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.
Brodesser DM, Schlangen K, Rodríguez-Rojas A, Kuropka B, Doulidis PG, Brandt S, Pratscher B.Malignant melanoma (MM) affects not only humans but also animals, with gray horses being particularly predisposed to acquiring the disease. Multiomics have greatly advanced the understanding of human MM. In contrasty little is known regarding the pathogenesis of gray-horse melanoma and the unique phenomenon of melanoma "dormancy" in some animals. To help close this gap in knowledge, melanoma tissue and intact skin collected from gray horses were subjected to transcriptome analysis using RNAseq. In the next step, cultured primary tumor cells and normal skin fibroblasts were established from gra...
Souto EPF, Dantas VW, Oliveira AM, Garcia DS, Vilela VLR, Neto EGM, Mota RA, Dantas AFM.Strongylus vulgaris remains a significant cause of disease in equids, especially in regions with insufficient deworming practices. Objective: To describe the epidemiological, clinical, pathological, and parasitological findings of vascular and extravascular lesions associated with S. vulgaris in equids. Methods: A retrospective analysis was conducted on necropsy reports from equids examined at the Animal Pathology Laboratory, Federal University of Campina Grande (2000-2024), targeting cases of vascular lesions associated with S. vulgaris. Epidemiological, clinical, and pathological findings we...
Tretow M, Hain AM, Bienert-Zeit A.The dental syndrome EOTRH is a painful, progressive dental disease with an unknown aetiology. The often painful nature of EOTRH emphasises the need for a better knowledge of the underlying pathogenic mechanism and risk factors. A comparative analysis of haematological, biochemical and endocrine values in EOTRH-affected and non-affected horses has not been described. Objective: To compare haematological, biochemical, and endocrine parameters in EOTRH-affected and non-affected horses to detect risk factors for horses developing EOTRH. Methods: Cross sectional. Methods: Blood samples of 154 Icela...
Thornton JJ, Roberts JF, AuCoin DP, Tuanyok A.We report a presumptive case of melioidosis caused by an atypical Burkholderia pseudomallei serotype in an American quarter horse in north-central Florida, USA, through archived formalin-fixed paraffin-embedded specimens dating back to 2006. This case underscores the potential pathologic impact of emergent B. pseudomallei in the Gulf region of the United States.
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...
Ablondi M, Eriksson S, Mikko S.Fragile foal syndrome (FFS) is a disease caused by a recessive lethal missense mutation in the PLOD1 gene located on ECA2. Despite its harmful effect, a relatively high frequency of FFS carriers was observed in Warmblood breeds spanning from 7.4% in a random sample of Swedish Warmblood breed to 17% in the Hanoverian and Danish Warmblood, indicating potential heterozygous advantage. Balancing selection can be further studied based on haplotype blocks and via detection of heterozygosity-rich region (ROHet) around the target of selection. In this study we evaluated the presence of haplotype block...
Hisaeda K, LE NAT, Kadekaru S, Ono T, Hiasa Y, Ohzawa E, Hata A, Kutara K, Sugimoto K, Une Y, Iwata E, Kunieda T, Zhang C, Kitagawa H.We evaluated metabolic abnormalities in six neonatal Noma foals (Nos. 54-57, 62, and 66) that died shortly after birth, using laboratory tests, pathological examinations, serum amino acid (AA) analyses, gas chromatography/mass spectrometry (GC/MS), and genetic analyses. Nonspecific clinical symptoms, such as poor suckling and weakness, were commonly observed at birth. Sepsis caused by various bacterial infections was detected in foal Nos. 54, 62, and 66, while a heart malformation was identified in foal No. 57. Laboratory tests showed high aspartate transaminase, lactate dehydrogenase, and cre...
Harte T, Smith D, Moore J, Wells B.An article published in 1992 by Marion M. Pollin and I.R. Griffiths reviewed the topic of primary dysautonomias of the autonomic nervous system of unidentified origin in multiple domestic species, specifically cats, dogs and horses. Thirty-one years later, we appear no closer to identifying the causal agents of these strikingly similar diseases. This article reviews the similarities and differences in clinical presentation and pathology of dysautonomia in canids, felids, equids, leporids and other less frequently reported species.
