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.
Vanniasinkam T, Barton MD, Heuzenroeder MW.Rhodococcus equi is a significant pathogen in foals predominantly causing a pyogranulomatous bronchopneumonia. Many vaccine candidates have been tested for the prevention of R. equi disease in foals. However, none of these have been developed for widespread commercial use. Previous studies have shown that a Th1 immune response is imperative for the protection of foals against R. equi disease. In this study a DNA and a protein vaccine based upon the well-characterised R. equi virulence-associated protein VapA were developed. The vaccines were tested in the BALB/c murine model and the results sh...
Saville WJ, Dubey JP, Oglesbee MJ, Sofaly CD, Marsh AE, Elitsur E, Vianna MC, Lindsay DS, Reed SM.Sarcocystis neurona and Sarcocystis fayeri infections are common in horses in the Americas. Their antemortem diagnosis is important because the former causes a neurological disorder in horses, whereas the latter is considered nonpathogenic. There is a concern that equine antibodies to S. fayeri might react with S. neurona antigens in diagnostic tests. In this study, 4 ponies without demonstrable serum antibodies to S. neurona by Western immunoblot were used. Three ponies were fed 1 x 10(5) to 1 x 10(7) sporocysts of S. fayeri obtained from dogs that were fed naturally infected horse muscles. A...
Luo Y, Uboh CE, Soma LR, Guan F, Rudy JA, Tsang DS.This method describes the simultaneous separation, identification, quantification and confirmation of betamethasone (BTM) and dexamethasone (DXM) in equine plasma by liquid chromatography (LC) integrated with multidimensional tandem mass spectrometry. Analytes were directly extracted from equine plasma by methyl tert-butyl ether (MTBE). The residues were reconstituted with sample solvent. LC separation of the analytes was performed on a Hypercarb column using acetonitrile/water/formic acid (95:5:0.5, v/v/v) as the mobile phase. Sample screening, quantification and confirmation were performed i...
Craigo JK, Li F, Steckbeck JD, Durkin S, Howe L, Cook SJ, Issel C, Montelaro RC.Among the diverse experimental vaccines evaluated in various animal lentivirus models, live attenuated vaccines have proven to be the most effective, thus providing an important model for examining critical immune correlates of protective vaccine immunity. We previously reported that an experimental live attenuated vaccine for equine infectious anemia virus (EIAV), based on mutation of the viral S2 accessory gene, elicited protection from detectable infection by virulent virus challenge (F. Li et al., J. Virol. 77:7244-7253, 2003). To better understand the critical components of EIAV vaccine e...
Cohen ND, O'Conor MS, Chaffin MK, Martens RJ.To identify farm characteristics and management practices associated with development of Rhodococcus equi pneumonia in foals. Methods: Prospective case-control study. Methods: 5230 foals on 138 breeding farms with 9136 horses. Methods: During 2003, participating veterinarians provided data from 1 or 2 farms with > or =1 foal with R equi pneumonia and unaffected farms. Data from affected and unaffected farms were compared by use of logistic regression analysis. Results: A number of variables relating to farm size and desirable management practices were significantly associated with increased od...
Janicek JC, Dabareiner RM, Honnas CM, Crabill MA.To determine clinical history, structures involved, treatment, and outcome of lacerations of the heel bulb and proximal phalangeal region (pastern) in horses. Methods: Retrospective study. Methods: 101 horses. Methods: Medical records of horses with lacerations of the heel bulb and pastern were reviewed, and follow-up information was obtained. Results: 75 horses were Quarter Horses. Most horses were not treated with antimicrobial drugs prior to referral. Mean +/- SD time from injury to referral was 24 +/- 45 hours (range, 1 to 168 hours). Lacerations were most frequently caused by contact with...
Seco Diaz O, Desrochers A, Hoffmann V, Reef VB.An 8-day-old Arabian-Morgan cross colt underwent cardiac evaluation. The foal was tachycardic, tachypneic, exercise intolerant and had a loud right-sided heart murmur and cyanotic mucous membranes. Total anomalous pulmonary venous connection was diagnosed with echocardiography and confirmed at postmortem examination. Total anomalous pulmonary venous connection is a very rare congenital cardiac abnormality that has not been reported before in the horse.
