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.
Sedgwick RL, ElBohy O, Daly JM.In this review, we explore how pseudotyped viruses (PVs) are being applied to the study of viruses affecting both humans and horses. For the purposes of this review, we define PVs as non-replicative viruses with the core of one virus and the surface protein(s) of another and encapsulating a reporter gene such as luciferase. These 'reporter' PVs enable receptor-mediated entry into host cells to be quantified, and thus can be applied to study the initial stages of viral replication. They can also be used to test antiviral activity of compounds and measure envelope protein-specific antibodies in ...
Lovett AL, Riley CB, Chapman V, Bell B, Bishop B, Grierson A, Johnstone LJ, Sykes BW.Horses are exquisitely sensitive to tetanus neurotoxin and are exposed to the risk of infection with throughout life. The vaccine against tetanus is highly effective at preventing disease, whereas tetanus in unvaccinated populations is associated with high mortality rates. Current guidelines in New Zealand and Australia for the available vaccine contain contradictions and limitations surrounding the optimal tetanus immunisation protocols for both adult horses and foals. This review critically evaluates the scientific literature on tetanus prophylaxis in horses within the context of equine pra...
Nakajima K, Kasuya K, Senba H, Tagami K, Kinoshita Y, Niwa H.Strangles is a globally widespread, commonly diagnosed and important infectious disease of equids caused by Streptococcus equi subsp. equi. We performed whole genome sequencing of 19 S. equi isolates collected from imported horses at the Japanese border. Of these isolates, 15 isolates were obtained from clinical cases and 4 were from subclinical cases. The 19 isolates were grouped into 3 Bayesian analysis of population structure (BAPS) groups by the core genome single nucleotide polymorphism analysis corresponding to exporting country, SeM typing, or exporter of the horses. The 19 isolates pos...
Afify AF, Hassanien RT, El Naggar RF, Rohaim MA, Munir M.Equid herpesviruses (EHVs) are a group of highly impactful viral pathogens that affect horses, presenting a substantial risk to the global equine industry. Among these, equid herpesvirus-1 (EHV-1) primarily causes respiratory infections. However, its ability to spread to distant organs can lead to severe consequences such as abortion and neurological diseases. These viruses can enter a dormant phase, with minimal activity, and later reactivate to trigger active infections at any time. Recently, there has been a notable rise in the prevalence of a particularly devastating strains of EHV-1 known...
Marsella R.Allergy to insects is the most common skin allergy in horses. Pruritus in affected patients can be extreme. Face, ears, mane, and tail area are commonly affected areas. Diagnosis of insect bite hypersensitivity (IBH) is clinical and is based on history, clinical signs, and response to repellents. Allergy tests are not to be used for diagnostic purposes. Currently, there is no specific treatment for IBH other than insect avoidance, treatment of secondary infections, and symptomatic relief of pruritus. Many allergic horses become also sensitized to pollens. For these patients, allergen specific ...
Magdesian KG.Alloimmune disorders occur in foals when pregnant mares produce antibodies against antigens on the foal's cells or tissues, and concentrate them within colostrum. Once foals nurse and absorb colostral antibodies, they can develop hematologic or cutaneous manifestations that can occur individually or in combination. These include neonatal isoerythrolysis, a hemolytic anemia directed against factors on the foal's erythrocytes, alloimmune thrombocytopenia when the antibodies are directed against platelet antigens, alloimmune neutropenia when they are directed against neutrophil antigens, and a co...
Pandit PS, Smith WA, Finno CJ, Aleman M, Conrad PA, Packham A, Plancarte M, Woolard K, Marsh A, Pusterla N.Equine protozoal myeloencephalitis (EPM) is a challenging disease to diagnose in horses with neurological signs. To optimize contemporary diagnostic testing, including the use of serum:CSF antibody ratios, the SarcoFluor antibody test for Sarcocystis neurona requires revalidation. The SarcoFluor, a previously validated immunofluorescent antibody test (IFAT) for the detection of antibodies specific to S. neurona in serum and cerebrospinal fluid (CSF) of naturally infected horses was analyzed using recent data and considering a serum:CSF antibody ratio threshold. Utilization of serum and CSF pho...
