Disease etiology in horses refers to the study of the causes and development of diseases within equine populations. It encompasses various factors, including genetic predisposition, environmental influences, infectious agents, and nutritional imbalances, that contribute to the onset and progression of diseases in horses. Understanding disease etiology is essential for identifying risk factors and implementing preventative measures in equine health management. This topic includes research on pathogen-host interactions, the impact of management practices on disease incidence, and the role of genetic and environmental factors in disease susceptibility. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, contributing factors, and implications of disease etiology in horses.
Rappocciolo G, Birch J, Ellis SA.There is good evidence that cytotoxic T lymphocytes play an important role in the clearance of equine herpesvirus-1 (EHV1) in horses. We have demonstrated that, in common with other alphaherpesviruses, EHV1 infection can lead to dramatic down-regulation of MHC class I expression at the cell surface, a common strategy for pathogen evasion of the host immune response. This down-regulation is specific for MHC class I and does not reflect a general shut-off of host-cell protein synthesis. The use of monoclonal antibodies that recognize different MHC class I epitopes has demonstrated that the effec...
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...
Cohen ND, Donahue JG, Carey VJ, Seahorn JL, Piercy D, Donahoe JK, Williams DM, Brown SE, Riddle TW.To identify factors associated with abortions during early gestation classified as mare reproductive loss syndrome (MRLS). Methods: Case-control study. Methods: 324 broodmares from 43 farms in central Kentucky, including 121 mares from 25 farms that had early-term abortions (ETAs) associated with MRLS (case horses), 120 mares from the same farms but that did not abort, and 83 mares from 18 farms that were not severely Impacted by MRLS. Methods: Farm managers were interviewed to obtain data on various management practices and environmental exposures for the mares. Data for case and control hors...
Ruohoniemi M, Ahtiainen H, Ojala M.Ossification of the cartilages in the foot is common in coldblooded horses, but prevalence as well as ossification pattern varies between breeds; research on estimation of heritability for the condition has been limited. Objective: Our purpose was to calculate estimates of 1) heritability for ossification parameters of the cartilages in the front feet of the Finnhorse and 2) genetic correlations between the different ossification parameters. Methods: Estimates of heritability for different ossification parameters of the cartilages in the front feet and of genetic correlations between different...
Akiba M, Uchida I, Nishimori K, Tanaka K, Anzai T, Kuwamoto Y, Wada R, Ohya T, Ito H.Equine paratyphoid is caused by Salmonella enterica serovar Abortusequi, and manifests mainly as abortion in the mare. We compared S. Abortusequi strains isolated in Japan and other countries using pulsed-field gel electrophoresis (PFGE) and fluorescent amplified-fragment length polymorphism (FAFLP) analysis. PFGE analysis of S. Abortusequi strains gave 21-27 fragments ranging in size from 33 to 602kb. Although two PFGE profiles were observed among the 20 S. Abortusequi isolates in Japan, the restriction fragments originating from the chromosome were common between the two profiles. The simila...
van Weeren PR, Knaap J, Firth EC.To elucidate the highly contentious role of copper in the pathogenesis of osteochondrosis. Objective: There would be no relationship between liver copper concentration of mares and foals and incidence of radiographically detectable osteochondrotic lesions in foals and yearlings was tested. Methods: Liver copper concentration was assessed in biopsies taken within 4 days after birth from both mares and foals and from the same foals at age 5 months. Biopsies were taken in the standing, sedated animal under ultrasonographic guidance. Radiographs were taken of both hocks (lateromedial, dorsoplantar...
Jefcoat AM, Wagner JG, Robinson NE.The research article involves an in-depth exploration of the role of neutrophils, a type of immune cell, in inflammation, especially in relation to horse diseases. The study discusses the historical […]
Broekman LE, Kuiper D.After giving a descriptive definition of megaesophagus attention is paid to the occurrence, the possible causes and pathogeneses, the clinical history and diagnosis, age, breed and sex of the horses with megaesophagus, and the prognosis. The most important characteristics of megaesophagus are summarized in two tables referring to 11 cases published in the literature and 18 own cases. Finally some conclusions based on published as well as not published own cases are given.
