Equine diseases encompass a wide range of health conditions that can affect horses, including infectious diseases, metabolic disorders, and genetic conditions. These diseases can impact the overall health, performance, and well-being of horses. Common equine diseases include equine influenza, equine herpesvirus, laminitis, and equine metabolic syndrome. Diagnosis and management of these diseases often require a combination of clinical evaluation, laboratory testing, and appropriate treatment strategies. This page gathers peer-reviewed research studies and scholarly articles that explore the etiology, pathophysiology, diagnosis, and treatment options for various equine diseases, providing valuable insights for veterinarians and researchers in the field.
Sharma AK, Rajashankar KR, Yadav MP, Singh TP.The structure of mare apolactoferrin (MALT) has been determined at 3. 8 A resolution by the molecular-replacement method, using the structure of mare diferric lactoferrin (MDLT) as the search model. The MDLT structure contains two iron-binding sites: one in the N-terminal lobe, lying between domains N1 and N2, and one in the C-terminal lobe between domains C1 and C2. Both lobes have a closed structure. MALT was crystallized using the microdialysis method with 10%(v/v) ethanol in 0.01 M Tris-HCl. The structure has been refined to a final R factor of 0.20 for all data to 3.8 A resolution. Compar...
Raudsepp T, Chowdhary BP.A pilot study comparing horse and donkey karyotypes on a molecular basis was initiated using the chromosomal microdissection approach. All equine meta- and submetacentric chromosomes, viz. ECA1 to ECA13 and the X and Y chromosomes, were microdissected. The DNA was PCR amplified, non-radioactively labelled and used as probes on equine metaphase chromosomes to confirm their origin. Once tested, the paints were used as probes on donkey metaphase chromosomes to detect homologous chromosomal segments between the two species. The results not only detected conservation of whole chromosome and/or arm ...
Toribio RE, Kohn CW, Lawrence AE, Hardy J, Hutt JA.A 5-year-old Quarter Horse mare was examined because of lethargy, fever, and weight loss of 1 month's duration. Thoracic auscultation revealed decreased lung sounds cranioventrally. Thoracic ultrasonography revealed bilateral anechoic areas with hyperechoic strands, consistent with pleural effusion and fibrin tags. A large amount of free fluid was evident during abdominal ultrasonography. Abnormalities included anemia, hyperproteinemia, hyperglobulinemia, hyperfibrinogenemia, and hypoalbuminemia. Thoracic radiography revealed alveolar infiltrates in the cranial and caudoventral lung fields. A ...
Dávila AM, Souza SS, Campos C, Silva RA.Since little information is available on the epizootiological status of Trypanosoma evansi in South America and particularly Brazil, we evaluated equine serum samples collected in 1993, 1994, 1995 and 1997 for the presence of antibodies against this trypanosome species. Our study shows corroborative evidence about the correlation among high T. evansi seroprevalence and the rainy season in the Pantanal, Brazil. The higher seroprevalence was 79.2% in horses from a ranch located in the Nhecolândia sub-region in 1994 and the lower 5.8% in animals from the same ranch in 1997. No seroprevalence was...
van Schie JT, Bakker EM, van Weeren PR.The objective of the in vitro experiments described in this paper was to quantify the effects of some instrumental variables on the quantitative evaluation, by means of first-order gray-level statistics, of ultrasonographic images of equine tendons. The experiments were done on three isolated equine superficial digital flexor tendons that were mounted in a frame and submerged in a waterbath. Sections with either normal tendon tissue, an acute lesion, or a chronic scar, were selected. In these sections, the following experiments were done: 1) a gradual increase of total amplifier gain output su...
Bragulla H.The pre- and perinatal development of the hoof cartilage is described concerning the histological structure and surrounding vessels. Beginning in the third month of fetal development, the anlage of the hoof cartilage is still present in typical shape and location. It is built out of mesenchymal connective tissue. During further fetal development, the connective tissue cells will differentiate into two cell populations, fibroblasts and chondroblasts. Vessels, traversing the hoof cartilage, are surrounded by loose connective tissue, which will partially develop fibrocartilage. At birth, hoof car...
