The equine immune system is a complex network of cells, tissues, and organs that work collaboratively to defend against pathogens and maintain homeostasis. It consists of innate and adaptive components, each with distinct functions and mechanisms. The innate immune system provides the first line of defense through physical barriers, phagocytic cells, and the complement system. The adaptive immune system involves lymphocytes, such as B cells and T cells, which generate specific responses to antigens and provide immunological memory. Research in equine immunology explores the interactions between these components, the impact of genetic and environmental factors on immune function, and the development of vaccines and therapeutics. This page gathers peer-reviewed studies and scholarly articles focusing on the mechanisms, regulation, and clinical applications of the equine immune system in health and disease.
DOLL ER, WALLACE E, RICHARDS MG.Manninger and Csontos reported that mares inoculated with equine abortion virus developed a transient fever 2 to 4 days after pharyngeal or intravenous inoculation and that an uninoculated horse in contact with the experimentally inoculated mares contracted a febrile disease resembling equine influenza. Also, mares that had aborted virus-infected fetuses were resistant to inoculation with equine influenza virus. From these observations, they proposed that virus abortions were a manifestation of infection of pregnant mares by the equine influenza virus. In reports on equine virus abortions, Kre...
CRAWFORD M.This disease has a very long history, with the earliest written description by Vegetius in the fourth century A.D. It has many names, such as periodic ophthalmia, recurrent ophthalmia, iridocyclitis, uveitis, moon-blindness, etc. Periodic ophthalmia is perhaps the name more generally used, but I prefer to use recurrent iridocyclitis because (a) there is no definite fixed period between the recurrent attacks and (b) because the essential lesion is iridocyclitis.
da Silveira BP, Kahn SK, Legere RM, Bray JM, Cole-Pfeiffer HM, Golding MC, Cohen ND, Bordin AI.Using a horse foal model, we show that enteral immunization of newborn foals with Rhodococcus equi overcomes neonatal vaccination challenges by reprogramming innate immune responses, inducing R. equi-specific adaptive humoral and cell-mediated immune responses and protecting foals against experimental pneumonia challenge. Foals were immunized twice via gavage of R. equi (immunized group) or saline (control group) at ages 1 and 3 days. At age 28 days, all foals were challenged intrabronchially with R. equi. Post-challenge, all 5 immunized foals remained healthy, whereas 67% (4/6) of control foa...
B B, G M, L G, G A, B B, T F, A G, D B, A K, G T, G S, A B, M F, L R.Equine penile tumors are common in horses and are often related to infection with equine papillomavirus type 2 (EcPV2). This study investigated the immune cell infiltrate (ICI) of these tumors in horses, focusing on the role of EcPV2. Using multiplex immunohistochemistry (mIHC) for CD3, CD20, and IBA-1 and immunohistochemistry (IHC) for FoxP3, 27 horses with papillomas (5/27), in situ carcinomas (CISs) (3/27), and squamous cell carcinomas (SCCs) (19/27) were evaluated. Eighteen cases tested positive for EcPV2 by either or both in situ hybridization (ISH) and polymerase chain reaction (PCR) (18...
Death studiesMay 28, 2025
1-11 doi: 10.1080/07481187.2025.2510477
Kaufman SVA, Nieforth LO.For practitioners involved in equine-assisted services (EAS), the death of a horse can be a significant life disruption. This study aims to understand the communicative resilience processes that equine-assisted service practitioners express following the death of an equine in their program. This study analyzed secondary qualitative data from a cross-sectional online survey completed by 84 participants. Analysis revealed practitioners engaged in all five communicative resilience processes following the death of an equine in their program. This research extends current resilience research by exa...
Ji Y, Xu D, Si W, Zhang Y, Khan MZ, Zhao X, Liu W.The present study investigated the host cell response to EHV-8 infection in rabbit kidney (RK-13) cells through transcriptomic and proteomic approaches. At 24 h post-infection, a total of 2118 differentially expressed genes (DEGs) were identified, with 1338 upregulated and 780 downregulated. At 48 h, 7388 DEGs were detected, with 4342 upregulated and 3046 downregulated genes. Proteomic analysis revealed 932 differentially expressed proteins (DEPs) at 24 h (364 upregulated and 568 downregulated) and 3866 DEPs at 48 h (2285 upregulated and 1581 downregulated). Of these, 237 upregulated and 336 d...
