Pathology in horses involves the study of diseases and abnormalities affecting equine health, encompassing a range of conditions that can impact various systems within the horse's body. This field examines the causes, mechanisms, and effects of diseases, as well as the structural and functional changes they induce in equine tissues and organs. Common pathological conditions in horses include laminitis, colic, equine infectious anemia, and respiratory disorders. Understanding these diseases involves evaluating clinical signs, diagnostic methods, and treatment options. This page compiles peer-reviewed research studies and scholarly articles that explore the etiology, pathogenesis, and clinical implications of pathological conditions in horses.
Smith MA, Ripley N, Gravatte H, Nielsen MK.With rising anthelmintic resistance in adult cyathostomins, the most pervasive equine parasites, the need to assess larvicidal efficacy has increased, yet available methods remain limited. Encysted larvae are quantified using mucosal digestion, wherein a 5% subsample of intestinal mucosa is processed, and a 2% aliquot is counted for early third stage (EL3) and late third stage/mucosal fourth stage (LL3/L4) larvae. This method is imprecise and post-treatment larval differences are often not observed. The following study aimed to assess standard and modified protocol precision and sensitivity. I...
Alvarado Soto GJ, Maldonado M, Armentrout A, Woolard K, Aleman M, Giaretta P, Willis AT.Achalasia is the most common motility disorder of the esophagus in humans and has been diagnosed in cats and dogs. We describe a 4-month-old Quarter Horse colt with failure to thrive, recurrent colic episodes, and aspiration pneumonia, in which fluoroscopic evaluation identified a caudal esophageal motility disorder consistent with achalasia. Necropsy examination confirmed achalasia.
O'Brien K, Mair T, Mudhar HS, Pesavento P, Miller H, Priestnall SL, Suárez-Bonnet A.Equine squamous cell carcinomas (eSCCs) are common, and a proportion are likely induced by papillomavirus 2 (EcPV-2). Accurate prediction of clinical outcomes is challenging with no recognized prognostic criteria or consistent histopathological classification scheme for eSCC. The aims of this study were to histopathologically subtype a large case series of eSCCs (genital and ocular) and correlate them with p16 and HER-2 expression, equine papillomavirus infection status, and various clinical and histopathological parameters to predict tumour behavior and prognosis. One hundred and eighty-five...
Palunas V, Fussell D, Helgert N, Long AE, Aitken MR, Abraham M.A 2-year-old Irish Sport Horse colt presented with acute, severe and rapidly progressive neurological signs, arriving recumbent to the hospital. Ante-mortem diagnostics did not reveal the cause of the recumbency, and the colt was euthanized after treatment and supportive care did not result in clinical improvement. A cranial cervical extradural mast cell tumour with eosinophilic granulomas and secondary compressive myelopathy with axonal degeneration was diagnosed on post-mortem evaluation. No other masses or clinically relevant findings were present, suggesting a primary neoplasm. Neoplasia a...
Onyiche TE, Peng TL.Potomac Horse Fever (PHF), also known as equine neorickettsiosis (EN) or equine monocytic ehrlichiosis is an acute, potentially fatal infectious disease in horses caused by the monocytotropic rickettsia bacterium Neorickettsia risticii. This obligate intracellular bacterium is maintained throughout the life cycle of digenetic trematodes which utilize multiple intermediate and definitive hosts. Research on N. risticii is scattered across multiple continents, with most studies originating from North and South America. Therefore, a systematic review is needed to consolidate global evidence, clari...
Stimpson S, Molloy E, Davis BW, Esparza B, Rosa LP, Illanes O.Grey coat color in horses, resulting from a 4.6 kb copy number variation (CNV) within the syntaxin 17 (STX17) gene (Grey locus), is linked to progressive hair depigmentation and a markedly increased risk of melanoma, likely to its function as a melanocyte-specific enhancer. Objective: This report details the clinical, pathological, and genomic findings of a 26-year-old flea-bitten grey mare with multiple melanocytic tumors, progressive dyspnea, and congestive heart failure. Due to the poor prognosis the horse was euthanized and submitted for necropsy to the Long Island University - Lewyt Colle...