The Journal of parasitologyJanuary 23, 2003
Volume 88, Issue 6 1130-1134 doi: 10.1645/0022-3395(2002)088[1130:GHOPIL]2.0.CO;2
Chapman MR, French DD, Klei TR.A survey in Louisiana of gastrointestinal helminths recovered at necropsy from 117 ponies with minimal exposure to anthelmintics between 1989 and 2000 is compared with a survey conducted 20 yr earlier in the same region. An objective of this study was to determine whether species diversity has been affected by the advent and use of the macrocyclic lactone (ML) parasiticides and by the increased anthelmintic pressure on the helminth species infecting the general equine population. Twenty-six cyathostome species and 8 strongyle species were recovered. Two cyathostome species that were not found ...
van der Meulen KM, Nauwynck HJ, Pensaert MB.Equine herpesvirus-1 (EHV-1) may cause abortion in vaccination- and infection-immune horses. EHV-1-infected peripheral blood mononuclear cells (PBMCs) play an important role in virus immune evasion. The mechanisms by which infected PBMCs can avoid destruction by EHV-1-specific antibody and equine complement were examined. The majority of EHV-1-infected PBMCs (68.6 %) lacked surface expression of viral antigens and these cells were not susceptible to complement-mediated lysis. In infected PBMCs with surface expression of viral antigens, 63 % showed focal surface expression, whereas 37 % showed ...
Hunt RJ.There are few diseases that instill a comparable sense of doom in the mind of a treating veterinarian as laminitis. There is a feeling of cautious optimism when a horse with laminitis responds favorably to treatment. Although this optimism all too often proves false when treating laminitic patients, management of the patient afflicted with chronic laminitis can be rewarding. Through diligent and careful client communication and instruction, many geriatric patients with chronic laminitis can be maintained for years as comfortable companions, for light riding use, or as productive breeding anima...
Botha CJ, Naudé TW.Well-known plant poisonings such as 'dunsiekte' (seneciosis) and 'jaagsiekte' (crotalariosis) of horses in southern Africa are briefly reviewed. Relatively unfamiliar mycotoxicoses such as stachybotryotoxicosis and perennial rye grass staggers and potentially occurring exotic intoxications such as equine nigropallidal encephalomalacia and ergot alkaloid poisoning are also discussed. This article is aimed at informing the southern African equine practitioner about probable poisonings that might occur locally in horses.
Dirikolu L, Hughes C, Harkins D, Boyles J, Bosken J, Lehner F, Troppmann A, McDowell K, Tobin T, Sebastian MM, Harrison L, Crutchfield J, Baskin SI....The epidemiological association between black cherry trees and mare reproductive loss syndrome has focused attention on cyanide and environmental cyanogens. This article describes the toxicokinetics of cyanide in horses and the relationships between blood cyanide concentrations and potentially adverse responses to cyanide. To identify safe and humane blood concentration limits for cyanide experiments, mares were infused with increasing doses (1-12 mg/min) of sodium cyanide for 1 h. Infusion at 12 mg/min produced clinical signs of cyanide toxicity at 38 min; these signs included increased heart...
Hughes C, Lehner F, Dirikolu L, Harkins D, Boyles J, McDowell K, Tobin T, Crutchfield J, Sebastian M, Harrison L, Baskin SI.An epidemiological association among black cherry trees (Prunus serotina), eastern tent caterpillars (Malacosoma americana), and the spring 2001 episode of mare reproductive loss syndrome in central Kentucky focused attention on the potential role of environmental cyanogens in the causes of this syndrome. To evaluate the role of cyanide (CN (-)) in this syndrome, a simple, rapid, and highly sensitive method for determination of low parts per billion concentrations of CN (-) in equine blood and other biological fluids was developed. The analytical method is an adaptation of methods commonly in ...
