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.
Lord CC, Woolhouse ME, Mellor PS.Factors affecting epidemics of African horse sickness in Spain were studied using a mathematical model. The model examined the likelihood of an epidemic after the introduction of the virus, and the effectiveness of vaccination strategies. Two host species (horses and donkeys) and one vector species (the biting midge Culicoides imicola) were included. A stratified random sampling method (Latin hypercube sampling) was used for sensitivity analysis of the likelihood of an epidemic. Systematic variation of vaccination parameters was used to consider alternative control strategies. In general, when...
Katz JB, Alstad D, Jenny AL, Carbone KM, Rubin SA, Waltrip RW.Borna disease was originally described as an equine neurologic syndrome over 200 years ago, although the infectious etiology of the disorder was unproven until the early 20th century. Borna disease virus (BDV) was finally isolated from horses dying of the disorder, and that virus has been used to experimentally reproduce Borna disease in several species of laboratory animals. However, BDV has never been inoculated back into horses to experimentally and etiologically confirm the classic clinical, pathologic, and serologic characteristics of the disease in that species. Three ponies were intrace...
Yudkowsky ML, Beech J, Fletcher JE.In equine hyperkalemic periodic paralysis (HyperPP), there is evidence suggesting that the primary defect in the sodium channel is associated with a secondary alteration in triacylglycerol-associated fatty acid metabolism (TAFAM) in skeletal muscle. Furthermore, TAFAM may be involved in the therapeutic action of phenytoin. The effects of phenytoin treatment on the transcript levels of three key proteins in TAFAM, hormone sensitive lipase (HSL), carnitine palmitoyltransferase (CPT), and fatty acid binding protein (FABP), were examined. These transcripts were quantitated by competitive reverse t...
Bougrine SI, Fihri OF, Fehri MM.A Western immunoblotting procedure has been developed for the detection of African horse sickness virus (AHSV) protein-specific antibody responses. This assay readily identifies antibodies specific for at least 4 distinct, AHSV proteins, including VP5, NS1, NS2 and NS3/NS3a. By using the AHSV non-structural proteins as 'markers', the Western blotting procedure could be employed to provide a reliable means of discriminating between animals vaccinated with a purified, inactivated AHSV vaccine and those either naturally infected or vaccinated with a live, attenuated AHSV vaccine.
Hamblin C, Salt JS, Mellor PS, Graham SD, Smith PR, Wohlsein P.Investigations have been carried out to elucidate the possible role of the donkey in the epidemiology of African horse sickness (AHS). These studies have shown that despite the absence of pyrexia or other observable clinical signs, donkeys become infected with virulent AHS virus serotype 4 (AHSV 4) and that they develop a viraemia which can persist for at least 12 days, albeit at a comparatively lower titre than that recorded for similarly infected ponies. AHSV 4 showed a similar tissue tropism in the pony and donkey but the virus appeared to replicate less efficiently in donkey tissues. The o...
Wohlsein P, Pohlenz JF, Salt JS, Hamblin C.African horse sickness virus (AHSV) antigen was demonstrated immunohistochemically in formalin-fixed, paraffin-embedded sections of tissues collected from three ponies suffering from the peracute form of the disease and from one pony affected by the fever form. The pattern of the antigen distribution indicated a particular organ tropism characterised by an accumulation of AHSV antigen in cardio-pulmonary tissues of the animals with the peracute disease and in the spleen of the pony with the fever form. AHSV antigen was identified in endothelial cells of small blood vessels, particularly capill...
Archambault D, Laganière G, St-Laurent G.The genetic variation in equine arteritis virus (EAV) nonstructural (NS) protein-encoding open reading frames (ORF) 3 and 4 genes was investigated. Nucleotide and deduced amino acid sequences from seven different EAV isolates (one European, one American and five Canadian isolates) and the Arvac vaccine strain were compared with those of the Bucyrus reference strain. ORF 3 nucleotide and amino acid sequence identities amongst these isolates (including the Arvac vaccine strain) and the Bucyrus reference strain ranged from 85.6 to 98.8%, and 85.3 to 98.2%, respectively, whereas ORF 4 nucleotide a...
Huovilainen A, Ek-Kommonen C.A serological study for antibodies against equine arteritis virus (EAV) in Finland was performed during 1996. All equine sera delivered to the Virology Unit at the National Veterinary and Food Research Institute were tested with a micro-neutralization test, using the Arvac strain as antigen. The study also included imported horses to evaluate EAV circulation in the countries of origin. Nucleocapsid gene sequences of 2 Finnish equine semen isolates were amplified with RT-PCR and sequenced. The genetic relationships of those isolates with strains isolated elsewhere in the world were analyzed. Th...
