The immune response in horses involves a complex network of cells, tissues, and molecules that work together to protect the animal from pathogens and other harmful agents. This process includes both innate and adaptive immune mechanisms. Innate immunity provides the first line of defense and involves components such as physical barriers, phagocytic cells, and the complement system. Adaptive immunity, on the other hand, is characterized by the activation of lymphocytes and the production of antibodies, which provide a targeted response to specific antigens. Key components of the equine immune system include T cells, B cells, and various cytokines that facilitate communication between immune cells. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, regulation, and implications of immune responses in equine health.
Källse A, Källberg M, Ström L.To evaluate long-term clinical outcomes, recurrence rates, and complications following photodynamic therapy (PDT) in horses with immune-mediated keratitis. Unassigned: Medical records of horses treated with PDT at the Swedish University of Agricultural Sciences Equine Clinic from May 2018 through October 2025 were reviewed retrospectively. Eyes with a clinical diagnosis of recurrent immune-mediated keratitis that had responded to immunosuppressive therapy and been subjected to PDT therapy were included. Infracyanine green was injected intrastromally, followed by irradiation with an 810-nm diod...
Charbonnel A, Thorin C, Allain S, Guicheux J, Boutet MA, de Fourmestraux C.Endoscopy and synovial membrane histology are complementary modalities for evaluating synovial inflammation. Cytokine involvement in non-septic arthritis is well documented but remains poorly characterized in septic synovitis. Objective: This study aimed to characterize the inflammatory cytokine profile associated with septic and non-septic synovitis and assess correlations among endoscopic, histological, and synovial fluid biomarker findings. Methods: Three groups were defined: horses undergoing elective or therapeutic endoscopy (Group 1, n=26), horses with confirmed septic synovitis (Group 2...
Cappai MG, Sarah M, Alice S, Andrea T, Giampaolo B, Raffaele C.Breeding stallions are subjected to sustained seasonal metabolic, endocrine, and immune demands requiring systemic energy engagement. Prospective longitudinal data in the same individuals are limited. Objective: To screen adaptive responses of breeding stallions of clinical relevance through longitudinal characterisation of temporal changes across the mating season and negative photoperiod: (i) health and nutritional status; (ii) oxidative status and immune modulation; and (iii) metabolic and endocrine biomarkers as correlates of reproductive potential. Methods: Prospective longitudinal observ...
Apaoblaza S, Albornoz A, Henriquez C, Quiroga J, Burgos RA, Moran G.Ivermectin has been reported to exert immunomodulatory effects on the innate immune system; however, the available evidence is contradictory, with both anti-inflammatory and, paradoxically, pro-inflammatory effects described depending on species, dose, and experimental context, while data specific to horses remain scarce. We hypothesised that ivermectin would exert a context-dependent immunomodulatory effect on equine leucocytes. To test this, total leucocytes isolated from six healthy horses were incubated with ivermectin (2 and 4 µg/mL) before stimulation with lipopolysaccharide (LPS) and n...
Akula S, Zhang B, Riihimäki M, Wernersson S, Raine A.The skin serves as the primary barrier tissue in horses and is frequently affected by immune-mediated dermatological conditions, most notably insect bite hypersensitivity (IBH). Yet, the cellular composition and transcriptional landscape of normal equine skin have never been characterized at single-cell resolution. Here, we present a single-cell RNA sequencing dataset of healthy equine skin comprising 85,574 high-quality transcriptomes from two horses, with one skin biopsy collected from each horse, divided into two portions for independent processing via manual or automated tissue dissociatio...
Styková E, Mudroňová D, Gancarčíková S, Žert Z, Kačírová J, Valocký I.Chronic equine proliferative pododermatitis (canker) is a hypertrophic hoof disease characterized by excessive proliferation of horn-producing tissues resulting from dyskeratosis of keratinocytes. Since its etiology remains unknown, this study investigated potential etiological agents and evaluated biochemical and immunological profiles. Ten horses with hoof canker and ten healthy controls of the Norik of Muran breed were included. Dermatophytes and bovine papillomavirus 1 and 2 (BPV 1/2) were not detected. Candida glabrata was the most frequently identified species in both affected and health...