Wells B.Beth Wells, equine grass sickness project lead at the Moredun Research Institute, encourages vets to report any equine grass sickness cases they encounter and explains how case reports and samples are being used to support research into this complex disease.
Marsella R.Autoimmune dermatopathies are not common in horses. These autoimmune diseases can be idiopathic or triggered by an antigen such as drugs, vaccines, or neoplasia. The most common one is pemphigus foliaceus, which manifests as a pustular, crusting eruption. Other more common pustular diseases should be ruled out before considering pemphigus. Vasculitis is relatively common in horses and can be triggered by a variety of antigenic stimulations. Systemic lupus and true idiopathic autoimmune vasculitis are very rare in horses. Every effort should be made to reach a final diagnosis, as the prognosis ...
Fortier C, El-Hage C, Normand C, Hue ES, Sutton G, Marcillaud-Pitel C, Jeffers K, Bamford N, Oden E, Paillot R, Hartley C, Gilkerson J, Pronost S.Reports of newly discovered equine hepatotropic flavi- and parvoviruses have emerged throughout the last decade in many countries, the discovery of which has stimulated a great deal of interest and clinical research. Although commonly detected in horses without signs of disease, equine parvovirus hepatitis (EqPV-H) and equine hepacivirus (EqHV) have been associated with liver disease, including following the administration of contaminated anti-toxin. Our aim was to determine whether EqPV-H and EqHV are present in Australian horses and whether EqPV-H was present in French horses and to examine ...
Pitchers KG, Boakye OD, Campeotto I, Daly JM.African horse sickness is a devastating viral disease of equids. It is transmitted by biting midges of the genus with mortalities reaching over 90% in naïve horses. It is endemic to sub-Saharan Africa and is seasonally endemic in many parts of southern Africa. However, outbreaks in Europe and Asia have occurred that caused significant economic issues. There are attenuated vaccines available for control of the virus but concerns regarding the safety and efficacy means that alternatives are sought. One promising alternative is the use of virus-like particles in vaccine preparations, which have...
Birkmann K, Jebbawi F, Waldern N, Hug S, Inversini V, Keller G, Holm A, Grest P, Canonica F, Schmid-Grendelmeier P, Fettelschoss-Gabriel A.Urticaria, independent of or associated with allergies, is commonly seen in horses and often shows a high reoccurrence rate. Managing these horses is discouraging, and efficient treatment options are lacking. Due to an incidental finding in a study on horses affected by insect bite hypersensitivity using the eosinophil-targeting eIL-5-CuMV-TT vaccine, we observed the prevention of reoccurring seasonal urticaria in four subsequent years with re-vaccination. In an exploratory case series of horses affected with non-seasonal urticaria, we aimed to investigate the role of eosinophils in urticaria....
Zečević I, Picardeau M, Vince S, Hađina S, Perharić M, Štritof Z, Stevanović V, Benvin I, Turk N, Lohman Janković I, Habuš J.Leptospirosis is one of the most common zoonotic infections and a major problem in terms of both veterinary medicine and public health. However, the disease is under-recognised and under-diagnosed worldwide, particularly in horses. Clinical leptospirosis in horses is mainly associated with recurrent uveitis (ERU), which has recently been studied more intensively, and reproductive disorders, the epidemiology of which is still relatively poorly understood. To enhance our comprehension of abortions caused by leptospirosis in horses and to identify the causative strains, a serological study was ca...
Onzere CK, Bastos RG, Bishop RP, Suarez CE, Fry LM. () is an apicomplexan parasite that causes severe hemolytic anemia in equids. Presently, there is inadequate knowledge of the immune responses induced by in equid hosts impeding understanding of the host parasite relationship and development of potent vaccines for control of infections. The objective of this study was to evaluate the host-parasite dynamics between merozoites and infected horses by assessing cytokine expression during primary and secondary parasite exposure, and to determine whether the pattern of expression correlated with clinical indicators of disease. Our findings showe...
Sun J, Xu X, Gao S, Pan Q, Liu Z, Huang Y, Lian Y.Prevotella heparinolytica is a Gram-negative bacterium that is commonly found in the oral, intestinal, and urinary tracts. It has been extensively studied in lower respiratory tract infections in horses, which has heparinolytic activity and can secrete heparinase and further induces virulence factors in cells and causes disease. However, no such cases have been reported in humans. Methods: A 58-year-old male patient from China presented to the respiratory clinic in Suzhou with a productive cough producing white sputum for 20 days and fever for 3 days. Prior to this visit, a chest computed to...