Sfraga H, Demeter EA, Pinn-Woodcock T, Guarino C, Young R, Cronk B, Cercone M.To investigate the presence of subclinical cranial nuchal bursitis and characterize its histopathologic features and association with Borrelia burgdorferi. Unassigned: This was a prospective descriptive cadaver study on a convenience population of horses in a B burgdorferi-endemic region (15 horses: 5 geldings and 10 mares of various breeds; 4 to 29 years old). Horses without history or clinical signs of cranial nuchal bursitis underwent euthanasia and tissue donation. Cranial nuchal bursa, synovial fluid, and nuchal ligament were collected postmortem. The bursa and ligament were evaluated via...
Boozarjomehri Amnieh S, Ropka-Molik K.The horse is a distinctive translational model for bridging mechanistic discovery and clinically relevant investigation because of its physiological complexity, long lifespan, athletic phenotype, and broad spectrum of naturally occurring conditions that parallel aspects of human health and disease. Its utility extends from musculoskeletal and joint research to immunology, metabolic disorders, and exercise physiology, particularly where naturally developed disease, clinically applicable imaging, and longitudinal sampling are required. Additionally, it offers opportunities to examine both chroni...
González N, Varela A, de Blas N, Gil L.At present, oviductal pathologies and their influence on mare fertility have not been clearly determined. Checking changes throughout the year in the oviductal structure may be relevant to understand the influence on the appearance of problems in oviductal functionality and, thus, the impact on fertility, which is the objective of this work. The oviducts of 56 mares were examined. Their anatomy, permeability, oviductal cellularity and the presence of pathologies were assessed to establish the correlations between the time of the year and each of these parameters. We cannot conclude whether the...
Kuwano A, Kusano K, Mita H, Tamura N, Tokushige H, Iimori M, Kurimoto S, Kawabata M, Ueno M, Okada Y, Kamiya K, Tanaka K.Pathological hoof-wall cavities unrelated to nailing (so called "Gidoh" in Japan) often occur in the feet of horses. In 2001, in facilities managed by the Japan Racing Association (JRA), Gidoh was found to occur most frequently in the toe of the fore-hoof, with no gender predilection, and was more prevalent in older horses. However, it remains unclear whether this trend has continued in recent years, which pathological type of Gidoh predominates, and whether there are differences in prevalence among seasons. Therefore, in spring (April) and autumn (October) of 2020, we surveyed all racehorses ...
Pfannkuche H, Maus J, Engel KM, Schiller J, Schneider MR.Skin sebaceous glands (SGs) synthesize and secrete sebum, a mixture of lipids and cellular debris that defends the external body surface against physicochemical challenges. Recent data define the SG as a dynamic entity with potential functions beyond skin protection, including immunomodulatory actions and the regulation of energy metabolism. We postulate that the SG also has important, unrecognized roles in physiological and pathological processes in domestic animals. Conversely, data derived from domestic animals may have translational relevance for humans. This review article summarizes SG s...
Elsawy BSM, Alzan HF., a recently discovered tick-borne hemoparasite infecting equids globally, has significant implications for equine health. Although it is closely related to (sharing 23% genomic divergence), it establishes an asymptomatic carrier state in persistently infected horses, creating a silent transmission reservoir. Its discovery and unique genetics justify its classification as a new taxon. A critical diagnostic challenge is that the lack of the gene in prevents its detection by the standard cELISA, emphasizing the need for species-specific tools. Although species-specific PCR assays, including ...
Barrantes Murillo DF, Camillo G, Souza Serrano B, Almeida Luciano LP, Castilho Bichara GV, Chaves Vás CA, Furlan Gouvêa FH, Brandini Nespoli PE....Facial abnormalities and brain defects in aborted equine fetuses are rarely reported, and the causes that predispose the occurrence of this condition are difficult to identify. This work reports the morphological and tomographic findings of a case of cryptophthalmia, microphthalmia, oronasal malformation, and hydrocephalus in an aborted equine fetus with umbilical cord torsion in the state of Mato Grosso, Brazil, from a primiparous Quarter Horse female, with 7 months of gestational age. The occurrence of miscarriage was associated with compromised maternal-fetal blood flow due to umbilical cor...