Luedke L, Clark A, Hendrickson DA, Bass L, Kawahisa-Piquini G, Impastato R, Sabino I, Chow L, Dow S, Pezzanite LM, Griffenhagen GM.Liposomal local anesthetics have been shown to extend analgesia duration and improve pain scores dose-dependently in horses. Our objective was to assess concurrent impact on systemic inflammatory markers. Unassigned: 18 mares (age, 2 to 20 years) with normal ovarian anatomy were enrolled. Laparoscopic bilateral ovariectomies were performed standing with sedation. Local analgesia was: 80 mL bupivacaine hydrochloride (BHCl; n = 6), 30 mL 0.75% BHCl + 20 mL (low-dose) liposomal bupivacaine (LB) expanded to 80 mL with saline (LB20, n = 6), or 30 mL 0.75% BHCl + 40 mL (high-dose) LB expanded to equ...
Alleaume C, Laloy E, Dupuis-Tricaud MC, Kuk N, Kariya E, Keck N, Depaquit J, Lachaud L, Ravel C.In this study, we describe the first documented cases of equine cutaneous leishmaniasis caused by Leishmania (Mundinia) martiniquensis in France and provide clinical and parasitological data relevant for the recognition of this emerging infection in horses. Three horses presenting localized cutaneous lesions were diagnosed with L. martiniquensis infection in different regions of France without spatial or temporal clustering. Lesions were clinically nonspecific and initially compatible with common equine dermatological conditions, including sarcoid-like tumors. Histopathological examination rev...
Hunyadi LM, Hyde SC, Sundman EA.The role of inflammation, allergy, and air quality in the pathogenesis of equine asthma has not yet been fully elucidated. Objective: To evaluate serum inflammatory cytokines, intradermal skin testing (IDT), and air quality in asthmatic horses. It was hypothesized that there would be an association between environmental allergies and poor air quality with asthma. Methods: 52 client-owned horses with clinical signs consistent with asthma were enrolled in this cross-sectional study. Horses were diagnosed with asthma based on the results of bronchoalveolar fluid (BALF) cytology. Blood samples wer...
Matas-Quintanilla M, Castillo C, Whitacre L, Ipharraguerre IR, Gutiérrez-Panizo C, Hernández J, Gutiérrez AM.Gastric ulceration is common in horses and remains challenging to diagnose, as gastroscopy is the gold standard. This study aimed to characterise the salivary and serum protein changes associated with a feed-deprivation protocol. Eight horses underwent this protocol, and gastric lesions were assessed by gastroscopy at the end of the experimental period. Saliva and blood samples were collected pre- and post-protocol, and pooled samples from each biological fluid and condition were analysed by two-dimensional gel electrophoresis to compare protein profiles. Fifteen salivary and five serum protei...
Tóth J, Buijs L, Lorenz R, Bakos Z.Eosinophilic keratoconjunctivitis (EKC) is an inflammatory eye disease of horses with an unknown cause and suspected immune-mediated pathogenesis. This single-center retrospective case series included 114 horses (163 affected eyes) examined at a German equine referral hospital from January 2012 to December 2020. Of these horses, 71 (62.3%) were Warmbloods, 77 (67.5%) were presented from July to September, and 49 (43.0%) had bilateral disease. The cornea was involved in 139 of 163 eyes (85.3%). During the study period, 114 EKC cases occurred among 5742 ophthalmology cases (2.0%), with an increa...
Williams Louie E, Cercone M, Delvescovo B, Chevalier J, Mitchell K.Horses with endotoxemia have variable myocardial function, but little is known about the severity or persistence of myocardial dysfunction (MD). Objective: Horses with experimentally induced endotoxemia have systolic and diastolic MD. Methods: Twelve systemically healthy horses. Methods: Horses were given Escherichia coli lipopolysaccharide 30 ng/kg over 60 min. Echocardiography and cardiac troponin I (cTnI) measurements were performed at baseline, 1, 3, and 5 h post-endotoxin. Fluid therapy (10 L), polymyxin B (6000 IU/kg), and flunixin meglumine (1.1 mg/kg) were administered intravenou...
Leal M, Silva E, Alpoim-Moreira J, Rebordão MR, Quaresma M, Li J, Szóstek-Mioduchowska A, Skarzynski D, Ferreira-Dias G.Endometrosis, characterized by excessive endometrial fibrosis, is a major reproductive disorder that impairs fertility and remains a significant challenge in equine breeding. The molecular mechanisms underlying equine endometrosis are not fully understood. This study investigated endometrial proteomic changes induced by endometrosis to identify the biological processes (BP) and pathways involved. Cyclic mares' endometrial biopsies were categorized as category IIA (n = 5) or category IIB (n = 5), according to Kenney and Doig's classification. LC-MS/MS assessed the endometrial proteome, ...
