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.
Heydrick FP, Comer JF, Wachter RF.Phospholipid analyses of Venezuelan equine encephalitis virus showed that virus propagated in L-cell monolayers had a higher sphingomyelin content and a lower phosphatidylcholine content than virus grown in chick fibroblast monolayers. Virus of L-cell origin also was found to possess greater thermal stability than virus derived from the chick fibroblast cell.
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...
Marois P, Boudreault A, DiFranco E, Pavilanis V.Rhesus monkeys and ferrets were exposed to intranasal inoculation of several strains of egg-adapted avian, equine and human influenza viruses and to strains of mouse-adapted equine influenza viruses. Local replication of virus and seroconversion were observed in the majority of these animals. However, clinical infection was observed only in ferrets.
Bykovsky AF, Yershov FI, Zhdanov VM.Morphogenesis of Venezuelan equine encephalomyelitis virus was studied by means of electron microscopy. Virus-specific structures (factories, viroplasts) were found at early stages of infection; these structures were composed of fibrillar and cylindrical formations, aggregates of ribosomes, and viral nucleoids. The latter emerged from fibrillar and cylindrical structures. Aggregates of viral nucleoids were found in the cytoplasm and occasionally in the nuclei of virus-infected cells. Viral envelopes and mature virions were formed on the cell membranes and on the membranes of intracellular vacu...
Rubarth S, Krook L.Following a description of the histopathology of so-called mucoid degeneration of the nasal conchae in the horse, the authors conclude that the morphologic nature of the disease is osteodystrophia fibrosa. The lesions are believed to be expressions of nutritional secondary hyperparathyroidism.
Ishikawa Y, Tufa SF, Keene DR, Bächinger HP, Winand NJ.Mutations in the collagen-modifying enzyme lysyl hydroxylase 1 (LH1) cause Warmblood Fragile Foal Syndrome (WFFS) in horses. We investigated the impact of this mutation on collagen structure and function. Our results show that LH1 deficiency leads to reduced lysine hydroxylation, altered collagen fibril organization, and tissue abnormalities resembling human Ehlers-Danlos syndrome. These findings highlight the critical role of LH1 in collagen biosynthesis and provide insights into the pathogenesis of WFFS.
Gerras J, Young K, Roberts D, Waldman G, Salmon JH, Gilger BC.To describe the ocular findings, chronology of disease, and serum leptospiral titers in a group of horses, mules, and donkeys following an outbreak of leptospirosis. Unassigned: Fifty Equidae in central North Carolina had ophthalmic examinations and serum leptospiral microscopic agglutination test (MAT) titers performed every 3-6 months for 24 months followed by a final examination at 34 months. Unassigned: Throughout the nearly three-year study period, 17 horses (34%; 17/49 horses) developed signs of uveitis; 20 eyes (20/34; 58.8%) of these 17 horses were visual at the initial examinati...
Styková E, Valocký I, Kačírová J, Fecskeová LK.Equine pastern dermatitis (EPD) is a multifactorial disease with a change in the skin microbiome. The present study monitored the influence of Weissella cibaria Biocenol™ 4/8 D37 CCM 9015 stabilized on alginite on the skin microbiota of healthy horses and model patients with EPD. Based on clinical signs, EPD lesions were identified as exudative or proliferative forms. A comparison of the initial microbial community based on 16S rRNA amplicon sequencing revealed that there was a statistically significant difference between healthy vs. exudative (R = 0.52, p = 0.003) and exudative vs. ...
Gillen A, Archer D, Ireland J, Rocchigiani G.Strangulating lipomata are the most common cause of small intestinal strangulating obstruction. Evaluation of histological features of pathological and non-pathological lipomata, and the histological properties of omental and retroperitoneal fat have not been described. Objective: To characterise histological features of equine abdominal lipomata, omental and retroperitoneal adipose tissue, and associations between them. Methods: Prospective observational anatomic (gross and histological). Methods: Horses undergoing emergency laparotomy for management of abdominal pain in a single hospital wer...
Engiles JB, Stefanovski D, van Eps A.To examine the effects of prolonged preferential weight bearing (PWB) and reduced ambulation (RA) on hoof lamellae using a nonpainful in vivo experimental model. Unassigned: 12 healthy Standardbred horses were housed in stocks continuously for 92 hours. A platform shoe was placed on 1 forelimb in the PWB group (n = 6) to increase the load on the supporting limb (SL) by approximately 10% bodyweight, whereas the RA group (n = 6) had normal weight bearing. Archived healthy horse (n = 8) samples were used as controls. Histomorphometry and histochemistry (terminal deoxynucleotidyl transferase dUTP ...
