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.
Borges LM, Ferreira LA, da Silva LS, de Oliveira RA, Mussi SV, Faria KA, Melo LS, Abud LJ, Costa GL, Soares SF.This study was carried out with the objective of evaluating the efficacy of a 2,6-dichlorophenol (2,6-DCP) lure to control Dermacentor nitens (Acari: Ixodidae). Slow-release formulations of the pheromone formulated with and without cypermethrin were prepared. Olfactometer bioassays were used to define the best dose of the pheromone and to evaluate the effect of cypermethrin with 2,6-DCP attractiveness. Sexually active males were released 15 cm from 2 cmx1 cm pieces of polypropylene treated with different odors: 2,6-DCP in a liposphere system (1.5, 30 and 300 microg--without cypermethrin and 30...
Hauck SM, Schoeffmann S, Amann B, Stangassinger M, Gerhards H, Ueffing M, Deeg CA.Spontaneous equine recurrent uveitis (ERU) is an incurable autoimmune disease affecting the eye. Although retinal-autoantigen specific T-helper 1 cells have been demonstrated to trigger disease progression and relapses, the molecular processes leading to retinal degeneration and consequent blindness remain unknown. To elucidate such processes, we studied changes in the total retinal proteome of ERU-diseased horses compared to healthy controls. Severe changes in the retinal proteome were found for several markers for blood-retinal barrier breakdown and whose emergence depended upon disease seve...
Kornaś S, Skalska M, Nowosad B.The objective of this study was to evaluate the level of roundworm infection in working horses slaughtered for meat. In these horses anthelmintics had not been used. Methods: Roundworms were collected post-mortem from small intestines of 83 horses. Results: The mean prevalence of roundworm infection was 12% and intensity--46.7 specimens per horse. Infection was found only in foals; 10 animals were infected (45.4%) among the 22 examined. Due to common occurrence of roundworms (Parascaris equorum) in foals this nematode control should focus particularly on regular anthelmintic treatment of young...
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.
Cotovio M, Monreal L, Navarro M, Segura D, Prada J, Alves A.In humans and experimental animals, disseminated intravascular coagulation (DIC) causes fibrin deposition in several organs, which eventually leads to ischemia and multiorgan failure. Objective: Horses who died or were euthanized for severe gastrointestinal disorders could have fibrin deposits in different tissues. Methods: Tissue-organ samples collected during postmortem examinations on 66 colic horses with poor prognoses (eg, severe intestinal ischemia, enteritis, peritonitis), from 11 colic horses with good prognoses (eg, large-colon obstruction or displacement), and from 16 slaughter horse...
Delesalle C, Dewulf J, Lefebvre RA, Schuurkes JA, Proot J, Lefere L, Deprez P.Intestinal hypoperfusion can lead to increased lactate concentrations in plasma and peritoneal fluid of horses with colic. Objective: The purposes of this study were to (1) evaluate the reliability of the Accusport analyzer to assess peritoneal fluid lactate (PFL) concentrations in healthy horses and those with colic, (2) identify clinical features associated with abnormal blood plasma lactate (BPL) and PFL concentrations, and (3) evaluate the prognostic value of BPL and PFL. Methods: BPL and PFL were determined in 20 healthy horses and in 106 horses with colic. Results: The Accusport was reli...
Laus F, Preziuso S, Spaterna A, Beribè F, Tesei B, Cuteri V.An outbreak of strangle-like disease involving 26 horses farmed in central Italy was investigated by clinic examination, endoscopy, cytology, bacteriology and polymerase chain reaction (PCR). At weekly interval, a total of three nasal swabs and one guttural pouches lavage fluid (GPLF) were collected, and no Streptococcus equi subsp. equi carrier was found. Some horses showed upper airways disease and endoscopic signs of pharyngeal lymphoid hyperplasia of different grade and/or abnormal endoscopic appearance of guttural pouches. Streptococcus dysgalactiae subsp. equisimilis was isolated from 14...
Newton JR, Laxton R, Wood JL, Chanter N.The objective of the study was to characterise the molecular epidemiology of Streptococcus zooepidemicus infection among isolates collected sequentially from recently weaned, pasture maintained Welsh mountain ponies with naturally occurring respiratory disease. Weekly nasopharyngeal and tracheal lavage samplings over a 10-week period were conducted in 29 ponies. Two PCR typing methods based on characterisation of the M-protein hypervariable (HV) region and the 16S-23S rRNA gene intergenic spacer were then applied to isolates of S. zooepidemicus recovered from nasopharyngeal swab and tracheal w...