Gonçalves S, Julliand V, Leblond A.Many factors have been identified as risk factors for colic in horses in several epidemiological studies. The aim of our paper was to review the results of 12 epidemiological studies, in order to assess the impact of each risk factor for colic. According to the literature, the factors that increase the risk of colic are feeding practices (type and quality of food, type and changes of feeding), the intrinsic factors of horses (sex, age and breed), management (type and changes of housing and activity), medical history (a previous colic, administration of a medical treatment) and parasite control...
Matera MG, Amorena M, Lucisano A.Equine obstructive pulmonary disease (COPD), or heaves or recurrent airway obstruction, is a common equine pulmonary disease similar to human asthma and/or CODP. Since bronchospasm and inflammation are the key features in heaves, the purpose of this paper is to review the contribution of neural mechanism that may be relevant to this disease. Equine airway receive cholinergic and adrenergic innervation, as well as observed in many species. It was suggested that the autonomic neural control in asthma might be defective with an imbalance between excitatory and inhibitory pathways, resulting in ex...
de la Calle J, Burba DJ, Ramaswamy CM, Hosgood G, Williams J, LeBlanc C, Moore RM.To compare plasma and synovial fluid endothelin-1 (ET-1) and nitric oxide (NO) concentrations in clinically normal horses and horses with joint disease. Methods: 36 horses with joint disease, and 15 horses without joint disease. Methods: Horses with joint disease were assigned to 1 of the 3 groups (ie, synovitis, degenerative joint disease [DJD], or joint sepsis groups) on the basis of findings on clinical and radiographic examination and synovial fluid analysis. Endothelin-1 and NO concentrations were measured in plasma from blood samples, collected from the jugular vein and ipsilateral cepha...
Lentz LR, Valberg SJ, Herold LV, Onan GW, Mickelson JR, Gallant EM.To determine whether alterations in myoplasmic calcium regulation can be identified in muscle cell cultures (myotubes) and intact muscle fiber bundles derived from Thoroughbreds affected with recurrent exertional rhabdomyolysis (RER). Methods: 6 related Thoroughbreds with RER and 8 clinically normal (control) Thoroughbred or crossbred horses. Methods: Myotube cell cultures were grown from satellite cells obtained from muscle biopsy specimens of RER-affected and control horses. Fura-2 fluorescence was used to measure resting myoplasmic calcium concentration as well as caffeine- and 4-chloro-m-c...
Al-Hizab F, Clegg PD, Thompson CC, Carter SD.To investigate the relationship between matrix metalloproteinase (MMP) activity and osteochondritis dissecans (OCD) in the equine joint. Methods: Equine articular cartilage was obtained from normal (N = 8) and osteochondrotic (OCD) (N = 6) femoropatellar joints from horses at necropsy. The activity of gelatinase MMPs was determined in sections of cartilage by in situ gelatin zymography. Results: Gelatinase activity was markedly increased in articular cartilage obtained from OCD samples and was particularly prominent in the deep cartilage zone. Activity was only seen in the pericellular area of...
McGowan CM, Fordham T, Christley RM.Telephone surveys of 34 racing yards with 1276 horses in training were made to establish the overall incidence of exertional rhabdomyolysis in the previous year. A case-control study was used to investigate the risk factors for the syndrome in 12 yards selected on the basis of the routine confirmation of diagnoses by the evaluation of the serum activities of creatine kinase and aspartate aminotransferase. The overall incidence of the syndrome was 6.7 per cent and 80 per cent of the trainers had at least one affected horse. In 74 per cent of the affected horses it frequently recurred, with an a...
Laverty S, Okouneff S, Ionescu M, Reiner A, Pidoux I, Webber C, Rossier Y, Billinghurst RC, Poole AR.Articular osteochondrosis (OCD) occurs in both man and animals. The etiology remains to be determined. Studies of OCD lesions in animals may provide clues as to its pathogenesis. The aim of our study was to determine whether there was evidence for increased degradation namely proteoglycan (PG) release and type II collagen cleavage in articular cartilage harvested from OCD lesions. We examined ex vivo explants at post-mortem from equine OCD lesions and macroscopically normal site and age matched cartilage. These were cultured over a 10 day period in serum-free medium. Type II collagen cleavage ...