Kitchen DL, Merritt AM, Burrow JA.To determine gastric secretory responses in horses treated with histamine and to determine the dose of histamine needed to elicit maximal gastric secretion. Methods: 6 adult horses with an indwelling gastric cannula. Methods: Gastric contents were collected in 15-minute periods, and volume, pH, hydrogen ion concentration, hydrogen ion output, sodium concentration, and sodium output were determined. Values were determined without any treatment (baseline), after administration of pyrilamine maleate (1 mg/kg of body weight, i.v., given during a 15-minute period), and during 1-hour infusions of hi...
Daels PF, Albrecht BA, Mohammed HO.The onset of eCG secretion in pregnant mares coincides with an increase in luteal steroid production and a relative shift toward androgen and estrogen synthesis. However, a cause-effect relationship between eCG and the shift in luteal steroidogenesis has not been demonstrated. In this study, we have investigated the effect of eCG on steroid production by the corpus luteum (CL) during equine pregnancy. All mares were supplemented with 44 mg altrenogest (a progestogen) per day on Days 18-50. Increasing doses of eCG were administered on Days 26-28, before the onset of endogenous eCG secretion, to...
Fagliari JJ, McClenahan D, Evanson OA, Weiss DJ.To determine whether plasma protein concentrations were altered in ponies with alimentary laminitis. Methods: 12 adult ponies. Methods: Acute laminitis was induced in 6 ponies by oral administration of carbohydrate (85% corn starch, 15% wood flour); the other 6 ponies were used as controls. A physical examination was performed and blood samples were collected immediately before and 4, 8, 12, 24, and 28 hours after administration of carbohydrate. Plasma protein concentrations were determined by means of sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Results: 19 plasma proteins rang...
Hardy J, Bertone AL, Muir WW.To determine oxygen metabolism, permeability, and blood flow in isolated joints in response to interleukin 1beta (IL-1beta) and contribution of innervation. Methods: One metacarpophalangeal (MCP) joint of 24 adult horses. Methods: The MCP joint was isolated for 6 hours in a pump-perfused, auto-oxygenated, innervated or denervated preparation. Isolated joints were assigned to the following 4 groups: control, control-denervated, inflamed, and inflamed-denervated, and inflammation was induced by intra-articular injection of IL-1beta. Circuit arterial and venous pressures, flows, and blood gas ten...
Okumura M, Fujinaga T.To establish a sensitive and specific monoclonal antibody (MAB) against equine keratan sulfate (KS) and to develop an enzyme immunoassay for measurement of the concentration of KS in serum and synovial fluid from horses. Methods: 18 synovial fluid and 48 serum samples were obtained from clinically normal horses and horses with arthritis. Methods: BALB/c mice were immunized with chondroitinase-ABC-digested proteoglycan monomer from equine joint cartilage, and MAB were raised, using Sp2/O cells as a fusion partner. A competitive ELISA was optimized, using one of the established MAB, and KS conce...
Fogarty U, Perl D, Good P, Ensley S, Seawright A, Noonan J.A cluster of 6 cases of equine granulomatous enteritis is described. Aluminium was demonstrated in the tissues and lesions of these horses and in the intimal bodies of intestinal vessels. The relationship between granulomatous lesions, aluminium, acidity and invading microorganisms, particularly parasites, is presented and discussed.
Lichtenfels JR, Kharchenko VA, Krecek RC, Gibbons LM.The results of an international collaborative effort to prepare a recommended list of scientific names for the small strongyles (Nematoda: Strongyloidea: Cyathostominea) of horses, donkeys and zebras are reported. Fifty-one valid species are recognized in 13 genera, including Cyathostomum, Coronocyclus, Cylicodontophorus, Cylicocyclus, Cylicostephanus, Skrjabinodentus, Tridentoinfundibulum, Petrovinema, Poteriostomum, Parapoteriostomum, Hsiungia, Cylindropharynx and Caballonema. In addition, 42 other species level names are listed as synonyms of the 51 recognized species or as species inquiren...
Anderson RC, Linder KE, Peregrine AS.Although the original description given by Stefanski (1954) was satisfactory, Anderson & Bemrick (1965), in describing H. deletrix (= Micronema deletrix), claimed Stefanski's description was "inadequate" and the species a "species inquirenda". Thus, infections in horses and humans have been assigned to H. deletrix. We believe the species reported in horses and humans is H. gingivalis and that H. deletrix is its synonym. H. gingivalis is separated herein from forms found free-living. The genital tract in the advanced fourth stage of H. gingivalis is didelphic and amphidelphic and terminal e...