Nasir L, Gault E, Morgan IM, Chambers G, Ellsmore V, Campo MS.BPV-1 DNA is the predominant viral type detected in equine sarcoids and represents the only reported natural cross species infection of papillomaviruses. In this study, nucleotide variations in the LCR and the E2 regions of equine sarcoid-associated BPV-1 were characterised by sequence analysis. Variants particular to sarcoid BPV-1 were identified in both the LCR and E2 sequence. The functionality of the most common LCR variant was examined in equine and bovine cells. These studies showed that the activity of the variant LCR was higher in equine cells than bovine cells; the activity of the var...
Loynachan AT, Williams NM, Freestone JF.A 5-day-old Thoroughbred foal was submitted to the necropsy service at the University of Kentucky Livestock Disease Diagnostic Center. The foal had a clinical history of seizure activity and severe icterus. A complete blood count and serum chemistry analysis indicated that the foal was anemic (hematocrit, 16%), hyperbilirubinemic (45 mg/dl), and hypoglycemic. At necropsy, all tissues were discolored various shades of yellow. Microscopically, there was degeneration and necrosis of cerebral neurons and cerebellar Purkinje cells; severe hepatocellular degeneration and necrosis; and deposition of ...
Boyle AG, Martin BB, Davidson EJ, Durando MM, Birks EK.Dynamic pharyngeal collapse (PC) is a condition seen in racehorses that can be career-ending. Objective: To characterise and grade PC and describe the effects of PC on athletic performance. Methods: Medical records were reviewed for 828 horses, of which 49 (6%) records were identified as horses with a primary diagnosis of PC. Tapes of video-endoscopy of the pharynx during exercise were reviewed. Each video recording was assigned a grade (0-4) reflecting the degree of PC and a classification for severity of upper airway obstruction. Earnings per race prior to diagnosis of PC were compared to ea...
Barrey E, Mucher E, Robert C, Amiot F, Gidrol X.Genomics using cDNA microarrays could provide useful information about physiological adaptations and metabolic disorders in endurance horses. Objective: In order to show that genes are modulated in leucocytes in relationship with performance and clinical status of the horses, gene expression in leucocytes, haematological and biochemical parameters were compared between successful and disqualified endurance horses. Methods: Blood samples were collected at rest (TO) and just after a 140-160 km endurance race (T1) in 2 groups of horses: 10 continuing successful (S) and 10 disqualified horses stop...
Buckley T, Creighton A, Fogarty U.Respiratory infections, recurrent airway obstruction (RAO) and exercise induced pulmonary haemorrhage (EIPH) are major causes of poor performance in horses. Fungi and mycotoxins are now recognised as a major cause of these conditions. The most notable fungi are Aspergillus and Fusarium. Fungal spores can originate from forage, bedding and feed and, in turn, these fungal spores can produce a series of mycotoxins as secondary metabolites.This study set out to ascertain the degree of fungal and mycotoxin contamination in feed and fodder used in Irish racing yards over a one-year period. Weather c...
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, ...
Lundström TS, Dahlén GG, Wattle OS.Swedish equine dental practices have empirically found that the prevalence of infundibular caries as a primary disorder in the first permanent premolar teeth (P2) of the horse upper jaw has increased during the last 10 years. A previously unknown bacterial species, Streptococcus devriesei (CCUG 47155T), which is related to Streptococcus mutans, has recently been isolated from these carious lesions. To understand the aetiology of caries in horses, it is essential to elucidate the relationship between S. devriesei and P2 infundibular caries. Methods: The anterior infundibulum of maxillary P2, or...
Kutasi O, Vörös K, Biksi I, Szenci O, Sötonyi P.This paper presents the embryological and pathological features as well as the terminology and classification of common atrioventricular canal, a type of endocardial cushion defect. The authors give a complete description of an extremely rare congenital cardiac malformation in an equine neonate. The diagnosis of a complete, balanced common atrioventricular canal of type C in Rastelli's classification scheme was based on two-dimensional, contrast and colour Doppler echocardiography and subsequent postmortem gross pathology. To support our diagnosis and study the pathophysiological effect of the...
