The study of diseases in horses encompasses a wide range of conditions affecting equine health, including infectious diseases, metabolic disorders, and genetic abnormalities. These diseases can impact various systems within the horse, such as respiratory, gastrointestinal, and musculoskeletal systems, and can lead to significant health challenges. Research in this area focuses on understanding the pathophysiology, diagnosis, prevention, and treatment of equine diseases. Common diseases studied include equine influenza, equine herpesvirus, and laminitis. This page provides access to peer-reviewed research studies and scholarly articles that explore the etiology, clinical presentation, and management strategies of diseases in horses, contributing to the advancement of equine veterinary medicine.
Whitton RC, Jackson MA, Campbell AJ, Anderson GA, Parkin TD, Morton JM, Boden LA.A retrospective cohort study was performed to compare the rates of musculoskeletal injury (MSI) in horses receiving local corticosteroid injection (LCI) with those that were untreated and those prior to treatment. Of the 1911 study horses, 392 had been treated. A LCI was defined as any injection of corticosteroid into or adjacent to a synovial structure, muscle, or tendon/ligament. A MSI was defined as any limb injury identified by a veterinarian, following which the horse did not race for at least 6 months, or was retired. Hazard ratios (HR) comparing hazard of injury following injection to t...
Theelen MJ, Wilson WD, Edman JM, Magdesian KG, Kass PH.Sepsis is an important cause of death in foals. Knowledge of which pathogens are likely to be involved is important for selection of antimicrobial drugs for initial treatment. Objective: To identify temporal trends in prevalence of bacteria isolated from foals with sepsis between 1979 and 2010. Methods: Retrospective review of medical records. Methods: All foals ≤30 days of age presented to the Veterinary Medical Teaching Hospital (VMTH) at the University of California, Davis between 1979 and 2010, with a diagnosis of sepsis confirmed by culture of bacteria from blood or internal organs (ant...
Theelen MJ, Wilson WD, Edman JM, Magdesian KG, Kass PH.Monitoring the development of antimicrobial resistance is important for the rational selection of appropriate antimicrobial drugs to initiate treatment of foals with sepsis. Objective: To identify temporal trends in antimicrobial susceptibility patterns of bacteria isolated from foals with sepsis. Methods: Retrospective review of medical records. Methods: Foals aged <30 days with a diagnosis of sepsis, confirmed by culture of bacteria, were included. Susceptibility data, expressed as minimum inhibitory concentrations (MICs) (MIC50 , MIC90 , MIC range) and percent of isolates that were suscepti...
Findley JA, Pinchbeck GL, Milner PI, Bladon BM, Boswell J, Mair TS, Suthers JM, Singer ER.The factors associated with outcome following solar foot penetration involving synovial structures treated using endoscopic lavage have not been described in the UK population. Objective: To provide descriptive data on horses with synovial contamination or sepsis following solar penetration in 4 UK equine referral hospitals and to identify specific factors associated with the outcome. Methods: Retrospective case series. Methods: Data were collected from 4 veterinary hospitals. Follow-up data were obtained via a telephone questionnaire. Two multivariable logistic regression models were generate...
Calzolari M, Monaco F, Montarsi F, Bonilauri P, Ravagnan S, Bellini R, Cattoli G, Cordioli P, Cazzin S, Pinoni C, Marini V, Natalini S, Goffredo M....West Nile virus (WNV) is one of the most serious public health threats that Europe and the Mediterranean countries are currently facing. In Italy, WNV emerged in 1998 and has been circulating since 2008. To tackle its continuous incursions, Italian national and regional institutions set up a surveillance program, which includes the serological screening of sentinel horses, sentinel-chickens and backyard poultry flocks and the surveillance on all equine neurological cases, resident captured and wild dead birds, and vectors. This communication aims to assess the importance of the entomological s...
da Piedade I, Skive B, Christensen H, Bojesen AM.We present the draft genome sequence of Streptococcus equi subsp. zooepidemicus S31A1, a strain isolated from equine infectious endometritis in Denmark. Comparative analyses of this genome were done with four published reference genomes: S. zooepidemicus strains MGCS10565, ATCC 35246, and H70 and S. equi subsp. equi strain 4047.
