Disease etiology in horses refers to the study of the causes and development of diseases within equine populations. It encompasses various factors, including genetic predisposition, environmental influences, infectious agents, and nutritional imbalances, that contribute to the onset and progression of diseases in horses. Understanding disease etiology is essential for identifying risk factors and implementing preventative measures in equine health management. This topic includes research on pathogen-host interactions, the impact of management practices on disease incidence, and the role of genetic and environmental factors in disease susceptibility. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, contributing factors, and implications of disease etiology in horses.
Bolfă PF, Leroux C, Pintea A, Andrei S, Cătoi C, Taulescu M, Tăbăran F, Spînu M.This study assesses the impact of equine infectious anaemia virus (EIAV) infection on the oxidant/antioxidant equilibrium of horses. Blood samples from 96 Romanian horses aged 1-25 years, were divided into different groups according to their EIAV-infection status, age, and time post-seroconversion. The effect of infection on oxidative stress was estimated by measuring enzymatic antioxidants (superoxide dismutase [SOD], glutathione peroxidase [GPx] and catalase), non-enzymatic antioxidants (uric acid and carotenoids), and lipid peroxidation (malondialdehyde [MDA]). Infection modified the oxidan...
Wong SS, Ngan AH, Riggs CM, Teng JL, Choi GK, Poon RW, Hui JJ, Low FJ, Luk A, Yuen KY.The newly described brittle tail syndrome causes weakening and breakage of the tail hair of horses. Extensive mycological and molecular studies showed that a novel fungus Equicapillimyces hongkongensis gen. nov., sp. nov. is the most likely cause of this syndrome. It is a septate branching hyaline mould which grows optimally at 30°C, requires nicotinic acid but is inhibited by cycloheximide, and specifically infects horse hair. Hyphae fill the core of infected hair shafts with short-necked structures resembling ascomata containing banana-shaped septate ascospore-like structures perforating th...
Azab W, El-Sheikh A, Abdel-Gawad A.Equine herpesvirus 4 (EHV-4) is an important pathogen that causes respiratory tract disease in horse populations worldwide. Glycoprotein G (gG) homologs have been identified in several alphaherpesviruses as minor non-essential membrane-anchored glycoproteins. In this study, EHV-4 gG deletion mutant has been generated by using bacterial artificial chromosome technology to investigate the role of gG in viral pathogenesis. Our findings reported here revealed no significant difference between parental EHV-4 and gG-negative strain in their replication cycle in cell culture. Furthermore, virus titer...
Barrey E, Jayr L, Mucher E, Gospodnetic S, Joly F, Benech P, Alibert O, Gidrol X, Mata X, Vaiman A, Guérin G.Recurrent exertional rhabdomyolysis (RER) is frequently observed in race horses like trotters. Some predisposing genetic factors have been described in epidemiological studies. However, the exact aetiology is still unknown. A calcium homeostasis disruption was suspected in previous experimental studies, and we suggested that a transcriptome analysis of RER muscles would be a possible way to investigate the pathway disorder. The purpose of this study was to compare the gene expression profile of RER vs. control muscles in the French Trotter to determine any metabolic or structural disruption. T...
Sasaki M, Kim E, Igarashi M, Ito K, Hasebe R, Fukushi H, Sawa H, Kimura T.Equine herpesvirus-1 (EHV-1), an α-herpesvirus of the family Herpesviridae, causes respiratory disease, abortion, and encephalomyelitis in horses. EHV-1 utilizes equine MHC class I molecules as entry receptors. However, hamster MHC class I molecules on EHV-1-susceptible CHO-K1 cells play no role in EHV-1 entry. To identify the MHC class I molecule region that is responsible for EHV-1 entry, domain exchange and site-directed mutagenesis experiments were performed, in which parts of the extracellular region of hamster MHC class I (clone C5) were replaced with corresponding sequences from equine...
Herder V, Barsnick R, Walliser U, Teifke JP, König P, Czerwinski G, Hansmann F, Baumgärtner W, Hewicker-Trautwein M.An equid herpesvirus 5 (EHV-5) infection was detected in lesioned skin from a nine-year-old Holsteiner stallion in the south of Germany. Macroscopically, the animal displayed a non-pruritic, multifocal, pustular dermatitis around both eyes, nostrils and the muzzle, which had been ongoing for one year. Histopathologically, skin lesions were characterized by orthokeratotic to parakeratotic hyperkeratosis, pustular dermatitis, epidermal hyperplasia, apoptotic keratinocytes, a lympho-plasmahistiocytic interface dermatitis with hydropic degeneration of keratinocytes, and perivascular to diffuse, ly...