Wierzbicka M, Minett D, Pawliński B, Siemieniuch-Tartanus M.Equine asthma is increasingly recognised as a biologically heterogeneous syndrome in which similar clinical manifestations may arise from distinct molecular mechanisms. Although clinical phenotypes have substantially improved disease classification, increasing evidence indicates that molecular endotypes more accurately reflect the biological mechanisms underlying disease heterogeneity. This review summarises current knowledge regarding the pathophysiological mechanisms of equine asthma, with particular emphasis on inflammatory pathways, molecular endotypes, genetic susceptibility, airway remod...
Dembek K.Critical illness-related corticosteroid insufficiency is a transient dysfunction of the hypothalamic-pituitary-adrenal axis, leading to inadequate cortisol responses during severe stress from endotoxemia and sepsis in horses and foals. This condition is associated with poor outcomes, and its diagnosis is complicated by interindividual variability in cortisol response. Recent advances in dynamic testing and point-of-care hormone tests offer promise for better assessment and treatment, enabling more precise steroid replacement therapy in affected equine patients.
Korac L, St George L, McCrae P, MacNicol J, Golestani N, Souccar-Young J, Karrow N, Cánovas Á, Avison A, Pearson W.Recently, a synovitis model using 75 ng intra-articular recombinant equine interleukin-1 (reIL 1β), showed promise for inducing a mild, self-limiting inflammatory response without overtly altering upper-body movement asymmetry in = 3 horses. This study aimed to evaluate the effect of this 75 ng reIL-1β model on gait biomechanics and synovial fluid (SF) inflammatory, pro-resolution, and cartilage turnover biomarkers in a larger equine sample. SF samples were collected from the left intercarpal joint of = 11 horses at baseline and at 6- and 12-hours following 75 ng reIL-1β injection and...
Ammons D, Chow L, Goodrich L, Barrett M, Nelson B, Impastato R, Stoneback JW, Dow S, Pezzanite LM.Define temporal cellular changes following joint injury using single-cell RNA sequencing in experimental equine posttraumatic osteoarthritis (PTOA). Unassigned: PTOA was induced in 4 Quarter Horses (3 to 5 years) via carpal osteochondral fragmentation and high-speed treadmill exercise. Synovial fluid (SF) cells and synovium were sampled over 18 weeks (November 2023 to April 2024). Single-cell suspensions were processed (10x Genomics Chromium iX), then aligned to the equine genome (Cell Ranger). Downstream analysis was completed in the R Seurat package. Differential gene expression (log2[fold c...
Miranda RPDR, de Miranda BA, Aranha AB, Gomes Ramos MFB, Oliveira EP, Dallago BSL, Adorno J, Macêdo IL, Castro MB, Campebell RC.Skin wounds are common in horses due to species-specific behavioral responses. Equine skin morphology, vascularization, and inflammatory responses to wounds are comparable to those in humans, supporting the translational relevance of equine wound-healing studies. Investigating biomaterials such as tilapia and frog skin may improve wound management. This study demonstrated that sterilized tilapia and frog skin exhibit promising wound-healing properties. Unassigned: Macroscopic, microscopic, and thermographic aspects of second-intention wound healing were compared in six horses with surgically i...
Zhou Y, Ren W, Zeng Y, Wang J, Meng J, Yao X, Zhai M.Kazakh horses are typical seasonal breeders, and ovarian activity is markedly reduced during the non-breeding period. Hormonal stimulation can induce ovarian functional responses during seasonal anestrus; however, the early ovarian transcriptional changes associated with this response remain incompletely understood. In this study, ovarian transcriptome sequencing was performed in 12 Kazakh mares examined during the seasonal anestrous period. The mares were classified into a non-hormonally stimulated seasonal quiescent group (DB, = 6) and a hormone-induced ovarian activation group (DY, = 6) f...
