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.
Padoan E, Ferraresso S, Pegolo S, Barnini C, Castagnaro M, Bargelloni L.Mild equine asthma (MEA) and severe equine asthma (SEA) are two of the most frequent equine airway inflammatory diseases, but knowledge about their pathogenesis is limited. The goal of this study was to investigate gene expression differences in the respiratory tract of MEA- and SEA-affected horses and their relationship with clinical signs. Methods: Clinical examination and endoscopy were performed in 8 SEA- and 10 MEA-affected horses and 7 healthy controls. Cytological and microbiological analyses of bronchoalveolar lavage (BAL) fluid were performed. Gene expression profiling of BAL fluid wa...
Strootmann T, Spitzbarth I, Della Tommasa S, Brehm W, Köller G, Troillet A.Research and provision of data on macrophages by cytological synovial fluid analysis and light microscopy in horses with septic arthritis MATERIAL AND METHODS: Records of 167 synovial fluid samples were evaluated and subdivided into different groups: (1) non-septic, (2) haematogenous septic arthritis in foals and (3) traumatic/iatrogenic septic arthritis. The effect of joint lavage on synovial fluid cytology and on the occurrence of macrophage phenotypes was investigated. Results: Regardless of aetiology and age of the horse, macrophage concentrations in synovial sepsis are decreased to a medi...
Macdonald SL, Abbas G, Ghafar A, Gauci CG, Bauquier J, El-Hage C, Tennent-Brown B, Wilkes EJA, Beasley A, Jacobson C, Cudmore L, Carrigan P, Hurley J....Cyathostomins are the most common and highly prevalent parasites of horses worldwide. Historically, the control of cyathostomins has mainly relied on the routine use of anthelmintic products. Increasing reports on anthelmintic resistance (AR) in cyathostomins are concerning. A potential method proposed for detecting emerging AR in cyathostomins has been estimating the egg reappearance period (ERP). This paper reviews the data available for the ERP of cyathostomins against the three major classes of anthelmintics, macrocyclic lactones, tetrahydropyrimidines, and benzimidazoles. Published peer-r...
Siwińska N, Żak-Bochenek A, Paszkowska M, Karczewski M, Długopolska D, Haider W.Colic, a condition affecting the gastrointestinal tract of horses, manifests as severe pain and may be a life-threatening condition. It is possible to distinguish between an acute, disposable process, as well as recurrent colic symptoms (abdominal pain) caused by an ongoing chronic inflammatory process. This paper presents a retrospective analysis of the histopathological findings of duodenal and rectal samples taken from horses with recurrent colic, with the aim to determine the frequency and extent of inflammation. The samples, i.e., duodenal biopsy (60 samples) and rectal biopsy (17 samples...
Pratt SL, Bowen M, Hallowell GH, Shipman E, Bailey J, Redpath A.Equine glandular gastric disease (EGGD) is a common condition of the horse. Misoprostol is reported to be superior to oral omeprazole and sucralfate for treatment. Long-acting intramuscular injectable omeprazole (LAIOMEP) is a novel treatment shown to be effective in a small population. This study aimed to determine LAIOMEP efficacy compared to misoprostol and oral omeprazole and identify characteristics that predict treatment outcome. All horses that underwent gastroscopy between 2012 and 2019 were reviewed. Lesions were characterised by 4 blinded observers, all of whom are diplomates in equi...
Taylor SD, Kritchevsky JE, Huang P, Olave C, Waxman SJ, Miller MA.To report history, clinical examination findings, clinicopathologic findings, diagnostic test results, treatment, and outcome in horses with a novel idiopathic hepatitis syndrome. 13 client-owned horses. Medical records of horses that were presented with fever and increased blood liver enzyme activity over a 16-month period were reviewed (December 1, 2020, to April 1, 2022). Collected data included signalment, history, clinical and clinicopathologic findings, diagnostic test results, treatment, clinical progression, and short-term outcome. Affected horses were presented between December and Ap...