Wilsher S, Lefranc AC, Allen WR.During embryo transfer (ET) the equine embryo can tolerate a wide degree of negative asynchrony but positive asynchrony of >2 days usually results in embryonic death. There is still confusion over whether this is due to the inability of the embryo to induce luteostasis or to an inappropriate uterine environment. Objective: To assess embryo survival and development in an advanced uterine environment. Objective: Embryo-uterine asynchrony, not the embryo's inability to induce luteostasis, is responsible for embryonic death in recipient mares with a >2 days chronologically advanced uterus. Methods...
Andersson LS, Swinburne JE, Meadows JR, Broström H, Eriksson S, Fikse WF, Frey R, Sundquist M, Tseng CT, Mikko S, Lindgren G.Insect bite hypersensitivity (IBH) is a chronic allergic dermatitis common in horses. Affected horses mainly react against antigens present in the saliva from the biting midges, Culicoides ssp, and occasionally black flies, Simulium ssp. Because of this insect dependency, the disease is clearly seasonal and prevalence varies between geographical locations. For two distinct horse breeds, we genotyped four microsatellite markers positioned within the MHC class II region and sequenced the highly polymorphic exons two from DRA and DRB3, respectively. Initially, 94 IBH-affected and 93 unaffected Sw...
Aleman M, Finno CJ, Higgins RJ, Puschner B, Gericota B, Gohil K, LeCouteur RA, Madigan JE.To describe epidemiological, clinical, and pathological features of neuroaxonal dystrophy in Quarter Horses (QHs) on a single farm. Methods: Prospective case series. Animals-148 horses. Methods: Neurologic, pathological, and toxicological evaluations were completed in selected neurologically affected horses over a 2-year period. Descriptive statistical analysis was performed. Results: 87 QHs and 1 QH-crossbred horse were affected. Most (50/88 [56.8%]) affected horses were 1 to 2 years old (median age, 2 years [range, 2 months to 34 years]). Neurologic deficits included obtundation (53/88 [60%]...
Pilo C, Altea A, Pirino S, Nicolussi P, Varcasia A, Genchi M, Scala A.A post-mortem survey was carried out on 46 Sardinian horses to evaluate the presence of Strongylus vulgaris and associated pathology. Horses were from local farms and had been treated with broad-spectrum anthelmintics at least 3 times a year. Examination of the cranial mesenteric arterial system (CMAS) showed parasite-induced lesions in all horses. S. vulgaris larvae were found in 39% of examined arteries, while their detection rate in coprocultures was 4%. Histology, carried out on 26 horses, showed mainly chronic and chronic-active lesions. Histometry showed a significant increase in thickne...
Dobromylskyj MJ, Copas V, Durham A, Hughes TK, Patterson-Kane JC.A 9-year-old Haflinger mare presented to the Liphook Equine Hospital with a history of weight loss, azotemia, and repeated episodes of ascites over a period of 10 days. The horse was euthanized after exploratory laparotomy revealed large numbers of variably sized masses distributed throughout the peritoneal cavity. Macroscopically, some masses were papillary, while others were nodular. Histologically, the masses were comprised of large to giant, variably shaped, and occasionally multinucleated neoplastic cells with marked anisokaryosis and anisocytosis and a high mitotic rate. Small to moderat...
Silva ML, Galiza GJ, Dantas AF, Oliveira RN, Iamamoto K, Achkar SM, Riet-Correa F.Outbreaks of eastern equine encephalitis observed from May 2008 to August 2009 in the Brazilian states of Pernambuco, Ceará, and Paraíba are reported. The disease occurred in 93 farms affecting 229 equids with a case fatality rate of 72.92%. Main clinical signs were circling, depression or hyperexcitability, ataxia, and progressive paralysis with a clinical manifestation period of 3-15 days. Main histologic lesions were a diffuse lymphocytic encephalomyelitis with neuronal death, satellitosis, neuronophagia, and hemorrhages being more severe in the cerebral gray matter of the telencephalon, ...