Barbazanges P, Richard EA, Debonnaire C, Le Digarcher G, Lemonnier LC, Toquet MP, Couroucé A.Guttural pouch (GP) disorders are clinically important in horses, yet the relationship between endoscopic findings and GP cytology remains poorly defined. Objective: To establish reference cytological values for GP lavage fluid in horses and to investigate associations between inflammatory cytology and endoscopic findings. Methods: Asymptomatic racing horses sampled in the field and horses referred for investigation of respiratory disorders. Methods: Prospective cross-sectional study. Horses underwent clinical examination, upper airway endoscopy, and bilateral transendoscopic GP lavage. A GP i...
Ferlini Agne G, Barratt DT, May BE, Hutchinson MR, Holmes J, Steel C, Simon O, Evans SG, Somogyi AA, Sykes BW, Franklin S.Equine gastric ulcer syndrome (EGUS) is highly prevalent in horses. Despite its presumed painful nature, evaluation of objective biomarkers associated with EGUS presence and severity remains limited. The objective of this study was to investigate the potential of interleukin-1 beta (IL-1β) release by peripheral blood mononuclear cells (PBMCs) following ex vivo stimulation of toll-like receptors 2 and 4 (TLR2 and TLR4) as a potential biomarker for EGUS status, with gastric lesions used as a proxy for presumed EGUS-associated pain. Venous blood was collected from 77 horses, PBMCs were isolated ...
Zhang B, Agdour H, Riihimäki M, Hansen S, Raine A.Circulating cell-free RNA (cfRNA) has emerged as a promising minimally invasive biomarker capable of capturing transcripts originating from multiple tissues and cell types, but its utility in chronic inflammatory airway diseases remains poorly understood. Equine asthma (EA), a naturally occurring respiratory disease that shares key clinical and immunopathological features with human asthma, provides a valuable comparative model for evaluating plasma cfRNA in this context. We performed transcriptomic profiling of plasma cfRNA from horses with EA and healthy controls and compared these findings ...
Fukushi N, Kirisawa R, Nishimura F, Tsujimura K, Toishi Y, Fukushi H.Equine herpesvirus myeloencephalopathy (EHM), caused by equine herpesvirus type 1 (EHV-1), poses a major threat to the equine industry because of its devastating impact on animal welfare and athletic performance. A single-nucleotide polymorphism (SNP), G2254, in ORF30 (UL30), which encodes the viral DNA polymerase, has been used as a marker of neuropathogenic EHV-1 strains, although its contribution to EHM pathogenesis remains controversial. In addition, other ORF30 SNPs have been reported in association with EHM, but their functional significance is unclear. Clinical observations indicate tha...
Lauková A, Focková V, Micenková L, Gancarčíková S, Plachá I, Grešáková Ľ, Kováčik A, Halo M, Gálik B, Pogány Simonová M.Antimicrobial proteinaceous postbiotic substances (PS) and/or bacteriocins can beneficially influence animal health, as previously shown with enterocins from non-autochthonous enterococcal strains. Therefore, the effectiveness of PS 412, produced by our beneficial autochthonous strain EF 412, was assessed in horses. In the pilot experiment, PS 412 was administered to 12 horses of various ages and breeds for 21 days via a small feed ball. Sampling was performed on days 0/1, 21, and 42 (after a 3-week cessation of PS 412). The horses served as their own controls. Although the number of horses w...
Fedorka CE, Funes JA, Razquin P, Roussel DA, Denison G, Burden CA, Hatzel JN, Sones JL, McCue PM.Persistent breeding-induced endometritis (PBIE) is characterized by a prolonged and dysregulated uterine inflammatory response following breeding. Although inflammatory cytokines are central to the post-breeding immune response, their assessment in the equine uterus has historically relied largely on gene expression analyses. Multiplex immunoassays provide an opportunity to simultaneously quantify multiple cytokine proteins within uterine secretions; however, the application of equine-specific multiplex immunoassays utilizing the Luminex platform to low-volume uterine lavage (LVL) fluid remain...
Siwińska N, Żak-Bochenek A, Trodd H, Czekaj Z, Kumiega E, Niedźwiedź A, Hewetson M.Equine gastric ulcer syndrome (EGUS) is commonly treated with proton pump inhibitors such as omeprazole, administered orally or by injection. In humans, omeprazole has been associated with acute interstitial nephritis (AIN) and acute kidney injury (AKI), potentially linked to oxidative stress, and urinary interleukins may serve as early non-invasive markers. However, this association has not been established in horses. Objective: To evaluate the effects of oral and injectable omeprazole on basic urinary parameters and selected interleukin levels, with particular emphasis on the potential risk ...
