhabditiform esophagus having a corpus, isthmus, and valved bulb. Female nematodes were amphidelphic and didelphic with reflexed ovaries. These morphologic features confirm Hali...
Administration of bovine, porcine and equine growth hormone to the horse: effect on insulin-like growth factor-I and selected IGF binding proteins. This study investigated the biochemical effects of administration of three types of recombinant growth hormone (GH; somatotropin) to the Thoroughbred horse. Equine or bovine or porcine GH was administered at a recommended dosage to 3-5-year old Thoroughbred geldings, for up to 21 days. It was shown that, in addition to equine GH, bovine and porcine GH were active in the horse; however, porcine GH caused injection-site reactions that were so serious that administration had to be terminated. The concentrations of a range of GH-related serum protein markers were determined before, during and afte...
Immortalization of equine trophoblast cell lines of chorionic girdle cell lineage by simian virus-40 large T antigen. Immortalized cell lines have many potential experimental applications including the analysis of molecular mechanisms underlying cell-specific gene expression. We have utilized a recombinant retrovirus encoding the simian virus-40 (SV-40) large T antigen to construct several immortalized cell lines of equine chorionic girdle cell lineage - the progenitor cells that differentiate into the equine chorionic gonadotropin (eCG) producing endometrial cups. Morphologically, the immortalized cell lines appear similar to normal chorionic girdle cells. Derivation of the immortalized cell lines from a cho...
A reduction in interstitial cells of Cajal in horses with equine dysautonomia (grass sickness). Equine dysautonomia (grass sickness) is a common, frequently fatal disease of horses characterised by dysfunction of the gastrointestinal tract. Interstitial cells of Cajal are the c-Kit-immunoreactive cells responsible for the generation of pacemaker activity in gastrointestinal smooth muscle. Impairment of this pacemaker action has been implicated in several motility disorders in humans and laboratory mammals. The aim of this study was to test the hypothesis that changes in interstitial cells of Cajal may be involved in the pathophysiology of the intestinal dysfunction observed in equine gra...
Epidemiology of equine grass sickness: a literature review (1909-1999). The geographical spread of grass sickness between 1909 and 1999, particularly in England and Wales, is described, and the experimental investigations to identify a causal agent are summarised. The epidemiological techniques used to investigate grass sickness vary from clinical observations, to more advanced methods such as case-control studies using logistic regression analyses. Several risk factors for grass sickness have been reported consistently (age, time of year and recent movement to new pasture or premises) and several others have been reported for which the findings remain inconsisten...
Muscle glycogen depletion and subsequent replenishment affect anaerobic capacity of horses. The purpose of this study was to determine the effect of muscle glycogen depletion and subsequent replenishment on anaerobic capacity of horses. In a blinded crossover study, seven fit horses performed glycogen-depleting exercise on two occasions. Horses were infused after glycogen-depleting exercise with either 6 g/kg body wt of glucose as a 13.5% solution in 0.9% NaCl (Glu) or with 0.9% NaCl (Sal) of equivalent volume. Subsequently, horses performed a high-speed exercise test (120% of maximal rate of oxygen consumption) to estimate maximum accumulated oxygen deficit. Replenishment of muscle ...
Determination of the acid-base status in 50 horses admitted with colic between December 1998 and May 1999. The purpose of the present study was to investigate the acid-base status and the concentration of organic acids in horses with colic caused by various disorders. Blood samples were collected from 50 horses with colic and from 20 controls. No intravenous fluids had been given prior to sample collection. Identified causes of colic included gastric ulceration, small intestinal volvulus, cecal intussusception, cecal rupture, colonic impaction, left dorsal colon displacement, right dorsal colon displacement, colonic volvulus, colitis, peritonitis, and uterine torsion. Thirty-seven horses recovered ...
Reversed-phase liquid chromatographic method for estrogen determination in equine biological samples. Equine unsaturated estrogens are the main components of brand formulations indicated for hormonal replacement therapy in both hypogonadic and postmenopausal women. These hormones are produced by the fetoplacental unit during equine gestation. A method is described for the quantitative determination of equilenin (EL), equilin (EQ), 17alpha-dihydroequilin (17dEQ), and estrone (El) in the plasma of a pregnant mare. Blood samples are obtained weekly during pregnancy by jugular venipuncture using sodium ethylenediaminetetracetic as the anticoagulant. For the quantitation of these estrogens, plasma ...
