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.
Momen M, Brounts SH, Binversie EE, Sample SJ, Rosa GJM, Davis BW, Muir P.Degenerative suspensory ligament desmitis is a progressive idiopathic condition that leads to scarring and rupture of suspensory ligament fibers in multiple limbs in horses. The prevalence of degenerative suspensory ligament desmitis is breed related. Risk is high in the Peruvian Horse, whereas pony and draft breeds have low breed risk. Degenerative suspensory ligament desmitis occurs in families of Peruvian Horses, but its genetic architecture has not been definitively determined. We investigated contrasts between breeds with differing risk of degenerative suspensory ligament desmitis and ide...
Bonhomme D, Werts C.Leptospirosis is a zoonotic infectious disease affecting all vertebrates. It is caused by species of the genus Leptospira, among which are the highly pathogenic L. interrogans. Different mammals can be either resistant or susceptible to the disease which can present a large variety of symptoms. Humans are mostly asymptomatic after infection but can have in some cases symptoms varying from a flu-like syndrome to more severe forms such as Weil's disease, potentially leading to multiorgan failure and death. Similarly, cattle, pigs, and horses can suffer from acute forms of the disease, including ...
Gunsalus K, Taylor R, Croix N.To report the clinical history, surgical management, and histologic findings of meibomian gland calcification and osseous metaplasia in a horse. Methods: A 21-year-old Selle Français gelding presented with a 9 months history of blepharitis, blepharospasm, and epiphora affecting the right eye. The horse was diagnosed with meibomianitis and impaction with associated granulomas, but not treated surgically for 6 years. Methods: Physical and ophthalmic examinations, and systemic bloodwork were performed. A diamond burr debridement was performed on a corneal ulceration, and meibomian gland nodul...
Gupta S, Vohra S, Sethi K, Gupta S, Kumar S, Kumar R.The kinetoplastid protozoan parasite, Trypanosoma evansi causes a fatal disease condition known as Surra in equines throughout the globe. Disease condition being acute in nature, entrust a huge economic and health impact on the equine industry. Till date, quinapyramine methyl sulphate (QPS) is the first line of treatment and a panacea for the T. evansi infection in equines. Still after the >70 years of its discovery, there is no clue about the mode of action of QPS in T. evansi. The establishment of in vitro cultivation of T. evansi in HMI-9 media has provided opportunity to study the alte...
Molla AM, Jemberu WT, Fentahun T.Epizootic lymphangitis (EZL) is a chronic, contagious disease of equids caused by the fungus Histoplasma capsulatum var. farciminosum. The disease is often prevalent in cart pulling equids in developing countries. This study was undertaken in Central and South Gondar zones of Amhara region, Ethiopia with the objectives of estimating the prevalence of EZL in cart pulling horses and mules and identifying the risk factors of the disease. Two towns, one high altitude and one mid altitude, from each of the two zones were included for the study. A total of 528 cart pulling horses and mules from the ...
Verwilghen D, Easley J, Zwick T, Uhlhorn M, Grulke S, Simhofer H, Townsend N, Liyou O, Bodeus F, Zani DD, Vlaminck L, Pearce C, Staszyk C....Suture exostosis is an intriguing and not uncommon pathology that has to be included in the differential diagnosis for horses with swelling of the head. Although several singular case reports have been published, no large case series is available. The aim of this study is to report a multicentric retrospective collection of suture exostosis cases. Data concerning horses with suture exostosis in the facial region were collected retrospectively. Information regarding breed, age, gender, history, imaging findings, initiated treatment, response to treatment and follow up was recorded. One hundred ...
Fritsch H, Pereira FM, Costa EA, Fonseca V, Tosta S, Xavier J, Levy F, Oliveira C, Menezes G, Lima J, Santos L, Silva L, Nardy V, Astete MKG....During these past years, several studies have provided serological evidence regarding the circulation of West Nile virus (WNV) in Brazil. Despite some reports, much is still unknown regarding the genomic diversity and transmission dynamics of this virus in the country. Recently, genomic monitoring activities in horses revealed the circulation of WNV in several Brazilian regions. These findings on the paucity of genomic data reinforce the need for prompt investigation of WNV infection in horses, which may precede human cases of encephalitis in Brazil. Thus, in this study, we retrospectively scr...