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...
Donovan K, Torres J, Zhu D, Herrington WG, Staplin N.Genome-wide association studies (GWAS) of disease progression are vulnerable to collider bias caused by selection of participants with disease at study entry. This bias introduces spurious associations between disease progression and genetic variants that are truly only associated with disease incidence. Methods of statistical adjustment to reduce this bias have been published, but rely on assumptions regarding the genetic correlation of disease incidence and disease progression which are likely to be violated in many human diseases. MR-Horse is a recently published Bayesian method to estimate...
MacNeill AL, Micheloud JF, Parvin R, Gjessing M, Airas NA, Sant'Ana FJF, Adamek M.Zoonotic poxviruses, including monkeypox virus (MPV), the causative agent for Mpox disease, have gained significant media and scientific attention due to recent outbreaks in human populations across the globe. The increase in human cases of poxvirus infection is not unexpected, as routine vaccination against smallpox (a disease caused by the poxvirus variola virus, which cross protects against other orthopoxviruses) was discontinued in the 1980s after its eradication. Large numbers of vertebrate and invertebrate species are susceptible to infection by . Clinical signs and histologic lesions ca...
Connolly KM, Estell K.Dysphagia describes a clinical sign of pathologies of the oral cavity, pharynx, and oesophagus that carries potentially serious consequences for horses. Given the diversity of differential diagnoses that may cause dysphagia, an understanding of the prevalence of dysphagia in hospitalised patients, the distribution of aetiologies and clinical outcomes could inform diagnosis, treatment, and prognosis. Objective: This study aims to describe the incidence, signalment, history, aetiology, treatment, and outcome of horses presenting to a referral hospital for dysphagia. Methods: Retrospective case s...
de Sousa ALV, de Sousa DER, de Macêdo IL, de Albuquerque Cerqueira L, da Fonseca YNG, Oliveira AB, das Chagas LVS, Gonçalves GB, Veado HC....This report describes the first documented case of intracerebral hemorrhage (ICH) in a horse following Bothrops snakebite envenomation. A 3-year-old mare developed acute kidney injury, systemic hemorrhage, and neurological signs before euthanasia. Postmortem findings confirmed massive ICH with intralesional venom identified by immunohistochemistry. Delayed treatment and insufficient antivenom likely contributed to the outcome. This case highlights the potential for cerebrovascular complications following Bothrops snakebite envenomation in horses, which may present as subtle neurological signs....
Cito F, Di Francesco CE, Averaimo D, Chiaverini A, Alessiani A, Di Domenico M, Cresci M, Rulli M, Cantelmi MC, Di Bernardo MD, Giammarino A.... subsp. (SEZ) is a major problem in equine veterinary medicine. Typically, a commensal in horses, SEZ can cause severe disease including respiratory infections, septicaemia and reproductive tract infections under certain conditions. Recent evidence suggests that humans can also develop severe disease infection through direct contact with infected animals or the consumption of contaminated unpasteurised milk and milk products. This study investigates SEZ strains isolated from nasal swabs of equidae in central Italy in 2023 to describe the epidemiology and genomic characteristics of circulating...
Dahlgren AR, Careddu F, Norris JW, Adili R, Kropp EM, Li Q, Holinstat M, Biunno I, Balduini A, Tablin F, Shavit JA, Finno CJ.SEL1L is a well-known protein in the endoplasmic reticulum associated degradation (ERAD) pathway. While it is known to be expressed in platelets, SEL1L has never been shown to play an active role. Here we find evidence that SEL1L regulates platelet function. We first identified SEL1L through the study of Atypical Equine Thrombasthenia (AET), an autosomal recessive platelet disorder found in Thoroughbred horses. A missense variant in (c.1810A>G p.Ile604Val) was found in AET-affected horses, which we show is associated with decreased protein expression. SEL1L is intracellular in equine platelet...