Harland MM, Fedele C, Berens v Rautenfeld D.Horses are highly susceptible to lymphedema. Knowledge of the morphological components of lymphatic collectors is therefore essential to understanding the function of the lymphatic system. A better knowledge of the lymphatic system allows the development of more effective treatments against lymphedema. The composition of hypodermal and deep lymphatic collectors was investigated with immunohistochemical staining, using antibodies against proteins of the collector walls from the skin in the hind limbs of 10 healthy horses. Lymphatic collectors can be subdivided into passive (elastic fibers) and ...
Liu IK, Turner JW, Van Leeuwen EM, Flanagan DR, Hedrick JL, Murata K, Lane VM, Morales-Levy MP.In this study of equids, we investigated the antibody response and the effect on the estrous cycle following a single inoculation of porcine zonae pellucidae (pZP) employing controlled-release methodology. We also investigated the use of two different water-soluble adjuvants as an alternative to oil-based adjuvants. Twenty-seven domestic mares were inoculated with various formulations of pZP and adjuvant. We showed that the anti-pZP antibodies generated as a result of the inoculations persisted for at least 43 weeks (length of the study). Of the various formulations used in the study, pZP and ...
Little CB, Flannery CR, Hughes CE, Goodship A, Caterson B.To determine whether the focal susceptibility to cartilage degeneration in joints is related to a differential response to cytokine stimulation. Methods: Compare aggrecan and collagen catabolism in in-vitro models of cartilage degradation induced by retinoic acid (RA), interleukin-1 (IL-1), tumor necrosis factor alpha (TNF) and IL-1 plus oncostatin M (OSM). Glycosaminoglycan (GAG) and hydroxyproline (HyPro) quantification and Western immunoblot analyses of aggrecan and collagen degradation products were undertaken in explant cultures of normal cartilage from regions of equine joints with a kno...
Jann H, Pasquini C.The authors describe the clinically relevant structures of the distal limb and the current diagnostic and treatment modalities. Specific problems include tendon laceration, septic tenosynovitis, and sep-tic arthritis of the distal joints. A detailed description of tendon repair, tendon sheath lavage, and postoperative convalescent methodology is provided. This article makes available to the reader information necessary to appropriately diagnose and treat wounds of the distal equine limb involving deep structures. Information on the overall prognosis is also provided.
Céleste CJ, Szöke MO.Hoof injuries are common in horses. Some wounds can pose diagnostic and treatment challenges because of the rigid nature of horn,the tissue involved, the deeper underlying structures eventually invaded, or the pattern of healing. By combining knowledge about the anatomy and biomechanical properties of the foot and healing characteristics of the hoof with adapted general principles of wound management, satisfactory clinical outcomes usually result.
Theoret CL.The equine practitioner who is presented with a wounded horse should fully understand the physiologic mechanisms involved in repair so as to design an appropriate treatment plan. In the following articles of this issue,experienced authors share their thoughts on the management of specific injuries, and the reader should benefit from acquisition of knowledge about the different phases of healing as well as the cytokines that regulate them,because these data dictate the approach to follow, particularly in com-plicated wounds, such as those afflicted by chronic inflammation and/or an excessive pr...
Bolin DC, Donahue JM, Vickers ML, Harrison L, Sells S, Giles RC, Hong CB, Poonacha KB, Roberts J, Sebastian MM, Swerczek TW, Tramontin R, Williams NM.During the spring and summer of 2001 and in association with the mare reproductive loss syndrome, 22 terminal and 12 clinical cases of equine pericarditis were diagnosed in central Kentucky. Actinobacillus species were the principal isolates from 8 of 10 nontreated, terminally affected and 3 of 10 clinically affected horses. Enterococcus faecalis and Streptococcus zooepidemicus were cultured from the remaining 2 nontreated terminal cases. No viruses were isolated in tissue culture. Nucleic acid of equine herpesvirus-2 was detected in pericardial and tracheal wash fluids of 3 and 1 individuals,...