Cutler TJ, MacKay RJ, Ginn PE, Greiner EC, Porter R, Yowell CA, Dame JB.Equine protozoal myeloencephalitis (EPM) is a debilitating neurologic disease of the horse. The causative agent. Sarcocystis neurona, has been suggested to be synonymous with Sarcocystis falcatula, implying a role for birds as intermediate hosts. To test this hypothesis, opossums (Didelphis virginiana) were fed muscles containing S. falcatula sarcocysts from naturally infected brown-headed cowbirds (Molothrus ater). Ten horses were tested extensively to ensure no previous exposure to S. neurona and were quarantined for 14 days, and then 5 of the horses were each administered 10(6) S. falcatula...
Blythe LL, Engel HN.Components of the equine nervous system are described including classical anatomy and newer sensory innervation maps that are useful for localizing lesions to and within the nervous system. The key components in a neurological examination that help differentiate primary neurologic disease from musculoskeletal disorders are explained. Gait deficits associated with neurologic dysfunction are listed as well as diagnostic aids and an overview of differential diagnoses.
Weaver MP, Jeffcott LB, Nowak M.Radiology and, more recently, scintigraphy are important ancillary diagnostic aids in the diagnosis of a horse with suspected back pain. Although the image quality is restricted by the size of the patient, radiographs have been used for several decades. With the introduction of modern fast-screen film systems, the quality of the images has greatly improved. These imaging techniques allow assessment of the anatomy and physiology of structures in the spine that are difficult or impossible to palpate. This article reviews the techniques and limitations of imaging the equine back, in addition to c...
Haussler KK.Pathologic changes have been observed at the spinous processes, intervertebral articulations, and sacroiliac joints in horses. Varying severity of degenerative articular changes are found in many articular processes, intertransverse, lumbosacral, and sacroiliac joints. Pathologic lesions tend to affect multiple vertebral locations within a specimen. Further studies need to be conducted to evaluate the clinical significance of the numerous vertebral and pelvic pathologic findings found in a sample of Thoroughbred racehorses that died because of unrelated injuries. Increased knowledge of osseous...
Haussler KK.A thorough knowledge of equine spinal anatomy, biomechanics, and potential pathology is required to understand the principles and theories behind chiropractic and to apply its techniques properly. Chiropractic provides additional diagnostic and therapeutic means that may help equine practitioners to identify and treat the primary cause of lameness or poor performance. Specialized training in the evaluation and treatment of vertebral joint dysfunction and neuromusculoskeletal disorders places chiropractic in the forefront of conservative treatment of spinal-related disorders. Nevertheless, limi...
Ridgway K, Harman J.This article introduces the importance of considering all related physical findings, evaluating the whole horse and determining the root cause in order to achieve the best treatment results, prevent recurrence, and return the patient to full function. The roles of shoeing, turnout, teeth, training aids and devices, compensatory lameness, working surface (footing), longing, ponying, hot walkers, and swimming are discussed in relationship to back dysfunction and rehabilitation. Postural analysis and measures for muscle and postural corrections are also presented. Ground and under saddle rehabili...
Valberg SJ.Clinical signs that are easily referred to spinal muscle pathology include atrophy of epaxial muscles, focal swelling and palpable tenderness, as well as enlarged muscles with increased tone. Less easily recognized signs include rigidity of the spine, shortened stride, hindlimb lameness, and indicators of poor performance. Muscle biopsy is one option in evaluating sore backs and is best used when physical examination and imaging procedures do not reveal a likely diagnosis or when conventional treatments are unsuccessful. Rhabdomyolysis of spinal muscles may be due to nutritional myodegeneratio...