Lykkjen S, Roed KH, Dolvik NI.Developmental orthopaedic diseases (DOD) such as osteochondrosis (OC)/osteochondrosis dissecans (OCD), palmar/plantar osteochondral fragments (POF), ununited palmar/plantar eminences (UPE) and dorsoproximal first phalanx fragments are well recognised in the horse. Aetiopathogeneses are controversial and molecular genetic screening of DNA has recently been employed for their elucidation. Precise phenotypic definition and knowledge of breed-specific prevalence and interrelations are essential for the interpretation of following genomic studies in Standardbred trotters. Objective: To assess the p...
Michl J, Modarai M, Edwards S, Heinrich M.Identification of toxic or harmful agents continues to be a key goal in agricultural chemistry. This paper reports a metabolomic analysis of Ranunculus repens and related species, which were recently postulated to be cocausative agents in the etiology of equine grass sickness (EGS). Specifically, samples collected at EGS sites were compared with those from non-EGS sites. Furthermore, interspecific and seasonal variations and the species' response to edaphic and climatic factors were investigated. (1)H NMR spectroscopy in combination with multivariate data analysis was applied to the crude meth...
Zhang J.Prion diseases (e.g. Creutzfeldt-Jakob disease (CJD), variant CJD (vCJD), Gerstmann-Straussler-Scheinker syndrome (GSS), Fatal Familial Insomnia (FFI) and Kuru in humans, scrapie in sheep, bovine spongiform encephalopathy (BSE or 'mad-cow' disease) and chronic wasting disease (CWD) in cattles) are invariably fatal and highly infectious neurodegenerative diseases affecting humans and animals. However, by now there have not been some effective therapeutic approaches or medications to treat all these prion diseases. Rabbits, dogs, and horses are the only mammalian species reported to be resistant...
Curling A.Equine recurrent uveitis has traditionally been treated with medical management to reduce ocular inflammation and control pain during a single episode. Newer management methods include surgical options such as cyclosporine implantation and vitrectomy. These methods were developed not only to control inflammation but also to eliminate the underlying cause of uveitis in order to prevent recurrence.
Curling A.Equine recurrent uveitis has traditionally been treated with medical management to reduce ocular inflammation and control pain during a single episode. Newer management methods include surgical options such as cyclosporine implantation and vitrectomy. These methods were developed not only to control inflammation but also to eliminate the underlying cause of uveitis in order to prevent recurrence.
Curling A.Equine recurrent uveitis is a cyclical disease that affects the eye and often leads to high management costs and unfavorable results, such as blindness. Research has improved understanding of the roles of various etiologies, especially leptospirosis, in initiating and perpetuating the pathogenesis of equine recurrent uveitis. Research has also led to the discovery that specific breeds and horses with specific coat color patterns may be predisposed to developing recurrent uveitis.
Pavone S, Gialletti R, Pepe M, Onofri A, Mandara MT.In this study we investigated the histological changes of the myenteric plexuses and interstitial cells of Cajal (ICC) in gut samples from horses with colic to try to find results useful in the prognostic evaluation of enteric lesions. A morphologic and quantitative study of myenteric ganglia, ganglion cells and neuronal chromatolytic and necrotic changes of 24 horses with colic was performed. For ganglion cells, enteroglial cells and ICC immunolabeling was also performed to identify cell functional disorders. A significant increase of neuronal chromatolysis and necrosis occurred in horses suf...
Dixon PM, Parkin TD, Collins N, Hawkes C, Townsend NB, Fisher G, Ealey R, Barakzai SZ.The historical and clinical findings in 200 referred cases of equine sinus disease were reviewed retrospectively. Univariable and multivariable analyses were performed to detect significant differences in historical or clinical features between various categories of sinus disease. The causes of sinus disease were classified as subacute primary (less than two months duration) (n=52), chronic primary (more than two months duration) (n=37), dental (n=40), sinus cyst (n=26), traumatic (n=13) or mycotic sinusitis (n=7), sinus neoplasia (n=10), dental-related oromaxillary fistula (n=8) and intrasinu...
Lehmann J, Ellenberger C, Hoffmann C, Bazer FW, Klug J, Allen WR, Sieme H, Schoon HA.The aim of the present study was to characterize the morpho-functional features of endometrosis in barren and foaling mares, using both conventional histopathological and immunohistochemical methods. Endometrial biopsy samples were collected during the physiological breeding season from 159 estrous, clinically healthy mares (mean age 12 years), and the quality and degree of endometrosis was histomorphologically defined. The mares were bred and those that foaled were put in the foaling group whereas those that did not foal were placed in the barren group. Foaling mares were then compared with b...