Mendes RP, Gonzaga MS, Matheus MM, Bittar MJ, Doria RGS, Corrêa RR.Developmental and eruption abnormalities are common and can result in progressive dental diseases. Ectopic eruption of the affected tooth may be the result of these processes. This study aims to report the occurrence of a permanent mandibular tooth in a horizontal position, with retention of the corresponding deciduous tooth, in a miniature horse. A 2-year-old female miniature horse was admitted to the veterinary hospital with a hard swelling on the left mandibular ramus, which had been growing continuously for three months. After a complete evaluation, it was concluded that the swelling was t...
Dillmann JB, Dos Santos TS, Dos Santos RC, Monteiro SG.Equine cutaneous pythiosis, caused by Pythium insidiosum, is a severe disease in tropical and subtropical regions, often leading to progressive granulomatous lesions with poor response to conventional therapies. Standard treatment includes surgical excision and immunotherapy, but recurrence is common, particularly in distal limb lesions. Maggot Debridement Therapy (MDT) with disinfected Lucilia cuprina larvae provides selective debridement, microbial control, and stimulation of granulation, representing a potential adjunctive option. This report describes the successful use of MDT combined wit...
Andrade AC, Fonseca SMC, Silva Filho GB, Melo ET, Santos JRP, Frota MLSL, Duarte JMBS, Evêncio-Neto J, Brito LB, Lima TS, Wicpolt NS, Riet-Correa F....We report an outbreak of Crotalaria juncea intoxication in horses exhibiting progressive weight loss and respiratory distress in northeastern Brazil. Necropsy revealed firm, non-collapsed lungs with extensive interstitial fibrosis, bronchiolar epithelial hyperplasia with club cells proliferation, and marked pulmonary arterial remodeling. Hepatic lesions consisted primarily of centrilobular necrosis, probably resulting from hypoxic injury related to anemia and prolonged agonic death. Pasture inspection identified significant invasion by shrubs of C. juncea in various phenological stages.
Boeger L, Volkmann N, Probst J, Kemper N, Venner M.The emergence of antimicrobial resistance raises concerns about using antibiotics in veterinary medicine, particularly in cases of bronchopneumonia in foals diagnosed early based on a screening programme. Many subclinical foals recover spontaneously, thus, interest in more restrictive antibiotic usage is increasing. Objective: To determine whether initiating antimicrobial therapy at a later stage of bronchopneumonia decreases antimicrobial usage without compromising successful resolution of pathology in affected foals. Methods: A total of 1200 warmblood foals born in 2020, 2022, 2023 and 2024 ...
Luedke LK.This article provides an overview of equine paranasal sinus disease with emphasis on relevant anatomy, diagnostic considerations, and commonly encountered pathologic conditions. It outlines the structure and drainage of the paranasal sinuses to establish a foundation for understanding disease development and spread. The discussion reviews available diagnostic modalities and their roles in localizing disease and determining underlying causes. Common sinus disorders are presented with attention to their general pathophysiology, diagnostic features, treatment approaches, and expected outcomes. Co...
Häussling MPP, Steinberg T, Büttner K, Hannig C, Hannig M, Lemke L, Zierau O, Staszyk C.Destructive lesions of the peripheral and infundibular cementum are increasingly recognized in equine dentistry. While similarities to human caries have been noted, current evidence does not conclusively support this classification. This study aims to assess the prevalence, distribution, and potential risk factors associated with these lesions in a defined horse population. Unassigned: A total of 114 horses from northern Germany underwent standardized oral examination between 2021 and 2023. Clinical data on peripheral and infundibular lesions, diastemata, and influencing factors such as age an...
Haussler KK.Congenital cervical vertebral anomalies in horses are structural changes in the neck vertebrae that develop during the fetal stage. These anomalies can vary in their severity and effects. Some horses may not show any clinical signs and can live normally, while others may develop serious problems such as spinal cord compression. This compression can lead to issues like ataxia or even paralysis, affecting the horse's mobility and quality of life. Recognizing and diagnosing these anomalies early are very important, as it helps guide decisions about the best treatment options and overall managemen...
Rissi DR, Mendes RE.Squamous cell carcinoma (SCC) is the most common ocular and periocular neoplasm of horses, typically arising from the limbus, third eyelid mucosa or mucocutaneous junctions of the upper and lower eyelids. Tumours are locally invasive, prone to recurrence and may rarely metastasize. Histological evaluation is required for definitive diagnosis and atypical SCC subtypes may be diagnostically challenging. Here we describe a clear cell SCC in the third eyelid of a 16-year-old female Quarter Horse. The red and invasive mass was surgically excised for histological evaluation. The lesion consisted of ...