Wilmink JM, van Weeren PR.Second-intention repair is faster in ponies than in horses and faster in body wounds than in limb wounds. To a large extent, the differences between horses and ponies can be explained by differences in the local inflammatory response, which are a result of the functional capacity of leukocytes. In ponies, leukocytes produce more inflammatory mediators,resulting in better local defense, faster cellular debridement, and a faster transition to the repair phases, with more wound contraction. In horses,leukocytes produce fewer mediators, initiating a weak inflammatory response, which becomes chroni...
Thompson JA, Brown SE, Riddle WT, Seahorn JC, Cohen ND.To estimate spatial risks associated with mare reproductive loss syndrome (MRLS) during 2001 among horses in a specific study population and partition the herd effects into those attributable to herd location and those that were spatially random and likely attributable to herd management. Animals-Pregnant broodmares from 62 farms in 7 counties in central Kentucky. Methods: Veterinarians provided the 2001 abortion incidence proportions for each farm included in the study. Farms were georeferenced and data were analyzed by use of a fully Bayesian risk-mapping technique. Results: Large farm-to-fa...
Doyle AJ, Stewart AA, Constable PD, Eurell JA, Freeman DE, Griffon DJ.To determine effects of sodium hyaluronate (HA) on corticosteroid-induced cartilage matrix catabolism in equine articular cartilage explants. Methods: 30 articular cartilage explants from fetlock joints of 5 adult horses without joint disease. Methods: Articular cartilage explants were treated with control medium or medium containing methylprednisolone acetate (MPA; 0.05, 0.5, or 5.0 mg/mL), HA (0.1, 1.0, or 1.5 mg/mL), or both. Proteoglycan (PG) synthesis was measured by incorporation of sulfur 35-labeled sodium sulphate into PGs, and PG degradation was measured by release of radiolabeled PGs...
Benton HP, Esquivel AV, Rice AD, Giri SN.Pirfenidone is under investigation as an anti-inflammatory and anti-fibrotic agent in several organs including lung. Since important features of arthritic conditions include inflammation and long-term damage to articular cartilage, we have investigated whether PD can suppress chondrocyte responses to bacterial lipopolysaccharide (LPS) and interleukin 1 (IL-1); modulators that induce a cascade of inflammatory responses that lead to articular joint tissue damage. PD (0 - 5microM) showed no effect on cell number or viability when incubated with high density primary equine chondrocyte cultures for...
Hodgkinson JE, Freeman KL, Lichtenfels JR, Palfreman S, Love S, Matthews JB.The efficacy of five daily fenbendazole (FBZ) treatments was tested against benzimidazole-resistant cyathostomins in naturally infected horses (n=13). Horses were treated with pyrantel embonate (PYR) to remove adult strongyles followed, 7 days later, by a 5-day course of FBZ. The PYR treatment produced an average faecal egg count reduction of 98%. All samples were negative by faecal egg count 7 days after the start of the FBZ treatment. Positive egg counts were observed from 28 days after the start of FBZ treatment and all horses displayed positive faecal egg counts by 77 days after treatment....
Gustafson-Seabury A, Raudsepp T, Goh G, Kata SR, Wagner ML, Tozaki T, Mickelson JR, Womack JE, Skow LC, Chowdhary BP.High-resolution gene maps of individual equine chromosomes are essential to identify genes governing traits of economic importance in the horse. In pursuit of this goal we herein report the generation of a dense map of horse chromosome 22 (ECA22) comprising 83 markers, of which 52 represent specific genes and 31 are microsatellites. The map spans 831 cR over an estimated 64 Mb of physical length of the chromosome, thus providing markers at approximately 770 kb or 10 cR intervals. Overall, the resolution of the map is to date the densest in the horse and is the highest for any of the domesticat...