Bosman LM, Ambele MA, Pepper MS.Regenerative medicine is a relatively new branch of therapeutics in equine medicine, which aims to restore and reconstitute tissue function and structure via cellular and/or noncellular approaches. Biological constituents such as mesenchymal stromal/stem cells (MSCs) are potent therapeutics, which can aid in damaged tissue regeneration due to their differentiation capacity into many different cell types such as adipose tissue, bone, and cartilage. MSCs can be successfully and conveniently isolated from equine subcutaneous adipose tissue (adipose-derived stromal cells, ASCs). In horses, there a...
Matté YA, Baldasso DZ, Rezende MA, Lui JFM, Seibel AC, Guizzo JA, Frandoloso R, Kreutz LC.Lawsonia intracellularis is an obligatory intracellular bacterium associated with equine proliferative enteropathy (EPE), which significantly impacts equine health. Despite its clinical relevance, epidemiological and diagnostic approaches for this infection in horses have remained underexplored. This study aimed to evaluate the humoral immune response in horses immunized with an experimental vaccine for L. intracellularis and to determine the occurrence of anti-L. intracellularis antibodies in horses from southern Brazil using the flow cytometry antibody test (FCAT). Unassigned: A total of 12 ...
Gamage C, Holl W, Parreño V, Thieulent CJ, Balasuriya UBR, Vissani MA, Barrandeguy ME, Carossino M.Group A rotavirus (RVA) infections are a leading cause of neonatal diarrhoea in foals. Neonatal mice could serve as a useful tool to study the pathogenesis of equine RVA (ERVA) as well as a preclinical model for assessment of vaccine efficacy. This study aimed to comparatively evaluate the clinical, virological and pathological features of ERVA G3P[12] and G14P[12] infection in neonatal mice and compare them with porcine OSU G5P[7] and bovine UK G6P[5] RVA reference strains. Neonatal mice orally inoculated with equine, bovine and porcine RVA developed short-lived diarrhoea at variable rates, G...
Lee S, Kyaw MT, Harada K, Kusakabe KT, Igase M, Sasaki N.Generally, most mesenchymal stem cells (MSCs) have lower pluripotency and limited differentiation potential than embryonic stem cells (ESCs). However, a small subpopulation of MSCs, called multilineage differentiating stress-enduring (MUSE) cells, exhibit pluripotency. MUSE cells express stage-specific embryonic antigen 3 (SSEA-3), a sphingoglycolipid. Here, we isolated and investigated the pluripotency of SSEA-3-positive MSCs (MUSE cells). Six thoroughbred horses were used as test subjects. MSCs were harvested from the bone marrow of the thoracic vertebrae under ultrasound guidance. Harvested...
Roth SP, Liso G, Brehm W, Wagner B, Schnabel CL, Troillet A.The anti-inflammatory and regenerative effects of autologous conditioned serum (ACS) in joint-associated disorders are presumably mediated by the biomolecules it contains, such as cytokines and chemokines. ACS is commonly used in equine practice after storage. Data regarding the influence of storage conditions of ACS on cytokine and chemokine concentrations are not available. Unassigned: To evaluate the effect of commonly used storage conditions on selected cytokine and chemokine concentrations in equine ACS. Unassigned: From 10 horse patients with clinically indicated ACS preparation six ACS ...
Legere RM, Ott JA, Poveda C, Vanover D, Borba KER, Yeon Joo J, Martin CL, da Silveira BP, Bray JM, Landrock K, Wright GA, Blazier JC, Hillhouse AE....Inhalation of Rhodococcus equi causes severe pneumonia in humans and animals worldwide, most commonly affecting horse foals. The standard for preventing R. equi pneumonia in foals is transfusion of hyperimmune plasma, which is expensive and carries the risk of adverse effects. Our goal was to passively immunize foals against R. equi by nebulizing mRNA encoding an equine monoclonal antibody (mAb) against the virulence-associated protein A (VapA) directly into the lungs. VapA-specific memory B cells from an immunized horse were used to identify and select the sequence for an equine immunoglobuli...