Ashraf R, Rashid S, Rasheed I, Asif S.This paper includes the study of early embryonic death (EED), predisposing factors of EED and treatment. EED refers to the fetal mortality which varies in mare and camelids but most probably not later than 50 days of gestation. This duration may be divided into very early mortality, early mortality and late embryonic mortality. This also varies in mare and camelids. There are different embryonic, maternal, environmental/external, and infectious and noninfectious factors which lead to early embryonic loss. Diagnosis is very difficult as in most of the cases resorption of fetus occurs but it is ...
Daraban Bocaneti F, Altamura G, Corteggio A, Tanase OI, Dascalu MA, Pasca SA, Hritcu O, Mares M, Borzacchiello G.Bovine papillomaviruses -1/-2 (BPVs) are small non-enveloped double-stranded DNA viruses able to infect the skin of bovids and equids, causing development of neoplastic lesions such as bovine cutaneous fibropapillomas and equine sarcoid. Matrix metalloproteinases (MMPs) are a group of zinc-dependent endopeptidases that degrade basal membrane and extracellular matrix, whose function is essential in physiological processes such as tissue remodeling and wound healing. MMPs activity is finely regulated by a balancing with expression of tissue inhibitors of MMPs (TIMPs), a process that is impaired ...
Hansen S, Olsen E, Raundal M, Agerholm JS.Cerebellar abiotrophy (CA) is an uncommon hereditary neurodegenerative disorder affecting the cerebellar Purkinje cells. Equine CA has been reported in several breeds, but a genetic etiology has only been confirmed in the Arabian breed, where CA is caused by an autosomal recessive mutation. Methods: Clinical and histological findings consistent with CA are reported in an 8.5-month-old Icelandic filly. The filly showed a perceived sudden onset of marked head tremor, incoordination, ataxia, lack of menace response and a broad-based stance. Cerebrospinal fluid, hematological and biochemical findi...
Vitour D, Zientara S, Fablet A, Bréard E, Sailleau C.African horse sickness (AHS) is a major arthropod-borne disease that causes significant losses in horses in sub-Saharan Africa. It is caused by the African horse sickness virus (AHSV), which is transmitted during a blood meal by Culicoides biting midges. The distribution of historical African culicoid vectors increases due to global warming. In addition, recent (Thailand, 2020) and earlier (Iberian Peninsula, 1965-66/1987-90) AHS outbreaks outside Africa demonstrate the adaptation of the virus to endogenous species in AHS-free regions, similar to what has been observed for bluetongue disease i...
Mizuguchi Y, Kato A, Aizu M.In this case report, two horses with chronic refractory infections in the tuber calcanei were successfully managed via intravenous antibiotic regional limb perfusion through the lateral saphenous vein after failure of conventional treatment approaches, including surgery and intravenous regional limb perfusion using the cranial branch of the medial saphenous vein. Surgical delay in these cases may have allowed the development of chronic infection, which prevented the conventional regional perfusion from working effectively. The spatial difference of the vessels relative to the tuber calcanei po...
Klouth E, Zablotski Y, Petersen JL, de Bruijn M, Gröndahl G, Müller S, Goehring LS.Equid Herpesvirus Myeloencephalopathy (EHM) is a multifactorial disease following an EHV-1 infection in Equidae. We investigated a total of 589 horses on 13 premises in Europe in search of risk factors for the development of EHM. We found that fever ( < 0.001), increasing age ( = 0.032), and female sex ( = 0.042) were risk factors for EHM in a logistic mixed model. Some breeds had a decreased risk to develop EHM compared to others (Shetland and Welsh ponies; = 0.017; = 0.031), and fewer EHV-1-vaccinated horses were affected by EHM compared to unvaccinated horses ( = 0.02). Data evaluation...
Fehér OE, Fehérvári P, Tolnai CH, Forgách P, Malik P, Jerzsele Á, Wagenhoffer Z, Szenci O, Korbacska-Kutasi O.West Nile virus (WNV) is an emerging pathogen in Hungary, causing severe outbreaks in equines and humans since 2007. The aim of our study was to provide a comprehensive report on the clinical signs of West Nile neuroinvasive disease (WNND) in horses in Hungary. Clinical details of 124 confirmed equine WNND cases were collected between 2007 and 2019. Data about the seasonal and geographical presentation, demographic data, clinical signs, treatment protocols, and disease progression were evaluated. Starting from an initial case originating from the area of possible virus introduction by migrator...