Rehrl S, Schulte W, Staszyk C, Lischer C.Equine odontoclastic tooth resorption and hypercementosis (EOTRH) is a destructive, painful and underdiagnosed dental disorder. Radiography is necessary to fully assess the disease as early stages occur on clinically normal teeth. Objective: To investigate the distribution pattern of appearance of EOTRH within the incisor arcade. In particular, we aimed to determine the influence of tooth position and horse age on the severity of EOTRH as well as on the frequency of the individual severity stages. Methods: Retrospective cross-sectional radiographic case study. Methods: Digital radiographs of 1...
AbouEl Ela NH, El Araby IE, Saleh AA, Abd El-Fattah AH, Hagag NM, Brooks SA, Radwan MA, Kalbfleisch T.Lavender foal syndrome (LFS) is a fatal hereditary condition that is inherited in an autosomal recessive pattern. This detrimental mutation is more common in Arabian foals of Egyptian origin than foals from other bloodlines. Heterozygous horses are carriers of the LFS trait and appear normal, while recessive homozygous foals died shortly after birth due to serious complications. In Egypt, in 2014, an Egyptian foal died after manifestations of neurological signs and abnormal coat colour as LFS signs. Therefore, it is important to identify LFS carriers in the population of Arabian horses in Egyp...
Senderska-Płonowska M, Siwińska N, Zak-Bochenek A, Rykała M, Słowikowska M, Madej JP, Kaleta-Kuratewicz K, Niedźwiedź A.Obesity is a common problem in horses. The associations between obesity and equine metabolic syndrome (EMS) and between EMS and laminitis are known. However, there is a lack of data on whether obesity itself can affect hoof lamellae. Forelimbs and blood from 12 draft horses (six obese and six lean) from a slaughterhouse were acquired. To exclude laminitis and EMS horses, insulin concentration was measured, and hooves were radiographed. Histological evaluation was performed. The shape of the primary and secondary epidermal lamellae (PEL and SEL) was evaluated, and the length of the keratinized ...
Kinnison T, McGilvray TA, Couëtil LL, Smith KC, Wylie CE, Bacigalupo SA, Gomez-Grau E, Cardwell JM.Current consensus defines mild-moderate equine asthma (mEA; previously inflammatory airway disease) by a hierarchy of indicators of lung pathology: cough, poor performance, increased tracheobronchial mucus, inflammatory bronchoalveolar lavage (BAL) cytology and pulmonary dysfunction. Exclusion criteria include fever, systemic disease, or increased resting respiratory effort. The aim of this review was to inform future research by identifying gaps, strengths and weaknesses in the current body of evidence supporting this consensus-proposed definition. Objectives were to critique evidence support...
Ameni G, Messele Kebede A, Zewude A, Girma Abdulla M, Asfaw R, Gobena MM, Kyalo M, Stomeo F, Gumi B, Sori T.Equine histoplasmosis commonly known as epizootic lymphangitis (EL) is a neglected granulomatous disease of equine that is endemic to Ethiopia. It is caused by variety , a dimorphic fungus that is closely related to variety c The objective of this study was to undertake a phylogenetic analysis of isolated from EL cases of horses in central Ethiopia and evaluate their relationship with isolates in other countries and/or clades using the internal transcribed spacer (ITS) region of rRNA genes. Clinical and mycological examinations, DNA extraction, polymerase chain reaction (PCR), Sanger seque...
Nout-Lomas YS.Mechanisms of traumatic nervous system injury to a degree are similar, but differences exist in etiology, pathophysiology, and treatment of brain, spinal cord, and peripheral nerve injury. The most common clinical abnormalities seen in the horse are abnormal level of consciousness, abnormal behavior, seizures, cranial nerve deficits, vestibular disease, tetra- and paraparesis or paraplegia, cauda equina syndrome, specific gait deficits, and muscle atrophy. Treatments are directed toward reducing inflammation and swelling, halting secondary injury, and promoting mechanisms of neuroregeneration ...
Toribio RE.Several viruses transmitted by biological vectors or through direct contact, air, or ingestion cause neurologic disease in equids. Of interest are viruses of the Togaviridae, Flaviviridae, Rhabdoviridae, Herpesviridae, Bornaviridae, and Bunyaviridae families. Variable degree of inflammation is present with these viruses but lack of an inflammatory response does not rule out their presence. The goal of this article is to provide an overview on pathophysiologic and clinical aspects of nonarboviral equine encephalitides, specifically on lyssaviruses (rabies) and bornaviruses (Borna disease).