Chen L, Li S, Li W, Yu Y, Sun Q, Chen W, Zhou H, Wang C, Li L, Xu M, Khan MZ, Li Y, Wang T.The Nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway has been extensively studied for its role in regulating antioxidant and antiviral responses. The Equid herpesvirus type 8 (EqHV-8) poses a significant threat to the equine industry, primarily manifesting as respiratory disease, abortions, and neurological disorders in horses and donkeys. Oxidative stress is considered a key factor associated with pathogenesis of EqHV-8 infection. Unfortunately, there is currently a dearth of therapeutic interventions available for the effective control of EqHV-8. R...
Kalinovskiy A, Leser S, Ehrle A, Reese S, Jones S, Gerhards H.Cataracts resulting from equine recurrent uveitis (ERU) or other forms of uveitis are usually associated with rapid progression. ERU is the most common ocular disease cause of blindness and cause of cataracts in horses. The necessity for the posterior capsulorhexis (PC) during phacoemulsification (PE) is controversial. This study aimed to evaluate vision and complications after PE combined with pars plana vitrectomy (PPV) in horses with uveitis-associated cataracts and compare the PE technique with and without posterior capsulorhexis. Methods: Thirty-two eyes of 28 horses with uveitis-associat...
Connard SS, Gaesser AM, Clarke EJ, Linardi RL, Even KM, Engiles JB, Koch DW, Peffers MJ, Ortved KF.The objective of this study was to characterize extracellular vesicles (EVs) in plasma and synovial fluid obtained from horses with and without naturally occurring post-traumatic osteoarthritis (PTOA). Methods: EVs were isolated from plasma and synovial fluid from horses with (n = 6) and without (n = 6) PTOA. Methods: Plasma and synovial fluid EVs were characterized with respect to quantity, size, and surface markers. Small RNA sequencing was performed, and differentially expressed microRNAs (miRNAs) underwent bioinformatic analysis to identify putative targets and to explore potential associa...
Olstad K, Bugge MD, Ytrehus B, Kallerud AS.The neuro-central synchondrosis (NCS) is a physis responsible for the growth of the dorsal third of the vertebral body and neural arches. When the NCS of pigs is tethered to model scoliosis, stenosis also ensues. It is necessary to describe the NCS for future evaluation of its potential role in equine spinal cord compression and ataxia (wobbler syndrome). Objective: To describe the NCS, including when it and other physes closed in computed tomographic (CT) scans of the cervical spine of foals, due to its potential role in vertebral stenosis. Methods: Post-mortem cohort study. Methods: The cerv...
Kleij L, Bruder E, Raoux-Barbot D, Lejal N, Nevers Q, Deloizy C, Da Costa B, Legrand L, Barrey E, Chenal A, Pronost S, Delmas B, Dhorne-Pollet S.Equine influenza virus (EIV) remains a threat to horses, despite the availability of vaccines. Strategies to monitor the virus and prevent potential vaccine failure revolve around serological assays, RT-qPCR amplification, and sequencing the viral hemagglutinin (HA) and neuraminidase (NA) genes. These approaches overlook the contribution of other viral proteins in driving virulence. This study assesses the potential of long-read nanopore sequencing for fast and precise sequencing of circulating equine influenza viruses. Therefore, two French Florida Clade 1 strains, including the one circulati...
Tanaka Y, Watanabe K, Takeyama A, Tagami M, Hamano H, Fukumoto N, Nambo Y, Kobayashi Y.Equine testicular arteritis commonly occurs as a consequence of the migration of nematode larvae or equine arteritis virus (EAV) infection. However, testicular arteritis without evidence of these infections has been reported, and the underlying pathogenesis remains unclear. We encountered testicular arteritis without evidence of nematode or EAV infection in a 3-year-old male heavy draft horse with scrotal enlargement. Grossly, the volume of the pampiniform plexus was markedly increased due to edema. Histologically, non-suppurative and necrotizing testicular arteritis, characterized by lymphocy...