Landolt GA.Acute poisoning and envenomation often represent a diagnostic and therapeutic challenge. Although identification ultimately may benefit the affected animal, treatment frequently must commence before an etiologic diagnosis is established. Therefore, the goals for the management of acutely intoxicated horses must be focused on emergency intervention and stabilization of the patient, prevention of further exposure, and aggressive decontamination. This article reviews the treatment steps that should be considered during the management of horses experiencing poisoning or envenomation.
Branch MV, Murray RC, Dyson SJ, Goodship AE.Understanding of the development of pathology and source of pain in distal tarsal osteoarthritis is poorly understood. Magnetic resonance imaging is often used in the analysis of human osteoarthritis (OA) because it is sensitive to early changes. Objective: In association with distal tarsal joint (DTJ) pain, there will be an alteration in the characteristic subchondral bone (SCB) thickness pattern of horses with no history of pain when subjected to low-level exercise. Methods: Sixteen cadaver tarsal joints were collected from 9 mature horses with a history of tarsal pain and radiographic evide...
Newton JR, Woodt JL, Chanter N.Recurring respiratory infections can contribute to prolonged burdens of disease, especially in younger horses and better knowledge of factors and effective interventions, such as vaccines, should improve therapeutic and preventive strategies. Objective: To identify factors and infections associated with naturally occurring respiratory disease in recently weaned Welsh Mountain ponies maintained at pasture and to determine whether ponies vaccinated with an experimental inactivated bacterial vaccine had lower burdens of disease and infection compared to nonvaccinated controls. Transferrin allele,...
Craig MI, Barrandeguy ME, Fernández FM.Equine herpesvirus 2 (EHV-2) was isolated from healthy animals; therefore, the association between EHV-2 infection and respiratory disease raises the question of the role of this agent in this pathology. To date, there are no reports that relate viral excretion to health, this study then analysed 153 nasal swabs from horses in different age groups (older and younger than 1 year old) and state of health (clinically healthy and with respiratory symptoms). Results showed that the percentage of horses with viral excretion was higher within the clinically healthy group, being significative (p < 0.0...
Parsons CS, Orsini JA, Krafty R, Capewell L, Boston R.To identify risk factors for development of acute laminitis in horses during hospitalization for illness or injury. Methods: Retrospective case-control study. Methods: 73 horses that developed laminitis (case horses) and 146 horses that did not develop laminitis (control horses) during hospitalization. Methods: Case and control horses were matched in a 2:1 ratio by the date on which each horse was evaluated. Potential risk factors investigated included age, breed, and sex; highest and lowest values recorded during hospitalization for fibrinogen concentration, WBC count, PCV, and total solids c...
Venter GJ, Koekemoer JJ, Paweska JT.Confirmed outbreaks of African horse sickness (AHS) occurred in the surveillance zone of the Western Cape in 1999 and 2004, both of which led to a two-year suspension on the export of horses. Light trap surveys in the outbreak areas showed that known vector competent Culicoides species, notably C. imicola, were abundant and present in numbers equal to those in the traditional AHS endemic areas. Isolations of AHS virus serotypes 1 and 7, equine encephalosis virus, and bluetongue virus from field-collected C. imicola in the surveillance zone demonstrated that this species was highly competent an...
Ripolles M, Sánchez-Guerrero MJ, Perdomo-González DI, Azor P, Valera M.Ewe Neck is a relatively common morphological defect in Pura Raza Español (PRE) horses and other Baroque type horse breeds, which adversely affects the breeding industry; (1) objectives: to establish the within-breed prevalence, possible associated factors, and heritability of Ewe Neck in PRE horses; (2) methods: the database included evaluations of 35,267 PRE horses. The Ewe Neck defect, 16 morphological traits, and 4 body indices were recorded. A Bayesian genetic animal model included the following systematic effects: sex, age, coat color, geographical area of the stud, and birth stud size ...
Newsholme SJ.Gross, histological and ultrastructural findings are described in 6 natural cases and in 2 experimental cases of African horsesickness. From the gross lesions the cases were divisible into 2 groups which represented the previously described pulmonary and mixed forms of the disease. Histologically, abundance of fibrin and inflammatory cells in oedematous lung suggests that the pulmonary lesion is an exudative pneumonia. Lymphoid depletion and necrosis in germinal centres were consistently present. Electron microscopy failed to demonstrate virus particles or virus-associated structures in the ti...