Garbís SD, Hanley L, Kalita S.Thiazide-based diuretics are included in the list of banned drugs in the horse-racing industry. One effect of their misuse is increased urine flow, contributing to dilution of other doping agents. Their determination is essential in ensuring compliance to horse-racing regulation. This study evaluates the feasibility of using liquid chromatography/mass spectrometry (LC/MS) with electrospray and atmospheric pressure chemical ionization interfaces to analyze thiazidic diuretics in equine urine samples. Existing LC and gas chromatography/MS methods are limited in their applicability to thiazide an...
McKelvie J, Little S, Foster AP, Cunningham FM, Hamblin A.It has been reported that equine peripheral blood mononuclear cells (PBMNs) do not proliferate in response to tetanus toxoid (TT) (Frayne and Stokes 1995, Research in Veterinary Science 59, 79-81). Here we demonstrate that lymphocyte proliferation responses to TT, which are characteristic of a recall antigen, may be achieved under certain culture conditions. Given that TT vaccination is routinely applied to many horses, TT is a suitable antigen for the investigation of cellular immune responses by peripheral blood mononuclear cells in the horse.
Maury W, Oaks JL, Bradley S.Previous cell infectivity studies have demonstrated that the lentivirus equine infectious anemia virus (EIAV) infects tissue macrophages in vivo and in vitro. In addition, some strains of EIAV replicate to high titer in vitro in equine fibroblasts and fibroblast cell lines. Here we report a new cell type, macrovascular endothelial cells, that is infectible with EIAV. We tested the ability of EIAV to infect purified endothelial cells isolated from equine umbilical cords and renal arteries. Infectivity was detected by cell supernatant reverse transcriptase positivity, EIAV antigen positivity wit...
Iniguez P, Zientara S, Marault M, Machin IB, Hannant D, Cruciere C.A random hexapeptide fusion-phage library was screened to isolate phages that bind to antibodies present in horse sera positive for equine arteritis virus (EAV). Analysis of the peptide sequences displayed by isolated phages identified seven groups. 25% of the isolated phages used as antigens in an ELISA test were specifically recognised by a pool of sera which was positive for EAV in virus neutralisation test (VN). Five of these, when used as antigen in ELISA, detected greater than 50% of sera (n = 30) containing antibodies to EAV as detected by VN. When these five phages were pooled together...
Mizuguchi M, Arai M, Ke Y, Nitta K, Kuwajima K.The equilibrium unfolding and the kinetics of unfolding and refolding of equine lysozyme, a Ca2+-binding protein, were studied by means of circular dichroism spectra in the far and near-ultraviolet regions. The transition curves of the guanidine hydrochloride-induced unfolding measured at 230 nm and 292.5 nm, and for the apo and holo forms of the protein have shown that the unfolding is well represented by a three-state mechanism in which the molten globule state is populated as a stable intermediate. The molten globule state of this protein is more stable and more native-like than that of alp...
Brown CM, Timoney PJ.An outbreak of disease, characterized by depression, anorexia, fever, limb oedema and lymphocytopenia, occurred on a farm for thoroughbreds in India in 1990. Twenty-six of the 88 horses on the farm were affected, predominantly adults. Signs were present in affected horses for 7-10 days, and the outbreak lasted 21 days. Seven of the 26 affected horses were tested for exposure to Getah virus using paired serum samples, acute and convalescent. Four of the 7 horses seroconverted to Getah virus, and the other three showed a 4-fold or greater rise in titre. The clinical and laboratory findings were ...
Bailey SR, Elliott J.5-hydroxytryptamine (5-HT) is a potent vasoconstrictor of equine digital arteries and veins which may play a role in the ischaemic disease, laminitis. The present investigation compared the properties of 5-HT1B/1D receptors in arteries with those in veins using isolated rings of equine digital blood vessels. The 5-HT1B/1D receptor-selective agonists, anpirtoline and sumatriptan were 17.9 and 10 times more potent and produced 4.1 and 5.6 times greater maximum contractions, respectively, in veins when compared to arteries. Other agonists tested were of equal potency and produced the same maximum...
Pirie RS, Mayhew IG, Clarke CJ, Tremaine WH.Intraoperative brain ultrasonography is commonly used clinically
in human and canine neonates (Johnson and Rumack 1980;
Babock and Han 1981; Cappe and Lam 1985; Hudson et al. 1990,
1991) and a single report exists of its use to assist in defining
hydrocephalus in an equine neonate (Foreman et al. 1983). This
technique has also been reported to be clinically useful in human
adults (Rubenstein et al. 1984) and ultrasound-guided brain biopsy
has also been described in mature dogs (Thomas et al. 1993).
