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Topic:Pathogenesis
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.
African horse sickness virus (AHSV) with a deletion of 77 amino acids in NS3/NS3a protein is not virulent and a safe promising AHS Disabled Infectious Single Animal (DISA) vaccine platform. African horse sickness virus (AHSV) is a virus species in the genus Orbivirus of the family Reoviridae. Currently, nine serotypes have been defined showing limited cross neutralization. AHSV is transmitted by species of Culicoides biting midges and causes African Horse Sickness (AHS) in equids with a mortality up to 95% in naïve domestic horses. AHS has become a serious threat for countries outside Africa, since endemic Culicoides species in moderate climates are competent vectors of closely related bluetongue virus. AHS outbreaks cause huge economic losses in developing countries. In the dev...
Treatment of Hydropsical Conditions Using Transcervical Gradual Fetal Fluid Drainage in Mares With or Without Concurrent Abdominal Wall Disease. Hydropsical conditions are exceedingly rare in the horse. However, when they occur, they are true emergencies due to the severe enlargement of the pregnant uterus, which can result in clinical signs, such as an enlarged round abdomen, dyspnea, reluctance to walk, and colic, and may lead to the development of abdominal wall disease. The pathogenesis of hydropsical conditions is not fully elucidated, but they have been associated with placentitis and fetal abnormalities. This report describes six cases of hydropsical conditions in mares with or without concurrent abdominal wall disease. Five out...
[Causes of abortion in horses – overview of the literature and own evaluations]. The aim of this study was to summarize the current status of the possible causes, clinical symptoms and pathogenesis of abortion in the mare and to evaluate the frequency of varying causes of abortion in German thoroughbred breeding. An analysis of the literature using electronic libraries, journals and textbooks was performed. In addition, the results of examinations of 123 abortions of thoroughbred breeding in central Germany were evaluated. In the literature, bacterial infections are the most frequently described cause of abortion. Other important causes are infections with equine herpesvir...
Modeling asthma: Pitfalls, promises, and the road ahead. Asthma is a chronic, heterogeneous, and recurring inflammatory disease of the lower airways, with exacerbations that feature airway inflammation and bronchial hyperresponsiveness. Asthma has been modeled extensively via disease induction in both wild-type and genetically manipulated laboratory mice (Mus musculus). Antigen sensitization and challenge strategies have reproduced numerous important features of airway inflammation characteristic of human asthma, notably the critical roles of type 2 T helper cell cytokines. Recent models of disease induction have advanced to include physiologic aero...
Genetic diversity of equine herpesvirus 1 isolated from neurological, abortigenic and respiratory disease outbreaks. Equine herpesvirus 1 (EHV-1) causes respiratory disease, abortion, neonatal death and neurological disease in equines and is endemic in most countries. The viral factors that influence EHV-1 disease severity are poorly understood, and this has hampered vaccine development. However, the N752D substitution in the viral DNA polymerase catalytic subunit has been shown statistically to be associated with neurological disease. This has given rise to the term "neuropathic strain," even though strains lacking the polymorphism have been recovered from cases of neurological disease. To broaden understan...
Streptococcus equi Infections in Horses: Guidelines for Treatment, Control, and Prevention of Strangles-Revised Consensus Statement. 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...
Development of septic polysynovitis and uveitis in foals experimentally infected with Rhodococcus equi. Rhodococcus equi is one of the most important causes of disease in foals. Infection is typically characterized by pyogranulomatous pneumonia although extrapulmonary infections occur occasionally. Uveitis and polysynovitis have been reported in foals naturally infected with R. equi and are thought to be the result of an immune-mediated process. However, the pathogenesis of these conditions is poorly understood. The objectives of this study were to document the occurrence of uveitis and polysynovitis after experimental infection with R. equi and to determine if these disorders are the direct res...
Bronchoalveolar lavage fluid neutrophilia is associated with the severity of pulmonary lesions during equine asthma exacerbations. The severe form of equine asthma is associated with pathological changes of the peripheral airways and pulmonary parenchyma that are only partly described. Also, the relationship between these structural alterations and the percentage of neutrophils found within the airway lumen, assessed by bronchoalveolar lavage fluid (BALF) cytology, remains ill-defined. Objective: To examine the histological lesions associated with equine asthma during disease exacerbation and remission, and their relationship with lung function and BALF neutrophilia. Methods: Observational retrospective study. Methods: Pe...