Ball MC, Dewberry TD, Freeman PG, Kemsley PD, Poe I.Between 2006 and 2012, there were 11 horses diagnosed with Hendra virus (HeV) on 9 independent premises in New South Wales (NSW). We defined a case of HeV as premises where one or more horses were confirmed to be infected with HeV by PCR. All the cases occurred in the north-eastern region of NSW. In 8 of the 9 cases, infection occurred within 2 months over the winter of 2011. With no exception, the affected horses were kept at pasture on properties visited by flying foxes. Of the 11 horses testing positive for HeV, 5 had an association with a fence, with the horses dead or dying on a fence l...
MacKay RJ.Brain injury after impact to the head is due to both immediate mechanical effects and delayed responses of neural tissues. In horses, traumatic brain injury occurs in three main settings: (1) poll impact in horses that flip over backwards; (2) frontal/parietal impact in horses that run into a fixed object, and (3) injury to the vestibular apparatus secondary to temporohyoid osteoarthropathy. Distinct forebrain, vestibular, midbrain, hindbrain, or multifocal syndromes may be encountered in horses with traumatic brain injury. The most important components of treatment are those consistent with p...
Lowman ME, Tipton CD, Labordère AL, Brown JA.Information regarding the microbiome in sinusitis using genetic sequencing is lacking and more-in-depth understanding of the microbiome could improve antimicrobial selection and treatment outcomes for cases of primary sinusitis. Objective: To describe sinus microbiota in samples from horses with sinusitis and compare microbiota and the presence of antimicrobial resistance genes between primary, dental-related and other secondary causes of sinusitis. Methods: Retrospective case series. Methods: Records of equine sinusitis from 2017 to 2021 were reviewed and historical microbial amplicon sequenc...
Boyle AG, Martin BB, Davidson EJ, Durando MM, Birks EK.Dynamic pharyngeal collapse (PC) is a condition seen in racehorses that can be career-ending. Objective: To characterise and grade PC and describe the effects of PC on athletic performance. Methods: Medical records were reviewed for 828 horses, of which 49 (6%) records were identified as horses with a primary diagnosis of PC. Tapes of video-endoscopy of the pharynx during exercise were reviewed. Each video recording was assigned a grade (0-4) reflecting the degree of PC and a classification for severity of upper airway obstruction. Earnings per race prior to diagnosis of PC were compared to ea...
Allen K, Franklin S.Two forms of dynamic upper respiratory tract obstruction affecting racehorses that involve the soft palate have been described: palatal instability (PI) and dorsal displacement of the soft palate (DDSP). Observation of DDSP is straightforward in that it is an all or nothing event, whereas observation of PI is subjective and interpretation may vary between clinicians. Objective: The aim of this study was to attempt to characterise PI and to investigate endoscopic features that precede DDSP. Methods: A retrospective study on the endoscopic observations of Thoroughbred racehorses referred for hig...
Martínez J, Montgomery DL, Uzal FA.Vascular mineralization (siderocalcinosis) in the brain of horses has been usually assumed to be an incidental age-related finding with no clinic significance. In the present study, eight 15-32-year-old horses of different breeds with cerebral siderocalcinosis were studied. Four of these horses had acute and severe central nervous system clinical signs of unknown etiology, 2 horses had neurological signs of known cause, and 2 horses did not have neurological signs. Gross examination of the brains in 4 animals revealed symmetrical foci of malacia in the cerebellar white matter. Histologically, ...
Bedenice D, Heuwieser W, Solano M, Rand W, Paradis MR.The medical records of 163 neonatal foals that had thoracic radiographs taken within 48 hours of admission to a referral hospital were reviewed. The objectives of this study were (1) to identify risk factors for the development of thoracic radiographic changes and (2) to identify prognostic indicators for survival in foals with radiographic evidence of pulmonary disease. Failure of transfer of passive immunity (IgG concentration < or = 400 mg/dL) was the only risk factor for radiographic evidence of respiratory disease identified by multivariate analysis. Hypoxemic patients (PaO2 1.7 mg/dL...