Jonsdottir S, Stefansdottir SB, Mirkovitch J, Ziegler A, Torsteinsdottir S, Marti E.Insect bite hypersensitivity (IBH) is an IgE-mediated dermatitis in horses caused by bites of spp. The allergens are salivary gland proteins from these insects, and nine major allergens from have been identified and expressed in . However, proteins expressed in procaryotic systems have limitations in cellular assays, particularly in functional assays assessing the allergen-induced release of mediators , such as sulphidoleukotrienes (sLT) from basophils. The aims of the study were to produce functional allergens in insect cells, to assess their allergenicity using a sLT release assay, and to...
Kutumbetov L, Myrzakhmetova B, Tussipova A, Zhapparova G, Tlenchiyeva T, Bissenbayeva K, Nurabayev S, Kerimbayev A.Equine rhinopneumonia, caused by equine herpesvirus types 1 and 4 (EHV-1 and EHV-4), continues to be a significant health and economic concern in the global equine industry, particularly in Kazakhstan. While vaccines targeting EHV-1 are available, there is currently no licensed monovalent vaccine for EHV-4, and existing formulations offer limited protection against this serotype. This study aimed to develop and evaluate a freeze-dried, live-attenuated EHV-4 vaccine with improved safety, stability, and immunogenicity. Methods: A field isolate of EHV-4 was attenuated through serial passaging in ...
Perkins GA, Wagner B, Rollins A, Sfraga H, Pearson E, Cercone M.To apply equine herpesvirus type 1 (EHV-1) antibody testing in nasal swabs and serum in nonclinical horses during a naturally occurring outbreak of (EHV-1). Previous experimental EHV-1 challenge studies showed stable serum anti-EHV-1 antibody concentrations paired with rapidly increasing nasal mucosal antibodies (mucAbs) prevent EHV-1 infection, viral shedding, and cell-associated viremia. From this, we hypothesized that EHV-1 antibody testing can confirm exposure in non-clinical horses during an outbreak. Unassigned: 2 horses with neurological signs from 1 farm were admitted to an equine hosp...
Dachraoui K, Ben Osman R, Ben Slama S, Sayadi A, Maachach Y, Trifi M, Labidi I, Lachheb J, Badr C, Larbi I, Zhioua E.A total of 20 horses belonging to the Pasteur Institute of Tunis used for the production of therapeutic serum antiscorpion venom were tested for the presence of antibodies anti-West Nile virus (WNV) during the 2023 outbreak of West Nile disease that affected humans and horses in Tunisia. Of the 20 samples tested in November 2023 by enzyme-linked immuno-sorbent assay (ELISA), five were positive, leading to a seroprevalence of 25%. Since the number of horses is not substantial, all samples were tested also by virus microneutralization test (MNT) using the Tunisian strain of WNV lineage 1 isolate...
Golen GS, Erganiş O, Balevi A. is an important bacterial pathogen and causes severe chronic granulomatous pneumonia in foals below 6 months of age. It has also become an opportunistic and emerging pathogen in immunocompromised humans. Vaccination is the most cost-effective strategy for controlling and preventing this infection. Although several potential virulence genes and candidate immunogens have been identified over the years, no effective vaccine is currently available to prevent disease in horses. Recently, bacterial vector vaccines have been shown to be promising for In this study, the gene of was cloned into P...
Roncaglia-Pereira VA, Dumard CH, Monteiro-Machado M, Melo PA, Fonseca J, Meirelles L, Cunha-Ribeiro L, Souza P, da Silva JL, Castilho L....In this study, we aim to report the persistent presence of anti-SARS-CoV-2 immunoglobulins in pre-immunized mare offspring. Three mares from Vital Brazil Institute were pre-immunized with recombinant SARS-CoV-2 spike protein and became pregnant during this period. After parturition, the mares' serum and colostrum/milk and foal serum were collected over 6 weeks. Our results have shown high and persistent presence of IgG and neutralizing antibodies over the weeks not only in the mares' serum, as expected, but in mares' colostrum/milk and foal serum as well-what were very surprising. This peculia...
Khaliji E, Marycz K, Horna M, Morgan JM, Galuppo LD, Vapniarsky N, Cassano JM.To evaluate IA autologous platelet-derived mitochondrial preparation versus vehicle control in a bilateral lipopolysaccharide (LPS)-induced model of equine synovitis. Unassigned: 2 ng of LPS was injected into bilateral intercarpal joints of 6 horses over 3 months. Autologous mitochondria, isolated with a commercial kit, were injected into one joint, while the contralateral joint received a vehicle control, a within-subject controlled experimental design. Mitochondrial organelle appearance was visualized on transmission electron microscopy. Outcome measures included synovial fluid and whole-blo...