Dash RF, Perkins JD, Chang YM, Morgan RE.Temporohyoid osteoarthropathy (THO) is characterised by bone proliferation and cartilage ossification caused by infectious and degenerative conditions, amongst others. Objective: To describe the variable appearance of the temporohyoid joint (THJ) on computed tomography (CT) and investigate associations between CT changes and potential risk factors. Methods: Cross-sectional study. Methods: Head CT examinations were assessed. A grading system was developed for osseous proliferation (grade 0 [normal] to 3 [severe]) and tympanohyoid cartilage change (grade 0 [normal] to 3 [complete ossification])....
Vychodilova L, Plasil M, Futas J, Kopecka A, Molinkova D, Wijacki T, Jahn P, Knoll A, Horin P.Although the Major Histocompatibility Complex (MHC) has been repeatedly associated with susceptibility to equine sarcoid, a disease associated with bovine papillomavirus infection, the role of the MHC in the mechanisms of the disease is not fully understood. The objectives of our work were to analyze associations between polymorphic markers of the MHC genomic subregions and of the Natural Killer Complex (NKC) genomic region and the presence of sarcoid in Arabian horses. Microsatellite loci located in the MHC class I, II and III subregions and two MHC class II genes (DRA, DQA1), along with a se...
Aleman M, McCue M, Bellone RR.Fatal anesthesia-induced malignant hyperthermia (MH) and rhabdomyolysis with hyperthermia documented in Quarter Horses (QH) breeds are caused by a missense variant in the ryanodine receptor 1 gene (RYR1: XP_023505430.1.:p.(R2454G), designated as MH). The reported cases to date have all been heterozygous, and the allele frequency is suspected to be low. Objective: To determine an accurate estimate of MH allele frequency in multiple horse breeds and investigate whether homozygous animals exist in the population. Methods: In total, 159 227 horses from 16 breeds who were either submitted for cli...
Martinez-Saez L, Marín-García PJ, Llobat ML.Osteochondrosis (OC) is a frequent manifestation of developmental orthopaedic disease, and its severe clinical presentation is known as OC dissecans (OCD). OC is defined as a disruption of the endochondral ossification process in the epiphyseal cartilage, and this disease has been reported in different mammalian species, including humans, dogs, pigs, and horses. OCD is an important cause of lameness in sport horses and is a common cause of impaired orthopaedic potential, whose clinical signs may be of minimal magnitude or manifest as severe joint effusion or clinically noticeable lameness. The...
Vasconcelos de Sousa AL, Riet-Correa F, Botelho de Castro M, Machado M.We reviewed the history, epidemiology, clinical signs, pathology, pathogenesis, treatment, control, and prophylaxis of Sorghum poisoning in livestock. Economic losses in the livestock industry associated with sorghum have been reported since the 19th century. Hyperacute/acute poisoning associated with cyanide (HCN) or nitrate/nitrite frequently occurs in ruminants that consume high quantities of growth and regrowth sorghum after drought, followed by rainfall, respectively. Chronic cystitis-ataxia syndrome primarily affects horses after weeks of grazing on sorghum pastures, while congenital art...
Furmanski M, Murcia PR.The ecological factors that led to the 1918 influenza pandemic remain unknown. We hypothesize that horses acted as intermediate hosts spreading a prepandemic avian-origin virus before 1918. This is supported by reports describing a large epizootic of unusually severe equine influenza beginning in 1915. Furthermore, the high horse demand during World War I resulted in one of the biggest equine mobilizations in North America between 1914 and 1918. This extensive movement of horses provided abundant opportunities for virus reassortment between prepandemic avian and human influenza viruses. Archiv...
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...
Simms N, Bertone JJ, Melgarejo T, O'Shea C, Linde A.Emerging research suggests the presence of a blood microbiome in clinically healthy individuals. Characterizing bacterial composition and abundance in blood from a group of healthy horses is of clinical interest. Objective: Horses in a closed herd environment will have blood microbiomes with similarities among individuals. Methods: Twenty trail-riding horses of different breeds and ages living in relative isolation on a dry lot pasture in Colorado at 7680 ft elevation. Methods: Cross-sectional study. Blood was collected from the jugular vein into serum, blood collection, and EDTA tubes. Samp...