Peng S, Magdesian KG, Dowd J, Blea J, Carpenter R, Ho W, Finno CJ.Increases in serum gamma-glutamyltransferase (GGT) activity have been reported in Thoroughbred (TB) racehorses and associated with maladaptation to training but the underlying etiology remains unknown. Objective: Classify the etiology of high GGT syndrome in racing TBs by assessment of pancreatic enzymes, vitamin E concentrations, and both a candidate gene and whole genome association study. We hypothesized that a genetic variant resulting in antioxidant insufficiency or pancreatic dysfunction would be responsible for high GGT syndrome in TBs. Methods: A total of 138 California racing TBs. Amy...
Brangsch H, Singha H, Laroucau K, Elschner M.Although glanders has been eradicated in most of the developed world, the disease still persists in various countries such as Brazil, India, Pakistan, Bangladesh, Nepal, Iran, Bahrain, UAE and Turkey. It is one of the notifiable diseases listed by the World Organization for Animal Health. Occurrence of glanders imposes restriction on equestrian events and restricts equine movement, thus causing economic losses to equine industry. The genetic diversity and global distribution of the causing agent, Burkholderia (B.) mallei, have not been assessed in detail and are complicated by the high clonali...
Akbari Shahkhosravi N, Kakavand R, Davies HMS, Komeili A.The health and performance of horses are significantly affected by diseases associated with the hoof. Laminitis is a critical hoof disease that causes pain and, potentially, severe hoof and bone pathology. Objective: To generate an equine hoof finite element (FE) model to investigate the impact of normal and toe-in hoof conformations on the degeneration (decrease in elastic modulus) of the laminar junction (LJ), as occurs in chronic laminitis. Methods: Computer software modelling. Methods: A hoof FE model was generated to investigate the biomechanics of hoof laminitis. A 3D model, consisting o...
Górski K, Borowska M, Stefanik E, Polkowska I, Turek B, Bereznowski A, Domino M.Dental disorders are a serious health problem in equine medicine, their early recognition benefits the long-term general health of the horse. Most of the initial signs of Equine Odontoclastic Tooth Resorption and Hypercementosis (EOTRH) syndrome concern the alveolar aspect of the teeth, thus, the need for early recognition radiographic imaging. This study is aimed to evaluate the applicability of entropy measures to quantify the radiological signs of tooth resorption and hypercementosis as well as to enhance radiographic image quality in order to facilitate the identification of the signs of E...
Silva CJFL, Trindade KLG, Cruz RKS, Manso HECCC, Coelho CS, Filho JDR, Nogueira CEW, Aragona F, Fazio F, Manso Filho HC.Erosions and gastric ulcers may be present in horses at any age and under different conditions of rearing and handling. In tropical regions, horses can feed on fruits rich in soluble carbohydrates, such as mangoes, but little is known about how these foods interact with their digestive systems. To test the hypothesis that the ingestion of ripe mangoes with peels could cause disturbances in the digestive processes of horses, an experiment was developed to monitor animals that had free access to ripe mangoes in their pasture areas. Horses (purebred Arabians, n = 5; ~340 kg, ~13 years) were evalu...
McGilloway M, Manley S, Aho A, Heeringa KN, Lou Y, Squires EJ, Pearson W.Leaky gut syndrome (LGS) is an idiopathic disorder characterised by alterations in intestinal permeability and low-grade systemic inflammation. Factors contributing to development of LGS are not well-understood but physiological stressors such as exercise and transport may play a role which may be of pathophysiological relevance in horses. Objective: To characterise the combined effect of transport stress and exercise on gastrointestinal permeability, and to determine whether these effects are associated with increased inflammatory biomarkers in plasma. Methods: Controlled, randomised and cros...