Xu J, Lasry JB, Svaren J, Wagner B, Darien BJ.P-selectin glycoprotein ligand-1 (PSGL-1, CD162) is a dimeric, mucin-like, transmembrane glycoprotein constitutively expressed on leukocytes. A high baseline level of P-selectin expression in circulating equine platelets suggests a primed state toward inflammation and thrombosis via P-selectin/PSGL-1 adhesion. To investigate the potential role of equine P-selectin in these events, we first identified the cDNA sequence of equine PSGL-1 (ePSGL-1) using degenerate PCR and RACE-PCR and then compared the predicted sequence with that of human PSGL-1 (hPSGL-1). ePSGL-1 protein subunit is predicted to...
Gibson VA, Stover SM, Gibeling JC, Hazelwood SJ, Martin RB.We hypothesized that recently formed, incompletely mineralized, and thus, relatively deformable osteons in the equine third metacarpus enhance in vitro load-controlled fatigue life in two ways. Macroscopically, there is a compliance effect, because reduced tissue elastic modulus diminishes the stress required to reach a given strain. Microscopically, there is a cement line effect, in which new osteons and their cement lines more effectively serve as barriers to crack propagation. We studied 18 4 x 10 x 100 mm beams from the medial, lateral, and dorsal cortices of metacarpal bones from 6 thorou...
Estrada-Franco JG, Navarro-Lopez R, Freier JE, Cordova D, Clements T, Moncayo A, Kang W, Gomez-Hernandez C, Rodriguez-Dominguez G, Ludwig GV....Equine epizootics of Venezuelan equine encephalitis (VEE) occurred in the southern Mexican states of Chiapas in 1993 and Oaxaca in 1996. To assess the impact of continuing circulation of VEE virus (VEEV) on human and animal populations, serologic and viral isolation studies were conducted in 2000 to 2001 in Chiapas State. Human serosurveys and risk analyses indicated that long-term endemic transmission of VEEV occurred among villages with seroprevalence levels of 18% to 75% and that medical personnel had a high risk for VEEV exposure. Seroprevalence in wild animals suggested cotton rats as pos...
Pollock RV.Advances in digital technology have vastly increased the speed and content of information transfer. Equine practitioners of the future should be in contact with their office and other information resources at all times through an array of digital networks. Patients and practitioners alike should benefit from better information access.
Garma-Aviña A, Valli VE, Lumsden JH.Four cases of equine congenital cutaneous papillomatosis were found during a review of 555 cutaneous tumours received at the pathology department, Ontario Veterinary College, during a 10-year period. A fifth case received after that period was also included. Two of the tumours were found in Thoroughbreds, one in a Standardbred, one in an Arabian and in one case the breed was not specified. The anatomical locations were the rib cage, head, hind leg and 2 on the forehead.
Archer DC, Boswell JC, Voute LC, Clegg PD.Gamma scintigraphy is a well established imaging modality, which in equine practice is predominantly used in the investigation of lameness and suspected musculoskeletal problems. Whilst there is a growing literature on the indications for scintigraphy in the horse, there has been little emphasis so far on identifying the validity of scintigraphy as a diagnostic test. In particular, to what extent can the results of a scintigraphic examination be trusted? In this opinionated review the current indications for skeletal scintigraphy in the horse are considered and its validity as a diagnostic tes...
Mazan MR.Inflammatory airway disease and recurrent airway obstruction are 2 nonseptic diseases of the equine respiratory system with a shared cause of exposure to particulate matter. They appear to occupy 2 ends of a spectrum of disease, but are differentiated by history, clinical signs, and response to treatment. Diagnosis can be made by sampling of respiratory fluids and lung function testing. Treatment consists of environmental modification and pharmacologic treatment with systemic or inhaled corticosteroids and bronchodilators.
Olszewski MA, Robinson NE, Derksen FJ.In vitro responses of equine small peripheral airways (SA) and lung parenchyma (LP) were studied. We examined their contractile and relaxant responses and investigated effects of histamine, and endogenous prostanoids as these mediators may play a role in development or recurrent airway obstruction in horses (heaves). SA and LP electrical field stimulation (EFS) induced nearly maximal and partial frequency-dependent contractions, respectively. These contractions were virtually abolished in SA but only partially inhibited in LP by atropine (ATR) and tetrodotoxin (TTX). Methacholine (MCh) contrac...