Uprety T, Swan M, Kennedy L, Bryant U, Cassone L, Loynachan A, Janes J, Evely MM, Calvaruso FC, Quick M, Morgan J, Abdelrazek S, Lahmers K, Carter C....Clostridium piliforme is an obligate intracellular filamentous bacterium that causes Tyzzer disease (TD) in many animals. The disease manifests as severe, multifocal necrotizing hepatitis, with a high fatality rate in foals. Through retrospective investigation, we detected C. piliforme in 43 equine necropsy cases from 2012 to 2024. Positive cases were diagnosed from February to July, peaking in May. The age of affected foals ranged from 4 days to 2 months. Histologically, all cases had necrotizing hepatitis with multifocal, coalescing pinpoint, tan or reddish foci. Since only a partial 16S rRN...
Quatember H, Nell B, Richter B, Rigler D, Dolezal M, Sykora S, Wallner B.A missense mutation in damage-specific DNA binding protein 2 (DDB2 c.1013 C>T; p.Thr338Met) has been described as a risk factor for ocular squamous cell carcinoma (OSCC) in the Haflinger breed. Here, we examined the impact of DDB2 C>T allele status on the development of OSCC, squamous cell carcinoma (SCC) at other localisations, or equine sarcoid (ES) in Haflingers and other breeds with a high incidence of these tumour types. We genotyped affected Haflinger, Noriker, Warmblood, and Icelandic horses. Results based on 56 Haflingers confirmed the significantly higher risk for OSCC in DDB2-TT Hafl...
Contino EK.Long before the concept of social license to operate came to the forefront of equestrian sports, veterinarians have always had a responsibility to advocate for the welfare of the horse. For performance horses this often means helping to ensure that the horse is performing positively and comfortably for its intended use. A horse that is struggling to perform at an optimal level may be doing so for a multitude of reasons, but regardless of the underlying cause, it often presents as any number of behavioral issues. This review explores various underlying physical causes of behavioral issues in pe...
is the leading cause of acute gastroenteritis worldwide in young humans and animals. In 2023-2024, a relatively high rotavirus detection rate (34.5%) was detected in children with diarrhea in Caracas. All rotavirus strains were typed as P[8], using a multiplex RT-PCR assay, while the G-type was not identified. This unusual pattern, not previously observed in Venezuela, prompted the VP7 gene sequencing of nineteen strains, which displayed a high sequence identity (99.3-100%) compatible with the G3 genotype. These strains clustered into a well-supported lineage IX encompassing human reassortant...
Brys M, Claerebout E, Saey V, Chiers K.A cross-sectional study was conducted to estimate the prevalence of chorioptic mange affecting the distal legs of horses in Belgium, focusing on the association between mange and chronic progressive lymphedema (CPL) in Belgian draft horses. Clinical examinations and skin scrapings were performed on the distal legs of 156 Belgian draft horses and 142 Belgian warmblood horses. In the Belgian draft horse breed, 144 (92.31%) horses were infested with Chorioptes bovis mites, and 126 (80.77%) displayed clinical signs of CPL. CPL prevalence in draft horses aged < 1 year was 17.86%, while mites we...
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...
Hauck SM, Dietter J, Kramer RL, Hofmaier F, Zipplies JK, Amann B, Feuchtinger A, Deeg CA, Ueffing M.Autoimmune uveitis is a blinding disease presenting with autoantibodies against eye-specific proteins as well as autoagressive T cells invading and attacking the immune-privileged target tissue retina. The molecular events enabling T cells to invade and attack the tissue have remained elusive. Changes in membrane protein expression patterns between diseased and healthy stages are especially interesting because initiating events of disease will most likely occur at membranes. Since disease progression is accompanied with a break-down of the blood-retinal barrier, serum-derived proteins mask the...