Górski K, Tremaine H, Obrochta B, Buczkowska R, Turek B, Bereznowski A, Rakowska A, Polkowska I.The aim of this paper is to thoroughly describe the etiology, diagnostic processes and recommended treatment of equine odontoclastic tooth resorption and hypercementosis (EOTRH). It is a relatively recently described disease. Most recent reports show that it is a common problem involving older equine patients. The most common and significant symptom of EOTRH is oral pain. The main clinical signs include periodontitis and gingivitis with a gingival recession, alveolar bone protrusion, periodontic fistulas and soreness of the incisors. When establishing the final diagnosis, it is necessary to co...
Herthel D, Hood DM.This article focuses on the initial assessment of the horse affected with chronic laminitis. Variations in the clinical presentation and primary considerations in making a differential diagnosis are included. The elements of a clinical history essential to sound, therapeutic management, and prognosis are summarized. The physical and radiographic assessment of the digital lesions and diagnostic approaches to the common systemic aspects of the disease are presented and discussed.
Griffiths NJ, Walton JR, Edwards GB.Equine anterior enteritis is an acute syndrome with unknown aetiology, although salmonellosis and infection with Clostridium perfringens have both been suggested as potential causes. The main aim of this preliminary study was to compare the prevalence of toxigenic types of C. perfringens in clinically healthy horses and in horses with anterior enteritis. From horses admitted with colic at Phillip Leverhulme Large Animal Hospital in 1995-1996, samples of gastric reflux, small intestinal contents and faeces were taken for isolation of C. perfringens. Five of those horses were admitted as anterio...
Marrs J, Small J, Milne EM, John HA.Hepatocellular and hepatobiliary damage was assessed in equine acute, subacute and chronic grass sickness cases (AGS, SAGS, CGS). Histopathological analysis showed that even in some early AGS cases enlarged hepatocytes, hepatocyte vacuolation indicative of lipid accumulation (steatosis), intrahepatocyte, canalicular and periportal deposition of pigments, frequent leucocyte infiltration and cholangitis occurred. Analysis of serum indicated significantly increased levels of unconjugated bilirubin in all groups and conjugated bilirubin in AGS and SAGS groups, increased levels of bile acids in som...
Cutler TJ, MacKay RJ, Ginn PE, Greiner EC, Porter R, Yowell CA, Dame JB.Equine protozoal myeloencephalitis (EPM) is a debilitating neurologic disease of the horse. The causative agent. Sarcocystis neurona, has been suggested to be synonymous with Sarcocystis falcatula, implying a role for birds as intermediate hosts. To test this hypothesis, opossums (Didelphis virginiana) were fed muscles containing S. falcatula sarcocysts from naturally infected brown-headed cowbirds (Molothrus ater). Ten horses were tested extensively to ensure no previous exposure to S. neurona and were quarantined for 14 days, and then 5 of the horses were each administered 10(6) S. falcatula...
Keen JA, McLaren M, Chandler KJ, McGorum BC.The mechanisms underlying the increased risk of laminitis in horses with equine Cushing's disease (ECD) are poorly understood. Objective: That abnormalities in glucose homeostasis, similar to those which cause microvascular dysfunction in human diabetics, contribute to development of laminitis in horses with ECD. Methods: Thirty-one aged horses were divided into 3 groups based on clinical signs and dexamethasone suppression testing (DST). Group 1 (n = 12) had clinical ECD as evidenced by hirsutism. Group 2 (n = 10) had a positive DST but no hirsutism. Group 3 (n = 9) were controls without ECD,...
Li L, Lu Z, Han O.From 1975 to 1989, a total of 73 strains of P. pseudomallei was isolated from the water samples and the pathological samples of human and domestic animals in 13 counties and cities located different latitude from four provinces Qiong, Yue, Gui and Xiang in China. Serological investigation demonstrated that the geographical distribution of the organism had a significant correlation with the positive rate of antibodies against P. pseudomallei and the native foci of the organisms distributed over the southern subtropical zone and the edge of tropical zone in Qiong, Yue and Gui. In endemic areas, ...
