Pathogenesis in horses refers to the biological mechanisms that lead to the development and progression of diseases within equine species. This process involves a complex interaction between the horse's immune system, genetic predispositions, environmental factors, and infectious agents such as bacteria, viruses, or parasites. Understanding pathogenesis is essential for identifying how diseases manifest and progress in horses, which can inform diagnostic and therapeutic strategies. Research in this area often focuses on specific diseases, examining factors such as pathogen entry, immune response, tissue damage, and recovery processes. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, contributing factors, and implications of pathogenesis in equine health.
Terron-Canedo N, Weir W, Nicolson L, Britton C, Nasir L.Bovine papillomavirus (BPV) types 1 and 2 play an important role in the pathogenesis of equine sarcoids (ES), the most common cutaneous tumour affecting horses. MicroRNAs (miRNAs), small non-coding RNAs that regulate essential biological and cellular processes, have been found dysregulated in a wide range of tumours. The aim of this study was to identify miRNAs associated with ES. Differential expression of miRNAs was assessed in control equine fibroblasts (EqPalFs) and EqPalFs transformed with the BPV-1 genome (S6-2 cells). Using a commercially available miRNA microarray, 492 mature miRNAs we...
Díez de Castro E, Zafra R, Acevedo LM, Pérez J, Acosta I, Rivero JL, Aguilera-Tejero E.Equine motor neuron disease (EMND) is a neuromuscular disorder that affects adult horses. Although EMND has been linked to vitamin E deficiency, its etiopathogenesis is poorly understood. Objective: To describe clinical features, laboratory results, and postmortem findings in a series of young horses with motor neuron disease (MND). Methods: A herd of 15 young Andalusian horses with weakness, weight loss, muscle atrophy, and muscle fasciculations related to restricted intake of green forage. Methods: A case series is presented in which horses were subjected to a clinical examination and plasma...
Gressler LT, Bordin AI, McQueen CM, Cohen ND, de Vargas AC.Rhodococcus equi preferentially infects macrophages causing pyogranulomatous pneumonia in young foals. Both the vapA and rhbC genes are up-regulated in an iron (Fe)-deprived environment, such as that found within macrophages. Chloroquine (CQ) is a drug widely used against malaria that suppresses the intracellular availability of Fe in eukaryotic cells. The main objective of this study was to evaluate the ability of CQ to inhibit replication of virulent R. equi within murine (J774A.1) and foal alveolar macrophages (AMs) and to verify whether the mechanism of inhibition could be Fe-deprivation-d...
Sarkar S, Balasuriya UB, Horohov DW, Chambers TM.Equine herpesvirus-1 (EHV-1) is a major respiratory viral pathogen of horses, causing upper respiratory tract disease, abortion, neonatal death, and neurological disease that may lead to paralysis and death. EHV-1 replicates initially in the respiratory epithelium and then spreads systemically to endothelial cells lining the small blood vessels in the uterus and spinal cord leading to abortion and EHM in horses. Like other herpesviruses, EHV-1 employs a variety of mechanisms for immune evasion including suppression of type-I interferon (IFN) production in equine endothelial cells (EECs). Previ...
Herteman N, Bullone M, Lavoie JP.Heaves is a severe debilitating condition of horses, characterized by lower airway inflammation and permanent structural changes of the bronchial wall. Chronic inflammation promotes the formation of new vessels, a phenomenon known as angiogenesis. Narrow band imaging (NBI) endoscopy is a noninvasive technique that enhances the visualization of submucosal vessels, and commonly is employed for the study of angiogenesis in human patients. Objective: Using NBI, we aimed to determine whether or not the central airways of horses with heaves undergo angiogenesis. Methods: Horses with heaves during ex...
Allano M, Labrecque O, Rodriguez Batista E, Beauchamp G, Bédard C, Lavoie JP, Leclere M.The aim of this study was to determine the effects of short distance transportation on airway mucus, cytology and bacterial culture to identify potential biases in the diagnosis of airway diseases in referral centres. Eight healthy adult horses were studied using a prospective cross-over design. Mucus scores, tracheal wash (cytology, bacterial culture) and bronchoalveolar lavage fluid (BALF; cytology) were obtained while stabled and following 2.5 h transportation (with and without hay). Neutrophil counts, percentages and BALF neutrophilia frequency increased following transport without hay (...
Sano Y, Matsuda K, Okamoto M, Takehana K, Hirayama K, Taniyama H.In horse, the characterizations of hyalocytes under the steady state are still unclear. Therefore, we investigated characterizations of hyalocytes in normal equine eyes by their immunohistochemical phenotype, histomorphology and distribution. Thirty-one eyes from 18 horses, divided into 4 groups (G) by age, were used: early (G1) and late gestation (G2) fetuses, 1- to 3-year-old (G3) and 8- to 24-year-old (G4) horses. Equine hyalocytes were histologically classified into 4 types, and they immunohistochemically expressed MHC II and CD163. Hyalocytes were detected on and/or around ciliary process...