Mohamed E, Van Cleemput J, Şahin B, Van den Broeck W, Boyen F, Nauwynck H.The equine respiratory and reproductive tract microbiomes are complex and subject to constant fluctuations. Among the microbial inhabitants, subsp. (SEZ) is recognized as the dominant bacterium. It is an opportunistic pathogen that may occasionally lead to various types of infections. A key virulence factor of SEZ is the streptolysin S (SLS) toxin, which is responsible for the characteristic β-hemolysis on blood agar and tissue damage. Viruses and bacteria may interact and aggravate lesions and disease. This study aimed to evaluate the impact of an SLS-containing supernatant from SEZ on the...
Gonzalez-Obando J, Jaimes-Dueñez J, Zuluaga-Cabrera A, Forero JE, Diaz A, Rojas-Arbeláez C, Ruiz-Saenz J.Equine influenza is a highly contagious disease caused by the equine influenza virus (EIV). The occurrence of EIV outbreaks in America is associated with low levels of vaccination coverage. In Colombia, no seroprevalence evaluation has been carried out to estimate the distribution of the virus within the country. Our aim was to perform a sero-epidemiological survey of equine influenza infections and to identify associated risk factors in horses from four departments of Colombia. Serological testing was carried out by using an ELISA for the detection of IgG antibodies against the influenza A vi...
Busquets N, Gardela J, José-Cunilleras E, Solé A, Salvador MJ, Obón E, Molina-López R, Aranda C, Montalvo T, Corbella I, Bou-Monclús MA....West Nile virus (WNV), mainly transmitted by mosquitoes, poses significant health risks to humans and horses, particularly in endemic regions. The first detection of WNV lineage 2 in Spain was in 2017 in Catalonia (northeastern Spain). In 2023, WNV was confirmed in a young yellow-legged gull and a probable human case was notified within the urban settings. We aimed to define the zone of WNV circulation in the Barcelona Metropolitan Area where these infections occurred and the effectiveness of the One Health approach for early WNV detection. The Catalan WNV surveillance and control programs in...
Zimmerman KL, Diehl KA.To determine if serum α2-macroglobulin (A2M) concentration varies based on donor species-canine or equine-and signalment. Methods: Serum A2M concentration ([A2M]) was measured in healthy dogs (n = 30) and horses (n = 31) using species-specific ELISAs. Results: Canine and equine [A2M] median (IQR; range) were 98.70 ng/mL (92.79 ng/mL; 34.33-696.18 ng/mL) and 557 000 ng/mL (437 900 ng/mL; 62 600-3 042 900 ng/mL), respectively. Equine [A2M] was significantly higher than canine [A2M]. Depending on the statistical analysis performed, sex had either no statistical (p...
Kirmse L, Thieme K, Doherr MG, Eule JC.To evaluate different laboratory procedures for determining the etiologic diagnosis of equine recurrent uveitis regarding intraocular infection with Leptospira spp. and to establish a diagnostic guideline. Methods: Eighty horses with a history of ERU were ophthalmologically examined. Serum and aqueous humor were collected. Total protein, albumin level, and MAT against Leptospira spp. were evaluated on serum and aqueous humor. PCR for Leptospira spp., EHV-1 and -4 was performed on aqueous humor. Goldmann-Witmer coefficient (GWC) and C-value (CC) were calculated based on MAT. In 42 cases, an add...
Carotenuto SE, Broussard G, Fox GA, Hayes WK.To assess the efficacy of a new equine F[ab'] antivenom (US Department of Agriculture code 6101.05) in removing serum venom and lowering the snakebite severity score (SSS) in animals suffering from naturally occurring viperid envenomation. Methods: Retrospective study, April 2020 to October 2021. Methods: Veterinary hospitals across four North American regions. Methods: Twenty-two dogs, one cat, and one horse. Methods: All patients received the new antivenom intravenously and were assessed for clinical response. Most dogs required one vial for clinical control of signs. Results: Among the dogs...