Petersen HH, Nielsen JP, Heegaard PM.The body's early defence in response to trauma, inflammation or infection, the acute phase response, is a complex set of systemic reactions seen shortly after exposure to a triggering event. One of the many components is an acute phase protein response in which increased hepatic synthesis leads to increased serum concentration of positive acute phase proteins. The serum concentration of these acute phase proteins returns to base levels when the triggering factor is no longer present. This paper provides a review of the acute phase proteins haptoglobin, C-reactive protein and serum amyloid A an...
Dubey JP, Desmonts G.SEROLOGICAL and parasitological surveys indicate that Toxoplasma gondii infection is widely prevalent in horses (Riemann et a! 1975). To study the pathogenesis of orally-induced toxoplasmosis, 13 equids aged between Aix months and 13 years (nine ponies, three horses and one mule) were each inoculated orally with 10,000 oocysts of the GT-I strain of TRondii. The equids were killed 33 to 476 days after inoculation and their tissues were bioassaycd for T gondit (Dubey 1985). Details of inoculation, housing, clinical response and parasitological and histological findings were previously reported (...
Pawelek KA, Huynh GT, Quinlivan M, Cullinane A, Rong L, Perelson AS.Influenza virus infection remains a public health problem worldwide. The mechanisms underlying viral control during an uncomplicated influenza virus infection are not fully understood. Here, we developed a mathematical model including both innate and adaptive immune responses to study the within-host dynamics of equine influenza virus infection in horses. By comparing modeling predictions with both interferon and viral kinetic data, we examined the relative roles of target cell availability, and innate and adaptive immune responses in controlling the virus. Our results show that the rapid and ...
Jahrling PB, Geisbert TW, Geisbert JB, Swearengen JR, Bray M, Jaax NK, Huggins JW, LeDuc JW, Peters CJ.A passive immunization strategy for treating Ebola virus infections was evaluated using BALB/ c mice, strain 13 guinea pigs, and cynomolgus monkeys. Guinea pigs were completely protected by injection of hyperimmune equine IgG when treatment was initiated early but not after viremia had developed. In contrast, mice were incompletely protected even when treatment was initiated on day 0, the day of virus inoculation. In monkeys treated with one dose of IgG on day 0, onset of illness and viremia was delayed, but all treated animals died. A second dose of IgG on day 5 had no additional beneficial e...
Saenz RA, Quinlivan M, Elton D, Macrae S, Blunden AS, Mumford JA, Daly JM, Digard P, Cullinane A, Grenfell BT, McCauley JW, Wood JL, Gog JR.A key question in pandemic influenza is the relative roles of innate immunity and target cell depletion in limiting primary infection and modulating pathology. Here, we model these interactions using detailed data from equine influenza virus infection, combining viral and immune (type I interferon) kinetics with estimates of cell depletion. The resulting dynamics indicate a powerful role for innate immunity in controlling the rapid peak in virus shedding. As a corollary, cells are much less depleted than suggested by a model of human influenza based only on virus-shedding data. We then explore...
Whitlock GC, Estes DM, Torres AG.Burkholderia mallei, the etiologic agent of the disease known as glanders, is primarily a disease affecting horses and is transmitted to humans by direct contact with infected animals. The use of B. mallei as a biological weapon has been reported and currently, there is no vaccine available for either humans or animals. Despite the history and highly infective nature of B. mallei, as well as its potential use as a bio-weapon, B. mallei research to understand the pathogenesis and the host responses to infection remains limited. Therefore, this minireview will focus on current efforts to elucida...