Teague P, Dark M, Verdugo D, Freeman D, McFarlane D.The equine pancreas remains understudied, particularly in the context of endocrine disease. This study aimed to characterize regional islet distribution and composition in the normal equine pancreas and investigate how hyperinsulinemia (HI) and pituitary pars intermedia dysfunction (PPID) influence pancreatic islet morphology and hormone expression. In the first experiment, pancreas samples from eight healthy horses were collected and analyzed across three anatomical locations: left lobe, body, and right lobe. The left lobe exhibited a greater relative islet area and perimeter compared to the ...
Karastoyanova N, Stamberov P, Nikolova S, Leshtakov P.To assess pathological lesions observed in an Early Iron Age (8th-century BCE) horse to gain insight into equine use and management in the past. Methods: The study is based on a nearly complete adult horse skeleton recovered from a pit at an archaeological site near Chirpan, Thracian Valley, southern Bulgaria. The assemblage is radiocarbon dated to the 8th century BCE and represents one of the few well-documented Early Iron Age equine skeletons from Bulgaria. Methods: Preserved skeletal elements were examined macroscopically following standard zooarchaeological and palaeopathological protocols...
Schliewert EC, Hooijberg EH, Goddard A.African horse sickness (AHS), caused by the vector-borne African horse sickness virus (AHSV), is endemic to sub-Saharan Africa and infection results in high mortality in naïve equine populations. Clinical signs include submucosal petechiae and prolonged bleeding post venepuncture indicative of hypocoagulation. Pathological activation of haemostasis may result from tissue factor expression as a result of vascular endothelial damage or dysfunction, the proposed pathologic mechanism in AHS, potentially resulting in disseminated intravascular coagulation (DIC). Objective: To describe haemostatic ...
Riet-Correa F, Micheloud JF, Machado M, Mendonça FS, Schild AL, Uzal FA, Lemos RAA.The objective of this paper is to review the information on toxic plants for ruminants and horses in South America, a continent in which there are 237 plants known to be toxic for livestock. Predisposing factors for plant toxicity include parts or vegetative state of the plants consumed, sprouting after rains, toxic dose, social facilitation, palatability, hunger, thirst, naivete, ingestion period, susceptibility/resistance, transportation, climatic alterations, and environmental degradation. Toxic plants can be forage or non-forage species. The latter can be invasive plants from other regions...
Dorrego A, Olvera-Maneu S, Jose-Cunilleras E, Gago P, Raez A, Rivera B, Oporto A, Gonzalez S, Cruz-Lopez F.The forest fly ) is an obligate haematophagous dipteran insect (order Diptera) that primarily infests horses and may contribute to the circulation of vector-borne pathogens. This study aimed to investigate the presence of , s.l., , and , important vector-borne pathogens of equids, in forest flies collected from horses in endemic areas of Spain. A total of 170 forest flies were collected from 39 equids across four geographical regions in Spain (Segovia, Madrid, Toledo, and Menorca) and blood samples were collected from 27 of these horses. All flies were morphologically and molecularly identifi...
Konstantinović N, Gotić J, Baban M, Csik G, Listeš E, Gagović E, Jurković Žilić D, Arežina I, Šubara G, Čulina FE, Delić N, Višal D....Hemotropic mycoplasmas (hemoplasmas) are uncultivable, cell wall-less bacteria that parasitizeon the surface of red blood cells of mammals, potentially causing anemia and other systemic signs. While widely distributed among domestic and wild animals, their occurrence in equids remains poorly understood, and no species has been identified as host-specific to horses or donkeys. This study presents the first systematic survey of hemoplasmas in equids from southeastern Europe and only the second molecularly confirmed case in horses in Europe. A total of 843 equids (817 horses and 26 donkeys) from ...
Bertuglia A, Cantatore F, Pallante M, Manassero L, Bergamini L, Riccio B, Pagliara E.To report the incidence, and clinical and pathological findings of developmental lateral patellar luxation in Standardbred yearlings diagnosed with femoropatellar dysplasia (FPD) and demonstrate that osteochondral lesions in the lateral trochlear ridge (LTR) of the femur observed in the affected horses are osteochondral lesions related to patellar maltracking.Retrospective case series. Medical records were retrospectively reviewed for Standardbreds <12 months of age diagnosed with FPD between 2017 and 2023.A total of 10 Standardbred yearlings developed FPD (incidence 6.4 cases per 1,000 foals)...