Hansen S, Otten ND, Ceron JJ, González-Arostegui LG, Peres-Rubio C.The contribution of redox imbalance to equine asthma (EA) pathogenesis remains unclear. Objective: (1) validate and measure a panel of redox biomarkers in the tracheal wash (TW) and bronchoalveolar lavage (BAL) samples from horses with neutrophilic and mastocytic mild-moderate EA (MEA) and severe EA. (2) Evaluate the same panel in saliva and serum for comparative purposes. Methods: A total of 117 horses: 37 healthy, 26 mastocytic MEA, 29 neutrophilic MEA, and 25 severe EA. Methods: Cross-sectional study using TW, BAL, and serum and saliva sampling. After assay validation, redox biomarkers-ferr...
Poh KC, Oyen K, Onzere CK, Kappmeyer LS, Bastos RG.The recent discovery of , a tick-borne hemoparasite that causes mild clinical signs of equine piroplasmosis, has added complexity to the diagnosis of this reportable disease, which is prevalent among equids globally. Knowledge gaps regarding competent tick vectors that can transmit and the recent outbreak of in the US has prompted us to conduct this study. Our objective was to investigate whether can transstadially transmit to horses. Unassigned: larvae (0.5 g) and nymphs ( = 500) were fed on a splenectomized -infected horse for parasite acquisition. During the tick feeding period, ...
Liu D, Zhao X, Wang X.Equine herpesvirus 1 (EHV-1), EHV-4, EHV-8, and EHV-9, are classified within the subfamily and are recognized as causative agents of respiratory, urogenital, and neurological disorders in horses. These viruses, collectively referred to as αEHVs, exhibits both unique and shared characteristics in terms of host interaction, pathogenesis, epidemiology, and immune evasion, which arise from both the identities and discrepancies among respective genomic homologs. The genomic architecture of αEHVs is similar to other members of the same subfamily, such as well-known HSV-1, VZV, and PRV. However, r...
Kukhar Y, Bailina G, Smagulova A, Uakhit R, Kiyan V.Equine skin mycoses are a significant concern in Kazakhstan's livestock industry due to the country's historical livestock farming practices, the development of equestrian sports, and food traditions. Skin infections are among the most common fungal infections in horses. Emerging pathogens of equine dermatophytosis include keratinophilic Chrysosporium spp., which can degrade and metabolize keratin found in superficial tissues. This, combined with their thermotolerance, contributes to their pathogenicity. In this study, we investigated the biological properties and pathogenicity of two Chrysosp...
Pawlina-Tyszko K, Semik-Gurgul E, Podstawski P, Herc W, Witkowski M, Ropka-Molik K.Alterations in the genes involved in the creation of the extracellular matrix (ECM) were observed in our earlier transcriptome studies of sarcoids and their cell culture model. For a complete characterization of the underlying molecular pathways, it is imperative to comprehend the involvement of ECM modifications in the oncogenic transformation of sarcoid fibroblasts. Thus, the aim of this investigation was to describe the expression patterns of a set of genes that are essential for the rearrangements of the extracellular matrix, namely collagen genes, and elucidate possible mechanisms underly...
Mizuguchi Y, Niwa H, Inoue H, Iwano H.Hypoproteinaemia/hypoalbuminaemia is a typical clinical feature of Lawsonia intracellularis infection in horses, but amino acid perturbations in these horses have not been investigated. Objective: Clarifying blood amino acid levels in horses suffering from Lawsonia intracellularis infection to identify novel aspects of the disease. Methods: Retrospective observational study. Methods: A total of 135 serum samples collected from horses from 59 farms were used in this study. Horses diagnosed with the clinical form of equine proliferative enteropathy (EPE) were enrolled as a clinical group (n =...
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...
Bauquier J, Takahashi C, Rosales C, Pitt J.There is limited published information on Malva parviflora toxicosis in horses. Four previously reported cases all resulted in death or euthanasia. The aim of this cluster investigation was to describe historical, clinical and clinicopathological findings of four ponies with suspected M. parviflora toxicosis and compare these to previously reported cases. Historical, clinical and clinicopathological findings were collated. Ponies were grazing pasture of approximately >90% M. parviflora. Pony 1 died rapidly without veterinary examination. Pony 2 was examined for prolonged recumbency attribut...
de Souza Lima E, de Oliveira Filho RB, Malta KC, Pires IC, Rosa DS, Chideroli RT, Aburjaile FF, de Jesus Sousa T, Ramos RTJ, Góes-Neto A....Corynebacterium pseudotuberculosis is a bacterium that causes significant economic damage to farmers, mainly in the semiarid region of Northeastern Brazil. In this context, only biovar ovis has been reported, and it is widespread in small ruminants. However, this report describes the first equine case in Brazil attributable to a biovar equi. Clinically, it is the causative agent of ulcerative lymphangitis, mastitis, necrotic and ulcerative dermatitis. A Quarter Horse from the semiarid Northeast presented ulcerative lymphangitis. Culture, nitrate reduction test, MALDI-TOF, and whole-genome sequ...