Identification of a staphylococcal complement inhibitor with broad host specificity in equid Staphylococcus aureus strains. Staphylococcus aureus is a versatile pathogen capable of causing a broad range of diseases in many different hosts. S. aureus can adapt to its host through modification of its genome (e.g. by acquisition and exchange of mobile genetic elements that encode host-specific virulence factors). Recently, the prophage φSaeq1 was discovered in S. aureus strains from six different clonal lineages almost exclusively isolated from equids. Within this phage, we discovered a novel variant of staphylococcal complement inhibitor (SCIN), a secreted protein that interferes with activation of the human complem...
Advanced nutritional and stem cells approaches to prevent equine metabolic syndrome. Horses metabolic disorders have become an important problem of modern veterinary medicine. Pathological obesity, insulin resistance and predisposition toward laminitis are associated with Equine Metabolic Syndrome (EMS). Based on pathogenesis of EMS, dietary and cell therapy management may significantly reduce development of this disorder. Special attention has been paid to the diet supplementation with highly bioavailable minerals and mesenchymal stem cells (MSC) which increase insulin sensitivity. In nutrition, there is a great interests in natural algae enriched via biosorption process with...
Increased sclerostin associated with stress fracture of the third metacarpal bone in the Thoroughbred racehorse. The exact aetiology and pathogenesis of microdamage-induced long bone fractures remain unknown. These fractures are likely to be the result of inadequate bone remodelling in response to damage. This study aims to identify an association of osteocyte apoptosis, the presence of osteocytic osteolysis, and any alterations in sclerostin expression with a fracture of the third metacarpal (Mc-III) bone of Thoroughbred racehorses. Methods: A total of 30 Mc-III bones were obtained; ten bones were fractured during racing, ten were from the contralateral limb, and ten were from control horses. Each Mc-II...
Phylogenetic Analysis and Characterization of a Sporadic Isolate of Equine Influenza A H3N8 from an Unvaccinated Horse in 2015. Equine influenza, caused by the H3N8 subtype, is a highly contagious respiratory disease affecting equid populations worldwide and has led to serious epidemics and transboundary pandemics. This study describes the phylogenetic characterization and replication kinetics of recently-isolated H3N8 virus from a nasal swab obtained from a sporadic case of natural infection in an unvaccinated horse from Montana, USA. The nasal swab tested positive for equine influenza by Real-Time Quantitative Reverse Transcription Polymerase Chain Reaction (RT-PCR). Further, the whole genome sequencing of the virus ...
Differential Expression of Serum MicroRNAs Supports CD4⁺ T Cell Differentiation into Th2/Th17 Cells in Severe Equine Asthma. MicroRNAs (miRNAs) regulate post-transcriptional gene expression and may be exported from cells via exosomes or in partnership with RNA-binding proteins. MiRNAs in body fluids can act in a hormone-like manner and play important roles in disease initiation and progression. Hence, miRNAs are promising candidates as biomarkers. To identify serum miRNA biomarkers in the equine model of asthma we investigated small RNA derived from the serum of 34 control and 37 asthmatic horses. These samples were used for next generation sequencing, novel miRNA identification and differential miRNA expression ana...
Comparative Genomic Sequencing and Pathogenic Properties of Equine Herpesvirus 1 KyA and RacL11. Equine herpesvirus 1 (EHV-1) is a major pathogen affecting equines worldwide. The virus causes respiratory disease, abortion, and, in some cases, neurological disease. EHV-1 Kentucky A (KyA) is attenuated in the mouse and equine, whereas wild-type pathogenic strain RacL11 induces severe inflammatory infiltration of the lung, causing infected mice to succumb. The complete DNA sequencing of the KyA genome revealed that genes UL17 (ORF17), US6 (ORF73; gI), US7 (ORF74; gE), and US8 (ORF75; 10 K) are deleted as compared to the RacL11 and Ab4 genomes. In-frame deletions in the US1 (ORF68), US4 (OR...