Vigre H, Chriél M, Hesselholt M, Falk-Rønne J, Kjaer Ersbøll A.A follow-up study focusing on health problems interfering with optimal training of Danish Standardbred trotters was conducted with the participation of seven professional trainers. Our aim was to estimate the incidence of health problems that cause interruptions of optimal training, and to identify associations between the hazard of lameness and selected risk factors. The study population was dynamic and contained data of 265 Standardbred trotters monitored during 5 months in 1997 and 1998. The horses were >or=2 years old. Optimal training was defined as when the horse followed scheduled tr...
Lian WC, Liau MY, Mao CL.Nervous disorders were found in two horses and verified as aseptic encephalitis by necropsy in the summer of 2000. To investigate agents that affected the horses, diagnostic procedures involving virus isolation, neutralization test and reverse transcription-polymerase chain reaction (RT-PCR) were performed. We intracranially inoculated litters of suckling mice with tissues suspected of containing aseptic encephalitis, including cerebrum, cerebellum, brain stem, thalamus, and cerebrospinal fluids; the mice were then observed for 14 days. Neutralizing antibodies against Japanese encephalitis (JE...
Collobert-Laugier C, Hoste H, Sevin C, Dorchies P.Forty-two horses from Normandy (France) were examined post-mortem for small strongyle infections from October to March. In the positive horses, total worm numbers ranged from 234 to 90,247 (mean 11,297). Encysted larvae represented the major part of the total cyathostome burdens with a high percentage (83%) being early third stage larvae. They were mostly recovered from the caecum (48%) and ventral colon (40%) and were less present in the dorsal colon (12%). Adult cyathostomes were mainly located in the ventral colon (64%) and less frequently in the dorsal colon (27%) and caecum (9%). Twenty s...
Fernandez-Fuente M, Martin-Duque P, Vassaux G, Brown SC, Muntoni F, Terracciano CM, Piercy RJ.Several human and animal myopathies, such as malignant hyperthermia (MH), central core disease and equine recurrent exertional rhabdomyolysis (RER) are confirmed or thought to be associated with dysfunction of skeletal muscle calcium regulation. For some patients in whom the genetic cause is unknown, or when mutational analysis reveals genetic variants with unclear pathogenicity, defects are further studied through use of muscle histopathology and in vitro contraction tests, the latter in particular, when assessing responses to ryanodine receptor agonists, such as caffeine. However, since musc...
Jaafar N, Khoueiry M, Khoury SJ, Makki A.Spinal neurosarcoidosis is a rare disease that can manifest as myelopathy, radiculopathy, or cauda equine syndrome. Spinal epidural lipomatosis is also a rare condition resulting from overgrowth of epidural fat tissue causing compressive myelopathy. To our knowledge, there are no reports linking epidural lipomatosis and spinal neurosarcoidosis. . We describe a case of progressive myelitis in the presence of concomitant spinal neurosarcoidosis and epidural lipomatosis which was a challenging diagnosis with complete response to treatment after addressing both diseases. Both etiologies are inflam...
Burns GA, Cummings JF.The pelvic flexure portion of the equine large colon is the proposed location of a pacemaker mechanism. This study was conducted to ascertain whether the distribution of certain putative neurotransmitters differs at the pelvic flexure compared to other sampling sites. Tissue samples were collected from the intestinal tracts of six horses. Serial sections from these samples were reacted with primary antisera specific for substance P, vasoactive intestinal polypeptide (VIP), methionine-Enkephalin, and calcitonin gene-related peptide (CGRP). The regional distribution of immunoreactive neuronal el...
Engiles JB, Stewart H, Janes J, Kennedy LA.As a pathologist, postmortem examination of the equine carpus can be daunting. The anatomy is complex and oftentimes, small or subtle lesions have significant impact on lameness and secondary lesions such as catastrophic musculoskeletal fractures and other injuries. In performance horses, particularly racehorses, the carpus is a common site of injury and source of lameness. Given the predisposition of racehorses to developing carpal disease, familiarity with clinically relevant anatomy and common developmental, degenerative, traumatic, and inflammatory processes are imperative for thorough pos...