Vallance SA, Spriet M, Stover SM.To enhance understanding of the nature and pathogenesis of scapular fractures in racehorses. Objective: Scapular fractures in racehorses have a consistent configuration related to sites of pre-existing stress modelling and remodelling. Methods: Fractured and intact scapulae collected post mortem were examined visually and with computed tomography (CT). Scapular fracture configuration, bone modelling changes and standardised CT morphometry and density measurements were recorded. Statistical comparisons were made between fractured, nonfractured contralateral and control scapulae. Results: Thirty...
Cavanagh HM, Mahony TJ, Vanniasinkam T.Two known serotypes of equine adenovirus (EAdV), equine adenovirus type 1 (EAdV-1) and equine adenovirus type 2 (EAdV-2) have been isolated from horses. EAdV-1 is predominantly associated with upper respiratory tract infections while EAdV-2 appears to be associated with gastrointestinal infections in horses. In this report the EAdV-1 genome has been sequenced for the first time. The EAdV-1 genome encoded genes are characteristic of the Mastadenovirus genus such as protein V and IX. Unexpectedly, phylogenetic reconstructions also revealed a close relationship between EAdV-1 and two recently cha...
Gilkerson JR.The clinical symptoms observed during the 2007 equine influenza outbreak are compared and contrasted with those observed in overseas outbreaks and described in the veterinary literature.
Britton AL, Major DA, Perry GH, Read AJ.The interaction and stabling of horses at equine events may have a substantial impact on the spread of a zoonotic disease. This study aimed to investigate the spread of equine influenza (EI) at an equestrian event at the start of the Australian outbreak. Around one-third of the competing horses were stabled overnight at the event and, of these, 70% developed symptoms of EI within 7 days. The index case was never positively identified, but stabling position and disease onset provided clues to its potential identity.
Chiavaccini L, Hassel DM, Shoemaker ML, Charles JB, Belknap JK, Ehrhart EJ.The black walnut extract (BWE) model of equine laminitis is associated with a systemic inflammatory response manifest by increased expression of inflammatory cytokines in the lungs and liver as well as the laminae. The specific role of the gastrointestinal tract in development of this response is unclear and is of utmost importance, as gastrointestinal disease and laminitis are intimately related. We investigated calprotectin expression and epithelial and endothelial apoptosis in the colon of horses exposed to orally administered BWE. Sections of colon from 19 horses including 7 controls not e...
Barrell EA, Kamm JL, Hendrickson DA.A 7-year-old mixed-breed stallion was admitted because of colic. Results: Entrapment of the left colon in the renosplenic space was diagnosed via rectal palpation and ultrasonographic examination, despite a renosplenic space ablation 6.5 years earlier. Results: The renosplenic entrapment was corrected with a combination of phenylephrine administration, rolling, and ballottement of the horse's abdomen during general anesthesia. The following week, left flank laparoscopic renosplenic space ablation was performed with the horse standing. On examination of the previous surgical site, only 4 bands ...
Silaghi C, Liebisch G, Pfister K.Equine Granulocytic Anaplasmosis (EGA) is caused by Anaplasma phagocytophilum, a tick-transmitted, obligate intracellular bacterium. In Europe, it is transmitted by Ixodes ricinus. A large number of genetic variants of A. phagocytophilum circulate in nature and have been found in ticks and different animals. Attempts have been made to assign certain genetic variants to certain host species or pathologies, but have not been successful so far. The purpose of this study was to investigate the causing agent A. phagocytophilum of 14 cases of EGA in naturally infected horses with molecular methods o...
Morán G, Burgos R, Araya O, Folch H.In horses, Recurrent Airway Obstruction (RAO) is an allergic disease that involves IgE mediated Type I Hypersensitivity responses. The development of this type of allergy involves a series of events that begins with reaginic antibodies, mainly IgE and some IgG subclasses. These reaginic antibodies bind with high affinity, via the Fc portion, to FcepsilonRI receptors on the membrane of mast cells and basophils. Once bound, environmental allergens cross-link the antibodies, which results in mast cell degranulation leading to the production of histamine and other chemical mediators that act toget...