Cochet M, Piumi F, Gorna K, Berry N, Gonzalez G, Danckaert A, Aulner N, Blanchet O, Zientara S, Donadeu FX, Munier-Lehmann H, Richardson J....Outbreaks of West Nile virus (WNV) occur periodically, affecting both human and equine populations. There are no vaccines for humans, and those commercialised for horses do not have sufficient coverage. Specific antiviral treatments do not exist. Many drug discovery studies have been conducted, but since rodent or primate cell lines are normally used, results cannot always be transposed to horses. There is thus a need to develop relevant equine cellular models. Here, we used induced pluripotent stem cells to develop a new in vitro model of WNV-infected equine brain cells suitable for microplat...
Kowalik S, O'reilly M, Niedźwiedź A, Kędzierski W.(1) Background: The number of horses suffering from chronic respiratory diseases, resembling human asthma, is increasing but there is still a lack of reliable and accurate methods to detect these disorders. Numerous studies have found elevated plasma concentrations of one of the myokines, namely, myostatin (MSTN), in people suffering from severe asthma. MSTN normally inhibits myoblast proliferation and differentiation through autocrine or paracrine signals. Therefore, given the pathogenesis of asthma, we hypothesize that MSTN could be a useful biomarker of equine asthma. Thus, this study aimed...
Boucher L, Leduc L, Leclère M, Costa MC.Understanding the importance of intestinal microbiota in horses and the factors influencing its composition have been the focus of many studies over the past few years. Factors such as age, diet, antibiotic administration, and geographic location can affect the gut microbiota. The intra- and inter-individual variability of fecal microbiota in horses complicates its interpretation and has hindered the establishment of a clear definition for dysbiosis. Although a definitive causal relationship between gut dysbiosis in horses and diseases has not been clearly identified, recent research suggests ...
Jasiński T, Turek B, Kaczorowski M, Brehm W, Skierbiszewska K, Bonecka J, Domino M.Osteoarthritis (OA) of the temporomandibular joint (TMJ) occurs spontaneously in humans and various animal species, including horses. In humans, obtaining tissue samples is challenging and clinical symptoms appear late in the disease progression. Therefore, genetically modified, induced, and naturally occurring animal models play a crucial role in understanding the pathogenesis and evaluating potential therapeutic interventions for TMJ OA. Among the naturally occurring models, the equine TMJ OA model is characterized by slow, age-related progression, a wide range of clinical examinations, and ...
Equine asthma (EA) is a respiratory syndrome associated with the increase of different leukocyte populations in the bronchoalveolar lavage fluid (BALF). Its pathogenetic mechanisms remain unclear. This study aimed to evaluate the associations between the mRNA expression of different cytokines in the BALF, different EA subtypes and lung function. Fifteen horses underwent physical examination, airway endoscopy, BALF cytology and lung function testing (8/15). One horse did not have evidence of EA and was used as healthy reference, while the others were classified as affected by neutrophilic or mi...
Tong P, Yang E, Liu B, Tian S, Suo Y, Pan J, Dang Y, Palidan N, Jia C, Kuang L, Xie J.Varicellovirus equidalpha1 (formerly Equid alphaherpesvirus 1, EqAHV-1) is among the most important viruses responsible for respiratory disease outbreaks among horses throughout the world. No reports to date have detailed the association between EqAHV-1 and respiratory disease among horses in China. This study described one such outbreak among a population of horses in north Xinjiang that occurred from April 2021 - May 2023. Results: qPCR revealed that EqAHV-1 was detectable in all samples and this virus was identified as a possible source of respiratory disease, although a limited subset of t...
Pirie RS, Couëtil LL, Robinson NE, Lavoie JP.In their editorial in Equine Veterinary Journal (EVJ) almost a quarter of a
century ago, Hall and Stark [1] referred to the inability of clinicians, both
human and veterinary, to separate and recognise the different clinical
entities responsible for chronic diseases of the airways, with the
subsequent development of several different approaches to terminology,
as well as treatment. In relation to equine nonseptic lower airway disease,
and despite many attempts to identify the most appropriate nomenclature,
this challenge remains as topical today as it did then. ‘Equine asthma’ has
...