Murray KO, Mertens E, Despres P.Zoonotic West Nile virus (WNV) circulates in natural transmission cycles involving certain mosquitoes and birds, horses, humans, and a range of other vertebrates are incidental hosts. Clinical infections in humans can range in severity from uncomplicated WNV fever to fatal meningoencephalitis. Since its introduction to the Western Hemisphere in 1999, WNV had spread across North America, Central and South America and the Caribbean, although the vast majority of severe human cases have occurred in the United States of America (USA) and Canada. By 2002-2003, the WNV outbreaks have involved thousa...
Steelman SM, Chowdhary BP, Dowd S, Suchodolski J, Janečka JE.The nutrition and health of horses is closely tied to their gastrointestinal microflora. Gut bacteria break down plant structural carbohydrates and produce volatile fatty acids, which are a major source of energy for horses. Bacterial communities are also essential for maintaining gut homeostasis and have been hypothesized to contribute to various diseases including laminitis. We performed pyrosequencing of 16S rRNA bacterial genes isolated from fecal material to characterize hindgut bacterial communities in healthy horses and those with chronic laminitis. Results: Fecal samples were collected...
Dougal K, de la Fuente G, Harris PA, Girdwood SE, Pinloche E, Newbold CJ.The horse has a rich and complex microbial community within its gastrointestinal tract that plays a central role in both health and disease. The horse receives much of its dietary energy through microbial hydrolysis and fermentation of fiber predominantly in the large intestine/hindgut. The presence of a possible core bacterial community in the equine large intestine was investigated in this study. Samples were taken from the terminal ileum and 7 regions of the large intestine from ten animals, DNA extracted and the V1-V2 regions of 16SrDNA 454-pyrosequenced. A specific group of OTUs clustered...
Savini G, Afonso A, Mellor P, Aradaib I, Yadin H, Sanaa M, Wilson W, Monaco F, Domingo M.Epizootic haemorrhagic disease (EHD) is an infectious non-contagious viral disease transmitted by insects of the genus Culicoides which affects wild and domestic ruminants. The causative agent, the epizootic haemorrhagic disease virus (EHDV), belongs to the family Reoviridae, genus Orbivirus and shares many morphological and structural characteristics with the other members of the genus such as bluetongue, African horse sickness and equine encephalosis viruses. In recent years EHD outbreaks have been reported in countries bordering the European Union. They caused disease in cattle and severe r...
Singh S, Jindal AK, Pilania RK.Kawasaki disease (KD) is a medium vessel vasculitis with predilection for coronary arteries. Due to lack of a reliable confirmatory laboratory test, the diagnosis of KD is based on a constellation of clinical findings that appear in a typical temporal sequence. These diagnostic criteria have been modified from time to time and the most recent guidelines have been proposed by the American Heart Association (AHA) in 2017. However, several children may have incomplete or atypical forms of KD and the diagnosis can often be difficult, especially in infants and young children. In this review, we hav...
Kellerman TS, Marasas WF, Thiel PG, Gelderblom WC, Cawood M, Coetzer JA.Leukoencephalomalacia (LEM) was induced by the oral administration of fumonisin B1 (FB1) to 2 horses: a filly received 59.5 mg/kg of a 50% preparation of FB1, administered in 21 doses of 1.25-4 mg/kg over 33 days; a colt, 44.3 mg/kg of 95% pure FB1 in 20 doses of 1-4 mg/kg in 29 days. Both animals developed nervous signs such as apathy, changes in temperament, inco-ordination, walking into objects, and one showed paralysis of the lips and tongue. Characteristic lesions of LEM were present in the brains. These trials proved conclusively that FB1 can induce LEM in horses.
Johnston GM, Eastment JK, Wood J, Taylor PM.To document the equine perioperative mortality rate and to highlight any factor associated with an increased risk of death up to 7 days after anaesthesia. Methods: A prospective observational epidemiological multicentre study. Methods: Data were recorded from all equidae undergoing general anaesthesia in 62 clinics. Power calculations indicated that 45 000 cases were required to detect the significance of important variables. Details of each horse, operation, anaesthetic agents and clinic personnel were recorded. Outcome at 7 days was recorded as: alive, put to sleep (PTS) or dead. Data were a...