Waller AS.Strangles, characterised by pyrexia followed by abscessation of the lymph nodes of the head and neck, was first described in 1251 (Rufus 1251) and the causative agent, Streptococcus equi, was identified in 1888 (Schutz 1888). However, despite more than a century of research into this disease, strangles remains the most frequently diagnosed infection of horses with over 600 outbreaks being identified in the UK alone each year (Parkinson and others 2011). Here, Andrew Waller reviews some of the recent advances in the understanding of the evolution of S equi and puts this into the context of prev...
Liu Q, Ma J, Wang XF, Xiao F, Li LJ, Zhang JE, Lin YZ, Du C, He XJ, Wang X, Zhou JH.The live equine infectious anemia virus (EIAV) vaccine strain EIAVDLV121 was developed by in vitro attenuation of a virulent strain, EIAVLN40, in the 1970s, and it has been demonstrated to induce protective immunity under laboratory and natural EIAV infection conditions. The detailed biological features of this attenuated virus remain to be further investigated. Experimental inoculation with EIAVDLV121 did not result in clinical symptoms even with immunosuppressive treatment in our previous studies. Here, we further investigated whether the replication of the vaccine strain EIAVDLV121 in exper...
Martel G, Kiss S, Gilbert G, Anne-Archard N, Richard H, Moser T, Laverty S.Focal ischemic chondronecrosis of epiphyseal growth cartilage (EGC) during endochondral ossification is believed to be a key early event on the pathway to osteochondrosis (OC) in both animals and humans. The lateral ridge of the equine trochlea is a site where severe osteochondritis dissecans lesions frequently arise and is a model for the study of naturally occurring disease. Non-invasive imaging to investigate EGC vascularity may help elucidate why focal ischemia occurs. 3T MRI susceptibility-weighted imaging (SWI) of femoral trochlea of OC predisposed (n = 10) and control (n = 6) da...
Baer A, Lundberg L, Swales D, Waybright N, Pinkham C, Dinman JD, Jacobs JL, Kehn-Hall K.Venezuelan equine encephalitis virus (VEEV) is a previously weaponized arthropod-borne virus responsible for causing acute and fatal encephalitis in animal and human hosts. The increased circulation and spread in the Americas of VEEV and other encephalitic arboviruses, such as eastern equine encephalitis virus and West Nile virus, underscore the need for research aimed at characterizing the pathogenesis of viral encephalomyelitis for the development of novel medical countermeasures. The host-pathogen dynamics of VEEV Trinidad donkey-infected human astrocytoma U87MG cells were determined by car...
Sarkar S, Chelvarajan L, Go YY, Cook F, Artiushin S, Mondal S, Anderson K, Eberth J, Timoney PJ, Kalbfleisch TS, Bailey E, Balasuriya UB.Previous studies in our laboratory have identified equine CXCL16 (EqCXCL16) to be a candidate molecule and possible cell entry receptor for equine arteritis virus (EAV). In horses, the CXCL16 gene is located on equine chromosome 11 (ECA11) and encodes a glycosylated, type I transmembrane protein with 247 amino acids. Stable transfection of HEK-293T cells with plasmid DNA carrying EqCXCL16 (HEK-EqCXCL16 cells) increased the proportion of the cell population permissive to EAV infection from <3% to almost 100%. The increase in permissiveness was blocked either by transfection of HEK-EqCXCL16 cell...
Lu Z, Sarkar S, Zhang J, Balasuriya UB.Equine arteritis virus (EAV), the causative agent of equine viral arteritis, has relatively broad cell tropism in vitro. In horses, EAV primarily replicates in macrophages and endothelial cells of small blood vessels. Until now, neither the cellular receptor(s) nor the mechanism(s) of virus attachment and entry have been determined for this virus. In this study, we investigated the effect of heparin on EAV infection in equine endothelial cells (EECs). Heparin, but not other glycosaminoglycans, could reduce EAV infection up to 93 %. Sequence analysis of the EAV E minor envelope protein reveale...
Cervantes DT, Ball JM, Edwards J, Payne S.Equine infectious anemia virus (EIAV) causes lifelong infections ranging from acutely fatal, to chronic, to asymptomatic. Within infected animals, EIAV is found as a quasispecies. Many experimental studies on EIAV, carried out in the U.S. over the past 70 years, have used either the highly virulent Wyoming (EIAVWYO) field strain or various derivatives of that strain. These infections have provided insights into the variety of genetic changes that accumulate in the env gene and LTR in experimentally infected horses. In the current study, we obtained EIAV sequences from blood samples collected f...