Fennouh C, Mokrani D, Dahmani H, Salhi O, Ouchetati I, Nabi M, Aouina K, Chettih I, Ouchene N, Khelifi Touhami NA.Fasciolosis, a parasitic disease of ruminants, poses significant economic and animal-health challenges in Algeria. This study aimed to assess spatial, temporal, and species-specific patterns of fasciolosis prevalence across diverse agro-climatic zones and to estimate associated economic losses. Between 2013 and 2023, eight wilayas El-Tarf, Skikda, Jijel (Region I), Blida, Mila (Region II), and M'Sila, Medea, Laghouat (Region III) were surveyed. Systematic postmortem inspections of 1,569,392 animals (349,176 cattle; 982,669 sheep; 235,639 goats; 1,882 camels; 26 horses) were performed by qualif...
Albornoz A, Morales B, Fernandez VB, Henriquez C, Quiroga J, Alarcón P, Moran G, Burgos RA.Equine asthma is a chronic respiratory disease characterised by neutrophilic inflammation, airway hyperresponsiveness, and impaired pulmonary function. Obesity, increasingly prevalent among domestic horses, has been identified as a potential risk factor for exacerbating inflammatory conditions. This study aimed to explore whether obesity modifies neutrophil metabolism and inflammatory responses in horses affected by asthma. Six asthmatic horses in clinical remission were categorised into two groups: obese and non-obese, based on body condition score. Serum levels of interleukin-1β (IL-1β) an...
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...
Duaso J, Perez-Ecija A, Navarro A, Martínez E, De Las Heras A, Mendoza FJ.Equine piroplasmosis (EP), caused by and , is a worldwide tick-borne disease with severe economic, commercial, and sanitary implications for equids. Although diagnosis is based on direct (blood smear or PCR) or indirect (serology) methods, these techniques are expensive, laborious, and false-negative and false-positive results can be yielded. Biochemistry blood profiles are routinely performed in horses. Biochemical parameters and ratios could be a reliable complementary diagnostic tool to assist clinicians in EP diagnosis, mainly in endemic areas, or for discarding similar disorders (piro-li...
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...
Tesena P, Vinijkumthorn R, Kingkaw A, Yanyongsirikarn P, Phasuk K, Ploypetch S, Phaonakrop N, Roytrakul S, Vongsangnak W, Prapaiwan N.Equine melanocytic neoplasm (EMN) is a skin tumor commonly observed in grey horses. Limited research has yet to investigate proteomic profiles of EMN, particularly in the early stages and their expression patterns. This study, therefore, aimed to identify signature proteins from tissue biopsies to distinguish early EMN, severe EMN, and normal groups. Results: Using proteomic analysis of 19 tissue samples (normal: n = 6, early EMN: n = 7, severe EMN: n = 6) through LC-MS/MS, 12,310 proteins were identified. Differentially expressed proteins (DEPs) and functional interaction analysi...
Ryu SH, Forbes E, Kim BS, Park KT.Five previously healthy horses in Korea, including a 19-year-old mixed-breed gelding, a 16-year-old mixed-breed mare, a 13-year-old Thoroughbred gelding, a 12-year-old Belgian warmblood mare, and a 12-year-old Andalusian mare, developed subcutaneous abscesses in the left neck after receiving intramuscular vaccination without prior skin disinfection. The vaccination used was Equivac® 2 in1, containing toxoid and cell-free extract. Within one week, the horses developed localised swelling and/or abscessation at the injection site. One case involved a ruptured abscess, while the others presente...
Kang H, Lee GKC, Bienzle D, Hammermüller J, Arroyo LG, Lillie BN, Beeler-Marfisi J.Macrophage populations in the lung, including resident alveolar macrophages (AMs) and recruited monocyte-derived macrophages (MDMs), recognize the inhaled particulates in barn dust that cause severe equine asthma and orchestrate an immune response though the cytokines they produce. Despite their importance, the specific contributions of these macrophage subsets to lower airway inflammation remain poorly understood. This exploratory in vitro study investigated the likely contributions of AMs and MDMs from healthy horses to the early inflammatory response using RNA-seq. If biologically importan...