Equine renal hemangiosarcoma: clinical presentation, pathologic features, and pSTAT3 expression. Hemangiosarcoma is an uncommon tumor in horses. We characterized 3 cases of equine renal hemangiosarcoma, focusing on clinical and pathologic features, and describe occurrence of the epithelioid variant of hemangiosarcoma in one of these cases. Nuclear expression of phosphorylated STAT3 (pSTAT3) was assessed to analyze potential inappropriate STAT3 activation as a component of tumor pathogenesis. Clinical signs in the 3 horses included insidious weight loss, followed in one case by serosanguineous nasal discharge and terminal epistaxis, and nonspecific signs of abdominal pain. Two of the heman...
Access to a main alphaherpesvirus receptor, located basolaterally in the respiratory epithelium, is masked by intercellular junctions. 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...
Reproductive effects of arteriviruses: equine arteritis virus and porcine reproductive and respiratory syndrome virus infections. Equine arteritis virus (EAV) and porcine reproductive and respiratory syndrome virus (PRRSV) are the most economically important members of the family Arteriviridae. EAV and PRRSV cause reproductive and respiratory disease in equids and swine, respectively and constitute a significant economic burden to equine and swine industries around the world. Furthermore, they both cause abortion in pregnant animals and establish persistent infection in their natural hosts, which fosters viral shedding in semen leading to sexual transmission. The primary focus of this article is to provide an update on t...
Is Sclerostin Glycoprotein a Suitable Biomarker for Equine Osteochondrosis? Osteochondrosis (OC) disease appears to be multifactorial in origin, including skeletal growth rates, nutrition, endocrinological factors, exercise, biomechanics, and other environmental factors. Endocrinological and metabolic factors seem to have an important role in the pathogeny of OC like the Wnt signaling pathway. One of the regulators in the Wnt signaling pathway is the sclerostin glycoprotein. The aim of this study was to investigate the sclerostin blood concentration according to the evolution of the disease, the environment, and the age but also its use as a possible biomarker for OC ...
Streptococcus equi subsp. zooepidemicus Invades and Survives in Epithelial Cells. subsp. () is an opportunistic pathogen of several species including humans. is found on mucus membranes of healthy horses, but can cause acute and chronic endometritis. Recently was found able to reside in the endometrium for prolonged periods of time. Thus, we hypothesized that an intracellular phase may be part of the pathogenesis and investigated if was able to invade and survive inside epithelial cells. HEp-2 and HeLa cell lines were co-cultured with two strains (1-4a and S31A1) both originating from the uterus of mares suffering from endometritis. Cells were fixed at different time...
The Contribution of Adipose Tissue-Derived Mesenchymal Stem Cells and Platelet-Rich Plasma to the Treatment of Chronic Equine Laminitis: A Proof of Concept. 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...
Longitudinal analysis of allergen-specific IgE and IgG subclasses as potential predictors of insect bite hypersensitivity following first exposure to Culicoides in Icelandic horses. Insect bite hypersensitivity (IBH) is an allergic dermatitis of horses caused by bites of Culicoides spp. IBH does not occur in Iceland because of the absence of Culicoides, but the prevalence is high in horses imported from Iceland to environments where Culicoides are present. Objective: Test, in a longitudinal study before and after Culicoides exposure, whether a primary sensitizing Culicoides allergen can be identified and if an increase of allergen-specific immunoglobulin (Ig)E or IgG subclasses precedes clinical signs of IBH. Methods: Thirty two horses imported from Iceland to Europe; 16 ...
Complications of intravenous catheterization in horses. Intravenous catheterization is a necessity for continuous administration of intravenous fluids and for intermittent intravenous access to avoid discomfort and potential complications of repeated needle insertions into the vein. Intravenous catheterization is commonly performed and well tolerated in horses, but catheter associated complications have been reported. The most commonly reported complication is thrombophlebitis, but others such as venous air embolism, exsanguination and catheter fragmentation may also occur. This article aims to review clinical signs, pathogenesis, diagnosis, therap...
The integration of a macrophage-adapted live vaccine strain of equine infectious anaemia virus (EIAV) in the horse genome. Integration is an important feature of retroviruses and retrovirus-based therapeutic transfection vectors. The non-primate lentivirus equine infectious anaemia virus (EIAV) primarily targets macrophages/monocytes . Investigation of the integration features of EIAV strains, which are adapted to donkey monocyte-derived macrophages (MDMs), is of great interest. In this study, we analysed the integration features of EIAV in equine MDMs during infection. Our previously published integration sites (IS) for EIAV in fetal equine dermal (FED) cells were also analysed in parallel as references. Sequenc...