Valberg SJ.Movement disorders are defined as involuntary movements that are not due to a painful stimulus or associated with changes in consciousness or proprioception. Diagnosis involves ruling out any lameness and neurologic disease and characterizing the gait during walking backward and forward and trotting. Shivers causes abnormal hindlimb hypertonicity during walking backward and, when advanced, a few strides walking forward. Stringhalt causes consistent hyperflexion during walking forward and trotting and variable difficulty when walking backward. Classification and potential causes are discussed a...
Aleman M.The vestibular system (VS) is the primary specialized sensory system responsible for maintaining balance (equilibrium) and orientation of the eyes, neck, trunk, and limbs during rest and movement. Two important reflexes are responsible for maintaining balance: vestibulo-ocular and vestibulospinal reflexes. These reflexes involve peripheral and central components of the VS. Whether central or peripheral disease, most of the disorders of the VS result in ipsilateral neurologic deficits. A few uncommon exceptions present with contralateral signs to the site of the lesion. This article provides a ...
Finno CJ, Johnson AL.Neuroaxonal degenerative disease in the horse is termed equine neuroaxonal dystrophy (eNAD), when pathologic lesions are localized to the brainstem and equine degenerative myeloencephalopathy (EDM) and degenerative changes extend throughout the spinal cord. Both pathologic conditions result in identical clinical disease, most commonly characterized by the insidious onset of ataxia during early development. However, later onset of clinical signs and additional clinical features, such as behavior changes, is also observed. A definitive diagnosis of eNAD/EDM requires histologic evaluation of the ...
Furr MO.Neurologic disease of foals is a diagnostic and therapeutic challenge for veterinarians. Disease conditions such as neonatal encephalopathy are seen as well as developmental and congenital defects, bacterial infections, and trauma. Neonatal encephalopathy can be considered a "syndrome" with a variety of causes resulting in a similar clinical presentation. These causes can be categorized as maladaptation, hypoxic/ischemic encephalopathy, and metabolic abnormalities, all leading to signs of cerebral and brainstem disease. Spinal cord signs may occasionally be seen, but these signs are usually ov...
Ruby RE, Janes JG.The variety of neurologic diseases which affect horses makes pathologic examination of the nervous system a complex and lengthy process. An understanding of the common causes of neurologic disease, antemortem neurolocalization, and supplementation of the necropsy examination with ancillary testing will help to diagnose a large number of causes of neurologic disease. A general understanding of neuropathology and collaborative relationship with your local pathologists will aid in the definitive diagnosis of neurologic diseases.
MacKay RJ, Howe DK.Advances in the understanding of equine protozoal myeloencephalitis (EPM) are reviewed. It is now apparent that EPM can be caused by either of 2 related protozoan parasites, Sarcocystis neurona and Neospora hughesi, although S neurona is the most common etiologic pathogen. Horses are commonly infected, but clinical disease occurs only infrequently; the factors influencing disease occurrence are not well understood. Epidemiologic studies have identified risk factors for the development of EPM, including the presence of opossums and prior stressful health-related events. Attempts to reproduce EP...
Durham AE.Outbreaks of liver disease in horses are common but the etiology of most remains unknown. Forage mycotoxins have been suspected to be a cause. Objective: To examine the association between outbreaks of liver disease and the presence of mycotoxins in forage stored on the same premises. Methods: Premises were identified where ≥4 horses were contemporaneously affected by liver disease, and a control group was formed from premises where ≥4 horses had been examined and found to have no evidence of liver disease. Methods: Forage was collected from 29 case and 12 control premises. The forage was ...
Ricard RM, St-Jean G, Duizer G, Atwal H, Wobeser BK.The purpose of this study was to identify the most common causes of equine abortion in Canada, and to compare findings to similar reports from other countries. Equine. Necropsy reports from 901 equine abortion cases were acquired from provincial veterinary diagnostic laboratories across Canada. The final diagnosis was classified into basic abortion causes (infectious, non-infectious, unknown) and into primary and secondary categories for analysis. Non-infectious causes of abortion were the most frequently identified in Canada, with fetoplacental causes, including umbilical cord torsion or plac...