Joswig AJ, Mitchell A, Cummings KJ, Levine GJ, Gregory CA, Smith R, Watts AE.Intra-articular injection of mesenchymal stem cells (MSCs) is efficacious in osteoarthritis therapy. A direct comparison of the response of the synovial joint to intra-articular injection of autologous versus allogeneic MSCs has not been performed. The objective of this study was to assess the clinical response to repeated intra-articular injection of allogeneic versus autologous MSCs prepared in a way to minimize xeno-contaminants in a large animal model. Intra-articular injections of bone marrow-derived, culture-expanded MSCs to a forelimb metacarpophalangeal joint were performed at week 0 ...
van Kasteren PB, Bailey-Elkin BA, James TW, Ninaber DK, Beugeling C, Khajehpour M, Snijder EJ, Mark BL, Kikkert M.Protein ubiquitination regulates important innate immune responses. The discovery of viruses encoding deubiquitinating enzymes (DUBs) suggests they remove ubiquitin to evade ubiquitin-dependent antiviral responses; however, this has never been conclusively demonstrated in virus-infected cells. Arteriviruses are economically important positive-stranded RNA viruses that encode an ovarian tumor (OTU) domain DUB known as papain-like protease 2 (PLP2). This enzyme is essential for arterivirus replication by cleaving a site within the viral replicase polyproteins and also removes ubiquitin from cell...
Bunning ML, Bowen RA, Cropp CB, Sullivan KG, Davis BS, Komar N, Godsey MS, Baker D, Hettler DL, Holmes DA, Biggerstaff BJ, Mitchell CJ.A total of 12 horses of different breeds and ages were infected with West Nile virus (WNV) via the bites of infected Aedes albopictus mosquitoes. Half the horses were infected with a viral isolate from the brain of a horse (BC787), and half were infected with an isolate from crow brain (NY99-6625); both were NY99 isolates. Postinfection, uninfected female Ae. albopictus fed on eight of the infected horses. In the first trial, Nt antibody titers reached >1:320, 1:20, 1:160, and 1:80 for horses 1 to 4, respectively. In the second trial, the seven horses with subclinical infections developed N...
Leclere M, Lavoie-Lamoureux A, Lavoie JP.Animal models have been developed to investigate specific components of asthmatic airway inflammation, hyper-responsiveness or remodelling. However, all of these aspects are rarely observed in the same animal. Heaves is a naturally occurring disease of horses that combines these features. It is characterized by stable dust-induced inflammation, bronchospasm and remodelling. The evaluation of horses during well-controlled natural antigen exposure and avoidance in experimental settings allows the study of disease mechanisms in the asymptomatic and symptomatic stages, an approach rarely feasible ...
Jónsson H, Schubert M, Seguin-Orlando A, Ginolhac A, Petersen L, Fumagalli M, Albrechtsen A, Petersen B, Korneliussen TS, Vilstrup JT, Lear T....Horses, asses, and zebras belong to a single genus, Equus, which emerged 4.0-4.5 Mya. Although the equine fossil record represents a textbook example of evolution, the succession of events that gave rise to the diversity of species existing today remains unclear. Here we present six genomes from each living species of asses and zebras. This completes the set of genomes available for all extant species in the genus, which was hitherto represented only by the horse and the domestic donkey. In addition, we used a museum specimen to characterize the genome of the quagga zebra, which was driven to ...
Love S, Murphy D, Mellor D.Cyathostomes are now the principle parasitic pathogen of the horse: a remarkable transformation during the last 25 years from virtual obscurity to focus of attention in equine parasitology. This rise to prominence coincides with the marked decrease in prevalence of large strongyle infections as a result of widespread use of modern anthelmintic compounds. On the basis that strongyle-associated diseases continue to commonly occur in the absence of these large strongyle species, clinical attention has turned to the pathogenicity of cyathostomes. Although many horses harbour burdens of tens of tho...
Schnabel LV, Pezzanite LM, Antczak DF, Felippe MJ, Fortier LA.The horse is a valuable species to assess the effect of allogeneic mesenchymal stromal cells (MSCs) in regenerative treatments. No studies to date have examined recipient response to major histocompatibility complex (MHC)-mismatched equine MSCs. The purposes of this study were to immunophenotype MSCs from horses of known MHC haplotype and to compare the immunogenicity of MSCs with differing MHC class II expression. Methods: MSCs and peripheral blood leukocytes (PBLs) were obtained from Thoroughbred horses (n=10) of known MHC haplotype (ELA-A2, -A3, and -A9 homozygotes). MSCs were cultured thro...
Montelaro RC, Parekh B, Orrego A, Issel CJ.The recurrent nature of equine infectious anemia has been attributed to relatively rapid antigenic variations in equine infectious anemia virus (EIAV) during persistent infection under selective immune pressures. This model was tested by serological and biochemical analysis of virus isolates recovered from separate febrile episodes in two experimentally infected ponies. Neutralization assays employing immune sera from the experimentally infected ponies demonstrated that distinct antigenic strains of virus predominate during sequential febrile episodes in a single pony. Analysis of the test str...