Ahern BJ, Parvizi J, Boston R, Schaer TP.Review the literature for single site cartilage defect research and evaluate the respective strengths and weaknesses of different preclinical animal models. Methods: A literature search for animal models evaluating single site cartilage defects was performed. Variables tabulated and analyzed included animal species, age and number, defect depth and diameter and study duration. Cluster analyses were then used to separate animals with only distal femoral defects into similar groups based on defect dimensions. Representative human studies were included allowing comparison of common clinical lesio...
O'Sullivan JD, Allworth AM, Paterson DL, Snow TM, Boots R, Gleeson LJ, Gould AR, Hyatt AD, Bradfield J.In September, 1994, an outbreak of severe respiratory disease affected 18 horses, their trainer, and a stablehand in Queensland, Australia. Fourteen horses and one human being died. A novel virus was isolated from those affected and named equine morbillivirus (EMV). We report a case of encephalitis caused by this virus. Results: A 35-year-old man from Queensland had a brief aseptic meningitic illness in August, 1994, shortly after caring for two horses that died from EMV infection and then assisting at their necropsies. He then suffered severe encephalitis 13 months later, characterised by unc...
Hauck SM, Dietter J, Kramer RL, Hofmaier F, Zipplies JK, Amann B, Feuchtinger A, Deeg CA, Ueffing M.Autoimmune uveitis is a blinding disease presenting with autoantibodies against eye-specific proteins as well as autoagressive T cells invading and attacking the immune-privileged target tissue retina. The molecular events enabling T cells to invade and attack the tissue have remained elusive. Changes in membrane protein expression patterns between diseased and healthy stages are especially interesting because initiating events of disease will most likely occur at membranes. Since disease progression is accompanied with a break-down of the blood-retinal barrier, serum-derived proteins mask the...
Schmoldt A, Benthe HF, Haberland G, Tarentino AL, Maley F, Berkmen YM, Lande A, Ti-sheng C, Teh-chao W.The chest roentgenographic findings in Takayasu's arteritis include widening of the ascending aorta, contour irregularities of the descending aorta, arotic calcifications, pulmonary arterial changes, rib notching, and hilar lymphadenopathy. The single most important diagnostic sign is a segmental calcification outlining a localized or diffuse narrowing of the aorta. The other signs may be suspicious or suggestive, but the diagnostic accuracy increases when several findings are present simultaneously.
de Laat MA, McGowan CM, Sillence MN, Pollitt CC.Hyperinsulinaemia is known to induce laminitis experimentally in healthy ponies with no history of the condition. Horses are more insulin sensitive than ponies and whether prolonged hyperinsulinaemia and euglycaemia would have a similar laminitogenic effect requires study. Objective: To determine if laminitis results when the prolonged euglycaemic hyperinsulinaemic clamp technique (p-EHC) is applied to clinically normal Standardbred horses, and to monitor hoof wall temperature seeking an association between vascular activity and laminitis development. Methods: Eight young, clinically normal St...
Corning S.The small strongyles of horses, also known as cyathostomins, are considered the most prevalent and pathogenic parasites of horses today. The clinical syndrome of larval cyathostominosis which occurs as a result of mass emergence of inhibited stages has a high fatality rate despite the best standard of care given to affected horses. Management of the challenge level of cyathostomins to prevent the syndrome is preferable. Many different management programmes have been tried over the past two decades, with mixed success. Programmes have relied heavily on repeated use of anthelmintic treatments th...
Costa MC, Weese JS.This article provides readers with the basic concepts necessary to understand studies using recent molecular methods performed in intestinal microbiome assessment, with special emphasis on the high throughput sequencing. This review also summarizes the current knowledge on this topic and discusses future insights on the interaction between the intestinal microbiome and equine health.