Canisso IF, Pinn TL, Gerdin JA, Ollivett TL, Buckles EL, Schweizer CM, Ainsworth DM.A 5-year-old Quarter horse broodmare was evaluated for inappetence, depression, and diarrhea 13 days after aborting a 9-month gestation fetus. Clinical and laboratory examination ruled out uterine rupture and peritonitis. Ultrasonography of the uterus combined with cytological analysis of peritoneal fluid suggested the existence of diffuse lymphoma. A multicentric B-cell lymphoma involving the uterus and ovary was confirmed at necropsy and histopathological examination. Lymhome multicentrique à cellules B comme cause possible d’avortement chez une jument poulinière Quarter Horse. Une jumen...
Slater J.Josh Slater looks back at the past 125 years of developments in equine infectious disease, including landmark discoveries in microbiology and genomics, and considers what the future may hold.
Kailaanmäki A, Kinnunen T, Kwok WW, Rytkönen-Nissinen M, Randell J, Virtanen T.The responses of allergen-specific CD4(+) T cells of allergic and healthy individuals are still incompletely understood. Our objective was to investigate the functional and phenotypic properties of CD4(+) T cells of horse-allergic and healthy subjects specific to the immunodominant epitope region of the major horse allergen Equ c 1. Specific T-cell lines (TCLs) and clones were generated from peripheral blood mononuclear cells with Equ c 1(143-160), the peptide containing the immunodominant epitope region of Equ c 1. The frequency, proliferative response, cytokine production and HLA restriction...
Akridge HD, Rankin SC, Griffeth GC, Boston RC, Callori NE, Morris DO.Meticillin-resistant Staphylococcus aureus (MRSA) strain USA 500 predominately colonizes horses and people working with them. Previous studies demonstrate that some Staphylococcus species exhibit higher affinity for corneocytes of specific mammalian species. Objective: The objective was to determine the relative affinities of various MRSA strains, meticillin-susceptible S. aureus (MSSA) strains and a meticillin-susceptible Staphylococcus pseudintermedius (MSSP) for equine corneocytes. We hypothesized that MRSA strain USA 500 would exhibit greater adhesion than other staphylococcal strains te...
Hamond C, Pinna A, Martins G, Lilenbaum W.Leptospirosis is a zoonotic disease of global importance and has a worldwide distribution. This infection displays clear seasonal nature in some regions of the tropics, where the rainy season is marked by high temperatures. Household and wild animals carry leptospires and contribute to their dissemination in nature. Transmission mainly occurs by contact with water contaminated with the urine of infected animals, and consequently, it is quite widespread especially in times of rain, since many areas are subject to flooding and have poor sanitation. Serological tests demonstrate that Leptospira s...
Angenvoort J, Brault AC, Bowen RA, Groschup MH.West Nile virus (WNV) is a flavivirus transmitted between certain species of birds and mosquito vectors. Tangential infections of equids and subsequent equine epizootics have occurred historically. Although the attack rate has been estimated to be below 10%, mortality rates can approach 50% in horses that present clinical disease. Symptoms are most commonly presenting in the form of encephalitis with ataxia as well as limb weakness, recumbency and muscle fasciculation. The most effective strategy for prevention of equine disease is proper vaccination with one of the numerous commercially avail...
Carrera JP, Forrester N, Wang E, Vittor AY, Haddow AD, López-Vergès S, Abadía I, Castaño E, Sosa N, Báez C, Estripeaut D, Díaz Y, Beltrán D....The eastern equine encephalitis (EEE) and Venezuelan equine encephalitis (VEE) viruses are pathogens that infect humans and horses in the Americas. Outbreaks of neurologic disease in humans and horses were reported in Panama from May through early August 2010. Methods: We performed antibody assays and tests to detect viral RNA and isolate the viruses in serum samples from hospitalized patients. Additional cases were identified with enhanced surveillance. Results: A total of 19 patients were hospitalized for encephalitis. Among them, 7 had confirmed EEE, 3 had VEE, and 1 was infected with both ...
Zhu C, Li Q, Guo W, Lu G, Yin X, Qi T, Xiang W, Ran D, Qu J.We report the complete genomic sequence of A/equine/Heilongjiang/1/2010, a strain of Florida sublineage clade 2 of H3N8 subtype equine influenza virus (EIV) isolated in northern China. This is the first announcement of a complete genomic sequence of EIV of such a clade in China.
Emmerich IU.In 2012, two newly developed active pharmaceutical ingredients for horses and food producing animals were released on the German market for veterinary drug products. Those are the parenterally applicable first generation cephalosporin Cefalonium (Cepravin®) and the nonsteroidal anti-inflammatory drug Suxibuzone (Danilon®). Furthermore, one established veterinary active pharmaceutical ingredient is applicable to additional species: The anticoccidial Amprolium (Eimeryl®) has again been authorized for chicken and turkeys. Additionally, two veterinary drugs with a new formulation as well as thr...