Lowman ME, Tipton CD, Labordère AL, Brown JA.Information regarding the microbiome in sinusitis using genetic sequencing is lacking and more-in-depth understanding of the microbiome could improve antimicrobial selection and treatment outcomes for cases of primary sinusitis. Objective: To describe sinus microbiota in samples from horses with sinusitis and compare microbiota and the presence of antimicrobial resistance genes between primary, dental-related and other secondary causes of sinusitis. Methods: Retrospective case series. Methods: Records of equine sinusitis from 2017 to 2021 were reviewed and historical microbial amplicon sequenc...
Yoon J, Park T, Kim A, Park J, Park BJ, Ahn HS, Go HJ, Kim DH, Lee JB, Park SY, Song CS, Lee SW, Choi IS.Equine parvovirus-hepatitis (EqPV-H) is one of the etiological agents of Theiler's disease, causing fulminant hepatitis; however, its transmission route and pathogenesis remain unclear. In the present study, we aimed to determine EqPV-H shedding in oral/nasal/vaginal swabs or semen samples from horses living in Korea using nested polymerase chain reaction. We then used the data obtained to investigate various risk factors associated with EqPV-H including viral shedding, hepatopathological changes, and genetic diversity. Our data revealed occurrence of EqPV-H shedding in these animals (oral: 3/...
Yan J, Sun D, Jiang Z, Zhou L, Gao X.Infundibular caries (IC) affects donkeys of all ages and causes pain, difficulty in mastication and weight loss. The study aimed to determine the epidemiology of IC in donkeys and examine the potential risk factors associated with the disease development. A total of 2118 donkeys in Inner Mongolia were sampled. The first section of the survey was performed by veterinarians and included the oral health of the donkeys. A survey on the donkey's signalment, diet, and husbandry was also conducted. The risk factors associated with IC were assessed using multivariable logistic regression analysis. Uni...
Easther R, Manthorpe E, Woolford L, Kawarizadeh A, Hemmatzadeh F, Ferlini Agne G.Equine idiopathic haemorrhagic cystitis (EIHC) is a recently described form of aseptic cystitis in horses in which there is no discernible underlying cause. This case report describes a 9-year-old Thoroughbred gelding that presented with stranguria, pollakiuria, and haematuria. Cystoscopy revealed ulceration and haemorrhage of the bladder mucosa, diffuse mural hyperaemia and marked urine sedimentation. Histopathological evaluation of the bladder revealed chronic active ulcerative neutrophilic, lymphoplasmacytic, and eosinophilic cystitis. There was no bacterial or fungal growth upon culture bu...
Roach J, Arango Sabogal JC, Smith K, Foote A, Verheyen K, de Mestre AM.Risk factors associated with equine reproductive efficiency have been identified along with those associated specifically with early pregnancy loss (EPL). In contrast, no studies have reported risk factors associated with abortion (loss between day 70 and 300 post-cover). Given the causes of abortion differ to those of EPL, likely too will the risk factors. A retrospective cohort study was carried out to identify risk factors associated with abortion in UK and Irish based Thoroughbreds, collecting data on 20 exposure variables over a five-year period. A generalized linear mixed model was utili...
Johnson SA, Richards RB, Frisbie DD, Esselman AM, McClure SR.Over the past three decades, electrohydraulic extracorporeal shock wave therapy (ESWT) as a treatment modality for equine orthopaedic disorders has sparked exponential interest among practitioners, but its clinical applications are quickly evolving and a current review highlighting modernised equine clinical use is lacking. The objective of this review is to summarise the most current ESWT technology, evidence for its use, proposed mechanisms of action and clinical applications in horses while also highlighting the areas requiring further investigation. The three ways to generate a shock wave ...
Lan Y, Li Y, Yu G, Zhang Z, Irshad I.Accumulating studies indicated that gut microbial changes played key roles in the progression of multiple diseases, which seriously threaten the host health. Gut microbial dysbiosis is closely associated with the development of diarrhea, but gut microbial composition and variability in diarrheic horses have not been well characterized. Here, we investigated gut fungal compositions and changes in healthy and diarrheic horses using amplicon sequencing. Results indicated that the alpha and beta diversities of gut fungal community in diarrheal horses changed significantly, accompanied by distinct ...