Vaz PK, Horsington J, Hartley CA, Browning GF, Ficorilli NP, Studdert MJ, Gilkerson JR, Devlin JM.Recombination in alphaherpesviruses allows evolution to occur in viruses that have an otherwise stable DNA genome with a low rate of nucleotide substitution. High-throughput sequencing of complete viral genomes has recently allowed natural (field) recombination to be studied in a number of different alphaherpesviruses, however, such studies have not been applied to equine herpesvirus 1 (EHV-1) or equine herpesvirus 4 (EHV-4). These two equine alphaherpesviruses are genetically similar, but differ in their pathogenesis and epidemiology. Both cause economically significant disease in horse popul...
Sarkar S, Balasuriya UB, Horohov DW, Chambers TM.Equine herpesvirus-1 (EHV-1) infects equine endothelial cells (EECs) lining the small blood vessels in the central nervous system. However, the effect of type I IFN on EHV-1 replication in the EECs is not well studied. Thus, the primary objective of this study was to investigate the effect of type-I IFN on the replication of the neuropathogenic T953 strain of EHV-1 in vitro in EECs. The initial data showed that the EHV-1 was partly resistant to the biological effect of exogenously supplied recombinant equine IFN-α. Subsequent investigation into the mechanism of resistance showed that EHV-1 in...
Boudreaux MK, Koehler J, Habecker PL, Del Piero F.Exercise-induced pulmonary hemorrhage (EIPH) is a common disorder of equine athletes. The role of polymorphisms in genes encoding hemostasis-regulatory proteins in horses with abnormal hemorrhage is unknown. Objective: The goal of this study was to evaluate the genes encoding 2 ectonucleotidases, CD39/NTPDase-1 and CD39L1/NTPDase-2, and one ecto-5' nucleotidase, CD73, in horses with abnormal hemorrhage or pathologic changes consistent with EIPH. Methods: Twenty-three horses with histories of abnormal hemorrhage, 8 horses with gastrointestinal signs, and 45 healthy horses were evaluated using p...
Barton AK, Shety T, Bondzio A, Einspanier R, Gehlen H.In chronic respiratory disease, matrix metalloproteinases (MMPs) contribute to pathological tissue destruction when expressed in excess, while tissue inhibitors of metalloproteinases (TIMPs) counteract MMPs with overexpression leading to fibrosis formation. They may be out of balance in equine pneumopathies and serve as biomarkers of pulmonary inflammation. We hypothesized that MMPs and TIMPs correlate to clinical findings and bronchoalveolar lavage fluid cytology in different equine chronic pneumopathies. Using a scoring system, 61 horses were classified controls as free of respiratory diseas...
Tennent-Brown BS, Morrice AV, Reed S.Neonatal encephalopathy is the most common neurologic condition affecting newborn foals and shares similarities with perinatal asphyxia syndrome of human infants. In many cases of neonatal encephalopathy there is no obvious episode of acute or chronic hypoxia and other mechanisms likely play a role in the pathogenesis. Increased concentrations of neuroactive progestagens are found in affected foals; whether these molecules are protective, as has been suggested, or play a role in the pathogenesis is unknown. Neurologic diseases other than neonatal encephalopathy affect foals occasionally and sh...
Silva MLCR, Auguste AJ, Terzian ACB, Vedovello D, Riet-Correa F, Macário VMK, Mourão MPG, Ullmann LS, Araújo JP, Weaver SC, Nogueira ML.Madariaga virus (MADV), the new species designation for the South American isolates of eastern equine encephalitis virus (EEEV), is genetically divergent and substantially different in ecology and pathogenesis from North American EEEV strains. We isolated and characterized a MADV isolate obtained from a horse in Brazil. Our results support previous phylogenetic studies showing there are three genetically distinct MADV lineages. The MADV isolate from Paraíba State belongs to the South American lineage III and is closely related to Peruvian, Colombian and Venezuelan isolates.
Reisinger N, Schaumberger S, Nagl V, Hessenberger S, Schatzmayr G.Laminitis is one of the most common diseases in horses. It is not only painful for the animal, but also has a significant financial impact on the equine industry. This multifactorial disease affects the connective tissue of the hoof. However, the pathogenesis of laminitis is still not fully understood. Endotoxins, also known as lipopolysaccharides (LPS), and bacterial exotoxins seem to play an important role during the development of laminitis. The aim of our study was to investigate the effect of increasing LPS concentrations (0, 2.5, 5, 10, and 100 μg/mL) on cell viability of isolated epide...