Paraschou G, Cook JM, Priestnall SL, Evans NJ, Staton GJ, Paterson GK, Winkler B, Whitbread TJ.Keratoma is an aberrant keratin mass thought to originate from epidermal horn-producing cells interposed between the stratum medium of the hoof wall and the underlying third phalanx. The cause is unknown, although the presence of keratomas is frequently associated with chronic irritation, focal infection, or trauma. A total of 167 donkeys with keratomas were presented in this study. The diagnosis of a keratoma was based on clinical signs, radiography, and histopathologic examination. Surgical excision was attempted on all donkeys with lameness unless euthanasia was advised. Histopathologic exa...
Vincze B, Gáspárdy A, Kulcsár M, Baska F, Bálint Á, Hegedűs GT, Szenci O.Alpha-fetoprotein has proved to be a good indicator of fetal well-being in human medicine for decades. Although this molecule is present in most of the mammalian species including horses, reference values in healthy and high-risk pregnant mares have not yet been published. The aim of the present study was to determine whether equine alpha-fetoprotein (eqAFP) is a good indicator of complicated pregnancies in Lipizzaner mares. A total of 111 serum samples from 30 mares have been analyzed for eqAFP levels throughout gestation (Days 60-325). After the pregnancy was confirmed, 23 mares had normal p...
Ludvikova E, Nishino S, Sakai N, Jahn P.The occurrence of sleep disorder in three half sibling Lipizzaner is described. Sleepiness, swaying, stumbling, carpal joints buckling and falling down onto the carpal joints had been present since early foal age in all of them. Clinical signs had gradually reduced since the age of 2 years in cases 1 and 3. Sleepiness was induced by going out from the stable in adulthood. A physostigmine test was performed in all three affected horses and produced positive results in cases 1 and 3. The result of the test in case 2 was unclear due to the almost continuous sleepiness of the foal. Hypocretin-1 co...
Mömke S, Distl O.Chronic pastern dermatitis predominantly affects draft horses, and this condition is characterized by hyperkeratotic-hyperplastic dermal alterations. Chronic pastern dermatitis resembles the acral-hemorrhagic phenotype of Darier-White disease in humans. The ATP2A2 gene has been shown to be responsible for human Darier-White. Thus, we chose ATP2A2 on equine chromosome 8 (ECA8) as candidate for chronic pastern dermatitis in coldblood horses. A linkage analysis was performed in 10 paternal half-sib families consisting of 85 German coldblood horses using a microsatellite closely linked to ATP2A2, ...
Björnsdóttir S, Arnason T, Lord P.A survival analysis was used to compare the culling rate of Icelandic horses due to the presence of radiographic and clinical signs of bone spavin. A follow-up study of 508 horses from a survey five years earlier was performed. In the original survey 46% of the horses had radiographic signs of bone spavin (RS) and/or lameness after flexion test of the tarsus. The horse owners were interviewed by telephone. The owners were asked if the horses were still used for riding and if not, they were regarded as culled. The owners were then asked when and why the horses were culled. During the 5 years, 9...
McKane SA, Slocombe RF.Necropsy studies of horses suffering exercise-induced pulmonary haemorrhage (EIPH) have identified mild inflammatory lesions with evidence of alveolar fibrosis and bronchiolitis. These lesions were thought to be the result of viral infections that predisposed the affected regions of the lung to EIPH. We have shown previously that during erythrophagocytosis in the alveolar space, there is a prolonged period of macrophage influx and activation. This present study used morphometric analysis to quantify the effects of macrophage activity during erythrophagocytosis, on the alveolar cell population ...
Uzal FA, Robles CA.Mal seco is a grass sickness-like syndrome of horses which has mainly been observed in Patagonia, Argentina, although some reports indicate that the disease may exist in other Argentinian provinces and in the south of Chile. The aetiology of mal seco remains unknown but the disease seems to be restricted to animals grazing on natural pastures and not receiving supplementary feeding. Mal seco is clinically characterized by total or partial bowel stasis and the main findings at post-mortem examination are almost exclusively restricted to the bowel. The most striking histopathological changes fou...