%ours of the central nervous system in the horse are
extremely rare, with the exception...
Trostle S.A working knowledge of normal endoscopic anatomy and the effects of positioning must be mastered to take advantage of endoscopic procedures involving the gastrointestinal system. Endoscopic procedures involving the gastrointestinal system offer advantages over conventional surgery in that they are less invasive and provide direct visualization. Laparoscopy can be used to evaluate horses with abdominal pain before and after surgery. It can be used to evaluate and biopsy abdominal masses and parenchymal organs such as the spleen, liver, and kidney. Endoscopic gastrointestinal surgical procedures...
Frazer GS, Rossol TJ, Threlfall WR, Weisbrode SE.Endometrial fibrosis is a major cause of infertility in broodmares. Because of the proven anti-inflammatory effects of dimethyl sulfoxide (DMSO) and its influence on collagen, the effect of DMSO on the endometrium was investigated in mares. Solutions of DMSO (25%, 50%, or 75%) were infused into the uterus of clinically normal mares. Examination of serially obtained biopsy specimens revealed epithelial ulceration and stromal inflammation that were proportional to the DMSO concentration infused, but vasodilatation was not observed. In all mares, the endometrium had returned to normal by day 21 a...
Troncoso I, Calvanese R, Saravia F, Muñoz-Leal S, Zegpi NA, Ortega R.Equine coital rash (ECE) is a highly contagious benign infection that induces lesions on external genitals, and it is caused by the equine herpesvirus type 3 (EHV-3). Although the disease is globally distributed, its presence in Chile has not been documented from a genetic point of view. Here, we performed polymerase chain reaction screenings for EHV-3 in lesions of external genitals in four horses belonging to a riding station at Bulnes, Ñuble Region, Chile. We sequenced a fragment of the glycoprotein G (gG) gene from three horses with clinical signs of ECE. The sequences were identical betw...
Neuhauser S, Handler J.The aims of this study were to compare two different methods of quantifying the colour of the luminal surface of the equine endometrium and to relate the results to histopathological evidence of inflammation and fibrosis. The mucosal surfaces of 17 equine uteri obtained from an abattoir were assessed using a spectrophotometer and by computer-assisted analysis of photographs. Values were converted into L(*)a(*)b(*) colour space. Although there was significant correlation between the two methods of quantification, variations in 'brightness', 'red' and 'yellow' values were noted. Within a given u...
Sato T, Sato G, Shoji Y, Itou T, Sakai T.After RNA extraction from horsehair shafts and roots, the mRNAs of beta-actin, muscle-type phosphofructokinase, and transforming growth factor-beta1 were detected by reverse transcription polymerase chain reaction assay. Low amounts of RNA were present in the horsehair. These specific mRNA transcripts were readily detected when more than three hair roots were used. However, detection of the mRNA transcripts was difficult in the hair shaft. These findings indicate that the small amounts of residual RNA in horsehair roots can be utilized as samples for molecular biological analysis.
Donoghue S, Meacham TN, Kronfeld DS.Cumulative nutritional demands on good brood mares are unrivalled among domestic livestock, but little attention has been given to the influence of nutrition on their reproductive performance and efficiency. We suggest that part of the decline in racing performance of progeny of mares over 10 years of age may be caused by suboptimal nutrition. This article contrasts the concepts of minimal and optimal nutrient requirements, revives Hammond's concept of nutrient partitioning to the conceptus and mammary gland, and discusses energy and nutrient requirements during gestation and lactation. Furthe...
Kostiuk D.A 4-year-old Morgan stallion was presented with a 9-week history of diarrhea. Biopsy of nodules in the rectal mucosa yielded a diagnosis of eosinophilic enterocolitis. Treatment with steroids was instituted and the feces firmed within 2 days. Continued treatment with oral prednisone kept the feces at a normal consistency for 4 months.
Okai K, Taharaguchi S, Orita Y, Yokota H, Taniyama H.To contribute to early diagnosis and treatment of gastric ulcer of foals, we examined the gastric mucosa of healthy and affected foals using an endoscope. In healthy foals, the characteristic changes in the development of the squamous mucosa were seen mainly in the squamous mucosa, and maturation of the squamous mucosa in the greater curvature (GC-S) occurred more slowly than that of the squamous mucosa in the lesser curvature (LC-S). Epithelial desquamation in the LC-S and GC-S was observed between 6 and 90 days but was not observed in the LC-S at about 60 days, whereas it was observed in the...