Orth DN, Nicholson WE.Equine Cushing's disease is caused by hypersecretion of ACTH by hyperplasia or adenomas of pars intermedia (PI) cells, in contrast to human Cushing's disease, which is caused by hyperplasia or adenomas of pars distalis (PD) ACTH-secreting cells. We assayed both bioactive and immunoreactive (IR) ACTH in two normal equine pituitary glands and in the PD, PI, and pars nervosa of four such glands, as well as in the PI adenomas of five horses with Cushing's disease. In normal horse pituitaries, as in those of other species, most of the bioactive and IR-ACTH was found in PD, much less in PI, and only...
The Journal of protozoologyAugust 1, 1980
Volume 27, Issue 3 288-292 doi: 10.1111/j.1550-7408.1980.tb04259.x
Simpson CF, Mayhew IG.Equine protozoal myeloencephalitis (EPM) was diagnosed in 10 horses. By electron microscopy, schizonts were found in intact host cells of the spinal cords or, more frequently, free in the extracellular spaces. Developmental stages of schizonts differed morphologically, and the late stage of schizogony was characterized by endopolygeny. These findings permitted tentative identification of the protozoon as a Sarcocystis sp. Free merozoites were present in the extracellular spaces or in cells of the spinal cord. Pericytes of capillaries were most frequently parasitized by merozoites were present ...
Baraúna RA, Ramos RTJ, Veras AAO, de Sá PHCG, Guimarães LC, das Graças DA, Carneiro AR, Edman JM, Spier SJ, Azevedo V, Silva A.The genomes of four strains (MB11, MB14, MB30, and MB66) of the species Corynebacterium pseudotuberculosis biovar equi were sequenced on the Ion Torrent PGM platform, completely assembled, and their gene content and structure were analyzed. The strains were isolated from horses with distinct signs of infection, including ulcerative lymphangitis, external abscesses on the chest, or internal abscesses on the liver, kidneys, and lungs. The average size of the genomes was 2.3 Mbp, with 2169 (Strain MB11) to 2235 (Strain MB14) predicted coding sequences (CDSs). An optical map of the MB11 strain gen...
Rugh KS, Garner HE, Sprouse RF, Hatfield DG.Systemic arterial hypertension is associated with equine laminitis, a disease precipitated by gross over-ingestion of carbohydrates. We examined the hearts from nine chronically hypertensive (161 +/- 11/99 +/- 6 mmHg) laminitic ponies and nine normotensive (128 +/- 2/76 +/- 3 mmHg) ponies postmortem for signs of left ventricular hypertrophy. The hypertensive ponies had hearts which were significantly larger (7.77 +/- 0.26 g/kg bodyweight (BW) vs. 5.67 +/- 0.22 g/kg BW), as well as increased combined left ventricle and septum weight (4.99 +/- 0.21 g/kg BW vs. 3.67 +/- 0.20 g/kg BW) and left ven...
Valberg SJ, Williams ZJ, Henry ML, Finno CJ.Shivers in horses is characterized by abnormal hindlimb movement when walking backward and is proposed to be caused by a Purkinje cell (PC) axonopathy based on histopathology. Objective: Define region-specific differences in gene expression within the lateral cerebellar hemisphere and compare cerebellar protein expression between Shivers horses and controls. Methods: Case-control study of 5 Shivers and 4 control geldings ≥16.2 hands in height. Methods: Using spatial transcriptomics, gene expression was compared between Shivers and control horses in PC soma and lateral cerebellar hemisphere w...
Becker E, Venter GJ, Greyling T, Molini U, van Hamburg H.Equine mortalities suspected to be due to African horse sickness (AHS) were reported from the arid Khomas Region, Namibia, in 2008. The area was previously considered a localized AHS-free area. Hartmann's mountain zebra (Equus zebra hartmannae), a potential but unconfirmed reservoir host of African horse sickness virus (AHSV), occurs in the region. Between 2009 and 2010 serum, blood and tissue samples from 31 culled E. z. hartmannae were analysed by reverse transcription-polymerase chain reaction (RT-PCR) (n = 31) and enzyme-linked immunosorbent assay (ELISA) (n = 18) to determine the p...
Westendorf J, Wobeser B, Epp T.The Kenney-Doig scale is a histopathology categorization (grading) system often used as the standard for assessing endometrial disease and communicating prognostic fertility information for equine breeding prospects. We investigated how Kenney-Doig categories compared within the same institution and across different institutions to determine if observer variability may contribute to category frequencies. We conducted a retrospective analysis of all equine endometrial submission records between 1998 and 2018 at the Western College of Veterinary Medicine (WCVM) and Prairie Diagnostic Services (P...