Henderson BE, Chappell WA, Johnston JG, Sudia WD.Henderson, B. E., W. A. Chappell, J. G. Johnston, Jr. and W. D. Sudia (CDC, Atlanta, Ga. 30333). Experimental Infection of horses with three strains of Venezuelan equine encephalomyelitis virus. I. Clinical and virological studies. Amer J Epidem 93: 194–205, 1971.—Clinical effect, viremias and antibody responses were compared in horses inoculated with the following strains of Venezuelan equine encephalomyelitis (VEE) virus: Fe3-7C, isolated from Culex (Melano-conion) spp. mosquitoes collected In 1963 in the Florida Everglades; TC-83, the Fort Detrick live, attenuated vaccine strain; and GJ...
Garton NJ, Gilleron M, Brando T, Dan HH, Giguère S, Puzo G, Prescott JF, Sutcliffe IC.Rhodococcus equi is a major cause of foal morbidity and mortality. We have investigated the presence of lipoglycan in this organism as closely related bacteria, notably Mycobacterium tuberculosis, produce lipoarabinomannans (LAM) that may play multiple roles as virulence determinants. The lipoglycan was structurally characterized by gas chromatography-mass spectrometry following permethylation, capillary electrophoresis after chemical degradation, and (1)H and (31)P and two-dimensional heteronuclear nuclear magnetic resonance studies. Key structural features of the lipoglycan are a linear alph...
Hurtgen JP.Inflammatory conditions of the uterus, collectively known as endometritis, can be classified as acute, chronic, active, or subclinical. This condition causes substantial reductions in mare fertility. To diagnose and treat mares with endometrial inflammation, it is imperative to identify predisposing factors and challenges to the reproductive tract of the mare in a chronological order; these factors change from those of the young maiden filly to the older, multiparous broodmare. This paper addresses predisposing factors, diagnostic procedures and therapy strategies for different mare groups.
Edmunds DH, Whittaker DK, Green RM.The progress of artificial caries-like lesions created in human, bovine, equine, and ovine enamel has been studied. Lesions were produced by exposure to an acid gel system or by 5-day exposure to a sequential batch culture technique using Streptococcus mutans NCTC 10832. Longitudinal ground sections were prepared. The lesions were of similar appearance in all species when examined in polarized light. The depth in human enamel was approximately half that in the animal species. Microradiography confirmed subsurface demineralization in all four species. Similar depth ratios were seen in the scann...
Anderson JR, Phelan MM, Foddy L, Clegg PD, Peffers MJ.Osteoarthritis is an age-related degenerative musculoskeletal disease characterized by loss of articular cartilage, synovitis, and subchondral bone sclerosis. Osteoarthritis pathogenesis is yet to be fully elucidated with no osteoarthritis-specific biomarkers in clinical use. equine cartilage explants ( = 5) were incubated in tumor necrosis factor-α (TNF-α)/interleukin-1β (IL-1β)-supplemented culture media for 8 days, with the media removed and replaced at 2, 5, and 8 days. Acetonitrile metabolite extractions of 8 day cartilage explants and media samples at all time points underwent one-d...
Chaichanasiriwithaya W, Rikihisa Y, Yamamoto S, Reed S, Crawford TB, Perryman LE, Palmer GH.Ehrlichia risticii causes an acute infectious disease in horses called Potomac horse fever. To investigate the biological diversity of E. risticii organisms, nine E. risticii isolates derived from the peripheral blood monocytes of clinically sick horses in Ohio and Kentucky during the summers of 1991 and 1993 were compared with Illinois and Virginia isolates originally obtained from horses in Maryland in 1984. Seven of the nine isolates (081, 606, 380, 679, As, Co, and Ov) formed large morulae (tightly packed inclusions of ehrlichial organisms). The remaining isolates, including 1984 isolates,...
Schindler AR, Vögtlin A, Hilbe M, Puorger M, Zlinszky K, Ackermann M, Ehrensperger F.Borna disease is a severe, immunopathological disorder of the central nervous system caused by the infection with the Borna disease virus (BDV). The detection of BDV in diseased animals, mainly sheep and horses, is achieved by histological, immunohistochemical and serological approaches and/or PCR-based technologies. In the present study, reverse transcription, real-time PCR assays were established for the detection of BDV in the brain tissue from sheep and horses, using loci for the p40 (nucleoprotein) and the p24 (phosphoprotein) genes. The PCRs were equally specific and sensitive, detecting...