Brenner S, Whitcomb MB.The clinical and ultrasonographic features of seven horses with coxofemoral subluxation are presented. Affected horses included five adult geldings (11-20 years), one large pony (6 years) and a 3-month-old filly. All were lame at the walk except for the pony with grade 3/5 lameness. Lameness was acute in all horses, but three horses progressed after initial improvement. Crepitus, muscle atrophy, and pelvic asymmetry were inconsistent findings. Ultrasonographic diagnosis of subluxation required dynamic visualization of femoral head displacement from the acetabulum while placing weight on the af...
Brankston G, Greer AL, Marshall Q, Lang B, Moore K, Hodgins D, Hennessey JTG, Beeler-Marfisi J.Ambient pollution is associated with the development and exacerbation of human asthma, but whether air pollution exposure is associated with lower airway inflammation in horses has not been fully evaluated. The Air Quality Health Index (AQHI) is an online tool used by asthmatic Ontarians to modify their outdoor activity when ambient pollution is high. A single AQHI value, falling on a scale from 1 to 10, is calculated from measurements of fine particulate matter (PM), nitrogen dioxide (NO), and ozone (O). Increased AQHI values predict an increased risk for presenting to a health care provider ...
Sun Y, MacLean AR, Aitken JD, Brown SM.Equine herpesvirus type 1 (EHV-1) gene 71 encodes a heavily O-glycosylated 192 kDa protein with no identified herpesvirus homologue. Isolation of a deletion mutant in gene 71 (ED71) demonstrated that its protein product is not essential in vitro. To investigate the role of the gene 71 protein in the virus life cycle, ED71 has been characterized in vitro in terms of cellular adsorption, penetration, egress and transmission compared to wild-type and revertant virus. ED71 virions adsorbed to cells less efficiently than wild-type and revertant virus with a consequential effect on virus penetration...
Boysen C, Davis EG, Beard LA, Lubbers BV, Raghavan RK.Kansas witnessed an unprecedented outbreak in Corynebacterium pseudotuberculosis infection among horses, a disease commonly referred to as pigeon fever during fall 2012. Bayesian geostatistical models were developed to identify key environmental and climatic risk factors associated with C. pseudotuberculosis infection in horses. Positive infection status among horses (cases) was determined by positive test results for characteristic abscess formation, positive bacterial culture on purulent material obtained from a lanced abscess (n = 82), or positive serologic evidence of exposure to organism ...
Zakia LS, Gomez DE, Caddey BB, Boerlin P, Surette MG, Arroyo LG.Next generation sequencing has demonstrated that alpha diversity of the fecal microbiota is significantly altered in horses with typhlocolitis. The objective of this study was to evaluate the bacterial composition of the cecum content of horses with and without typhlocolitis through direct and culture-enriched 16S gene sequencing of six healthy horses and six horses with acute typhlocolitis; a case-control study design. Cecal content was collected after euthanasia. An aliquot was used for direct 16S gene sequencing. Another was serially diluted with brain heart infusion (BHI) and plated onto f...
Figueiredo AS, Lampe E, de Albuquerque PPLF, Chalhoub FLL, de Filippis AMB, Villar LM, Cruz OG, Pinto MA, de Oliveira JM.Among the hepacivirus species recently described, the non-primate hepacivirus/hepacivirus A found in horses and donkeys is closely related to the human hepatitis C virus (HCV). Therefore, the equine is an attractive surrogate large animal model for the study of HCV therapy, pathogenesis and prophylaxis. Despite global efforts, epidemiological and genetic studies have not elucidated the risk factors, virus distribution or genetic variability of the hepacivirus A, which are also important issues for the equine welfare. Little information about this background scenery is available in Brazil. The ...
Eberth JE, Graves KT, MacLeod JN, Bailey E.Chondrodysplastic dwarfism in Miniature horses appeared to be a recessive genetic trait based on the occurrence of affected offspring by normal parents. Dwarf phenotypes vary and range from abnormal abortuses to viable offspring with evidence of skeletal dysplasia. A genome-wide association study implicated a region of ECA1 with dwarfism in Miniature horses. Aggrecan (ACAN) was a candidate gene in that region, and exons were sequenced to compare DNA sequences for dwarf and non-dwarf horses. Sequencing led to the discovery of variants in exons 2, 6, 7 and 15 associated with dwarfism. The four v...