Denoix JM.Knowledge of the normal functional behavior and mechanical properties of the vertebral column is important to understand the pathogenesis of back lesions, to identify the clinical manifestations of back pain, and to ensure a rational approach to physical therapy. The purpose of this article is to present a synthesis of in vivo and in vitro data obtained from different but complementary investigations. Presently, in vivo studies are limited; few gait-specific kinematic and electromyographic investigations are in process. Higher stresses to reach the maximal range of intervertebral motion can be...
Graf von Schweinitz D.Infrared thermographic imaging (ITI) is the most sensitive objective imaging currently available for the detection of back disease in horses. It is, however, only a physiological study primarily of vasomotor tone overlying other superficial tissue factors. Interpretation requires extreme care in imaging protocol and in understanding the significance of altered sympathetic nervous tone and the sympathetic distribution. Most discussions on back pain have centered on nociception and inflammatory events. ITI provides information and localization for more significant than diagnosing areas of hot sp...
Jeffcott LB.This article is presented as an introduction to the complex subject of back pain and its management in horses. It considers some of the historical perspectives and deals with some of the limiting factors when attempting to evaluate back pain. The clinical indications of a back problem are considered, as is the important distinction of primary versus secondary back pain. Finally, a list of considerations capable of causing back pain and impaired performance is included.
Riggs CM, Whitehouse GH, Boyde A.This study examined material from Thoroughbred horses, the majority of which had been in race training, for evidence of pathology in the third metacarpal (McIII) and third metatarsal (MtIII) bones which might be related to the occurrence of distal condylar fractures. Whole bone samples were studied and documented by macrophotography prior to macroradiography and computed tomographic (CT) imaging. Microradiographs were made from 100 microm thick mediolateral sections cut perpendicular to the dorsal and palmar/plantar articular surfaces of distal condylar regions of McIII and MtIII. Blocks were ...
Riis RC, Jackson C, Rebhun W, Katz ML, Loew E, Summers B, Cummings J, de Lahunta A, Divers T, Mohammed H.The characteristics of the ocular manifestations of equine motor neuron disease (EMND) are described. Forty-two horses with histories, clinical signs and necropsies compatible with EMND were the subjects of this study. Ophthalmoscopic lesions that varied in severity were found in 40 of 42 horses and appeared as a distinct pigmented reticulated pattern at the tapetal-nontapetal junction or throughout the fundus, depending upon severity. The pattern colours ranged from yellow brown to black. Areas of hyperreflectivity formed mosaic patterns in the tapetal fundus. ERG B-wave amplitudes were usual...
Firth EC, Delahunt J, Wichtel JW, Birch HL, Goodship AE.This study was performed to test the hypothesis that a localised bone hypertrophy could occur within the subchondral cancellous architecture of the third and radial carpal bones. Using 2 levels of controlled and defined exercise, it was observed that a high intensity treadmill exercise protocol resulted in functional adaptation of the carpal bones. The increase in trabecular thickening and density was seen to be localised to those regions underlying common sites of cartilage degradation, the interface of the thickened trabeculae with the normal architecture in the third carpal bone was coincid...
Hammond RA, Hannon R, Frean SP, Armstrong SJ, Flower RJ, Bryant CE.To determine the amount of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) enzymes induced in vitro in equine alveolar macrophages in response to lipopolysaccharide (LPS). Sample Population-Alveolar macrophages obtained from 12 horses. Methods: Alveolar macrophages were collected by bronchoalveolar lavage from 12 horses and incubated for 6 hours with LPS (0.001 to 10 microg/ml) or vehicle. Total RNA was extracted and purified. After first-strand cDNA synthesis, mRNA induction was measured, using a polymerase chain reaction (PCR) technique for COX-2, iNOS, and glyceraldehyde...