Bowles KS, Beadle RE, Mouch S, Pourciau SS, Littlefield-Chabaud MA, Le Blanc C, Mistric L, Fermaglich D, Horohov DW.Equine recurrent airway obstruction (RAO; a term combining both chronic obstructive pulmonary disease (COPD) and summer pasture associated obstructive pulmonary disease (SPAOPD)) is one of the most common equine respiratory diseases with up to 50% of horses affected worldwide. The etiopathogenesis of RAO is unknown although pulmonary hypersensitivity to inhaled mold antigens may be involved. Recent work in our laboratory demonstrating elevated levels of IL-4 and IL-13 mRNA in the airways and peripheral blood of horses with RAO is consistent with an atopic component to RAO. Little is known rega...
Doxey DL, Milne EM, Woodman MP, Gilmour JS, Chisholm HK.The number of neurons in the coeliacomesenteric ganglia and the myenteric and submucosal plexuses of the jejunum, ileum and small colon, and the pathological changes induced in them, were studied in various types of equine dysautonomia. In all forms of dysautonomia, severe and extensive neuron loss and damage occurred in the ileum. In acute and subacute dysautonomia, jejunal neuron loss and damage were severe, but in chronic cases significantly less loss or damage occurred. The damage followed the same pattern in the small colon but it was always less obvious than in the jejunum. The distribut...
Higuchi T, Ichijo S, Osame S, Ohishi H.In order to clarify the cause of white muscle disease (W.M.D.) in foals, tocopherol and selenium concentrations in serum and glutathione peroxidase activities in blood were measured. Examination was made on the samples from horses affected with W.M.D., the foal kept with them in the same stable, the foals kept in the stables without affected foals, and respective mares. The heavy-breed horses in Fukuoka prefecture and Tokachi district were also examined for comparison. Serum tocopherol levels of these foals were normal because after intake of colostrum. Mares of affected foals showed lower toc...
Earley ET, Rawlinson JR, Baratt RM, Galloway SS, Smedley RC, Scarlett JM, Refsal KR, Dotzel AR, Cox VS, Perkins GA.Equine odontoclastic tooth resorption and hypercementosis (EOTRH) is a frequently diagnosed condition in adult horses. The underlying etiology is still unknown. Hematologic, biochemical, and endocrine values have not been reported in EOTRH-affected horses. The main objective of the study was to describe the hematologic, biochemical, and endocrine parameters in horses with EOTRH. Descriptive cross-sectional study of client-owned animals with EOTRH. A complete blood count, biochemistry panel, and endocrine profile were performed in horses diagnosed with EOTRH. Diagnosis was based on oral and rad...
Visser MB, Pollitt CC.Laminitis is known to involve deregulation of proteases and destruction of the lamellar basement membrane with the host inflammatory response also playing a role. Leukocyte infiltration has been well characterized in the black walnut model of laminitis induction, but not in carbohydrate induced models. Increased gene expression of multiple cytokines, including IL-6, has also been implicated in laminitis development. Using real time PCR, immunohistochemistry and zymography methods, we characterize leukocyte infiltration and IL-6 gene expression in oligofructose (OF) induced laminitis. As well, ...
Silva Serra AC, Júnior EC, Cruz JF, Lobo PS, Júnior ET, Bandeira RS, Bezerra DA, Mascarenhas JD, Santos Guerra SF, Soares LS. To perform a molecular analysis of rotavirus A (RVA) G3P[6] strains detected in 2012 and 2017 in the Amazon region of Brazil. Eighteen RVA G3P[6] strains were collected from children aged under 10 years hospitalized with acute gastroenteritis, and partial sequencing of each segment genome was performed using Sanger sequencing. Phylogenetic analysis showed that all G3P[6] strains had a DS-1-like genotype constellation. Two strains had the highest nucleotide identities with equine-like G3P[6]/G3P[8] genotypes. Several amino acid alterations in VP4 and VP7 neutralizing epitopes of equine-l...