Kriek NP, Kellerman TS, Marasas WF.An isolate of Fusarium verticillioides (MRC826) that induced experimental leukoencephalomalacia, also caused acute toxicity when fed to pigs and administered per rumen fistula to sheep. Pigs developed severe pulmonary oedema while sheep manifested severe nephrosis and hepatosis. A less toxic isolate (F. verticillioides MRC602), fed to baboons, resulted in acute congestive heart failure or hepatic cirrhosis, depending on the dose. Both isolates were toxic to rats and caused similar lesions, namely, hepatic cirrhosis and intraventricular cardiac thrombosis.
Couëtil LL, Hoffman AM, Hodgson J, Buechner-Maxwell V, Viel L, Wood JL, Lavoie JP.The purpose of this consensus statement is to provide a review of current knowledge and opinions concerning inflammatory airway disease (IAD) and to help practitioners differentiate IAD from heaves (or recurrent airway obstruction; RAO) and other inflammatory respiratory diseases of horses.
Kapoor A, Simmonds P, Cullen JM, Scheel TK, Medina JL, Giannitti F, Nishiuchi E, Brock KV, Burbelo PD, Rice CM, Lipkin WI.The recent identification of nonprimate hepaciviruses in dogs and then in horses prompted us to look for pegiviruses (GB virus-like viruses) in these species. Although none were detected in canines, we found widespread natural infection of horses by a novel pegivirus. Unique genomic features and phylogenetic analyses confirmed that the tentatively named equine pegivirus (EPgV) represents a novel species within the Pegivirus genus. We also determined that EPgV causes persistent viremia whereas its clinical significance is undetermined.
Dakin SG, Werling D, Hibbert A, Abayasekara DR, Young NJ, Smith RK, Dudhia J.Macrophages (Mφ) orchestrate inflammatory and reparatory processes in injured connective tissues but their role during different phases of tendon healing is not known. We investigated the contribution of different Mφ subsets in an equine model of naturally occurring tendon injury. Post mortem tissues were harvested from normal (uninjured), sub-acute (3-6 weeks post injury) and chronically injured (>3 months post injury) superficial digital flexor tendons. To determine if inflammation was present in injured tendons, Mφ sub-populations were quantified based on surface antigen expression of...
Rivas F, Zahid OK, Reesink HL, Peal BT, Nixon AJ, DeAngelis PL, Skardal A, Rahbar E, Hall AR.Hyaluronan (or hyaluronic acid, HA) is a ubiquitous molecule that plays critical roles in numerous physiological functions in vivo, including tissue hydration, inflammation, and joint lubrication. Both the abundance and size distribution of HA in biological fluids are recognized as robust indicators of various pathologies and disease progressions. However, such analyses remain challenging because conventional methods are not sufficiently sensitive, have limited dynamic range, and/or are only semi-quantitative. Here we demonstrate label-free detection and molecular weight discrimination of HA w...
Bian J, Khaychuk V, Angers RC, Fernández-Borges N, Vidal E, Meyerett-Reid C, Kim S, Calvi CL, Bartz JC, Hoover EA, Agrimi U, Richt JA, Castilla J....Adaptation of prions to new species is thought to reflect the capacity of the host-encoded cellular form of the prion protein (PrP) to selectively propagate optimized prion conformations from larger ensembles generated in the species of origin. Here we describe an alternate replicative process, termed nonadaptive prion amplification (NAPA), in which dominant conformers bypass this requirement during particular interspecies transmissions. To model susceptibility of horses to prions, we produced transgenic (Tg) mice expressing cognate PrP Although disease transmission to only a subset of infecte...
Dubey JP, Lindsay DS, Saville WJ, Reed SM, Granstrom DE, Speer CA.Equine protozoal myeloencephalitis (EPM) is a serious neurological disease of horses in the Americas. The protozoan most commonly associated with EPM is Sarcocystis neurona. The complete life cycle of S. neurona is unknown, including its natural intermediate host that harbors its sarcocyst. Opossums (Didelphis virginiana, Didelphis albiventris) are its definitive hosts. Horses are considered its aberrant hosts because only schizonts and merozoites (no sarcocysts) are found in horses. EPM-like disease occurs in a variety of mammals including cats, mink, raccoons, skunks, Pacific harbor seals, p...