Williams NJ, Slovis NM, Browne NS, Troedsson MHT, Giguėre S, Hernandez JA.Diarrhea remains an important cause of morbidity and mortality in neonatal foals, and correct identification of etiologic agents is essential for effective disease management. Objective: To examine the association between diarrhea and detection of Enterococcus durans or other enteropathogens in neonatal foals on 1 breeding farm in Kentucky, USA. Methods: Fifty-nine Thoroughbred foals and their broodmares. Methods: Prospective observational study. Study foals and broodmares were sampled and tested for E. durans and other enteropathogens during the first 10 days after foaling. The frequency of...
Albanese V, Munsterman A, Klohnen A.Enterolithiasis is a well-documented cause of colic in horses, especially in some geographic areas such as California and Florida. This retrospective case-control study aims at comparing the prevalence of gastric ulcers in horses affected by enterolithiasis to that in horses affected by other types of large intestinal obstruction. Two hundred and ninety-six horses were included in the study sample. Horses that had surgery for the removal of one or more enteroliths were included in the study as cases. Patients that had surgery for large intestinal simple obstructions other than enterolithiasis ...
Glaser AL, de Vries AA, Dubovi EJ.Three murine monoclonal antibodies (MAbs) that neutralize equine arteritis virus (EAV) infectivity were identified and characterized. The antibodies, 93B, 74D(B) and 38F, recognized the major envelope glycoprotein (GL) encoded by open reading frame (ORF) 5 in immunoblots and by immunoprecipitation. All three MAbs were used to compare the Bucyrus isolate of EAV and MAb neutralization-resistant (NR) escape mutants with the vaccine virus and 19 independent field isolates of EAV by virus neutralization. The different abilities of the MAbs to neutralize virus isolates indicated that they recognize ...
Debrue M, Hamilton E, Joubert P, Lajoie-Kadoch S, Lavoie JP.Recent finding suggests that T-cells may be involved in the pathogenesis of heaves in horses. However, little is known concerning their possible contribution to pulmonary neutrophilia, a characteristic finding in heaves. Interleukin (IL)-17 is a cytokine secreted by activated T-cells that indirectly promotes the maturation, chemotaxis and activation of neutrophils. We therefore hypothesized that IL-17 may be involved in the recruitment of neutrophils into the airways and that its mRNA expression would be increased in bronchoalveolar lavage (BAL) cells of horses with heaves. Heaves susceptible ...
Kinnunen PM, Palva A, Vaheri A, Vapalahti O.Borna disease virus (BDV) has gained lot of interest because of its zoonotic potential, ability to introduce cDNA of its RNA transcripts into host genomes, and ability to cause severe neurobehavioural diseases. Classical Borna disease is a progressive meningoencephalomyelitis in horses and sheep, known in central Europe for centuries. According to current knowledge, BDV or a close relative also infects several other species, including humans at least occasionally, in central Europe and elsewhere, but the existence of potential 'human Borna disease' with its suspected neuropsychiatric symptoms ...
Sykes BW, Bowen M, Habershon-Butcher JL, Green M, Hallowell GD.To date, risk factors for equine glandular gastric disease (EGGD) have not been described in Thoroughbred racehorses. Objective: To determine management factors associated with EGGD, identify clinical signs in affected horses, and compare these to equine squamous gastric disease (ESGD). Methods: The study was carried out on 109 Thoroughbred racehorses from 8 training yards (3 in the United Kingdom and 5 in Australia). Methods: Gastroscopic examination alongside a questionnaire regarding management, feeding, exercise, and health. Results: Management factors and clinical signs were different for...
Burns TA, Geor RJ, Mudge MC, McCutcheon LJ, Hinchcliff KW, Belknap JK.Insulin resistance has been associated with risk of laminitis in horses. Genes coding for proinflammatory cytokines and chemokines are expressed more in visceral adipose tissue than in subcutaneous adipose tissue of insulin-resistant (IR) humans and rodents. Objective: To investigate adipose depot-specific cytokine and chemokine gene expression in horses and its relationship to insulin sensitivity (SI). Methods: Eleven light breed mares. Methods: Animals were classified as IR (SI=0.58+/-0.31x10(-4) L/min/mU; n=5) or insulin sensitive (IS; SI=2.59+/-1.21x10(-4) L/min/mU; n=6) based on results o...