Amorim GB, Segabinazzi LG, Oliveira OM, Perecmanis S, Arruda R, Canisso IF.Misoprostol, a synthetic PGE1, is becoming a common therapy for mares with suspected uterine tube obstruction. Recently, there have been concerns that uterine administration of misoprostol induces exacerbated uterine inflammation; however, this has not been critically evaluated. This study aimed to assess the inflammatory response and potential systemic reactions after uterine administration of misoprostol, either during prebreeding or immediately after postembryo flushing. Privately owned embryo donor mares (n = 11) were randomly assigned in a crossover design to receive misoprostol (3 mL +...
Patterson Rosa L, Whitaker B, Allen K, Peters D, Buchanan B, McClure S, Honnas C, Buchanan C, Martin K, Lundquist E, Vierra M, Foster G, Brooks SA....Commonly known as "Kissing Spines" (KS), the pathological mechanisms underlying impingement and overriding of spinous processes (ORSPs) in horses are poorly understood. Thoroughbreds, Warmbloods, and stock-type breeds, including Paint Horses and Quarter Horses are at increased risk for developing clinical signs of KS. A total of 155 stock-type and Warmblood horses presented at collaborating veterinary clinics and hospitals were examined using a strict clinical and radiographical phenotyping scheme to grade each horse from 0 for unaffected controls to 4 for severe KS. Following genotyping with ...
Alam ME, Kamal MM, Rahman M, Kabir A, Islam MS, Hassan J.Anthrax is a rapidly fatal infectious disease affecting herbivores and people. In the farm animals, cattle and sheep are more susceptible, followed by goats and horses, while dwarf pigs and Algerian sheep are relatively resistant. Bacillus anthracis, the causative agent of anthrax, produces spores and persists for decades in the soil, initiating an outbreak through a favorable climate shift. Anthrax is enzootic in many Asian and African countries, and is reported in Australia, some parts of Europe, and America. The clinical courses of this disease in animals are peracute, acute, subacute, and ...
Ayad A, Besseboua O, Aissanou S, Stefaniuk-Szmukier M, Piórkowska K, Musiał AD, Długosz B, Kozłowska A, Ropka-Molik K.Genetic disorders are recognised as hereditary diseases with the most significant economic impact on horse breeding, causing important foal losses, costs of treatments of horses, and maintenance of the mare during the pregnancy. The Selle Francais horses are recognized in many countries and are showing great results in equestrian sports around the world (dressage, show jumping and eventing). The study aimed to detect the presence of three mutant alleles associated with inherited diseases including Fragile Foal Syndrome (FFS), Cerebellar Abiotrophy (CA), Polysaccharide Storage Myopathy (PSSM1) ...
Andersen C, Jacobsen S, Walters M, Lindegaard C.Osteoarthritis (OA) is a significant health issue in humans as well as horses. Experimental models of equine carpal OA have been used to investigate OA pathogenesis and potential therapeutic candidates. A 5-scale scoring system (OARSI) for macroscopic pathological cartilage changes already exists, but there is a need for a scoring system with better differentiation of severity. The aim of this study was therefore to develop and validate such a scoring system. Results: New scoring system were developed for cartilage erosions (Copenhagen Equine Total Cartilage Score, CEqTCS) along with synovial ...
Mohammadi A, Te Moller NCR, Ebrahimi M, Plomp S, Brommer H, van Weeren PR, Mäkelä JTA, Töyräs J, Korhonen RK.In this study, we mapped and quantified changes of proteoglycan (PG) content and biomechanical properties in articular cartilage in which either blunt or sharp grooves had been made, both close to the groove and more remote of it, and at the opposing joint surface (kissing site) in equine carpal joints. In nine adult Shetland ponies, standardized blunt and sharp grooves were surgically made in the radiocarpal and middle carpal joints of a randomly chosen front limb. The contralateral control limb was sham-operated. At 39 weeks after surgery, ponies were euthanized. In 10 regions of interest (...
Cardenas NC, Sanchez F, Lopes FPN, Machado G.Most animal disease surveillance systems concentrate efforts in blocking transmission pathways and tracing back infected contacts while not considering the risk of transporting animals into areas with elevated disease risk. Here, we use a suite of spatial statistics and social network analysis to characterize animal movement among areas with an estimated distinct risk of disease circulation to ultimately enhance surveillance activities. Our model utilized equine infectious anemia virus (EIAV) outbreaks, between-farm horse movements, and spatial landscape data from 2015 through 2017. We related...