Pavulraj S, Bera BC, Joshi A, Anand T, Virmani M, Vaid RK, Shanmugasundaram K, Gulati BR, Rajukumar K, Singh R, Misri J, Singh RK, Tripathi BN....Equine influenza viruses (EIV)-H3N8 continue to circulate in equine population throughout the world. They evolve by the process of antigenic drift that leads to substantial change in the antigenicity of the virus, thereby necessitating substitution of virus strain in the vaccines. This requires frequent testing of the new vaccines in the in vivo system; however, lack of an appropriate laboratory animal challenge model for testing protective efficacy of equine influenza vaccine candidates hinders the screening of new vaccines and other therapeutic approaches. In the present investigation, BALB/...
Saey V, Famaey N, Smoljkic M, Claeys E, van Loon G, Ducatelle R, Ploeg M, Delesalle C, Gröne A, Duchateau L, Chiers K.Thoracic aortic rupture and aortopulmonary fistulation are rare conditions in horses. It mainly affects Friesian horses. Intrinsic differences in biomechanical properties of the aortic wall might predispose this breed. The biomechanical and biochemical properties of the thoracic aorta were characterized in warmblood horses, unaffected Friesian horses and Friesians with aortic rupture in an attempt to unravel the underlying pathogenesis of aortic rupture in Friesian horses. Samples of the thoracic aorta at the ligamentum arteriosum (LA), mid thoracic aorta (T1) and distal thoracic aorta (T2) we...
Dorman D.The central nervous system's extrapyramidal system provides involuntary motor control to the muscles of the head, neck, and limbs. Toxicants that affect the extrapyramidal system are generally clinically characterized by impaired motor control, which is usually the result of basal ganglionic dysfunction. A variety of extrapyramidal syndromes are recognized in humans and include Parkinson's disease, secondary parkinsonism, other degenerative diseases of the basal ganglia, and clinical syndromes that result in dystonia, dyskinesia, essential tremor, and other forms of tremor and chorea. This cha...
Sano Y, Matsuda K, Okamoto M, Takehana K, Hirayama K, Taniyama H.Antigen-presenting cells (APCs) in the uveal tract participate in ocular immunity including immune homeostasis and the pathogenesis of uveitis. In horses, although uveitis is the most common ocular disorder, little is known about ocular immunity, such as the distribution of APCs. In this study, we investigated the distribution of CD163-positive and MHC II-positive cells in the normal equine uveal tract using an immunofluorescence technique. Eleven eyes from 10 Thoroughbred horses aged 1 to 24 years old were used. Indirect immunofluorescence was performed using the primary antibodies CD163, MHC...
Abraham G.This review provides an overview of the early and current literature including contributions that highlight the parasympathetic cholinergic receptor systems in domestic animal tissues. Muscarinic acetylcholine receptors (mAChRs) belong to the subfamily of G protein-coupled receptors and regulate many fundamental functions of the central and peripheral nervous systems and have been subject to research over at least 40 years. Nonetheless, there are few studies specifying mAChRs in domestic animal tissues. This review focuses on the pharmacology of muscarinic acetylcholine receptor (mAChR) system...
Banse HE, Frank N, Kwong GP, McFarlane D.In horses, hyperinsulinemia and insulin resistance (insulin dysregulation) are associated with the development of laminitis. Although obesity is associated with insulin dysregulation, the mechanism of obesity-associated insulin dysregulation remains to be established. We hypothesized that oxidative stress in skeletal muscle is associated with obesity-associated hyperinsulinemia in horses. Thirty-five light breed horses with body condition scores (BCS) of 3/9 to 9/9 were studied, including 7 obese, normoinsulinemic (BCS ≥ 7, resting serum insulin < 30 μIU/mL) and 6 obese, hyperinsulinemic...
BMC research notesSeptember 24, 2015
Volume 8 471 doi: 10.1186/s13104-015-1441-0
Boukharta M, Azlmat S, Elharrak M, Ennaji MM.Three equine influenza viruses, A/equine/Nador/1/1997(H3N8), A/equine/Essaouira/2/2004(H3N8), and A/equine/Essaouira/3/2004(H3N8), were isolated from different Equidae during local respiratory disease outbreaks in Morocco in 1997 and 2004. Their non-structural (NS) genes were amplified and sequenced. Results: The results show high homology of NS nucleotide sequences of A/equine/Nador/1/1997 with European strains (i.e., A/equine/newmarket/2/93 and A/equine/Grobois/1/1998) and clustered into the European lineage. However, NS gene of A/equine/Essaouira/2/2004(H3N8) and A/equine/Essaouira/3/2004(H...
Valberg SJ, McKenzie EC, Eyrich LV, Shivers J, Barnes NE, Finno CJ.Although exertional rhabdomyolysis (ER) is common in Arabian horses, there are no dedicated studies describing histopathological characteristics of muscle from Arabian horses with ER. Objective: To prospectively identify distinctive histopathological features of muscle from Arabian endurance horses with a history of ER (pro-ER) and to retrospectively determine their prevalence in archived samples from Arabian horses with exertional myopathies (retro-ER). Methods: Prospective and retrospective histopathological description. Methods: Middle gluteal muscle biopsies obtained from Arabian controls ...