Mullen KR, Rivera BN, Tidwell LG, Ivanek R, Anderson KA, Ainsworth DM.Studies of neonatal health risks of unconventional natural gas development (UNGD) have not included comprehensive assessments of environmental chemical exposures. We investigated a clustering of dysphagic cases in neonatal foals born between 2014 and 2016 in an area of active UNGD in Pennsylvania (PA),USA. We evaluated equine biological data and environmental exposures on the affected PA farm and an unaffected New York (NY) farm owned by the same proprietor. Dams either spent their entire gestation on one farm or moved to the other farm in late gestation. Over the 21-month study period, physic...
Hoffman RM, Wilson JA, Kronfeld DS, Cooper WL, Lawrence LA, Sklan D, Harris PA.Carbohydrates may be hydrolyzed or fermented in the digestive tract, and this distinction is important for the evaluation of the diet of herbivores. Both hydrolyzable and fermentable carbohydrates are included in the nonstructural carbohydrate (NSC) fraction as estimated by difference using proximate analysis. Our objectives were to measure hydrolyzable carbohydrates in forages and concentrates, to compare these values with nonstructural carbohydrate, to test for prediction of hydrolyzable carbohydrate concentration in forages from its near-infrared spectrum, and to examine seasonal variation ...
Current HIV researchMarch 10, 2010
Volume 8, Issue 1 87-93 doi: 10.2174/157016210790416424
Carpenter S, Dobbs D.Equine infectious anemia virus (EIAV) is one of the most divergent members of the lentivirus subfamily of retroviruses and is considered a useful comparative model for molecular studies of lentivirus replication. The Rev protein of EIAV is functionally homologous with other lentiviral Revs and facilitates export of incompletely spliced viral mRNAs through a Crm1-dependent pathway. The trans- and cis-acting elements that mediate EIAV Rev function are similar to, but distinct from, the well-characterized elements in human immunodeficiency virus (HIV-1), the prototypical Rev protein. In addition,...
Horín P, Smola J, Matiasovic J, Vyskocil M, Lukeszová L, Tomanová K, Králík P, Glasnák V, Schröffelová D, Knoll A, Sedlinská M, Krenková L....Polymorphic markers identified in the horse genes encoding the interleukin 12 p40 subunit, interferon gamma, tumor necrosis factor receptor 1, and inducible nitric oxide synthase were identified and tested, along with additional markers, for associations with two important horse infections: Rhodococcus equi and Lawsonia intracellularis. Eight immune response-related and 14 microsatellite loci covering 12 out of 31 equine autosomes were used for the association analysis. Markers located on horse Chromosomes Eca10 and 15 were significantly associated with the presence of high numbers of R. equi ...
Beisser AL, McClure S, Wang C, Soring K, Garrison R, Peckham B.To determine the incidence of and compare the types of catastrophic musculoskeletal injuries (CMIs) sustained in Thoroughbreds and Quarter Horses during racing at 3 Midwestern racetracks from 2000 to 2006. Methods: Retrospective cohort study. Methods: 139 Thoroughbred and 50 Quarter Horse racehorses euthanized because of CMIs. Methods: Veterinary officials from 3 Midwestern racing jurisdictions provided injury reports for Thoroughbreds and Quarter Horses that sustained CMIs (which required euthanasia) and the total number of race starts for each year. The number of CMIs/1,000 starts was determ...
Poyet JL, Srinivasula SM, Alnemri ES.vCLAP, the E10 gene product of equine herpesvirus-2, is a caspase-recruitment domain (CARD)-containing protein that has been shown to induce both apoptosis and NF-kappaB activation in mammalian cells. vCLAP has a cellular counterpart, Bcl10/cCLAP, which is also an activator of apoptosis and NF-kappaB. Recent studies demonstrated that vCLAP activates NF-kappaB through an IkappaB kinase (IKK)-dependent pathway, but the underlying mechanism remains unknown. In this report, we demonstrate that vCLAP associates stably with the IKK complex through direct binding to the C-terminal region of IKKgamma....
Kono Y.The antigenic structure of 16 viruses isolated from four horses which were inoculated with a clone of equine infectious anemia (EIA) virus was compared by the neutralization test. The antigenic structure of viruses isolated after development of neutralizing antibody differed from virus to virus. Back mutation of the antigenic structure was also demonstrated by serial passage of the virus in horses. These results suggest that EIA virus is subject to multidirectional antigenic variation. The possibility that the variants originated in the heterologous virus population in the inoculum seems to be...