Hendrikx WM, Jansen J, de Vries TJ.An infection with second-stage larvae of the warble-fly H. diana in a horse is described. The second-stage larvae were incapable of developing into the third stage, because horses are unsuitable hosts and because the infected horse was treated with an insecticide. Since the horse was used for dragging trees in the forests, the infection was likely contracted via contact with H. diana, a normal parasite of roe deer in the Netherlands.
Menzies-Gow NJ, Bailey SR, Berhane Y, Brooks AC, Elliott J.To determine the effect of endotoxin (lipopolysaccharide [LPS]) on vasoactive mediator production by cultured equine digital vein endothelial cells (EDVECs). Methods: EDVECs obtained from forelimb digital veins of 7 healthy adult horses. Methods: EDVECs were incubated with or without LPS (1 microg/mL) for 0, 2, 4, 6, 22, and 24 hours. The EDVECs were incubated for 18 hours with LPS (10 pg/mL to 1 microg/mL) with or without ibuprofen, cycloheximide, or L-nitroarginine methyl ester. Medium concentrations of prostacyclin, cyclic guanosine monophosphate, endothelin-1, and thromboxane A(2) were det...
Polyak MM, Morton AJ, Grosche A, Matyjaszek S, Freeman DE.Several therapeutic agents have been tested in models of ischaemia and reperfusion injury (IRI) in equine jejunum, with mixed results. This study was based on the use of an organ perfusion solution (OPS) designed to protect human allografts from IRI. Objective: A modified OPS can preserve the integrity of equine large colon during 12 h of isolated pulsatile perfusion, in the absence of oxygen and blood. Methods: Segments of large colon were removed from anaesthetised horses, the contents removed and the mucosa rinsed with 0.9% saline. Experimental segments were perfused for 12 h with one litre...
Hornof WJ, Dunlop CI, Prestage R, Amis TC.Six horses were anesthetized and placed in lateral recumbency for 1 hour and then were turned to the opposite side for an additional hour. A short-lived radioactive gas, 81mKr, was used to determine the relative spatial distribution of ventilation (V) and perfusion (Q) in these horses. Effects of time, side down, and turning on the distribution were evaluated. A consistent gradient of V/Q was found at all times, with the highest V/Q values at the top (non-dependent) portion of the lung field and the lowest at the bottom (dependent). This gradient was also present within each lung, as well as b...
Colborne GR, Routh JE, Weir KR, McKendry JE, Busschers E.To determine the frontal plane position of the ground reaction force vector at its centre of pressure under the hoof of walking horses, and its projection through the distal limb joints, and to relate this to hoof geometric measurements. Methods: Reflective markers were glued to the forelimb hooves and skin of 26 horses, over palpable landmarks representing centres of the coffin, fetlock and carpal joints, and the dorsal toe at its most distal point. A 4-camera kinematic system recorded the position of these markers as the horse walked in hand across a force platform, to generate a frontal pla...
Burgess BA, Morley PS.There is a recognizable standard of practice for infection control in veterinary medicine. Effort must be given to control and prevention of infectious disease transmission within a facility and among animal populations. In the critical care setting, patients typically have a high degree of systemic illness and immune compromise, are commonly subjected to invasive procedures and placement of indwelling devices, and frequently receive antimicrobials and gastric protectants. Every equine critical care unit is distinctive in its physical and operational features and the types of patients that are...
Moran JA, Lemberger K, Cadoré JL, Lepage OM.An 11-year-old Andalusian stallion developed marked signs of colic associated with an acute small intestine obstruction. Exploratory laparotomy revealed a distal jejunum full-thickness wall induration and multiple small adherent intraluminal masses. Fifteen centimeters of jejunum, including the induration, and several intraluminal masses were resected. Histologic examination revealed an adenocarcinoma and multiple polypoid adenomas. The horse was discharged, and no complications were reported 12 months postoperatively. Colic was considered secondary to partial jejunal lumen obstruction by the ...