Frondoza CG, Fortuno LV, Grzanna MW, Ownby SL, Au AY, Rashmir-Raven AM.Objective Pro-inflammatory mediators such as prostaglandin E-2 (PGE2) play major roles in the pathogenesis of osteoarthritis (OA). Although current pharmacologic treatments reduce inflammation, their prolonged use is associated with deleterious side effects prompting the search for safer and effective alternative strategies. The present study evaluated whether chondrocyte production of PGE2 can be suppressed by the combination of avocado/soybean unsaponifiables (ASU) and α-lipoic acid (LA). Design Chondrocytes from articular cartilage of equine joints were incubated for 24 hours with: (1) con...
van Weeren PR, Jeffcott LB.Twenty years ago a supplement of Equine Veterinary Journal was devoted to equine osteochondrosis (OC) and recognised the importance of this developmental disease to the equine industry. In the accompanying editorial several controversial issues were identified and a number of areas for further research were highlighted. Today, equine OC is still a major clinical problem, but the on-going research has resulted in much improved knowledge and understanding of this highly complicated disease. There is still conflicting evidence on the prevalence of OC due to the dynamic character of the condition,...
Dewachi O, Joubert P, Hamid Q, Lavoie JP.Heaves, a condition associated with airway neutrophilia, is believed to result from an allergic response to environmental dust particles. However, the contribution of neutrophils to the allergic response is poorly understood. It has been hypothesized that Th2-type cytokines can directly activate neutrophils to produce pro-inflammatory mediators. The present study focused on the presence of receptors for the Th2-type cytokines interleukin (IL)-5 and IL-9 on peripheral blood neutrophils of horses with heaves. Neutrophils were isolated from peripheral blood of horses with heaves (n=7), and normal...
Lindsay DS, Mitchell SM, Vianna MC, Dubey JP.Equine protozoal myeloencephalitis is a major cause of neurological disease in horses from the Americas. Horses are considered accidental intermediate hosts. The structure of sporocysts of the causative agent, Sarcocystis neurona, has never been described. Sporocysts of S. neurona were obtained from the intestines of a laboratory-raised opossum fed skeletal muscles from a raccoon that had been fed sporocysts. Sporocysts were 11.3 by 8.2 microm and contained 4 sporozoites. The appearance of the sporocyst residuum was variable. The residuum of some sporocysts was composed of many dispersed granu...
Vannucci FA, Kelley MR, Gebhart CJ.Lawsonia intracellularis is an obligate intracellular bacterium and the causative agent of proliferative enteropathy (PE). The disease is endemic in pigs, emerging in horses and has also been reported in a variety of other animal species, including nonhuman primates. Comparing the whole genome sequences of a homologous porcine L. intracellularis isolate cultivated for 10 and 60 passages in vitro, we identified a 18-kb prophage-associated genomic island in the passage 10 (pathogenic variant) that was lost in the passage 60 (non-pathogenic variant). This chromosomal island comprises 15 genes dow...
Velineni S, Timoney JF.Streptococcus zooepidemicus is an important opportunistic pathogen of the equine respiratory and reproductive tracts. A normal tonsillar and mucosal commensal, it becomes invasive under conditions of stress such as virus infection, weaning, high temperature, prolonged transportation and failure of uterine involution. The aim of this study was to evaluate the vaccine potential of several surface exposed and secreted proteins of a novel mucoid clone of SzNC78 (ST-307) from an epizootic of equine respiratory disease. Methods: An expression gene library of SzNC78 was probed with a pool of convales...
Moore BR, Reed SM, Biller DS, Kohn CW, Weisbrode SE.Magnification of cervical radiographs prevents accurate interpretation of vertebral canal absolute minimum sagittal diameter (MSD) values and application of the established MSD values for diagnosis of cervical stenotic myelopathy (CSM). Variability in MSD determination in human beings, owing to radiographic magnification, is minimized by assessing a ratio of the vertebral canal diameter to the sagittal width of the vertebral body. This relative measurement technique improves the accuracy of diagnosis of cervical spinal stenosis in human beings. The MSD of the vertebral canal was determined in ...
Mungall BA, Kyaw-Tanner M, Pollitt CC.Utilizing an in vitro laminitis explant model, we have investigated how bacterial broth cultures and purified bacterial proteases activate matrix metalloproteinases (MMPs) and alter structural integrity of cultured equine lamellar hoof explants. Four Gram-positive Streptococcus spp. and three Gram-negative bacteria all induced a dose-dependent activation of MMP-2 and MMP-9 and caused lamellar explants to separate. MMP activation was deemed to have occurred if a specific MMP inhibitor, batimastat, blocked MMP activity and prevented lamellar separation. Thermolysin and streptococcal pyrogenic ex...