Votion DM, Vandenput SN, Duvivier DH, Lambert P, van Erck E, Art T, Lekeux PM.To assess sensitivity of scintigraphic alveolar clearance rate as an indicator of alveolar epithelium damage in horses. Methods: 5 healthy horses (group A) and 5 with chronic obstructive pulmonary disease (COPD; group B). Methods: Horses underwent clearance rate (k [%/min]) determination. Clearance rate of group-B horses was determined after remission of the disease following 2 months at pasture (remission 1), stabling in a controlled environment (remission 2), and during crisis induced by exposure to moldy hay and straw. Methacholine challenge test was performed at each investigation period t...
Wijnberg ID, van der Kolk JH, Hiddink EG.Two miniature Shetland ponies showing clinical signs of Digitalis purpurea (foxglove) poisoning were examined. One animal died shortly afterwards, but the second was treated successfully with the anti-arrhythmic agent, phenytoin, and was discharged after 16 days.
Arun S, Neubauer H, Gürel A, Ayyildiz G, Kusçu B, Yesildere T, Meyer H, Hermanns W.In the course of an epidemiological study of glanders on a number of Turkish islands in the Sea of Marmara, 1128 horses were examined by using the intracutaneous mallein test. Thirty-five (3-1 per cent) developed an increase in rectal temperature and a swelling at the point of injection. Ten of these horses were killed and glanders was confirmed in five cases by the presence of lesions and by the immunohistological demonstration of the causative agent, Burkholderia mallei. Clinical and pathological findings indicated that in all cases the infection was restricted to the mucous membrane of the ...
Stockenström S, Sydenham EW, Shephard GS.The widespread occurrence of F. moniliforme and the toxic effects of its secondary metabolites, the fumonisins B1(FB1), B2(FB2) and B3(FB3), make it imperative that fumonisin contamination of maize, a major constituent of animal feed as well as the staple diet of many populations, be closely monitored to reduce the risk of fumonisin exposure. Equine leukoencephalomalacia and porcine pulmonary oedema have been associated with the intake of feed heavily contaminated with fumonisins. In addition, high levels of fumonisins in the maize-based staple diets of certain populations have been linked to ...
Grieder FB, Vogel SN.To investigate the role of type I interferon (IFN) and its regulatory transacting proteins, interferon regulatory factors (IRF-1 and IRF-2), in early protection against infection with virulent Venezuelan equine encephalitis virus (VEE), we utilized mice with targeted mutations in the IFN-alpha/beta receptor, IRF-1, or IRF-2 genes. IFN-alpha/beta-receptor knockout mice are highly susceptible to peripheral infection with virulent or attenuated VEE, resulting in their death within 24 and 48 h, respectively. Treatment of normal macrophages with anti-IFN-alpha/beta antibody prior to and during infe...
Brook D.A case of what can be presumed to be secondary nutritional hyperparathyroidism, due to high phosphorus diet, in a six year old pony is discussed. The findings are compared to those found when the disease occurs in young growing horses.
Wauters J, Martens A, Pille F, Dumoulin M, Gasthuys F, Sys S, Meyer E.Synovial fluid samples from culture-confirmed infected joints (n=13), joints with pronounced non-infectious synovitis (n=11) and healthy joints (n=14) were collected from 24 equine patients and seven slaughterhouse horses. The samples from the joints with non-infectious synovitis and healthy joints served as negative controls. After isolation, counting and identification of neutrophils, the percentage viability, and the proportion apoptotic and necrotic neutrophils were determined by flow cytometry. Viability was significantly higher in infected samples compared to the controls. A significant ...
Irwin CF.A total of 487 Standardbred and Thoroughbred mares at two studs were manually tested for pregnancy at 20 to 24, 30 to 34, and greater than 42 days after service and the abortion rate compared to that obtained in previous years when only the greater than 42-day test was performed. The results indicated that early manual pregnancy testing does not increase the abortion rate if undertaken carefully and enables non-pregnant mares to be re-mated earlier in the same season.