Criado-Fornelio A, Martinez-Marcos A, Buling-Saraña A, Barba-Carretero JC.Molecular epizootiology of piroplasmids (Babesia spp., Theileria spp.) and Hepatozoon canis was studied in mammals from southern Europe (mainly from Spain, but also from Portugal and France). Partial amplification and sequencing of the 18s rRNA gene was used for molecular diagnosis. In some particular cases (B. ovis and B. bovis) the complete 18s rRNA gene was sequenced. Blood samples were taken from domestic animals showing clinical symptoms: 10 dogs, 10 horses, 10 cows, 9 sheep and 1 goat. In addition, DNA samples were isolated from blood of 12 healthy dogs and from spleen of 10 wild red fox...
Weese JS, Holcombe SJ, Embertson RM, Kurtz KA, Roessner HA, Jalali M, Wismer SE.Disruptions in the gastrointestinal microbiota may trigger development of post partum colic. Objective: To determine the effects of the periparturient period on the faecal microbiome and identify associations between the faecal microbiota and post partum colic. Methods: Longitudinal case-control study. Methods: Pre- and post partum faecal samples were collected from mares on 3 farms in central Kentucky. Next generation sequencing of the V4 region of the 16S rRNA gene was performed on samples from 13 mares that developed colic, 13 mares that did not display colic and 5 nonpregnant controls. Res...
Chandriani S, Skewes-Cox P, Zhong W, Ganem DE, Divers TJ, Van Blaricum AJ, Tennant BC, Kistler AL.Theiler's disease is an acute hepatitis in horses that is associated with the administration of equine blood products; its etiologic agent has remained unknown for nearly a century. Here, we used massively parallel sequencing to explore samples from a recent Theiler's disease outbreak. Metatranscriptomic analysis of the short sequence reads identified a 10.5-kb sequence from a previously undescribed virus of the Flaviviridae family, which we designate "Theiler's disease-associated virus" (TDAV). Phylogenetic analysis clusters TDAV with GB viruses of the recently proposed Pegivirus genus, altho...
Bellone RR, Brooks SA, Sandmeyer L, Murphy BA, Forsyth G, Archer S, Bailey E, Grahn B.The appaloosa coat spotting pattern in horses is caused by a single incomplete dominant gene (LP). Homozygosity for LP (LP/LP) is directly associated with congenital stationary night blindness (CSNB) in Appaloosa horses. LP maps to a 6-cM region on ECA1. We investigated the relative expression of two functional candidate genes located in this LP candidate region (TRPM1 and OCA2), as well as three other linked loci (TJP1, MTMR10, and OTUD7A) by quantitative real-time RT-PCR. No large differences were found for expression levels of TJP1, MTMR10, OTUD7A, and OCA2. However, TRPM1 (Transient Recept...
Schnabel LV, Pezzanite LM, Antczak DF, Felippe MJ, Fortier LA.The horse is a valuable species to assess the effect of allogeneic mesenchymal stromal cells (MSCs) in regenerative treatments. No studies to date have examined recipient response to major histocompatibility complex (MHC)-mismatched equine MSCs. The purposes of this study were to immunophenotype MSCs from horses of known MHC haplotype and to compare the immunogenicity of MSCs with differing MHC class II expression. Methods: MSCs and peripheral blood leukocytes (PBLs) were obtained from Thoroughbred horses (n=10) of known MHC haplotype (ELA-A2, -A3, and -A9 homozygotes). MSCs were cultured thro...
Catlin BW.The clinical significance, Gram stain reaction, and genus affiliation of Gardnerella vaginalis have been controversial since Gardner and Dukes described the organism as the cause of "nonspecific vaginitis," a common disease of women which is now called bacterial vaginosis. The organism was named G. vaginalis when taxonomic studies showed that it was unrelated to bacteria in various genera including Haemophilus and Corynebacterium. Electron microscopy and chemical analyses have elucidated the organism's gram-variable reaction. Controversy over the etiology of bacterial vaginosis was largely res...