Bogedale K, Jagannathan V, Gerber V, Unger L.The aim of this study was to investigate microRNA (miRNA) differential expression in the two most common equine skin tumours, equine sarcoid (ES) and squamous cell carcinoma (SCC), and its potential influence on the tumour microenvironment at post-transcriptional level. We investigated miRNA fingerprints in four subgroups: mild (ESM) and aggressive (ESA) ES and ocular SCC (oSCC) and genital SCC (gSCC). Three tumours and three control samples were included in each of the four subgroups. Following next generation sequencing, miRNA differential expression analysis using DESeq2 was carried out. Pa...
Cox A, Dixon P, Smith S.Equine periodontal disease (EPD) is a common and painful condition, the aetiology and pathology of which are poorly understood. To characterise the histopathological lesions associated with EPD, the skulls of 22 horses were assessed grossly for the presence of periodontal disease, and a standard set of interdental tissues taken from each for histopathological examination. Histological features of EPD included ulceration and neutrophilic inflammation of the gingival epithelium. Mononuclear and eosinophilic inflammation of the gingival lamina propria and submucosa was commonly present irrespecti...
Sreenivasan CC, Jandhyala SS, Luo S, Hause BM, Thomas M, Knudsen DEB, Leslie-Steen P, Clement T, Reedy SE, Chambers TM, Christopher-Hennings J....Equine influenza, caused by the H3N8 subtype, is a highly contagious respiratory disease affecting equid populations worldwide and has led to serious epidemics and transboundary pandemics. This study describes the phylogenetic characterization and replication kinetics of recently-isolated H3N8 virus from a nasal swab obtained from a sporadic case of natural infection in an unvaccinated horse from Montana, USA. The nasal swab tested positive for equine influenza by Real-Time Quantitative Reverse Transcription Polymerase Chain Reaction (RT-PCR). Further, the whole genome sequencing of the virus ...
Fukushi H, Yamaguchi T, Yamada S.Equine herpesvirus type 9 (EHV-9), which we isolated from a case of epizootic encephalitis in a herd of Thomson's gazelles (Gazella thomsoni) in 1993, has been known to cause fatal encephalitis in Thomson's gazelle, giraffe, and polar bear in natural infections. Our previous report indicated that EHV-9 was similar to the equine pathogen equine herpesvirus type 1 (EHV-1), which mainly causes abortion, respiratory infection, and equine herpesvirus myeloencephalopathy. We determined the genome sequence of EHV-9. The genome has a length of 148,371 bp and all 80 of the open reading frames (ORFs) fo...
Murray MJ.Ulceration of the gastric squamous epithelial mucosa was induced in 10 horses using a feeding protocol previously shown to expose the gastric mucosa to repeated periods of high acidity. The feeding protocol consisted of alternating feed deprivation with free access to hay. Over a period of seven days, each horse was provided hay for 84 hr and deprived of hay for 84 hr. Hay was never withheld for longer than 24 hr at a time. Gastroscopy was performed on each horse at the beginning of the protocol after 12 hr of feed deprivation, and after a total of 36 hr, 60 hr, and 84 hr of feed deprivation. ...
Mullaney T, Murphy AJ, Kiupel M, Bell JA, Rossano MG, Mansfield LS.Opossums (Didelphis spp.) are the definitive host for the protozoan parasite Sarcocystis neurona, the causative agent of equine protozoal myeloencephalitis (EPM). Opossums shed sporocysts in feces that can be ingested by true intermediate hosts (cats, raccoons, skunks, armadillos and sea otters). Horses acquire the parasite by ingestion of feed or water contaminated by opossum feces. However, horses have been classified as aberrant intermediate hosts because the terminal asexual sarcocyst stage that is required for transmission to the definitive host has not been found in their tissues despite...
Schwab UE, Fulcher ML, Randell SH, Flaminio MJ, Russell DG.We describe a method for creating differentiated equine bronchial epithelial cell cultures that can be used for in vitro studies including airway disease mechanisms and pathogen-host interactions. Our method is based on the culturing of human tracheobronchial epithelial cells at an air-liquid interface (ALI) in specific serum-free, hormone-supplemented medium. Bronchial epithelial cells are isolated and grown on T-Clear® insert membranes. Within 2 to 3 wk, cells differentiate into ciliated and mucus producing cells as demonstrated by confocal and electron microscopy. Furthermore, the demonstr...