Pusterla N, Barnum S, Young A, Mendonsa E, Lee S, Hankin S, Brittner S, Finno CJ.While the main goal in the management of an EHM outbreak focuses on identifying early clinical disease in order to physically separate infected horses, little effort is placed towards monitoring healthy horses. The assumption that EHV-1 shedding parallels clinical disease is erroneous, as subclinical shedders have been shown to be actively involved in viral spread. In an attempt to document the frequency of EHV-1 shedders and their impact on environmental contamination, we collected nasal swabs from 231 healthy horses and 203 environmental samples for the testing of EHV-1 by qPCR. Six horses a...
Hammond SA, Li F, McKeon BM, Cook SJ, Issel CJ, Montelaro RC.Persistent infection of equids by equine infectious anemia virus (EIAV) is typically characterized by a progression during the first year postinfection from chronic disease with recurring disease cycles to a long-term asymptomatic infection that is maintained indefinitely. The goal of the current study was to perform a comprehensive longitudinal analysis of the course of virus infection and development of host immunity in experimentally infected horses as they progressed from chronic disease to long-term inapparent carriage. We previously described the evolution of EIAV genomic quasispecies (C...
Kulkarni MA, Berrang-Ford L, Buck PA, Drebot MA, Lindsay LR, Ogden NH.In Canada, the emergence of vector-borne diseases may occur via international movement and subsequent establishment of vectors and pathogens, or via northward spread from endemic areas in the USA. Re-emergence of endemic vector-borne diseases may occur due to climate-driven changes to their geographic range and ecology. Lyme disease, West Nile virus (WNV), and other vector-borne diseases were identified as priority emerging non-enteric zoonoses in Canada in a prioritization exercise conducted by public health stakeholders in 2013. We review and present the state of knowledge on the public heal...
Billich C, Sauder C, Frank R, Herzog S, Bechter K, Takahashi K, Peters H, Staeheli P, Schwemmle M.The recent observation that Borna disease virus (BDV)-reactive antibodies from psychiatric patients exhibit only low avidity for BDV antigen called into question their diagnostic value and raised the possibility that antigenically related microorganisms or self antigens caused the production of these antibodies. We further characterized the specificity of these antibodies. Methods: We established a peptide array-based screening test that allows the identification of antibodies directed against linear epitopes of the two major BDV proteins, the nucleoprotein (N) and the phosphoprotein (P). Resu...
Matsumura T, Sugiura T, Imagawa H, Fukunaga Y, Kamada M.The dissemination of equine herpesvirus types 1 (EHV-1) and 4 (EHV-4) among various horse populations in Japan was investigated through the isolation and typing of virus strains from horses with respiratory diseases. Type specific monoclonal antibody pools were used for the typing of isolates. The 42 strains of EHV-1 and 64 strains of EHV-4 were isolated from 4593 nasal swabs and/or blood plasma samples collected from 3326 horses during a period from 1979 to 1990. All the strains of EHV-1 were isolated from racehorses only and during the winter season exclusively, when the epizootic of respira...
Coldman AJ, Elwood JM, Gallagher RP.The relationship of testicular seminoma with several factors was explored using a case-control study. Previously recognized associations with cryptorchidism and infantile inguinal hernia were confirmed and relationships were also found with cycling and horse-riding. These findings represent the first relationships of testicular cancer with well-defined postnatal risk factors.
Minke JM, Audonnet JC, Fischer L.The increasing international movement of horses combined with the relaxation of veterinary regulations has resulted in an increased incidence of equine infectious diseases. Vaccination, along with management measures, has become the primary method for the effective control of these diseases. Traditionally modified live and inactivated vaccines have been used and these vaccines have proven to be very successful in preventing disease. However, there are a number of equine infectious diseases for which conventional technology has shown its limitations. The advent of recombinant technology has sti...