Page AE, Adam E, Arthur R, Barker V, Franklin F, Friedman R, Grande T, Hardy M, Howard B, Partridge E, Rutledge M, Scollay M, Stewart JC, Vale A....The ability to identify horses at risk for catastrophic injuries continues to be a pressing issue for the racing industry, especially given recent events in North America. Objective: Since most catastrophic injuries occur in areas of existing pathology and this pathology is likely to elicit an inflammatory response, it was hypothesised that analysis of messenger RNA (mRNA) expression would detect significant changes in select genes in horses at risk for a catastrophic injury. Methods: Prospective cohort study. Methods: Five racing jurisdictions across the United States participated in this stu...
Punsmann S, Hoppe J, Klopfleisch R, Venner M.Acute interstitial pneumonia in foals has been sparsely described in literature, and the individual authors disagree on the underlying aetiology. Histopathological follow-up from surviving foals is not available. Objective: Description of clinical and histopathological findings in the course of acute interstitial pneumonia and in recovery. Investigating the aetiology and possible triggering factors of acute interstitial pneumonia. Methods: Case series. Methods: Post-mortem examination of nine affected foals; seven died during the acute phase, and two had recovered from acute interstitial pneum...
Prasse KW, Topper MJ, Moore JN, Welles EG.Eight tests of hemostasis were measured in 233 horses with colic. Blood samples were obtained at admission and for 4 consecutive days of hospitalization. Data were analyzed retrospectively by outcome, by broad-category diagnosis group, by small intestinal disorder, and by smaller categories for comparing specific diseases. Nonsurviving horses and horses with the most severe forms of intestinal ischemia had changes interpreted as hypercoagulative, the intensity of which was increased on the first and second mornings (sample times 2 and 3) after admission, when most significant differences for r...
Cawdell-Smith AJ, Todhunter KH, Anderson ST, Perkins NR, Bryden WL.In Australia, there have been recent reports of unusual abortions in mid- to late-gestation mares. These were clinically distinct from other recognised causes of pregnancy loss and the term 'equine amnionitis and fetal loss' (EAFL) was adopted to describe this syndrome. Initial investigations concluded that possible causal factors included the presence on affected stud farms of Processionary caterpillars (Ochrogaster lunifer). Objective: To determine if exposure of pregnant mares to Processionary caterpillars or their shed exoskeletons can induce EAFL. Methods: Processionary caterpillars and t...
Weese JS.Because nosocomial and zoonotic diseases are inherent and ever-present risks in veterinary hospitals, proactive policies should be in place to reduce the risk of sporadic cases and outbreaks. Policies should ideally be put in place before disease issues arise, and policies should be effectively conveyed to all relevant personnel. Written policies are required for practical and liability reasons and should be reviewed regularly. Although no infection control program can eliminate disease concerns, proper implementation of barrier precautions and isolation can reduce the exposure of hospitalized...
Coultous RM, Leadon DP, Shiels BR, Sutton D, Weir W.Equine piroplasmosis (EP) is a notifiable disease in Ireland and a significant concern to domestic and international equine industries. Information regarding EP presence in Ireland is currently limited. This retrospective surveillance study describes a serological and molecular analysis of blood samples submitted to the Irish Equine Centre for EP testing between January 2013 and April 2016. Methods: Following serological testing, seropositive samples were screened using a PCR targeting the 18S ribosomal RNA gene. Amplicon sequences were bioinformatically analysed to identify the parasite speci...
de la Rebière de Pouyade G, Riggs LM, Moore JN, Franck T, Deby-Dupont G, Hurley DJ, Serteyn D.Laminitis is a local manifestation of a systemic inflammatory response that is characterized by neutrophil activation and movement of neutrophils into the laminar tissues. Given the evidence for the involvement of neutrophils in the development of laminitis, we measured concentrations of neutrophil elastase, a serine protease released from the azurophilic granules of neutrophils, in plasma, skin and laminar tissues obtained from control horses and horses given black walnut heartwood extract (BWHE) to induce laminitis. Healthy horses (5-15 years old) were randomly assigned to 4 groups: 3 experi...
Ryan A, Bertone AL, Kaeding CC, Backstrom KC, Weisbrode SE.There is no consensus regarding the safety of radiofrequency energy treatment for chondroplasty. Objective: Use of a radiofrequency thermal probe will produce a dose-dependent detrimental effect on chondrocytes in a setting mimicking the arthroscopic procedure. Methods: Controlled laboratory study. Methods: Paired patellae from 11 horses were fibrillated; one served as the control while the contralateral patella was treated with 20, 40, and 60 watts of radiofrequency energy for 4 minutes. Proteoglycan synthesis, proteoglycan degradation, and cell viability were measured. Explant histologic sec...