Luo Y, Uboh CE, Soma LR, Guan FY, Rudy JA, Tsang DS.A method for the simultaneous separation, identification, quantification and confirmation of the presence of 21 glucocorticoids (GCC) in equine plasma by liquid chromatography coupled with triple stage quadrupole tandem mass spectrometry (LC/TSQ-MS/MS) is described. Plasma sample augmented with the 21 GCC was extracted with methyl tert-butyl ether (MTBE) and analyzed by positive electrospray ionization. Desoxymetasone or dichlorisone acetate was used as the internal standard (IS). Quantification was performed by IS calibration. For each drug, one major product ion was chosen and used for scree...
Van Pelt RW, Langham RF, Gill HE.A 2-year-old Standardbred colt with a history of intermittent lameness of the left hindlimb had hemangiosarcomatous involvement of the tarsal synovial sheath. Tibiotarsal and proximal intertarsal synovial sacs were visibly distended and there was pronounced distension of the tarsal synovial sheath. A large, firm mass was palpable in the sheath at about the level of the tuber calcis. Three circumscribed sessile growths were surgically excised from the sheath. The growths were lobulated, moderately vascular, and of fibrotic consistency. Microscopically, the pattern of the hemangiosarcomas appear...
Flynn C, Forster HV, Pan LG, Bisgard GE.The objective of this study was to determine the role of hilar nerve (lung vagal) afferents in the hyperpnea of exercise. Ten ponies were studied before and 2-4 wk and 3-12 mo after sectioning only the hilar branches of the vagus nerves (HND). After HND, lung volume feedback to the medullary centers was attenuated as indicated in the anesthetized state by 1) attenuation or absence of the Hering-Breuer inflation reflex (P less than 0.01) and 2) attenuation of the lengthened inspiratory time (TI) when the airway was occluded at end expiration (P less than 0.01). Moreover, after HND in the awake ...
Pezzanite LM, Hackett ES, McCready E, Easley JT.Bilateral sinus disease is relatively uncommon in horses, accounting for 3%-4.5% of horses with sinonasal disease, but may require bilateral paranasal surgery for complete resolution. Complications and recurrence following bilateral sinusotomy have not been reported or compared to those following unilateral procedures. To describe clinical features and outcomes in horses undergoing standing single, caudally based bilateral frontonasal sinusotomy compared to unilateral frontonasal surgery. Records of horses (n = 37) undergoing surgical treatment for sinus disease (five bilateral, 32 unilatera...
Wang L, Tong G, Liu H, Yang Z, Qiu H, Kong X, Wang M.Proviral DNA was extracted from donkey leukocyte infected with Chinese donkey leukocyte attenuated equine infectious anemia virus (DLA-EIAV), and peripheral blood lymphocytes (PBL) from a horse infected with the virulent EIAV strain Liaoning (EIAV L). The entire proviral DNA from both viruses was cloned and sequenced. The lengths of complete genomic sequences of DLA-EIAV and EIAV L provirus were 8266 bp and 8235 bp, respectively. Sequence comparison indicated that DLA-EIAV shares 97.0% and 97.5% in sequence homology with EIAV L and donkey-adapted EIAV (DA-EIAV), respectively. Lots of variation...
Parente EJ, Martin BB, Tulleners EP.Many disorders of the upper respiratory tract which cause severe
respiratory compromise and poor performance have been
described in the equine athlete (Williams et al. 1990; Morris 1991;
King et al. 1994). Until recently, the diagnosis of upper respiratory
tract dysfunction was based on observations made during resting
endoscopic examination; and conclusions regarding the extent and
exact nature of the dysfunction during exercise were often
inaccurate. This report describes 2 horses presented to the George
D. Widener Hospital in which no significant abnormalities were
noted during res...
Bertone AL, Stashak TS, Sullins KE.Large colon resection and anastomosis was performed in 11 horses at various levels of the colon, using several surgical methods. The level of resection ranged from the pelvic flexure to the cecocolic ligament. Nine of 11 horses survived and at follow-up (4 months to 7 years) were free of clinical signs referable to disease of the gastrointestinal tract. Seven horses could be evaluated as to athletic or reproductive function and all returned to original potential.