Fussell D, Bizikova P, Breuhaus B, Harris RA, Moore AR, Chen L, Linder KE.Bullous amyloidosis is a rare disease in humans that has not been described in a veterinary species in the peer-reviewed literature. The human disease is characterised by haemorrhagic vesicles and bullae on the skin and mucosae, which form due to amyloid deposition. Objective: To describe the clinical features, laboratory analysis and histopathological features of an unique presentation of bullous disease in a horse. Methods: A 17-year-old thoroughbred mare presented for weight loss and severe oral cavity ulcers. Methods: Investigations involved haematological evaluation, chemistry profiles, g...
Cohen ND, Carey VJ, Donahue JG, Seahorn JL, Donahoe JK, Williams DM, Harrison LR.To identify factors associated with abortions of mares during late gestation attributed to mare reproductive loss syndrome (MRLS). Methods: Case-control study. Methods: 282 broodmares from 62 farms in central Kentucky, including 137 mares that had late-term abortions (LTAs) associated with MRLS, 98 mares from the same farms that did not abort, and 48 mares that aborted from causes other than MRLS. Methods: Farm managers were interviewed to obtain data on a wide range of management practices and environmental exposures for the mares. Data for case and control horses were compared to identify ri...
Mair TS, Stokes CR, Bourne FJ.Mast cells in the equine respiratory mucosa were studied at both light--and transmission electron--microscope levels. Mast cells were identified at all levels of the tract, with the greatest cell density in the nasopharynx. The majority (57 to 94 per cent) of this cell population were located within the connective tissue of the lamina propria. Up to 20 per cent of these cells were associated with the mucosal glandular tissue, whilst small numbers were present within the surface epithelium and in association with nodular lymphoid tissue. In the peripheral lung tissue 20 per cent of the mast cel...
Wilkins PA, Lowe JE.Right dorsal colon fistulas, 2.5 cm in diameter, were created in 2 healthy ponies, using a 2-stage surgical procedure. The first stage consisted of resection of portions of the 16th and 17th ribs on the right side, followed by surgical creation of a 6- to 8-cm-diameter adhesion between the right dorsal colon and the body wall. Fistulas were created approximately 2 weeks after the first surgery by sharp dissection through the adhesion into the lumen of the colon. The fistulas have been satisfactorily maintained for > 2 years by de Pezzer catheters (45 F). Ponies with fistulas have been used ...
May CE, Schulman ML, Howell PG, Lourens CW, Gouws J, Joone C, Monyai MS, le Grange M, Bezuidt OK, Harper CK, Guthrie AJ.Taylorella equigenitalis is the causative agent of contagious equine metritis (CEM), a sexually transmitted infection of horses. We report here the genome sequence of T. equigenitalis strain ERC_G2224, isolated in 2015 from a semen sample collected in 1996 from a Lipizzaner stallion in South Africa.
Watson RE, England JJ, Larson KA.A cell line, derived from a spontaneous equine connective tissue tumor (equine sarcoid), has been established. The morphological and growth characteristics indicative of malignant transformation of the cells include a disoriented, rapid growth and loss of contact inhibition. Further evidence of transformation is the agglutination of these cells by concanavalin A and their ability to divide in semisolid media.
Weiss DJ, Geor RJ, Burris SM, Smith CM.Pentoxifylline has been reported to improve peripheral vascular circulation by altering the flow properties of blood. To determine if the hemorrheological effects of pentoxifylline were mediated by alterations in neutrophil function and/or flow properties, we evaluated the drug's effects on equine neutrophils in vitro. Pentoxifylline, at a concentration of 1 x 10(-1) M, but not at concentrations of 1 x 10(-6) M to 1 x 10(-2) M, markedly suppressed neutrophil superoxide production, zymosan phagocytosis and adherence to nylon wool. Pentoxifylline failed to improve neutrophil filterability throug...
Hubbell JA, Reed SM, Myer CW, Muir WW.The records of 131 horses undergoing general anaesthesia and positive contrast cervical myelography with metrizamide were examined to determine the effect of the procedure on the 'patient'. Three per cent of minimally ataxic and moderately ataxic horses had serious complications after myelography. Thirty-two per cent of severely ataxic horses died or were destroyed after general anaesthesia and myelography. Although general anaesthesia and myelography are essential components of a complete neurological evaluation of a horse, they impose a significant risk.
Matthews AG.Evidence is presented to suggest that the acidic prealbumin esterases in horse serum represent a protease-inhibitory protein. The esterase activity may arise from residual enzymic activity of the bound protease.