Hodgson E, Romano TR, Stewart A, Bond S, Wise J.The pathogenesis of gastric ulceration is not well understood in foals, and its relationship with gastric acidity requires further investigation. A wireless capsule, designed for intraesophageal pH monitoring in humans, was adapted to measure intragastric pH in adult horses. Objective: To (1) determine the feasibility of wireless intragastric pH measurement in foals; (2) determine capsule attachment duration; and (3) describe the intragastric pH profiles recorded. Methods: Eight healthy foals aged 24-98 days. Methods: Prospective interventional study. Capsules were attached to the glandular g...
Brandt S.Sarcoids are benign, yet locally aggressive skin tumours that commonly affect horses and other equid species. The lesions are induced by bovine papillomavirus types 1, 2, and probably 13 in conjunction with other factors including trauma and a genetic predisposition. Although sarcoids have a substantial impact on the health and welfare of affected equids, information on the immune response to bovine papillomavirus infection and resulting sarcoids is limited. However, there is evidence that sarcoid disease is associated with an impaired immune response to bovine papillomavirus infection. This o...
Dillmann JB, Dos Santos TS, Dos Santos RC, Monteiro SG.Equine cutaneous pythiosis, caused by Pythium insidiosum, is a severe disease in tropical and subtropical regions, often leading to progressive granulomatous lesions with poor response to conventional therapies. Standard treatment includes surgical excision and immunotherapy, but recurrence is common, particularly in distal limb lesions. Maggot Debridement Therapy (MDT) with disinfected Lucilia cuprina larvae provides selective debridement, microbial control, and stimulation of granulation, representing a potential adjunctive option. This report describes the successful use of MDT combined wit...
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...
Martano M, Montagnaro S, Power K, Cuccaro B, Cutarelli A, Maiolino P, Restucci B.This study investigated the presence of δ bovine papillomaviruses (BPV-1, BPV-2, BPV-13, BPV-14) in equine skin lesions from Southern Italy, focusing on equine sarcoids and their histopathological correlations. 63 equine skin samples were analysed using PCR and sequencing for BPV detection, and their histopathological features were assessed. BPV DNA was detected in 69.84% of the samples, with BPV-1 and BPV-2 being the most prevalent genotype, followed by BPV-13, while BPV-14 was not detected. BPV DNA was also found in non-sarcoid tumours and non-neoplastic conditions. Histopathological analys...
Neira-Egea P, Alamar Malvoisin C, de la Cuesta-Torrado M, Bautista-Erler C, Vitale V, Jolly S, Cesarini C. spp. are ubiquitous yeasts that are part of most mammals' microbiota and can become opportunistic pathogens under predisposing conditions. Interestingly, recent studies in human medicine report an increased abundance of spp. in association with inflammatory bowel disease (IBD). Gastrointestinal candidiasis has been primarily reported in neonatal foals, but not in adult horses. The aim of this study is to describe the morphological, histopathological, and microbiological features of gastric lesions associated with infiltration in five horses referred to two tertiary hospitals for different r...
Parashar R, Singla LD, Kaur P, Sharma SK.Relative association of haemato-biochemical findings with oxidative stress markers was evaluated between natural patent and latent infection of in horses to divulge the role of these parameters in the pathogenesis of illness due to non-availablity in literature. Blood samples were collected from 429 equines of 16 districts of the Punjab and samples positive by conventional microscopy (patent Group I; oll = 13), by polymerase chain reaction (PCR) (latent group II; = 38) and healthy control (group III, = 64) were compared for haematological-biochemical index and stress parameters....
Muderspach ND, Daucke R, Nielsen MW, Scoggin KE, Fedorka CE, Miller LMJ, May MG, Troedsson MHT, Ferreira-Dias G, Agerholm JS, Schoof EM....Endometrial fibrosis leads to subfertility when periglandular fibrosis impairs endometrial gland function. Identifying distinct protein expressions in mares suffering from this condition is essential for understanding the pathogenesis and developing treatments to delay fibrotic progression. To gain a better understanding of protein dynamics underlying this condition, Data-Independent Acquisition Mass Spectrometry was utilized to comprehensively characterize and compare the equine endometrial and plasma proteome from mares with different severities of endometrial fibrosis. Mares in diestrus wer...