Belshan M, Baccam P, Oaks JL, Sponseller BA, Murphy SC, Cornette J, Carpenter S.Genetic and biological variation in the regulatory protein Rev of equine infectious anemia virus (EIAV) were examined throughout a clinically dynamic disease course of an experimentally infected pony. Following infection with the virulent EIAV(Wyo), the pony underwent a variable disease course, including an acute fever episode at 12 days postinfection (DPI), multiple recurrent fever episodes until 135 DPI, a prolonged subclinical period, and two late fever episodes. Viral RNA was isolated from the inoculum and sequential sera samples, and the rev exon 2/gp45 overlapping ORFs were amplified, cl...
Minces LR, Brown PJ, Veldkamp PJ.Streptococcus equi subsp. zooepidemicus rarely causes meningitis in humans by contact with domestic animals or their unpasteurized products. In this paper we reviewed the literature pertaining to the epidemiological and clinical aspects relating to this infection on previously reported cases of human disease. Additionally, the case of a 51-year-old female who acquired meningitis with this organism after contact with a horse is described. This patient was successfully treated with ceftriaxone, yet penicillin remains the treatment of choice. This aetiological agent should be considered in the pr...
Gryspeerdt AC, Vandekerckhove AP, Garré B, Barbé F, Van de Walle GR, Nauwynck HJ.Equine herpesvirus 1 (EHV1) replicates in the respiratory tract of horses, after which infected leukocytes transport virus throughout the body, resulting in abortion or nervous system disorders. Two EHV1 strains circulate in the field: neurovirulent and non-neurovirulent. To investigate differences in replication in the upper respiratory tract (URT), an experimental inoculation study in ponies was performed with both strains. Two groups of six ponies, were inoculated intranasally with 10(6.5) TCID(50) of either strain. Clinical signs, nasal shedding and viremia were evaluated. At early time po...
Sykora S, Brandt S.Squamous cell carcinoma (SCC) is a common disease that seriously impairs the health and welfare of affected horses and other equids. In humans, almost all cervical carcinomas, a high percentage of anogenital SCCs and a subset of SCCs of the head and neck are caused by high-risk human papillomavirus (hrHPV) infection. Since hrHPV-induced human cancers and equine SCC have similar cytological and histopathological features, it has been hypothesised that equine SCCs could also be induced by papillomaviruses. This review provides an overview of the current evidence for an aetiological association b...
Gizaw Y, Megersa M, Fayera T.Dourine is a venereal transmitted trypanosomosis causing a major health problem threatening equines worldwide. The origin and identification of Trypanosoma equiperdum within the subgenus Trypanozoon is still a subject of debate. Unlike other trypanosomal infections, dourine is transmitted almost exclusively by coitus. Diagnosis of dourine has continued to be a challenge, due to limited knowledge about the parasite and host-parasite interaction following infection. The pathological lesions caused by the diseases are poorly described and are observed mainly in the reproductive organs, in the ner...
Aleman M, Finno CJ, Higgins RJ, Puschner B, Gericota B, Gohil K, LeCouteur RA, Madigan JE.To describe epidemiological, clinical, and pathological features of neuroaxonal dystrophy in Quarter Horses (QHs) on a single farm. Methods: Prospective case series. Animals-148 horses. Methods: Neurologic, pathological, and toxicological evaluations were completed in selected neurologically affected horses over a 2-year period. Descriptive statistical analysis was performed. Results: 87 QHs and 1 QH-crossbred horse were affected. Most (50/88 [56.8%]) affected horses were 1 to 2 years old (median age, 2 years [range, 2 months to 34 years]). Neurologic deficits included obtundation (53/88 [60%]...
Westermann CM, Dorland L, Votion DM, de Sain-van der Velden MG, Wijnberg ID, Wanders RJ, Spliet WG, Testerink N, Berger R, Ruiter JP, van der Kolk JH.The aim of the current study was to assess lipid metabolism in horses with atypical myopathy. Urine samples from 10 cases were subjected to analysis of organic acids, glycine conjugates, and acylcarnitines revealing increased mean excretion of lactic acid, ethylmalonic acid, 2-methylsuccinic acid, butyrylglycine, (iso)valerylglycine, hexanoylglycine, free carnitine, C2-, C3-, C4-, C5-, C6-, C8-, C8:1-, C10:1-, and C10:2-carnitine as compared with 15 control horses (12 healthy and three with acute myopathy due to other causes). Analysis of plasma revealed similar results for these predominantly...