Hinchcliff KW, Couetil LL, Knight PK, Morley PS, Robinson NE, Sweeney CR, van Erck E.Published studies of exercise-induced pulmonary hemorrhage (EIPH), when assessed individually, often provide equivocal or conflicting results. Systematic reviews aggregate evidence from individual studies to provide a global assessment of the quality of evidence and to inform recommendations. Objective: Evaluate evidence to determine: if EIPH adversely affects the health, welfare or both of horses; if EIPH affects the athletic capacity of horses; the efficacy of prophylactic interventions for EIPH; and if furosemide affects the athletic capacity of horses. Methods: None. Methods: Systematic re...
Murray MJ, Schusser GF, Pipers FS, Gross SJ.Gastroscopic examinations were performed on 67 Thoroughbred horses in training at a race track and repeat examinations performed in 35 horses, 2 to 3 months later. Horses were age 2-9 years and included 16 two-year-olds, 32 three-year-olds and 19 horses > or = 4-years-old. Forty-two of the 67 horses had raced within the 2 months before the initial examination and the remaining 25 horses were in training. Sixty-two of the 67 horses (93%) had one or more lesions present in the gastric mucosa and lesions were present in all of the 42 horses that had raced. Thirty-two of the 35 horses, examined...
Birch HL, Bailey AJ, Goodship AE.Injuries to the superficial digital flexor tendon are common in horses required to gallop and jump at speed. Partial rupture of this tendon usually occurs in the central core of the midmetacarpal region and may be preceded by localised degenerative changes. Post mortem examination of apparently normal equine flexor tendons has revealed an abnormal macroscopic appearance in the central core, characterised by a reddish discolouration. We have previously shown that there is also physical damage to the collagen fibres. In the present study we tested the hypothesis that the abnormal appearance is a...
Bertuglia A, Lacourt M, Girard C, Beauchamp G, Richard H, Laverty S.The role of osteoclasts in osteochondral degeneration in osteoarthritis (OA) has rarely been investigated in spontaneous disease or animal models of OA. Objective: The objectives of the current study were to investigate osteoclast density and location in post-traumatic OA (PTOA) and control specimens from racehorses. Methods: Cores were harvested from a site in the equine third carpal bone, that undergoes repetitive, high intensity loading. Histological and immunohistochemical (Cathepsin K and Receptor-activator of Nuclear Factor kappa-β ligand (RANKL)) stained sections were scored (global an...
Williams KJ, Maes R, Del Piero F, Lim A, Wise A, Bolin DC, Caswell J, Jackson C, Robinson NE, Derksen F, Scott MA, Uhal BD, Li X, Youssef SA, Bolin SR.Pulmonary fibrosis and interstitial lung disease are poorly understood in horses; the causes of such conditions are rarely identified. Equine herpesvirus 5 (EHV-5) is a gamma-herpesvirus of horses that has not been associated with disease in horses. Pathologic and virologic findings from 24 horses with progressive nodular fibrotic lung disease associated with EHV-5 infection are described and compared with 23 age-matched control animals. Gross lesions consisted of multiple nodules of fibrosis throughout the lungs. Histologically, there was marked interstitial fibrosis, often with preservation ...
Valentine BA.A study of 57 cutaneous melanocytic tumors from 53 horses revealed 4 distinct clinical syndromes: melanocytic nevus, dermal melanoma, dermal melanomatosis, and anaplastic malignant melanoma. Melanocytic nevus and anaplastic melanoma each had histopathologic features that distinguished them from dermal melanoma and dermal melanomatosis. Dermal melanoma and dermal melanomatosis were histologically similar but could be differentiated by their clinical features. Melanocytic nevi were diagnosed in 29 horses with an average age of 5 years; they were solitary, superficial masses that occurred in both...
Dixon PM, Dacre I.Equine dentistry is a very important but until recently rather neglected area of equine practice, with many horses suffering from undiagnosed, painful dental disorders. A thorough clinical examination using a full mouth speculum is a pre-requisite to performing any equine dental procedure. Common incisor disorders include: prolonged retention of deciduous incisors, supernumerary incisors and overjet--the latter usually accompanied by cheek teeth (CT) overgrowths. Overjet can be surgically corrected, but perhaps should not be in breeding animals. In younger horses, traumatically fractured incis...