Milne EM, Woodman MP, Doxey DL.Forty-five cases of chronic grass sickness were given scores for selected clinical measurements when they were first examined, to assess their value in predicting survival. Sixteen cases survived. The clinical scores for the degree of dysphagia, appetite, colic and the degree of reduction in gut sounds were significantly lower in the survivors than in the non-survivors. In addition, only the non-survivors had severe rhinitis. Ponies were significantly less likely to survive than cob types.
Doxey DL, Milne EM, Ellison J, Curry PJ.Responses to questionnaires were received from 31 owners of horses or ponies treated for chronic grass sickness (dysautonomia). Contrary to previous opinions the respondents indicated that the majority of the animals were capable of strenuous work, had regained the weight they had lost and, apart from a few residual problems such as difficulty in coping with dry fibrous food, had returned to a normal life. They had recovered slowly and had involved the owners in considerable extra work, but all the owners indicated that they considered the effort to have been worthwhile.
Purdy CW, Porter RC, Ford SJ.Immunogenicity and safety of an equine herpesvirus 1 (ehv-1) vaccine were studied in 111 foals varying in age from 1 to 122 days. Each of 88 principals was given 1 im injection of vaccine. Five of the 88 foals were revaccinated; 69 of the vaccinated principals and 23 nonvaccinated foals (serving as controls) were challenge exposed intranasally with virulent ehv-1.
The vaccine failed to cause adverse local or systemic reaction in 88 principals with serunirneutralization (sn) titers against ehv-1 varying between 0 to 1:256 at time of vaccination. After vaccination, the foals' body temperature...
Thomsen LN, Thomsen PD, Downing A, Talbot R, Berg LC.The synovial membrane lines the luminal side of the joint capsule in synovial joints. It maintains joint homeostasis and plays a crucial role in equine joint pathology. When trauma or inflammation is induced in a joint, the synovial membrane influences progression of joint damage. Equine synovial membrane research is hampered by a lack of markers of fibroblast-like synoviocytes (FLS) to distinguish FLS from other fibroblast-like cells in musculoskeletal connective tissues. The aim of this study is to identify potential FLS markers of the equine synovial membrane using microarray to compare bet...
Nakajima H, Yoshino T, Ushimi C.Equine infectious anemia virus was purified from infected horse serum samples. Electron microscope observation on negatively stained preparations of purified virus showed roughly spherical particles sized between 100 and 200 nm in diameter. In disrupted particles, an envelope was visible but no internal structure could be resolved. Since the purified virus fraction had a strong antigenic activity to antiserum in immunodiffusion reaction, these particles are thought to be the causative virus of equine infectious anemia.
Oliveira-Filho JP, Monteiro LN, Delfiol DJ, Sequeira JL, Amorim RM, Fabris VE, Del Piero F, Borges AS.Sarcoidosis is a rare equine skin disease characterized primarily by an exfoliative and granulomatous dermatitis but also presenting granulomatous inflammation of multiple systems. The current report presents the clinical and histopathological findings of sarcoidosis in a 16-year-old American Quarter Horse gelding with nested polymerase chain reaction Mycobacterium spp. DNA detection within hepatic and skin samples. Mycobacterium spp. may play a role in the pathogenesis of equine sarcoidosis as has been proposed for human sarcoidosis.
Di Febo T, Luciani M, Ciarelli A, Bortone G, Di Pancrazio C, Rodomonti D, Teodori L, Tittarelli M.Monoclonal antibodies (MAbs) against horse IgG were produced by immunizing Balb/c mice with purified horse IgG and were characterized in indirect ELISA versus purified immunoglobulins from donkey, cow, buffalo, sheep, pig, and chicken. Three MAbs (1B10B6C9, 1B10B6C10, 1B10B6E9) reacted only with horse and donkey IgG and IgM and, in western blotting, were specific for the Fc fragment of equine IgG. MAb 1B10B6E9 was used in chemiluminescent immunoblotting assay for the diagnosis of dourine and in indirect immunofluorescence assay (IFA) for the diagnosis of African horse sickness and dourine.