Milinovich GJ, Trott DJ, Burrell PC, Croser EL, Al Jassim RA, Morton JM, van Eps AW, Pollitt CC.Carbohydrate-induced laminitis in horses is characterized by marked changes in the composition of the hindgut microbiota, from a predominantly Gram-negative population to one dominated by Gram-positive bacteria. The objective of this study was to monitor changes in the relative abundance of selected hindgut bacteria that have previously been implicated in the pathophysiology of equine laminitis using fluorescence in situ hybridization (FISH). Caecal cannulae were surgically implanted in five Standardbred horses and laminitis induced by oral administration of a bolus dose of oligofructose. Caec...
McIlwraith CW, Kawcak CE, Frisbie DD, Little CB, Clegg PD, Peffers MJ, Karsdal MA, Ekman S, Laverty S, Slayden RA, Sandell LJ, Lohmander LS, Kraus VB.We report the results of a symposium aimed at identifying validated biomarkers that can be used to complement clinical observations for diagnosis and prognosis of joint injury leading to equine osteoarthritis (OA). Biomarkers might also predict pre-fracture change that could lead to catastrophic bone failure in equine athletes. The workshop was attended by leading scientists in the fields of equine and human musculoskeletal biomarkers to enable cross-disciplinary exchange and improve knowledge in both. Detailed proceedings with strategic planning was written, added to, edited and referenced to...
Silaghi C, Liebisch G, Pfister K.Equine Granulocytic Anaplasmosis (EGA) is caused by Anaplasma phagocytophilum, a tick-transmitted, obligate intracellular bacterium. In Europe, it is transmitted by Ixodes ricinus. A large number of genetic variants of A. phagocytophilum circulate in nature and have been found in ticks and different animals. Attempts have been made to assign certain genetic variants to certain host species or pathologies, but have not been successful so far. The purpose of this study was to investigate the causing agent A. phagocytophilum of 14 cases of EGA in naturally infected horses with molecular methods o...
Leroux C, Craigo JK, Issel CJ, Montelaro RC.A primary mechanism of lentivirus persistence is the ability of these viruses to evolve in response to biological and immunological selective pressures with a remarkable array of genetic and antigenic variations that constitute a perpetual natural experiment in genetic engineering. A widely accepted paradigm of lentivirus evolution is that the rate of genetic variation is correlated directly with the levels of virus replication: the greater the viral replication, the more opportunities that exist for genetic modifications and selection of viral variants. To test this hypothesis directly, we ex...
Christoffersen M, Woodward E, Bojesen AM, Jacobsen S, Petersen MR, Troedsson MH, Lehn-Jensen H.The objective of the study was to evaluate the gene expression of inflammatory cytokines (interleukin [IL]-1β, IL-6, IL-8, IL-10, tumor necrosis factor [TNF]-α, IL-1 receptor antagonist [ra] and serum amyloid A (SAA) in endometrial tissue and circulating leukocytes in response to uterine inoculation of 105 colony forming units (CFU) Escherichia coli in mares. Before inoculation, mares were classified as resistant or susceptible to persistent endometritis based on their uterine inflammatory response to infusion of 109 killed spermatozoa and histological assessment of the endometrial quality. ...
Cook RF, Leroux C, Cook SJ, Berger SL, Lichtenstein DL, Ghabrial NN, Montelaro RC, Issel CJ.An infectious nonpathogenic molecular clone (19-2-6A) of equine infectious anemia virus (EIAV) was modified by substitution of a 3.3-kbp fragment amplified by PCR techniques from a pathogenic variant (EIAV(PV)) of the cell culture-adapted strain of EIAV (EIAV(PR)). This substitution consisted of coding sequences for 77 amino acids at the carboxyl terminus of the integrase, the S1 (encoding the second exon of tat), S2, and S3 (encoding the second exon of rev) open reading frames, the complete env gene (including the first exon of rev), and the 3' long terminal repeat (LTR). Modified 19-2-6A mol...
Kawcak CE, McIlwraith CW, Norrdin RW, Park RD, James SP.Subchondral bone plays a role in the pathogenesis of osteochondral damage and osteoarthritis in horses and humans. Osteochondral fragmentation and fracture, subchondral bone necrosis and osteoarthritis are common diseases in athletic horses, and subchondral bone is now thought to play an integral role in the pathogenesis of these diseases. There have been numerous research efforts focused on articular cartilage damage and its pathogenesis, yet comparatively little effort focused on subchondral bone pathology or the coordinated disease states of the osteochondral tissues. The purpose of this re...