Pérez J, Mozos E, Martín MP, Day MJ.The distribution of T (CD3), B (CD79) lymphocytes, immunoglobulin (IgG, IgM and IgA)-producing plasma cells, macrophages (lysozyme, Mac387) and MHC Class II antigen was analysed in the inflammatory infiltrate associated with 19 equine squamous cell carcinomas (SCCs) and six cases of precancerous lesions (actinic keratosis). The SCCs came from the penis (11 cases), conjunctiva (four), skin (two), nasal cavity (one) and oral cavity (one). Seven cases were well-differentiated and 12 moderately differentiated. Nine cases showed no invasion of peritumoral deep tissues (locally invasive), whereas th...
Mostafa MB, Elemmawy YM.There is limited knowledge about causes of musculoskeletal injury in jumping Thoroughbred horses. The objective of this study was to describe the relationships between musculoskeletal disorders and linear and angular limb measurements acquired from photographs of horses with markers at specific reference points. The diagnosed musculoskeletal disorders in either fore or hind limbs were flexor tendonitis, suspensory ligaments desmitis, and osteoarthritis of the distal intertarsal and tarso-metatarsal and carpometacarpal joints. Lengths and angles in 17 clinically normal jumping Thoroughbred hors...
McGorum BC, Scholes S, Milne EM, Eaton SL, Wishart TM, Poxton IR, Moss S, Wernery U, Davey T, Harris JB, Pirie RS.Equine grass sickness (EGS) is of unknown aetiology. Despite some evidence suggesting that it represents a toxico-infection with Clostridium botulinum types C and/or D, the effect of EGS on the functional targets of botulinum neurotoxins, namely the soluble N-ethylmaleimide-sensitive factor attachment receptor (SNARE) proteins, is unknown. Further, while it is commonly stated that, unlike EGS, equine botulism is not associated with autonomic and enteric neurodegeneration, this has not been definitively assessed. Objective: To determine: 1) whether botulism causes autonomic and enteric neurodeg...
Fischer B, Clark-Price S.Anesthetizing the neonatal foal presents significant challenges as a result of physiologic differences from the adult equine. This article gives the reader an overview of these differences and the impact they have on anesthetic drug selection, monitoring, and support of the equine neonate. Special emphasis is directed to the sick neonate and appropriate preparation and maintenance of anesthesia in the face of commonly presented disease conditions.
Wong DM, Ghosh A, Fales-Williams AJ, Haynes JS, Kanthasamy AG.The cervical spinal cords of 2 horses with equine degenerative myeloencephalopathy (EDM) were evaluated for evidence of oxidative damage to the central nervous system (CNS) using immunohistochemical staining for 3-nitrotyrosine (3-NT) and 4-hydroxynonenol (4-HNE). Neurons of the CNS from horses with EDM had positive immunohistochemical staining, whereas control samples did not, thus supporting the theory that oxidative damage is a potential underlying factor in horses with EDM. In addition, serum vitamin E concentration was low in both EDM-affected horses, and vitamin E concentration was also ...
Clark RK, Galantino-Homer HL.Equine laminitis is a common, painful, debilitating condition of the hoof that is a leading cause of disability in horses, often necessitating euthanasia. The equine hoof represents an extreme evolutionary adaptation of an epidermal structure homologous to the human or murine nail units. Immunohistochemistry is frequently utilized in the study of the pathophysiology of laminitis. The complex, multilayered, extensively interdigitated epidermal-dermal lamellar interface renders precise interpretation of immunofluorescence localization difficult, especially when effective technique and reagents r...
Kirisawa R, Toishi Y, Hashimoto H, Tsunoda N.An equine foamy virus (EFV) was isolated for the first time in Japan from peripheral blood mononuclear cells of a broodmare that showed wobbler syndrome after surgery for intestinal volvulus and the isolate was designated as EFVeca_LM. Complete nucleotide sequences of EFVeca_LM were determined. Nucleotide sequence analysis of the long terminal repeat (LTR) region, and genes revealed that EFVeca_LM and the EFV reference strain had 97.2% to 99.1% identities. For a sero-epidemiological survey, indirect immunofluorescent antibody tests were carried out using EFVeca_LM-infected cells as an antige...