Tripathi VN, Harding WC, Willingham-Lane JM, Hondalus MK.Rhodococcus equi is a facultative intracellular, Gram-positive, soilborne actinomycete which can cause severe pyogranulomatous pneumonia with abscessation in young horses (foals) and in immunocompromised people, such as persons with AIDS. All strains of R. equi isolated from foals and approximately a third isolated from humans contain a large, ~81-kb plasmid which is essential for the intramacrophage growth of the organism and for virulence in foals and murine in vivo model systems. We found that the entire virulence plasmid could be transferred from plasmid-containing strains of R. equi (dono...
Teifke JP, Kidney BA, Löhr CV, Yager JA.We examined 12 formalin-fixed paraffin-embedded feline skin tumours which had the histopathological features of fibropapillomas for the presence of papillomavirus (PV) DNA using touchdown polymerase chain reaction (PCR), DNA sequencing and nonradioactive in situ hybridization. Nine of the tumours contained a 102-bp PCR product demonstrated using consensus PV primers that amplify a portion of the L1 gene. The nucleotide sequences are closely related, but not identical to that of ovine PV type 2, rabbit oral PV and reindeer PV. The deduced amino acid sequences had strong homologies with the majo...
Lyle CH, Blissitt KJ, Kennedy RN, Mc Gorum BC, Newton JR, Parkin TD, Stirk A, Boden LA.Sudden death adversely affects racehorse welfare, jockey safety and the public perception of horseracing. Objective: To describe the risk of racing-associated sudden death in Thoroughbred racehorses in the UK from 2000 to 2007, to identify whether there were risk factors uniquely associated with sudden death and to improve the understanding of the pathogenesis of racing-associated sudden death by identification of risk factors for such cases. Methods: A sudden death was defined as an acute collapse and death, in an apparently healthy Thoroughbred racehorse, during or immediately after racing, ...
Beeler-Marfisi J, Clark ME, Wen X, Sears W, Huber L, Ackerley C, Viel L, Bienzle D.To evaluate experimental induction of recurrent airway obstruction (RAO) with inhaled fungal spores, lipopolysaccharide, and silica microspheres in horses. Methods: 7 horses with and 3 horses without a history of RAO. Methods: RAO-susceptible horses ranged in age from 17 to approximately 30 years, and control horses ranged in age from 7 to approximately 15 years. Pure mold cultures were derived from repeated culture of hay and identified via gene amplification and sequencing. Pulmonary function testing and bronchoalveolar lavage were performed before and after nebulization with a suspension of...
Ainsworth DM, Wagner B, Franchini M, Grünig G, Erb HN, Tan JY.To evaluate time-dependent alterations in gene expression of chemokines in bronchial epithelium of recurrent airway obstruction (RAO)-affected horses and whether alterations resulted from increases in gene expression of interleukin (IL)-17 in cells isolated from bronchoalveolar lavage fluid (BALF). Methods: 8 RAO-susceptible horses and 9 control horses. Methods: In 2 experiments, both groups of horses were evaluated after being maintained on pasture and after being stabled and fed dusty hay for 1, 14, 35, and 49 days (experiment 1) or 14 and 28 days (experiment 2). In experiment 1, gene expres...
Padoan E, Ferraresso S, Pegolo S, Castagnaro M, Barnini C, Bargelloni L.The goal of the present study was to investigate mRNA expression levels of several cytokines and inflammatory mediators in broncho-alveolar lavage (BAL) fluid and respiratory epithelium in recurrent airway obstruction (RAO)-affected horses. RAO, also called heaves, is a common, performance-limiting, equine respiratory disease with clinical signs and pathophysiological similarities to human asthma, and characterized by bronchospasm, neutrophilic infiltration and increased mucus in the airways. Six RAO-affected horses were examined twice within 15 days and seven clinically healthy horses were ex...
Gonzalez-Salazar D, Estrada-Franco JG, Carrara AS, Aronson JF, Weaver SC.To assess the role of horses as amplification hosts during the 1993 and 1996 Mexican Venezuelan equine encephalitis (VEE) epizootics, we subcutaneously infected 10 horses by using four different equine isolates. Most horses showed little or no disease and low or nonexistent viremia. Neurologic disease developed in only 1 horse, and brain histopathologic examination showed meningeal lymphocytic infiltration, perivascular cuffing, and focal encephalitis. Three animals showed mild meningoencephalitis without clinical disease. Viral RNA was detected in the brain of several animals 12-14 days after...