Seltenhammer MH, Heere-Ress E, Brandt S, Druml T, Jansen B, Pehamberger H, Niebauer GW.Equine melanoma shows striking features particularly with regard to clinical development in grey horses: in contrast to malignant melanoma in humans and in solid coloured horses that are characterized by early onset of metastasis, pigment cell tumours display almost benign clinical features in ageing grey horses. Through evolution, grey horses appear to be in a favourable position in regard to the biological behaviour of melanomas. Yet unknown factors inhibiting or retarding early melanoma metastasis may be responsible for this phenomenon. In this study, immunostaining profiles and histopathol...
Wang E, Bowen RA, Medina G, Powers AM, Kang W, Chandler LM, Shope RE, Weaver SC.Following a 19-year hiatus, Venezuelan equine encephalitis (VEE) reemerged in western Venezuela in December 1992. This outbreak is important in understanding VEE emergence because phylogenetic studies imply that sympatric, enzootic, subtype ID VEE viruses mutated to generate the epizootic/epidemic. Although the 1992-1993 strains belong to subtype IC, a serotype implicated in extensive outbreaks during the 1960s and in 1995, relatively small numbers of human and equine cases occurred in 1992-1993. We, therefore, evaluated the pathogenicity of these Venezuelan enzootic ID and epizootic IC viruse...
Dakin SG, Dudhia J, Werling NJ, Werling D, Abayasekara DR, Smith RK.The contribution of inflammation to the pathogenesis of tendinopathy and high prevalence of re-injury is not well established, although recent evidence suggests involvement of prostaglandins. We investigated the roles of prostaglandins and inflammation-resolving mediators in naturally occurring equine tendon injury with disease stage and age. Levels of prostaglandins E(2) (PGE(2)), F(2α) (PGF(2α)), lipoxin A(4) (LXA(4)) and its receptor FPR2/ALX were analysed in extracts of normal, sub-acute and chronic injured tendons. To assess whether potential changes were associated with altered PGE(2) ...
Van de Walle GR, Peters ST, VanderVen BC, O'Callaghan DJ, Osterrieder N.Equine herpesvirus 1 (EHV-1) is a member of the Alphaherpesvirinae, and its broad tissue tropism suggests that EHV-1 may use multiple receptors to initiate virus entry. EHV-1 entry was thought to occur exclusively through fusion at the plasma membrane, but recently entry via the endocytic/phagocytic pathway was reported for Chinese hamster ovary cells (CHO-K1 cells). Here we show that cellular integrins, and more specifically those recognizing RGD motifs such as alphaVbeta5, are important during the early steps of EHV-1 entry via endocytosis in CHO-K1 cells. Moreover, mutational analysis revea...
Seltenhammer MH, Simhofer H, Scherzer S, Zechner R, Curik I, Sölkner J, Brandt SM, Jansen B, Pehamberger H, Eisenmenger E.Equine melanomas occur most commonly in grey horses at age 5 years or more. Generally, benign and malignant melanomas are distinguished by microscopy, but a more distinct classification would be helpful. Objective: The objectives of this study were to gain further evidence concerning the occurrence of melanotic tumours, and to evaluate the impact of heredity on melanoma development. Methods: A clinical study was conducted on a defined population of 296 grey horses of Lipizzaner breed. Individuals were classified according to their stage of disease using a 0-5 scale. Heritability was estimated ...
Harrington DJ, Sutcliffe IC, Chanter N.Streptococcus equi is the aetiological agent of strangles, one of the most prevalent diseases of the horse. The animal suffering and economic burden associated with this disease necessitate effective treatment. Current antibiotic therapy is often ineffective and thus recent attention has focused on vaccine development. A systematic understanding of S. equi virulence, leading to the identification of targets to which protective immunity can be directed, is a prerequisite of the development of such a vaccine. Here, the virulence factors of S. equi are reviewed.