Tinker MK, White NA, Lessard P, Thatcher CD, Pelzer KD, Davis B, Carmel DK.A 1 year prospective study was conducted on 31 horse farms to identify risk factors for equine colic. Farms were randomly selected from a list from 2 adjacent counties of Virginia and Maryland, USA. The association between colic and farm or individual horse risk factors related to management, housing, pasture, use, nutrition, health and events was first examined by univariate statistical analysis. Individually significant (P < = 0.25 for farm factors, P < = 0.10 for horse factors) variables were used in a stepwise multivariable forward logistic regression to select explanatory factors (P < = 0...
Scase T, Brandt S, Kainzbauer C, Sykora S, Bijmholt S, Hughes K, Sharpe S, Foote A.The aetiology of genital squamous cell carcinoma (SCC) in horses remains unknown, but the similarity to the disease in man, for which papillomavirus infection has been shown to be a causal factor, requires to be investigated in horses. Objective: One or more novel papillomaviruses cause equine genital SCC and its associated premalignant lesions. Methods: DNA was extracted from samples of equine genital SCC and performed rolling circle amplification, in order to identify closed circular DNA viral genomes within the samples. The amplified DNA was subcloned and sequenced and the DNA sequence comp...
McFarlane D, Dybdal N, Donaldson MT, Miller L, Cribb AE.Equine pituitary pars intermedia dysfunction (PPID) is a spontaneously occurring progressive disease affecting aged horses and ponies. The pathogenesis of PPID is poorly understood, but the available evidence supports a loss of dopaminergic inhibition of the melanotropes of the pars intermedia. Horses with PPID have increased plasma concentrations of pars intermedia pro-opiomelanocortin-derived peptides that decrease in response to dopamine or dopamine agonist administration. Dopamine and dopamine metabolite concentrations are decreased in the pars intermedia of affected horses compared to age...
Rosanowski SM, Chang YM, Stirk AJ, Verheyen KL.To date, no large scale studies have reported race-day events requiring veterinary attention in British Thoroughbreds racing on the flat. Quantifying and describing common injuries and health conditions affecting racehorses will enable targeted risk factor analysis aimed at reducing their occurrence. Objective: To describe the type and incidence of race-day veterinary events experienced by Thoroughbred racehorses participating in flat racing in the UK. Methods: Retrospective cohort study (2000 to 2013). Methods: Veterinary events recorded by race-day veterinarians were retrieved and linked to ...
Payne SL, Salinovich O, Nauman SM, Issel CJ, Montelaro RC.Comparisons of peptide and oligonucleotide maps of glycoproteins and RNA from nine isolates of equine infectious anemia virus (EIAV) that were generated during parallel infections of two Shetland ponies revealed that each isolate was structurally unique. Each EIAV isolate contained a unique subset of variant peptides, oligonucleotides, or both, indicating that structural variation in EIAV is a random and noncumulative process and that a large spectrum of possible EIAV variants can be generated in infected animals.
Martin BB, Reef VB, Parente EJ, Sage AD.To determine results for horses undergoing a high-speed treadmill examination, including videoendoscopy of the pharynx and larynx before and during exercise, echocardiography before and after exercise, and electrocardiography before, during, and after exercise, because of poor performance. Methods: Retrospective study. Methods: 348 horses. Results: A definitive diagnosis was obtained for 256 (73.5%) horses. One hundred forty-eight horses had dynamic obstruction of the airway during exercise, 33 had clinically important cardiac arrhythmias alone, 22 had a combination of dynamic airway obstructi...
Bhoora R, Quan M, Franssen L, Butler CM, van der Kolk JH, Guthrie AJ, Zweygarth E, Jongejan F, Collins NE.A quantitative real-time polymerase chain reaction (qPCR) assay using a TaqMan minor groove binder (MGB) probe was developed for the detection of Babesia caballi infection in equids from South Africa. Nine previously published sequences of the V4 hypervariable region of the B. caballi 18S rRNA gene were used to design primers and probes to target unique, conserved regions. The B. caballi TaqMan MGB qPCR assay was shown to be efficient and specific. The detection limit, defined as the concentration at which 95% of positive samples can be detected, was determined to be 0.000114% parasitized eryt...