Montelaro RC, Parekh B, Orrego A, Issel CJ.The recurrent nature of equine infectious anemia has been attributed to relatively rapid antigenic variations in equine infectious anemia virus (EIAV) during persistent infection under selective immune pressures. This model was tested by serological and biochemical analysis of virus isolates recovered from separate febrile episodes in two experimentally infected ponies. Neutralization assays employing immune sera from the experimentally infected ponies demonstrated that distinct antigenic strains of virus predominate during sequential febrile episodes in a single pony. Analysis of the test str...
Azlaf R, Dakkak A.The objectives of this epidemiological study on cystic echinococcosis (CE) in Morocco (2001-2004) were to update the prevalence of CE in different animal species living in the most important areas of the country and to collect protoscoleces and germinal layers for genetic research purposes. The post mortem inspection concerned 2948 sheep, 2337 goats, 618 cattle, 482 camels and 455 equines (325 horses, 60 mules and 70 donkeys) in five different regions: the Rif (Mediterranean coast and high mountains of the Rif), the Loukkos (Atlantic northwest plain), the center (Rabat and Casablanca regions),...
Hauswirth R, Haase B, Blatter M, Brooks SA, Burger D, Drögemüller C, Gerber V, Henke D, Janda J, Jude R, Magdesian KG, Matthews JM, Poncet PA....During fetal development neural-crest-derived melanoblasts migrate across the entire body surface and differentiate into melanocytes, the pigment-producing cells. Alterations in this precisely regulated process can lead to white spotting patterns. White spotting patterns in horses are a complex trait with a large phenotypic variance ranging from minimal white markings up to completely white horses. The "splashed white" pattern is primarily characterized by an extremely large blaze, often accompanied by extended white markings at the distal limbs and blue eyes. Some, but not all, splashed white...
Schneider J, Kaaden O, Copeland TD, Oroszlan S, Hunsmann G.Two glycopolypeptides with molecular weights 160,000 and 120,000 (gp120) are regularly recognized by human immunodeficiency virus (HIV)-specific antisera in lysates of cells persistently infected with HIV. In the present study, gp120 was characterized as the major envelope glycopolypeptide of HIV. Gp120 was identified as the external viral glycoprotein by radiosequencing and by its presence in purified virus. However gp120 was predominantly shed as a soluble protein into the culture fluid. Furthermore gp120 was precipitated by sera from horses infected with equine infectious anaemia virus (EIA...
Field H, de Jong C, Melville D, Smith C, Smith I, Broos A, Kung YH, McLaughlin A, Zeddeman A.Hendra virus is a recently emerged zoonotic agent in Australia. Since first described in 1994, the virus has spilled from its wildlife reservoir (pteropid fruit bats, or 'flying foxes') on multiple occasions causing equine and human fatalities. We undertook a three-year longitudinal study to detect virus in the urine of free-living flying foxes (a putative route of excretion) to investigate Hendra virus infection dynamics. Pooled urine samples collected off plastic sheets placed beneath roosting flying foxes were screened for Hendra virus genome by quantitative RT-PCR, using a set of primers a...
Castillo-Olivares J, Wood J.West Nile virus (WNV) is a flavivirus closely related to Japanese encephalitis and St. Louis encephalitis viruses that is primarily maintained in nature by transmission cycles between mosquitoes and birds. Occasionally, WNV infects and causes disease in other vertebrates, including humans and horses. West Nile virus has re-emerged as an important pathogen as several recent outbreaks of encephalomyelitis have been reported from different parts of Europe in addition to the large epidemic that has swept across North America. This review summarises the main features of WNV infection in the horse, ...
van Dinten LC, van Tol H, Gorbalenya AE, Snijder EJ.Equine arteritis virus (EAV), the prototype Arterivirus, is a positive-stranded RNA virus that expresses its replicase in the form of two large polyproteins of 1,727 and 3,175 amino acids. The functional replicase subunits (nonstructural proteins), which drive EAV genome replication and subgenomic mRNA transcription, are generated by extensive proteolytic processing. Subgenomic mRNA transcription involves an unusual discontinuous step and generates the mRNAs for structural protein expression. Previously, the phenotype of mutant EAV030F, which carries a single replicase point mutation (Ser-2429...