Bykovsky AF, Yershov FI, Zhdanov VM.Morphogenesis of Venezuelan equine encephalomyelitis virus was studied by means of electron microscopy. Virus-specific structures (factories, viroplasts) were found at early stages of infection; these structures were composed of fibrillar and cylindrical formations, aggregates of ribosomes, and viral nucleoids. The latter emerged from fibrillar and cylindrical structures. Aggregates of viral nucleoids were found in the cytoplasm and occasionally in the nuclei of virus-infected cells. Viral envelopes and mature virions were formed on the cell membranes and on the membranes of intracellular vacu...
de Laat MA, Clement CK, McGowan CM, Sillence MN, Pollitt CC, Lacombe VA.Equine laminitis, a disease of the lamellar structure of the horse's hoof, can be incited by numerous factors that include inflammatory and metabolic aetiologies. However, the role of inflammation in hyperinsulinaemic laminitis has not been adequately defined. Toll-like receptor (TLR) activation results in up-regulation of inflammatory pathways and the release of pro-inflammatory cytokines, including interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α), and may be a pathogenic factor in laminitis. The aim of this study was to determine whether TLR4 expression and subsequent pro-infla...
Wu W, Blythe DC, Loyd H, Mealey RH, Tallmadge RL, Dorman KS, Carpenter S.Two variants of equine infectious anemia virus (EIAV) that differed in sensitivity to broadly neutralizing antibody were tested in direct competition assays. No differences were observed in the growth curves and relative fitness scores of EIAVs of principal neutralizing domain variants of groups 1 (EIAV(PND-1)) and 5 (EIAV(PND-5)), respectively; however, the neutralization-resistant EIAV(PND-5) variant was less infectious in single-round replication assays. Infectious center assays indicated similar rates of cell-to-cell spread, which was approximately 1,000-fold more efficient than cell-free ...
Quintana AM, Hussey SB, Burr EC, Pecoraro HL, Annis KM, Rao S, Landolt GA.To evaluate whether an equine-derived canine H3N8 influenza A virus was capable of infecting and transmitting disease to ponies. Methods: 20 influenza virus-seronegative 12- to 24-month-old ponies. Methods: 5 ponies were inoculated via aerosol exposure with 10(7) TCID(50) of A/Canine/Wyoming/86033/07 virus (Ca/WY)/pony. A second group of 5 ponies (positive control group) was inoculated via aerosol exposure with a contemporary A/Eq/Colorado/10/07 virus (Eq/CO), and 4 sham-inoculated ponies served as a negative control group. To evaluate the potential for virus transmission, ponies (3/inoculatio...
Wyler M, Sage SE, Marti E, White S, Gerber V.The diagnostic value of allergen-specific immunoglobulin E (IgE) in horses with asthma is uncertain. A recently developed protein microarray detected abnormally high latex-specific IgE concentrations in the serum of horses with severe asthma. Objective: The main objective was to characterize the IgE profiles of asthmatic horses in Switzerland using a protein microarray platform in serum and bronchoalveolar lavage fluid (BALF). The secondary objective was to determine whether serological and BALF allergen-specific IgE concentrations correlated. Methods: Forty-four asthmatic and 39 control horse...
Lanz S, Gerber V, Marti E, Rettmer H, Klukowska-Rötzler J, Gottstein B, Matthews JB, Pirie S, Hamza E.Equine recurrent airway obstruction (RAO) is an inflammatory, obstructive airway disease induced by exposure of susceptible horses to inhaled organic dust particles. The immunological process underlying RAO is still unclear. Previous studies have shown that RAO is linked to the Interleukin-4 receptor (IL-4R) gene in one Warmblood family (F1), but not in another (F2). It has also been shown that in F1, but not in F2, RAO is associated with resistance against parasites, suggesting that this association may have an immuno-genetic basis. Therefore, we hypothesized that the T helper (h)1/Th2/regula...
Wilson ME, Holz CL, Kopec AK, Dau JJ, Luyendyk JP, Soboll Hussey G.Equine herpesvirus type 1 (EHV-1) is the cause of respiratory disease, abortion storms, and outbreaks of herpesvirus myeloencephalopathy (EHM). Infection of the spinal cord is characterised by multifocal regions of virally infected vascular endothelium, associated with vasculitis, thrombosis and haemorrhage that result in ischaemia and organ dysfunction. However, the mechanism of thrombosis in affected horses is unknown. Objective: To evaluate tissue factor (TF) procoagulant activity and thrombin-antithrombin complex (TAT) levels in horses following infection with EHV-1. Methods: In vitro and ...