Niedzwiedz A, Borowicz H, Januszewska L, Markiewicz-Gorka I, Jaworski Z.It has been reported that equine recurrent airway obstruction (RAO) is a state of oxidative stress. Oxidant-antioxidant imbalance is known to increase the conversion of deoxyguanosine to 8-hydroxy-2-deoxyguanosine (8-OHdG) in DNA. 8-OHdG can easily be measured using ELISA tests in serum or urine samples. In this study, we analysed serum 8-OHdG levels in horses with recurrent airway obstruction and in healthy controls. Results: The study material consisted of seven healthy horses and seven horses with symptomatic RAO. All horses were exposed to moldy hay and straw for 48 h to induce clinical e...
Ward CL, Wood JL, Houghton SB, Mumford JA, Chanter N.Seventy-three bacterial isolates from 65 horses with and without evidence of lower airway disease were identified to assess whether the association with disease was accounted for by a small or large number of species. Just over half (50.5 per cent were Actinobacillus equuli, 17.8 per cent were A suis-like, 11 per cent were Pasteurella pneumotropica, 8.2 per cent were A lignieresii, 6.8 per cent were P haemolytica and 5.5 per cent were P mairii. These results suggest that a range of Actinobacillus and Pasteurella species can be isolated from the lower airways of horses, with many of the isolate...
Takafuji VA, McIlwraith CW, Howard RD.To evaluate the effects of equine recombinant interleukin-1alpha (rEqIL-1alpha) and recombinant interleukin-1beta (rEqIL-1beta) on proteoglycan metabolism and prostaglandin E2 (PGE2) synthesis by equine articular chondrocytes in explant culture. Methods: Near full-thickness articular cartilage explants (approx 50 mg) harvested from stifle joints of a 3-year-old and a 5-year-old horse. Methods: Expression constructs containing cDNA sequences encoding EqIL-1alpha and EqIL-1beta were generated, prokaryotically expressed, and the recombinant protein purified. Near full-thickness articular cartilag...
Sellers RF, Maarouf AR.Outbreaks of vesicular stomatitis, serotype New Jersey, during epidemics in the United States and northern Mexico, 1982-5, were examined by backward trajectories of winds to investigate spread and possible sources. The outbreaks selected for analysis did not involve introduction of disease by infected animals. The findings indicate that wind could have been responsible for carrying infection from northern Mexico to Arizona and New Mexico and thence to Colorado and Utah and on to Wyoming, Idaho and Montana. The results of these analyses are consistent with the findings from T1 RNAse fingerprint...
Gale P, Kelly L, Snary EL.The emergence of bluetongue virus and Schmallenberg virus in Great Britain (GB) during the last decade has highlighted the need for understanding the relative importance of the various pathways of the entry of livestock arboviruses so as to help focus surveillance and mitigation. This study summarizes what is known for the main routes of entry and assesses the strength of the current evidence for and against. Entry through infected arthropod vectors is considered at the level of each life cycle stage for tick-, biting midge- and mosquito-borne viruses, and while there is evidence that this cou...
Wang L, Pawlak E, Johnson PJ, Belknap JK, Alfandari D, Black SJ.To determine whether increased gene expression of a disintegrin and metalloproteinase with thrombospondin motifs-4 (ADAMTS-4) in laminae of horses with starch gruel-induced laminitis was accompanied by increased enzyme activity and substrate degradation. Methods: Laminae from the forelimb hooves of 8 healthy horses and 17 horses with starch gruel-induced laminitis (6 at onset of fever, 6 at onset of Obel grade 1 lameness, and 5 at onset of Obel grade 3 lameness). Methods: Gene expression was determined by use of cDNA and real-time quantitative PCR assay. Protein expression and processing were ...
Thomas SJ, de Solis CN, Coleman MC.Equine asthma is a common condition in horses, for which few host-related risk factors have been identified. The objective of this study was to identify host-related risk factors for the development of equine asthma. A retrospective, case-control study was performed, utilizing horses presented to the Texas A&M University, Veterinary Medical Teaching Hospital from January 2014 December 2018. Incident cases of mild to severe equine asthma (n = 37), diagnosed clinically with cytologic support of disease were examined. For each case, two control populations were identified, including one tem...