Proteome Dynamics in Biobanked Horse Peripheral Blood Derived Lymphocytes (PBL) with Induced Autoimmune Uveitis. Equine recurrent uveitis is the only spontaneous model for recurrent autoimmune uveitis in humans, where T cells target retinal proteins. Differences between normal and autoaggressive lymphocytes were identified in this study by analyzing peripheral blood derived lymphocytes (PBL) proteomes from the same case with interphotoreceptor retinoid binding protein induced uveitis sampled before (Day 0), during (Day 15), and after uveitic attack (Day 23). Relative protein abundances of PBL were investigated in a quantitative, label-free differential proteome analysis in cells that were kept frozen for...
Development of an elisa for the diagnosis of reactive IgE antibodies anti-therapeutic horse sera. Hypersensitive diseases that involve IgE reactivity are important concern of public, especially those encompassing the potential pathogenesis from the administration of horse serum-based therapeutics such as antivenoms. A method for the definitive diagnosis of reactive IgE is important for identifying allergic patients to control severe collateral effects during planned and emergency application of immunotherapies when the allergy source cannot be avoided for treatment. To date, no tests have been developed to accompany the wide range of antivenoms produced from horse sera. The aim of this was...
Genomic Dissection of an Icelandic Epidemic of Respiratory Disease in Horses and Associated Zoonotic Cases. Iceland is free of the major infectious diseases of horses. However, in 2010 an epidemic of respiratory disease of unknown cause spread through the country's native horse population of 77,000. Microbiological investigations ruled out known viral agents but identified the opportunistic pathogen subsp. () in diseased animals. We sequenced the genomes of 257 isolates of to differentiate epidemic from endemic strains. We found that although multiple endemic clones of were present, one particular clone, sequence type 209 (ST209), was likely to have been responsible for the epidemic. Concurrent ...
Investigation of the Fim1 putative pilus locus of Streptococcus equi subspecies equi. The Gram-positive bacterium subspecies () is the causative agent of strangles, among the most frequently diagnosed infectious diseases of horses worldwide. Genome analysis of strain 4047 (4047) identified a putative operon, Fim1, with similarity to the pilus loci of other Gram-positive bacteria. The Fim1 locus was present in all strains of and its close relative subspecies () that have been studied to date. In this study we provide evidence that the putative structural pilus proteins, SEQ_0936 and CNE, are produced on the cell surface during growth and infection. Although the proteins ...
Differential Expression of Tubulin Acetylase and Deacetylase Between the Damaged Central and Peripheral Branch of Dorsal Root Ganglion Neurons. BACKGROUND The differences between the peripheral and central branches of the dorsal root ganglion (DRG) have not been fully elucidated. This study aimed to explore the expression of tubulin post-translational modifications (acetylation and deacetylation) between damaged peripheral and central branches of DRG neurons. MATERIAL AND METHODS Fifty Sprague-Dawley rats were randomly assigned to five groups with 10 rats in each group. These five groups consisted of spinal nerve ligation (SNL) at 24 hour and 48 hour, and cauda equina compression (CEC) at 24 hour and 48 hour, and a sham group. SNL inj...
Changes in concentrations of haemostatic and inflammatory biomarkers in synovial fluid after intra-articular injection of lipopolysaccharide in horses. Septic arthritis is a common and potentially devastating disease characterized by severe intra-articular (IA) inflammation and fibrin deposition. Research into equine joint pathologies has focused on inflammation, but recent research in humans suggests that both haemostatic and inflammatory pathways are activated in the joint compartment in arthritic conditions. The aim of this study was to characterize the IA haemostatic and inflammatory responses in horses with experimental lipopolysaccharide (LPS)-induced joint inflammation. Inflammation was induced by IA injection of LPS into one antebrach...
Function of bacteriophage G7C esterase tailspike in host cell adsorption. Bacteriophages recognize and bind to their hosts with the help of receptor-binding proteins (RBPs) that emanate from the phage particle in the form of fibers or tailspikes. RBPs show a great variability in their shapes, sizes, and location on the particle. Some RBPs are known to depolymerize surface polysaccharides of the host while others show no enzymatic activity. Here we report that both RBPs of podovirus G7C - tailspikes gp63.1 and gp66 - are essential for infection of its natural host bacterium E. coli 4s that populates the equine intestinal tract. We characterize the structure and funct...