Heilen LB, Roßgardt J, Dern-Wieloch J, Vogelsberg J, Staszyk C.Horses' hypsodont (high-crowned) teeth face permanent dental wear. This is compensated for by a continuous eruption, which requires a high adaptability of odontoblasts; otherwise, the dental pulp would be exposed. Here, we report on how equine odontoblasts respond to the challenge of maintaining a high production rate of dentin. We analyzed CD90, a marker of odontoblastic differentiation, and nestin, a marker of mature odontoblasts, in equine pulpal tissue via immunofluorescence. For comparison, we examined the hypselodont (ever-growing) incisors and brachydont (short-crowned) molars of rats. ...
Shahid MA, Guitart AS, Bertin FR, Simon O, Ceusters J, Serteyn D, Whitworth DJ.A minimally invasive microbiopsy-based method for the isolation of mesenchymal stem cells (MSCs) from equine skeletal muscle (M-MSCs) provides a readily accessible source of MSCs for clinical applications. We examined the expression of genes associated with immunomodulation and anti-inflammatory pathways, in addition to those of growth factors and the major histocompatibility complex (MHC) molecules I and II, at constitutive levels and after priming with inflammatory cytokines, an immunostimulant, and heat-shocking. While there was notable variation between the M-MSCs from each of the horses i...
Young KAS, Schnabel LV, Gilger BC.Equine ocular disease is common and often challenging to treat using traditional methods. This has led to the development of new therapies. Like human medicine, veterinary medicine is adopting cellular and gene therapy as innovative approaches. Equine ocular disease is a particularly promising area for these techniques. Notably, immune-mediated diseases (such as immune-mediated keratitis and equine recurrent uveitis), ulcerative keratitis, and infectious ocular diseases are of interest. Several ocular gene therapy products are approved for use in humans, and more are currently being researched...
Böckmann S, Trzebiatowski L, Georgiev P, Büttner K, Wehrend A.Immunoglobulins ingested via colostrum must remain intact to be absorbed by the neonate. Equine colostrum contains antitrypsin activity, which likely protects these proteins from proteolysis in the gastrointestinal tract. Objective: To quantify antitrypsin activity in equine colostrum and milk, describe its temporal changes during the first five days after parturition, compare actitvity between left and right mammary glands, evaluate differences between nulliparous and pluriparous mares, and examine associations with immunoglobulin G (IgG) concentrations and mare age. Methods: This retrospecti...
Bartenschlager F, Kuropka B, Schmitz P, Dumke F, Landmann K, Gruber AD, Weise C, Schnabel CL, Gehlen H, Mundhenk L.Mucus hypersecretion and accumulation are hallmark features of equine asthma (EA), a meaningful respiratory disorder in horses occurring in mild to moderate (MEA) and severe (SEA) forms. Changes of the proteomic composition of airway mucus in EA are poorly understood. Using label-free quantitative liquid chromatography-mass spectrometry, we analyzed airway mucus from SEA (n = 10), MEA (n = 6), and healthy (n = 8) horses. We identified and quantified 2,275 proteins including gel-forming mucins MUC5AC and MUC5B and membrane-bound mucins MUC1 and MUC4. Compared with healthy controls, ...
Toddy T, Ledbetter EC, Knickelbein KE.To describe the demographics and treatment outcomes of horses definitively diagnosed with epithelial or stromal immune-mediated keratitis (IMMK) by use of in vivo confocal microscopy (IVCM) and/or histopathology. Unassigned: Medical records of horses presented to the Cornell University Equine Hospital definitively diagnosed with epithelial or stromal IMMK with IVCM and/or histopathology between 2020 and 2024 were reviewed. Patient signalment, affected eye(s), diagnostics, treatments, and outcomes were assessed. Unassigned: 22 horses met the inclusion criteria. The mean age was 16.9 years (SD, ...
Acevedo-Jiménez GE, Morales-González C, Akbarin MM, Rodríguez-Murillo C, González-Fernández VD, Avila-De la Vega LM, García-Flores MM....Equine infectious anemia virus (EIAV) is a globally significant equine pathogen, and its control relies on effective serological surveillance. The agar gel immunodiffusion (AGID) test, the WOAH-prescribed method, has limitations in sensitivity. This study developed and validated an indirect ELISA using a synthetic peptide derived from a conserved region of the EIAV gp90 surface glycoprotein. The assay was evaluated using 773 horse sera from the Metropolitan Zone of the Valley of Mexico and compared to the AGID test. The gp90-EIAV ELISA demonstrated a sensitivity of 85.3 % and a specificity o...