Lacourt M, Gao C, Li A, Girard C, Beauchamp G, Henderson JE, Laverty S.To correlate degenerative changes in cartilage and subchondral bone in the third carpal bone (C3) of Standardbred racehorses with naturally occurring repetitive trauma-induced osteoarthritis. Methods: Fifteen C3, collected from Standardbred horses postmortem, were assessed for cartilage lesions by visual inspection and divided into Control (CO), Early Osteoarthritis (EOA) and Advanced Osteoarthritis (AOA) groups. Two osteochondral cores were harvested from corresponding dorsal sites on each bone and scanned with a micro-computed tomography (CT) instrument. 2D images were assembled into 3D reco...
Neundorf RH, Lowerison MB, Cruz AM, Thomason JJ, McEwen BJ, Hurtig MB.To determine the prevalence and severity of osteoarthritis in the metacarpophalangeal joints of Thoroughbred racehorses via development and validation of a quantitative macroscopic evaluation system. Methods: Metacarpophalangeal joints from 50 Thoroughbred racehorses. Methods: Joints were collected from horses that died or were euthanized within 60 days of racing. Metacarpophalangeal joints were assessed for osteoarthritic degeneration by use of macroscopic and histologic scoring systems, polarized light microscopy, and cartilage biochemical analysis. The global macroscopic score for the entir...
Patterson-Kane JC, Rich T.Superficial digital flexor tendon (SDFT) injury in equine athletes is one of the most well-accepted, scientifically supported companion animal models of human disease (i.e., exercise-induced Achilles tendon [AT] injury). The SDFT and AT are functionally and clinically equivalent (and important) energy-storing structures for which no equally appropriate rodent, rabbit, or other analogues exist. Access to equine tissues has facilitated significant advances in knowledge of tendon maturation and aging, determination of specific exercise effects (including early life), and definition of some of the...
Marasas WF, Kellerman TS, Pienaar JG, Naudé TW.When 2 horses were dosed with cultures of a Fusarium moniliforme isolate that had previously caused only hepatosis, 1 developed brain oedema and hepatosis, and the other only leukoencephalomalacia. A 3rd horse developed both leukoencephalomalacia and hepatosis after being dosed with another isolate obtained from maize which was associated with a natural outbreak of the nervous form of the disease. Since leukoencephalomalacia and hepatosis could be induced by the same culture material, it was concluded that both syndromes were manifestations of the same toxicosis. There was also some evidence t...
Riggs CM, Vaughan LC, Evans GP, Lanyon LE, Boyde A.Mechanical test specimens were prepared from the cranial and caudal cortices of radii from eight horses. These were subjected to destructive tests in either tension or compression. The ultimate stress, elastic modulus and energy absorbed to failure were calculated in either mode of loading. Analysis was performed on the specimens following mechanical testing to determine their density, mineral content, mineral density distribution and histological type. A novel technique was applied to sections from each specimen to quantify the predominant collagen fibre orientation of the bone near the plane...
Perkins GA, den Bakker HC, Burton AJ, Erb HN, McDonough SP, McDonough PL, Parker J, Rosenthal RL, Wiedmann M, Dowd SE, Simpson KW.Little is known about the gastric mucosal microbiota in healthy horses, and its role in gastric disease has not been critically examined. The present study used a combination of 16S rRNA bacterial tag-encoded pyrosequencing (bTEFAP) and fluorescence in situ hybridization (FISH) to characterize the composition and spatial distribution of selected gastric mucosal microbiota of healthy horses. Biopsy specimens of the squamous, glandular, antral, and any ulcerated mucosa were obtained from 6 healthy horses by gastroscopy and from 3 horses immediately postmortem. Pyrosequencing was performed on bio...
Giles RC, Donahue JM, Hong CB, Tuttle PA, Petrites-Murphy MB, Poonacha KB, Roberts AW, Tramontin RR, Smith B, Swerczek TW.Pathology case records of 3,514 aborted fetuses, stillborn foals, or foals that died < 24 hours after birth and of 13 placentas from mares whose foals were weak or unthrifty at birth were reviewed to determine the cause of abortion, death, or illness. Fetoplacental infection caused by bacteria (n = 628), equine herpesvirus (143), fungi (61), or placentitis (351), in which an etiologic agent could not be defined, was the most common diagnosis. Complications of birth, including neonatal asphyxia, dystocia, or trauma, were the second most common cause of mortality and were diagnosed in 19% of the...