Riggs CM, Whitehouse GH, Boyde A.This study examined material from Thoroughbred horses, the majority of which had been in race training, for evidence of pathology in the third metacarpal (McIII) and third metatarsal (MtIII) bones which might be related to the occurrence of distal condylar fractures. Whole bone samples were studied and documented by macrophotography prior to macroradiography and computed tomographic (CT) imaging. Microradiographs were made from 100 microm thick mediolateral sections cut perpendicular to the dorsal and palmar/plantar articular surfaces of distal condylar regions of McIII and MtIII. Blocks were ...
Båverud V, Gustafsson A, Franklin A, Lindholm A, Gunnarsson A.Clostridium (C.) difficile, or its cytoxin, was demonstrated in faecal samples from 10 of 25 (40%) mature horses investigated with acute colitis treated primarily with antibiotics for disorders other than diarrhoea. C. difficile was not found in faecal samples from 140 horses without signs of enteric disorders, from 21 nondiarrhoeic horses treated with antibiotics, nor from 22 horses with colitis untreated with antibiotics. Except for C. difficile neither Salmonella nor any other investigated intestinal pathogen was isolated in any of the diarrhoeic horses. The findings strongly support some e...
Boyde A.This review describes results obtained with tissue from prior studies of equine and human osteoarthritis (OA). The main methods considered are scanning electron microscopy, novel methods in light microscopy and X-ray Micro-tomography. The same samples have been re-utilised in several ways. The tissues described are hyaline articular cartilage (HAC; or substitutes), with its deep layer, articular calcified cartilage (ACC), whose deep surface is resorbed in cutting cone events to allow the deposition of subchondral bone (SCB). Multiple tidemarks are normal. Turnover at the osteochondral (ACC-HAC...
Wang SZ, Rushlow KE, Issel CJ, Cook RF, Cook SJ, Raabe ML, Chong YH, Costa L, Montelaro RC.The potential for antibody-dependent enhancement of replication of macrophage/monocyte tropic viruses has posed a significant problem in the development of vaccines for several animal and human viruses and has raised significant concern in the design of potential AIDS vaccines. Using the previously described equine infectious anemia virus/Shetland pony system as a model for HIV-1 vaccine development, we have evaluated the efficacy of a recombinant subunit vaccine containing a baculovirus-expressed envelope surface glycoprotein (gp90) of EIAV. The results of these trials demonstrate not only th...
Yin H, Lu W, Luo J.The importance of babesiosis in livestock in China is discussed and mainly focused on bovine and equine babesiosis. Babesiosis is still one of the most important diseases affecting livestock and has caused great economic loss. Nine species of Babesia have been recognized in livestock: B. bigemina, B. bovis, B. major, B. motasi, B. ovis, B. perroncitoi, B. trautmanni, B. equi (Theileria equi), B. caballi. The distribution of Babesia follows the distribution of the tick vectors. The main vectors of bovine babesiosis are the one-host tick Boophilus microplus and the three-host ticks Rhipicephalus...
Leroux C, Craigo JK, Issel CJ, Montelaro RC.A primary mechanism of lentivirus persistence is the ability of these viruses to evolve in response to biological and immunological selective pressures with a remarkable array of genetic and antigenic variations that constitute a perpetual natural experiment in genetic engineering. A widely accepted paradigm of lentivirus evolution is that the rate of genetic variation is correlated directly with the levels of virus replication: the greater the viral replication, the more opportunities that exist for genetic modifications and selection of viral variants. To test this hypothesis directly, we ex...
Lin M, Zhang C, Gibson K, Rikihisa Y.Neorickettsia risticii is an obligate intracellular bacterium of the trematodes and mammals. Horses develop Potomac horse fever (PHF) when they ingest aquatic insects containing encysted N. risticii-infected trematodes. The complete genome sequence of N. risticii Illinois consists of a single circular chromosome of 879 977 bp and encodes 38 RNA species and 898 proteins. Although N. risticii has limited ability to synthesize amino acids and lacks many metabolic pathways, it is capable of making major vitamins, cofactors and nucleotides. Comparison with its closely related human pathogen N. senn...