Nasir L, Campo MS.Bovine papillomavirus (BPV) is perhaps the most extensively studied animal papillomavirus. In cattle BPVs induce benign tumours of cutaneous or mucosal epithelia, called papillomas or warts. Cattle papillomas are benign tumours and generally regress without eliciting any serious clinical problems in the host, but occasionally persist and provide the focus for malignant transformation to squamous cell carcinoma, as in the case of cancer of the urinary bladder and cancer of the upper alimentary canal. BPV is the only papillomavirus that jumps species: the virus also infects equids, and gives ris...
Boyle AG, Timoney JF, Newton JR, Hines MT, Waller AS, Buchanan BR.This consensus statement update reflects our current published knowledge and opinion about clinical signs, pathogenesis, epidemiology, treatment, complications, and control of strangles. This updated statement emphasizes varying presentations in the context of existing underlying immunity and carrier states of strangles in the transmission of disease. The statement redefines the "gold standard" for detection of possible infection and reviews the new technologies available in polymerase chain reaction diagnosis and serology and their use in outbreak control and prevention. We reiterate the impo...
Thorpe CT, Clegg PD, Birch HL.Tendon injury is one of the most common causes of wastage in the performance horse; the majority of tendon injuries occur to the superficial digital flexor tendon (SDFT) whereas few occur to the common digital extensor tendon. This review outlines the epidemiology and aetiology of equine tendon injury, reviews the different functions of the tendons in the equine forelimb and suggests possible reasons for the high rate of failure of the SDFT. An understanding of the mechanisms leading to matrix degeneration and subsequent tendon gross failure is the key to developing appropriate treatment and p...
Asplin KE, Sillence MN, Pollitt CC, McGowan CM.The purpose of this study was to determine the effects of prolonged administration of insulin, whilst maintaining normal glucose concentrations, on hoof lamellar integrity in vivo on healthy ponies with no known history of laminitis or insulin resistance. Nine clinically healthy, unrelated ponies were randomly allocated to either a treatment group (n =5; 5.9+/-1.7 years) or control group (n =4; 7.0+/-2.8 years). The treatment group received insulin via a euglycaemic hyperinsulinaemic clamp technique modified and prolonged for up to 72 h. Control ponies were infused with an equivalent volume of...
Pelkonen S, Lindahl SB, Suomala P, Karhukorpi J, Vuorinen S, Koivula I, Väisänen T, Pentikäinen J, Autio T, Tuuminen T.Streptococcus equi subspecies zooepidemicus (S. zooepidemicus) is a zoonotic pathogen for persons in contact with horses. In horses, S. zooepidemicus is an opportunistic pathogen, but human infections associated with S. zooepidemicus are often severe. Within 6 months in 2011, 3 unrelated cases of severe, disseminated S. zooepidemicus infection occurred in men working with horses in eastern Finland. To clarify the pathogen's epidemiology, we describe the clinical features of the infection in 3 patients and compare the S. zooepidemicus isolates from the human cases with S. zooepidemicus isolates...
Arrigo NC, Adams AP, Weaver SC.The eastern equine encephalitis (EEE) complex consists of four distinct genetic lineages: one that circulates in North America (NA EEEV) and the Caribbean and three that circulate in Central and South America (SA EEEV). Differences in their geographic, pathogenic, and epidemiologic profiles prompted evaluation of their genetic diversity and evolutionary histories. The structural polyprotein open reading frames of all available SA EEEV and recent NA EEEV isolates were sequenced and used in evolutionary and phylogenetic analyses. The nucleotide substitution rate per year for SA EEEV (1.2 x 10(-4...