Bullone M, Lavoie JP.Animal models have been studied to unravel etiological, immunopathological, and genetic attributes leading to asthma. However, while experiments in which the disease is artificially induced have helped discovering biological and molecular pathways leading to allergic airway inflammation, their contribution to the understanding of the causality of the disease has been more limited. Horses naturally suffer from an asthma-like condition called "heaves" which presents sticking similarities with human asthma. It is characterized by reversible airway obstruction, airway neutrophilic inflammation, an...
Daly K, Proudman CJ, Duncan SH, Flint HJ, Dyer J, Shirazi-Beechey SP.We aimed to determine the effects of variations in dietary composition on equine gut microbiota and their fermentation products, and proposed that dietary modifications profoundly affect microbial ecosystems and their metabolites. Bacterial communities within the large intestine of three groups of horses were compared using oligonucleotide-RNA hybridisation methodology. Each group consisting of six horses was maintained on (1) a grass-only diet, (2) a concentrate diet (i.e. supplemented with hydrolysable carbohydrates) and (3) a concentrate diet but horses were affected by simple colonic obstr...
Leroux C, Cadoré JL, Montelaro RC.Equine Infectious Anemia Virus (EIAV) is a lentivirus, of the Retrovirus family, with an almost worldwide distribution, infecting equids. It causes a persistent infection characterized by recurring febrile episodes associating viremia, fever, thrombocytopenia, and wasting symptoms. The disease is experimentally reproducible by inoculation of Shetland ponies or horses with EIAV pathogenic strains. Among lentiviruses, EIAV is unique in that, despite a rapid virus replication and antigenic variation, most animals progress from a chronic stage characterized by recurring peaks of viremia and fever ...
Boyle AG, Timoney JF, Newton JR, Hines MT, Waller AS, Buchanan BR.This consensus statement update reflects our current published knowledge and opinion about clinical signs, pathogenesis, epidemiology, treatment, complications, and control of strangles. This updated statement emphasizes varying presentations in the context of existing underlying immunity and carrier states of strangles in the transmission of disease. The statement redefines the "gold standard" for detection of possible infection and reviews the new technologies available in polymerase chain reaction diagnosis and serology and their use in outbreak control and prevention. We reiterate the impo...
Hammond SA, Cook SJ, Lichtenstein DL, Issel CJ, Montelaro RC.Equine infectious anemia virus (EIAV) provides a natural model system by which immunological control of lentivirus infections may be studied. To date, no detailed study addressing in parallel both the humoral and cellular immune responses induced in horses upon infection by EIAV has been conducted. Therefore, we initiated the first comprehensive characterization of the cellular and humoral immune responses during clinical progression from chronic disease to inapparent stages of EIAV infection. Using new analyses of antibody avidity and antibody epitope conformation dependence that had not been...
Atasheva S, Garmashova N, Frolov I, Frolova E.Venezuelan equine encephalitis virus (VEEV) represents a continuous public health threat in the United States. It has the ability to cause fatal disease in humans and in horses and other domestic animals. We recently demonstrated that replicating VEEV interferes with cellular transcription and uses this phenomenon as a means of downregulating a cellular antiviral response. VEEV capsid protein was found to play a critical role in this process, and its approximately 35-amino-acid-long peptide, fused with green fluorescent protein, functioned as efficiently as did the entire capsid. We detected a...
Pezzanite LM, Fortier LA, Antczak DF, Cassano JM, Brosnahan MM, Miller D, Schnabel LV.This study tested the hypothesis that Major Histocompatibility Complex (MHC) incompatible equine mesenchymal stromal cells (MSCs) would induce cytotoxic antibodies to donor MHC antigens in recipient horses after intradermal injection. No studies to date have explored recipient antibody responses to allogeneic donor MSC transplantation in the horse. This information is critical because the horse is a valuable species for assessing the safety and efficacy of MSC treatment prior to human clinical application. Methods: Six MHC heterozygote horses were identified as non-ELA-A2 haplotype by microsat...