Cook RF, Leroux C, Cook SJ, Berger SL, Lichtenstein DL, Ghabrial NN, Montelaro RC, Issel CJ.An infectious nonpathogenic molecular clone (19-2-6A) of equine infectious anemia virus (EIAV) was modified by substitution of a 3.3-kbp fragment amplified by PCR techniques from a pathogenic variant (EIAV(PV)) of the cell culture-adapted strain of EIAV (EIAV(PR)). This substitution consisted of coding sequences for 77 amino acids at the carboxyl terminus of the integrase, the S1 (encoding the second exon of tat), S2, and S3 (encoding the second exon of rev) open reading frames, the complete env gene (including the first exon of rev), and the 3' long terminal repeat (LTR). Modified 19-2-6A mol...
Dahmani M, Davoust B, Sambou M, Bassene H, Scandola P, Ameur T, Raoult D, Fenollar F, Mediannikov O.Our study aimed to assess the diversity of the species of Anaplasmataceae in Senegal that infect animals and ticks in three areas: near Keur Momar Sarr (northern region), Dielmo and Diop (Sine Saloum, central region of Senegal), and in Casamance (southern region of Senegal). Methods: A total of 204 ticks and 433 blood samples were collected from ruminants, horses, donkeys and dogs. Ticks were identified morphologically and by molecular characterization targeting the 12S rRNA gene. Molecular characterization of species of Anaplasmataceae infecting Senegalese ticks and animals was conducted usin...
Billich C, Sauder C, Frank R, Herzog S, Bechter K, Takahashi K, Peters H, Staeheli P, Schwemmle M.The recent observation that Borna disease virus (BDV)-reactive antibodies from psychiatric patients exhibit only low avidity for BDV antigen called into question their diagnostic value and raised the possibility that antigenically related microorganisms or self antigens caused the production of these antibodies. We further characterized the specificity of these antibodies. Methods: We established a peptide array-based screening test that allows the identification of antibodies directed against linear epitopes of the two major BDV proteins, the nucleoprotein (N) and the phosphoprotein (P). Resu...
Matsumura T, Sugiura T, Imagawa H, Fukunaga Y, Kamada M.The dissemination of equine herpesvirus types 1 (EHV-1) and 4 (EHV-4) among various horse populations in Japan was investigated through the isolation and typing of virus strains from horses with respiratory diseases. Type specific monoclonal antibody pools were used for the typing of isolates. The 42 strains of EHV-1 and 64 strains of EHV-4 were isolated from 4593 nasal swabs and/or blood plasma samples collected from 3326 horses during a period from 1979 to 1990. All the strains of EHV-1 were isolated from racehorses only and during the winter season exclusively, when the epizootic of respira...
Coldman AJ, Elwood JM, Gallagher RP.The relationship of testicular seminoma with several factors was explored using a case-control study. Previously recognized associations with cryptorchidism and infantile inguinal hernia were confirmed and relationships were also found with cycling and horse-riding. These findings represent the first relationships of testicular cancer with well-defined postnatal risk factors.
Minke JM, Audonnet JC, Fischer L.The increasing international movement of horses combined with the relaxation of veterinary regulations has resulted in an increased incidence of equine infectious diseases. Vaccination, along with management measures, has become the primary method for the effective control of these diseases. Traditionally modified live and inactivated vaccines have been used and these vaccines have proven to be very successful in preventing disease. However, there are a number of equine infectious diseases for which conventional technology has shown its limitations. The advent of recombinant technology has sti...
Belshan M, Baccam P, Oaks JL, Sponseller BA, Murphy SC, Cornette J, Carpenter S.Genetic and biological variation in the regulatory protein Rev of equine infectious anemia virus (EIAV) were examined throughout a clinically dynamic disease course of an experimentally infected pony. Following infection with the virulent EIAV(Wyo), the pony underwent a variable disease course, including an acute fever episode at 12 days postinfection (DPI), multiple recurrent fever episodes until 135 DPI, a prolonged subclinical period, and two late fever episodes. Viral RNA was isolated from the inoculum and sequential sera samples, and the rev exon 2/gp45 overlapping ORFs were amplified, cl...