Hughes KJ, Nicolson L, Da Costa N, Franklin SH, Allen KJ, Dunham SP.Inflammatory airway disease (IAD) is a common disorder of performance horses and is associated with poor performance and accumulation of mucus and inflammatory cells in lower airway secretions. Horses with IAD frequently have increased relative counts of neutrophils in bronchoalveolar lavage fluid (BALF); less commonly relative counts of eosinophils and/or mast cells may be increased. The aetiopathogenesis of IAD is unknown and may involve innate and/or acquired immune responses to various factors including respirable dust constituents, micro-organisms, noxious gases and unconditioned air. The...
McFarlane D.Parkinson's disease (PD) is a leading cause of neurologic disability in the aged population. Remarkable progress has been made in the past decade to understand the cellular and molecular events that occur in PD. However attempts to unravel the early, initiating factors in the pathogenesis of dopaminergic neurodegeneration and PD have been limited by the lack of a suitable animal model. Models in which there has been genetic or environmental manipulation are not of use in determining the natural cause of a disease. While a large scale prospective human study would be ideal, the relatively low p...
Johnson PJ.Cutaneous neoplasia represents a clinical problem with which veterinarians are commonly challenged. This article addresses equine cutaneous squamous cell carcinoma, squamous cell papilloma, melanoma, mastocytosis, and lymphosarcoma. Current concepts regarding the origin, pathogenesis, diagnosis and treatment of each neoplasm is emphasized.
Hauck SM, Hofmaier F, Dietter J, Swadzba ME, Blindert M, Amann B, Behler J, Kremmer E, Ueffing M, Deeg CA.Equine recurrent uveitis is a severe and frequent blinding disease in horses which presents with auto-reactive invading T-cells, resulting in the destruction of the inner eye. Infiltration of inflammatory cells into the retina and vitreous is driven by currently unknown guidance cues, however surgical removal of the vitreous (vitrectomy) has proven therapeutically successful. Therefore, proteomic analyses of vitrectomy samples are likely to result in detection of proteins contributing to disease pathogenesis. Vitreous from healthy and ERU diseased horses were directly compared by quantitative ...
Gould AR.The nucleotide sequence of the matrix protein of equine morbillivirus (EMV) was determined to be 1062 nucleotides and coded for a deduced protein of M(r) 40148 having a net charge of + 19 at neutral pH. The matrix protein gene was separated from the P and F genes by intercistronic regions of 546 and 469 nucleotides, respectively. The nucleotide sequence which coded for the F protein was 1641 nucleotides and coded for a deduced protein of 546 amino acids having an M(r) of 60,447 and a charge + 4 at neutral pH. Partial sequence information was also determined for the P/V proteins. M, P and F pro...
Smith KC.Abortion or neonatal disease may follow infection with several alpha, beta and gamma-herpesviruses. The alpha-herpesvirus, equid herpesvirus-1 (EHV-1), causes single or epizootic abortions or neonatal deaths in equids, and the closely related virus EHV-4 causes sporadic equine abortions. In cattle, the alpha-herpesviruses, bovine herpesvirus-1 (infectious bovine rhinotracheitis virus) and bovine herpesvirus-5 (bovine encephalitis virus), and a gamma-herpesvirus, bovine herpesvirus-4, have all been implicated as causes of abortion. In pigs, suid herpesvirus-1 (SHV-1: pseudorabies virus), an alp...
Alexandersen S, Carpenter S.The polymerase chain reaction was used to amplify and clone parts of the envelope gene and overlapping S3 open reading frame, thought to encode rev, of the virulent in vivo-derived Th-1 isolate of equine infectious anemia virus (EIAV). The results indicated that EIAV consists of a heterogeneous mixture of genotypes present at the first febrile cycle after initial infection. We showed that the Th-1 isolate apparently contains nondefective genotypes as well as types which have transmembrane protein truncations or are rev deficient. Furthermore, we could confirm the presence of a hypervariable re...