Ng T, Hathaway D, Jennings N, Champ D, Chiang YW, Chu HJ.To meet the urgent need of controlling West Nile virus (WNV) infection in the equine population, we have developed a killed WNV vaccine. A dose titration study in horses was first conducted to evaluate serum neutralization antibody responses against WNV in these animals. Horses were vaccinated intramuscularly twice with the test vaccine at low, medium and high dose, three weeks apart. Serum samples were collected periodically and were measured for serum neutralizing antibody using a plaque reduction neutralization test. Significant increases in serum neutralizing antibody were detected in all ...
Takai S.An overview of epidemiology of R. equi infection in foals is presented, emphasizing the importance of the virulence-associated antigens and plasmids as epidemiological markers. The monoclonal antibody-based colony blot test has been developed to identify rapidly and accurately virulent R. equi. Epidemiological studies conducted during the recent 5 years have revealed that: (1) avirulent R. equi are widespread in the feces of horses and their environment on every farm; (2) the feces of horses and the environment of the horse farms having endemic R. equi infections demonstrated heavy contaminati...
Aguilar PV, Weaver SC, Basler CF.Eastern equine encephalitis virus (EEEV) causes sporadic but often severe cases of human and equine neurological disease in North America. To determine how EEEV may evade innate immune responses, we screened individual EEEV proteins for the ability to rescue the growth of a Newcastle disease virus expressing green fluorescent protein (NDV-GFP) from the antiviral effects of interferon (IFN). Only expression of the EEEV capsid facilitated NDV-GFP replication. Inhibition of the antiviral effects of IFN by the capsid appears to occur through a general inhibition of cellular gene expression. For ex...
Keel MK, Songer JG.Clostridium difficile is a confirmed pathogen in a wide variety of mammals, but the incidence of disease varies greatly in relation to host species, age, environmental density of spores, administration of antibiotics, and possibly, other factors. Lesions vary as well, in severity and distribution within individuals, and in some instances, age groups, of a given species. The cecum and colon are principally affected in most species, but foals and rabbits develop severe jejunal lesions. Explanations for variable susceptibility of species, and age groups within a species, are largely speculative. ...
Vázquez-Boland JA, Giguère S, Hapeshi A, MacArthur I, Anastasi E, Valero-Rello A.Rhodococcus equi is a soil-dwelling pathogenic actinomycete that causes pulmonary and extrapulmonary pyogranulomatous infections in a variety of animal species and people. Young foals are particularly susceptible and develop a life-threatening pneumonic disease that is endemic at many horse-breeding farms worldwide. R. equi is a facultative intracellular parasite of macrophages that replicates within a modified phagocytic vacuole. Its pathogenicity depends on a virulence plasmid that promotes intracellular survival by preventing phagosome-lysosome fusion. Species-specific tropism of R. equi fo...
Canisso IF, Segabinazzi LGTM, Fedorka CE.Post-breeding endometritis (i.e., inflammation/infection of the endometrium), is a physiological reaction taking place in the endometrium of mares within 48 hours post-breeding, aimed to clear seminal plasma, excess sperm, microorganisms, and debris from the uterine lumen in preparation for the arrival of an embryo. Mares are classified as susceptible or resistant to persistent breeding-induced endometritis (PBIE) based on their ability to clear this inflammation/infection by 48 hours post-breeding. Mares susceptible to PBIE, or those with difficulty clearing infection/inflammation, have a def...
Thompson JM, Whitmore AC, Konopka JL, Collier ML, Richmond EM, Davis NL, Staats HF, Johnston RE.Vaccination represents the most effective control measure in the fight against infectious diseases. Local mucosal immune responses are critical for protection from, and resolution of, infection by numerous mucosal pathogens. Antigen processing across mucosal surfaces is the natural route by which mucosal immunity is generated, as peripheral antigen delivery typically fails to induce mucosal immune responses. However, we demonstrate in this article that mucosal immune responses are evident at multiple mucosal surfaces after parenteral delivery of Venezuelan equine encephalitis virus replicon pa...
Giguère S, Viel L, Lee E, MacKay RJ, Hernandez J, Franchini M.Work in humans and laboratory animals has identified a central role for cytokines and chemokines in development and persistence of lower airway inflammation. The objectives of this study were to determine interleukin (IL)-1 beta, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha induction in bronchoalveolar lavage (BAL) of control horses and horses with heaves both during remission and exacerbation of the disease, and to determine the effect of therapy with inhaled fluticasone propionate on the cytokine profile of horses with heaves. IL-1 beta an...