Rovel T, Coudry V, Denoix JM, Audigie F.CASE DESCRIPTION Over a 2-year period, 6 horses (4 Selle Français, 1 Hanoverian, and 1 Thoroughbred) were referred for evaluation of forelimb lameness. All horses had radiographic evidence of synostosis of the first and second ribs (SFSR). CLINICAL FINDINGS For 1 horse, the SFSR was considered the probable cause of the lameness (grade 3/5), with a shortening of the cranial phase of the stride in the affected limb. For 3 horses, it was considered a possible cause of the lameness (grade 1/5) for the same reason. For 2 horses, SFSR was considered an incidental finding unassociated with any clini...
Gaughan EM, Gift LJ, Frank RK.Tubular duplication of the cervical portion of the esophagus was diagnosed in a 10-day-old female Quarter Horse. The foal was examined because of the development of a 12- to 15-cm diameter mass at the caudal aspect of the mandible after suckling. The foal was dyspneic when in lateral recumbency. Radiography and ultrasonography revealed a fluid- and gas-filled mass. Endoscopy revealed a normal-appearing upper airway and esophagus. Complete surgical resection of the mass was successful. The mass had a 3-mm diameter communication with the esophageal lumen at the pharyngoesophageal oriface. Histol...
Hildebrand SV, Howitt GA.Succinylcholine was administered by infusion to halothane-anesthetized ponies to determine dosage requirements for surgical relaxation up to 3 hours' duration. This was not possible to do, since 4 of 6 ponies studied developed severe reactions characterized by prolonged muscle fasciculations after the initial succinylcholine dose, muscle rigidity, hyperthermia, hypercapnia, tachycardia, increasing pulse pressure, and metabolic acidosis. The reactions resembled those associated with malignant hyperthermia, a disease recognized in persons and swine. Two ponies showed signs of the phase II or des...
Mohammed HO, Divers TJ, Kwak J, Omar AH, White ME, de Lahunta A.To investigate the influence of oxidative stress in terms of antioxidant capacity and lipid peroxidation on the probability of motor neuron disease (MND) in horses. Methods: 88 horses with MND (cases) and 49 controls. Methods: Blood samples were collected from all horses enrolled, and RBCs and plasma were harvested. Activity of the enzyme erythrocytic superoxide dismutase 1 (SOD1) was determined in the RBCs. Plasma concentrations of α-tocopherols and β-carotenes and activity of glutathione peroxidase were also evaluated. Degree of lipid peroxidation was measured by determining plasma concent...
Raftery AG, Garcia NC, Thompson H, Sutton DG.A 15-year-old Clydesdale cross gelding was investigated and managed over a 2-year period for intermittent collapse. The horse presented initially after an observed episode of collapse at rest, and had a resting tachycardia, elevated Cardiac Troponin I and polycythaemia. Multiple dysrhythmias were detected on telemetric electrocardiography. Vital parameters, cardiac rhythm and red cell count returned to reference range with prolonged rest but further resting syncopal episodes were observed, and due to safety concerns and limited treatment options the horse was euthanased. Post mortem evaluation...
Tangyuenyong S, Viriyakhasem N, Peansukmanee S, Kongtawelert P, Ongchai S.Cartilage erosion in degenerative joint diseases leads to lameness in affected horses. It has been reported that andrographolide from Andrographis paniculata inhibited cartilage matrix-degrading enzymes. This study aimed to explore whether this compound protects equine cartilage degradation in the explant culture model and to determine its effect on matrix metalloproteinase-2 (MMP-2) expression, a matrix-degrading enzyme, in equine chondrocyte culture. Equine articular cartilage explant culture was induced by 25 ng/mL interleukin-1β, a key inducer of cartilage degeneration, in cultures with...