Van Cleemput J, Poelaert KCK, Laval K, Maes R, Hussey GS, Van den Broeck W, Nauwynck HJ.The respiratory epithelium of humans and animals is frequently exposed to alphaherpesviruses, originating from either external exposure or reactivation from latency. To date, the polarity of alphaherpesvirus infection in the respiratory epithelium and the role of respiratory epithelial integrity herein has not been studied. Equine herpesvirus type 1 (EHV1), a well-known member of the alphaherpesvirus family, was used to infect equine respiratory mucosal explants and primary equine respiratory epithelial cells (EREC), grown at the air-liquid interface. EHV1 binding to and infection of mucosal e...
Kulbrock M, Lehner S, Metzger J, Ohnesorge B, Distl O.Equine recurrent uveitis (ERU) is a common eye disease affecting up to 3-15% of the horse population. A genome-wide association study (GWAS) using the Illumina equine SNP50 bead chip was performed to identify loci conferring risk to ERU. The sample included a total of 144 German warmblood horses. A GWAS showed a significant single nucleotide polymorphism (SNP) on horse chromosome (ECA) 20 at 49.3 Mb, with IL-17A and IL-17F being the closest genes. This locus explained a fraction of 23% of the phenotypic variance for ERU. A GWAS taking into account the severity of ERU, revealed a SNP on ECA18 n...
Angelone M, Conti V, Biacca C, Battaglia B, Pecorari L, Piana F, Gnudi G, Leonardi F, Ramoni R, Basini G, Dotti S, Renzi S, Ferrari M, Grolli S.Laminitis, a highly debilitating disease of the foot in ungulates, is characterized by pathological changes of the complex lamellar structures that maintain the appendicular skeleton within the hoof. Laminitis is a multifactorial disease that involves perturbation of the vascular, hematological, and inflammatory homeostasis of the foot. Interestingly, the pathogenesis of the disease resembles what is observed in metabolic syndromes and sepsis-induced organ failure in humans and animals. We hypothesized that local administration of mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP) mi...
Lichtenstein DL, Issel CJ, Montelaro RC.Equine infectious anemia virus (EIAV) provides a uniquely dynamic system in which to study the mechanism and role of genomic variation in lentiviral persistence and pathogenesis. We have used a Shetland pony model of infection to investigate the association of specific long terminal repeat (LTR) and env gene genomic sequences with the initiation of infection and the onset of disease. We analyzed viral RNA isolated from a pathogenic stock of virus (EIAV PV) and from plasma taken during the first disease episode from two ponies infected with EIAV PV. Overall sequence variation within gp90 was lo...
Schein E, Rehbein G, Voigt WP, Zweygarth E.The vertebrate development of Babesia equi from infected Hyalomma marginatum in Morocco was investigated in vitro and in vivo. It was demonstrated that the sporozoites of B. equi initiate a phase of exo-erythrocytic schizogony in lymphocytes both in vitro and in vivo. On the other hand, sporozoites did not invade erythrocytes in vitro. The complete vertebrate life cycle of B. equi was simulated in vitro, from the invasion of lymphocytes by sporozoites, to the development of macro- and microschizonts, the invasion of erythrocytes by merozoites, and the subsequent intra-erythrocytic schizogony. ...
Huser CA, Davies ME.The objective of this study was the development and characterization of an in vitro model of the initiation of traumatic osteoarthritis (OA). Articular cartilage was obtained from seven healthy horses and from four horses diagnosed with OA. Cartilage disks were subjected to a single-impact load (500 g from 25, 50, or 100 mm) using a simple drop-tower device and cultured in vitro for up to 20 days. Cartilage sections were examined histologically to observe surface damage and proteoglycan loss. Percentage cell death was determined using TUNEL, release of glycosaminoglycans (GAG) to the medium wa...
Olstad K, Ytrehus B, Ekman S, Carlson CS, Dolvik NI.The developmental pattern of the cartilage canal blood supply to epiphyseal growth cartilage has been linked to osteochondrosis (OC) in the tarsus of foals. This pattern has not yet been described in the distal femur, another site frequently affected by OC. Objective: To describe the developmental pattern of the blood supply to the distal femoral epiphyseal growth cartilage in 8 Standardbred foals age 0-7 weeks. Methods: One foal was sacrificed weekly from birth to age 7 weeks (n=8) to undergo a barium perfusion procedure to demonstrate vessels within cartilage canals of one hindlimb. The dist...