Niedzwiedz A, Jaworski Z, Kubiak K.Equine recurrent airway obstruction (RAO), also known as heaves, is one of the most common respiratory problems in older horses. When RAO-affected horses stay pastured or in a dust-free environment for a prolonged time, clinical signs as well as airway inflammation wane. A number of environmental, immunologic, infectious, and genetic factors play an important role in the pathogenesis of RAO, and the immunologic basis of this disease is still poorly understood. Objective: The aim of this study was to investigate the concentrations of allergen-specific IgE in the serum of horses suffering from R...
Andreassen SM, Berg LC, Nielsen SS, Kristensen AT, Jacobsen S.Studies in humans have shown that haemostatic and inflammatory pathways both play important roles in the pathogenesis of joint disease. The aim of this study was to assess mRNA expression of haemostatic and inflammatory factors in cultured equine fibroblast-like synoviocytes exposed to lipopolysaccharide (LPS), fibrinogen and thrombin. Synovial membranes were collected from metacarpo-phalangeal joints of 6 skeletally mature horses euthanized for non-orthopaedic reasons. Passage 4 fibroblast-like synoviocytes were left non-treated or treated with either 0.1 μg/ml LPS, 5 mg/ml fibrinogen or 5 U...
Schauer M, Kleinwort KJH, Degroote RL, Wiedemann C, Kremmer E, Hauck SM, Deeg CA.The GTP-binding protein septin 7 is involved in various cellular processes, including cytoskeleton organization, migration and the regulation of cell shape. Septin 7 function in lymphocytes, however, is poorly characterized. Since the intracellular signaling role of septin 7 is dependent on its interaction network, interaction proteomics was applied to attain novel knowledge about septin 7 function in hematopoietic cells. Our previous finding of decreased septin 7 expression in blood-derived lymphocytes in ERU, a spontaneous animal model for autoimmune uveitis in man, extended the role of sept...
Benoit S, Taouji S, Benachour A, Hartke A.Rhodococcus equi is an important gram-positive intracellular facultative pathogen in foals of less than 3 months of age, that causes suppurative bronchopneumonia, lymphadenitis and/or enteritis. The disease in young foals mainly occurs in spring and summer when weather conditions are favorable for survival and multiplication of the bacteria in the environment. R. equi is widespread in the environment of horsebreeding farms: it has been isolated from the soil of paddocks and from the feces of adult horses and foals. Aerosol infection via dust of paddocks seems to be the major route of foal infe...
Stothart MR, McLoughlin PD, Medill SA, Greuel RJ, Wilson AJ, Poissant J.Gut microbiomes are widely hypothesised to influence host fitness and have been experimentally shown to affect host health and phenotypes under laboratory conditions. However, the extent to which they do so in free-living animal populations and the proximate mechanisms involved remain open questions. In this study, using long-term, individual-based life history and shallow shotgun metagenomic sequencing data (2394 fecal samples from 794 individuals collected between 2013-2019), we quantify relationships between gut microbiome variation and survival in a feral population of horses under natural...
Russell J, Matika O, Russell T, Reardon RJ.Osteochondrosis is considered multifactorial in origin, with factors such as nutrition, conformation, body size, trauma and genetics thought to contribute to its pathogenesis. Few studies have investigated the effects of genetic variability of osteochondrosis in Thoroughbreds. Objective: To describe the prevalence and genetic variability of a subset of osteochondrosis lesions in a group of Thoroughbred yearlings. Methods: Retrospective cohort study. Methods: Radiographs of 1962 Thoroughbred yearlings were retrieved from clinical records obtained between 2005 and 2013. Pedigree information was ...
Maile CA, Hingst JR, Mahalingan KK, O'Reilly AO, Cleasby ME, Mickelson JR, McCue ME, Anderson SM, Hurley TD, Wojtaszewski JFP, Piercy RJ.Equine type 1 polysaccharide storage myopathy (PSSM1) is associated with a missense mutation (R309H) in the glycogen synthase (GYS1) gene, enhanced glycogen synthase (GS) activity and excessive glycogen and amylopectate inclusions in muscle. Equine muscle biochemical and recombinant enzyme kinetic assays in vitro and homology modelling in silico, were used to investigate the hypothesis that higher GS activity in affected horse muscle is caused by higher GS expression, dysregulation, or constitutive activation via a conformational change. PSSM1-affected horse muscle had significantly higher gly...
Henríquez C, Perez B, Morales N, Sarmiento J, Carrasco C, Morán G, Folch H.Recurrent airway obstruction (RAO) is an equine immune-mediated disease with a high incidence worldwide. The aim of this work was to contribute to the understanding of RAO pathogenesis by studying T cells bearing regulatory markers in peripheral blood (PB) and in bronchoalveolar lavage fluid (BALF) recovered from the same group of susceptible horses before and after exposure to moldy hay, which has been shown to induce RAO signology in our horse herd. With this purpose, mononuclear cells were obtained from the BALF and PB from horses before and after antigenic challenge and were stained with f...