Lai AC, Lin YP, Powell DG, Shortridge KF, Webster RG, Daly J, Chambers TM.An outbreak of influenza occurred among thoroughbred racehorses in Hong Kong in November-December 1992, with morbidity of 37%. All horses involved had been vaccinated against equine-1 and equine-2 influenza viruses but not against the virus responsible for the 1989 equine influenza outbreak in northern China (influenza A/equine/Jilin/89, subtype H3N8). Therefore the source and nature of the virus causing the Hong Kong outbreak was investigated. Virus isolated from a horse infected during the outbreak was used for genetic analysis. All the viral gene segments were similar to those of equine-2 (...
Catone G, Marino G, Mancuso R, Zanghì A.The present study describes the clinicopathological features of a mature cystic ovarian teratoma occurred in a 4 year old, cyclic, nulliparous Andalusian mare. The mass was discovered in the left ovary during a breeding soundness examination, and was hard in consistency and variously echogenic. Laparoscopy was performed to confirm the neoplastic change, followed by a unilateral laparotomic ovariectomy in the standing animal. On the cut surface the teratomatous ovary showed a large cyst filled with hair and sebaceous material and three small cysts containing mucous fluid, surrounded by solid ar...
Luthersson N, Ýr Þorgrímsdóttir Ú, Harris PA, Parkins T, Bennet ED.To investigate equine squamous gastric disease (ESGD) and equine glandular gastric disease (EGGD) in Icelandic horses moving from pasture into training. 81 horses (median age, 3 years; interquartile range, 1 year) from 10 farms representing 4 different Icelandic regions. Initial gastroscopy was undertaken within 2 weeks of moving from pasture into a training establishment. A total of 71 horses underwent endoscopic examination again 8 weeks later. Various management and behavioral factors were assessed through face-to-face questionnaires with the owners or trainers. Multivariable logistic regre...
Laus F, Corsalini J, Mandara MT, Bazzano M, Bertoletti A, Gialletti R.Equine grass sickness (EGS) has been reported in several European and extra-European countries. Despite this, no scientific paper about clinical cases of EGS in Italy has been published. EGS is a disease affecting almost exclusively horses kept on pasture, characterized by clinical signs related to lesions in autonomic nervous system (ANS), particularly in the enteric nervous system (ENS). According to clinical presentation, acute, subacute and chornic syndromes can be observed, with various sympthoms including dullness, anorexia, dysphagia, drooling of saliva, tachycardia, ptosis, patchy swea...
Nissen SD, Saljic A, Kjeldsen ST, Jespersen T, Hopster-Iversen C, Buhl R.Second-degree atrioventricular (AV) block is the most common cardiac arrhythmia in horses, affecting 40-90% depending on breed. Usually, the AV blocks occur while the horses are resting and disappear upon exercise and are, therefore, considered to be uneventful for horses. However, if the AV blocks occur frequently, this may result in syncope and collapse. Identifying the cause of second-degree AV block is difficult and often subscribed to high vagal tone. In this report, we present an eight-year-old Quarter horse with a high burden of second-degree AV blocks and multiple collapses. The clinic...
Kay PH, Dawkins RL, Bowling AT, Bernoco D.The fourth component of complement (C4) is polymorphic in most species studied, and is encoded by a gene or genes within the MHC. In man and mouse there are two closely linked C4 and steroid 21-hydroxylase (21-OH) genes. Therefore we have used Southern blotting to determine whether equine C4 and 21-OH genes are linked. C4 restriction fragment length polymorphism (RFLP) was found with the enzymes EcoRI and BamHI. Comparison of the sizes of EcoRI-digested fragments of genomic DNA hybridizing with C4 and 21-OH probes revealed that equine C4 and 21-OH genes are separated by no more than 13 kb. Fur...
Milne EM, Pirie RS, McGorum BC, Shaw DJ.Equine dysautonomia, or grass sickness, is a frequently fatal disease of unknown etiology, manifested as poor gastrointestinal motility and colic as a result of degenerative changes in the autonomic nervous system. Examination of ileal biopsies collected at laparotomy is currently the best antemortem diagnostic method to distinguish equine dysautonomia from colic cases, which can present with similar signs, but their value has not been previously critically evaluated. Using simulated biopsies collected postmortem from 23 cases of equine dysautonomia and 11 of colic, the sensitivity and specifi...