Nasir L, Brandt S.The Papillomaviridae family comprises a large number of viruses that can infect a broad range of hosts including mammals, birds and reptiles giving rise to benign lesions of the skin or mucosal membranes. They are characterized by great genetic diversity yet adhere to common biological principles. In this review, we first describe the structure and function of the viral proteins encoded by papillomaviruses (PVs), with a particular emphasis on bovine papillomaviruses (BPV). We then discuss the role of BPV types 1 and 2 in the pathogenesis of equine sarcoids and present recent evidence implicati...
Croser EL, Marsh GA.The Henipavirus genus represents a group of paramyxoviruses that are some of the deadliest of known human and veterinary pathogens. Hendra and Nipah viruses are zoonotic pathogens that can cause respiratory and encephalitic illness in humans with mortality rates that exceed 70%. Over the past several years, we have seen an increase in the number of cases and an altered clinical presentation of Hendra virus in naturally infected horses. Recent increase in the number of cases has also been reported with human Nipah virus infections in Bangladesh. These factors, along with the recent discovery of...
Davies Morel MC, Lawlor O, Nash DM.Endometritis is an important cause of sub-fertility in mares. The critical indicator of reproductive success and financial return for commercial studs is live foaling rate. Endometrial bacteriology and/or cytology are used to diagnose endometritis and thus identify mares at risk of early embryonic death. However, mares with endometritis may conceive but then abort in late gestation. The aims of this study were to establish, as part of a standard breeding examination (1) whether a threshold percentage of uterine polymorphonuclear neutrophils (PMNs) exists above which a significant reduction in ...
Singha H, Goyal SK, Malik P, Khurana SK, Singh RK.Equine infectious anemia (EIA)-a retroviral disease caused by equine infectious anemia virus (EIAV)-is a chronic, debilitating disease of horses, mules, and donkeys. EIAV infection has been reported worldwide and is recognized as pathogen of significant economic importance to the horse industry. This disease falls under regulatory control program in many countries including India. Control of EIA is based on identification of inapparent carriers by detection of antibodies to EIAV in serologic tests and "Stamping Out" policy. The current internationally accepted test for diagnosis of EIA is the ...
Casey M.Equine dental disease has a high prevalence. Because of developmental, functional, and anatomic differences, limited inference can be made from brachydont dental pathology to that of equine cheek teeth. This article reviews the pathology of equine cheek teeth and their associated oral tissues, with specific information on periodontitis, pulpitis, maxillary infundibular changes, dental fractures, dental overgrowths, mucosal ulceration, and the regenerative capacity of equine teeth.
Foster DL.This article discusses the primary odontogenic problems of the mature performance horse, including wolf teeth; hooks; overbite, overjet, underjet, and wry bite; equine odontoclastic tooth resorption and hypercementosis; infundibular caries; and secondary oral problems. It outlines the author's methods of taking the history, oral examination, and use of diagnostic nerve blocks.
Vairo S, Favoreel H, Scagliarini A, Nauwynck H.Currently, little is known on the cellular pathogenesis of equine arteritis virus (EAV). The purpose of the present study was to identify the target cells in ponies experimentally inoculated with EAV 08P178 (EU, clade-1). EAV-target organs (respiratory tissues with associated lymphoid tissues and large intestines), collected at 3 and 7 days post inoculation (dpi) and with virus titers≥10(5.0) TCID50/g, were processed with double immunofluorescence staining for the simultaneous detection of EAV N-protein and one of the following cell markers: CD172a (myeloid cells), CD3 (T lymphocytes), IgM (...
Walker RL, Runyan CA.To determine whether previously unidentified variations of the SzP protein of Streptococcus equi subsp zooepidemicus were present in horses with various clinical signs of infection and whether any relationship could be identified between SzP protein variants and naturally occurring clinical conditions. Methods: 23 isolates of S equi subsp zooepidemicus were recovered from specimens of horses with various clinical conditions and used as a representative population of isolates for evaluation of different SzP protein variants. Methods: Genetic heterogeneity of the isolates was demonstrated by rep...
Yamashita-Kawanishi N, Chambers JK, Uchida K, Tobari Y, Yoshimura H, Yamamoto M, Yumoto N, Aoki H, Sugiura K, Higuchi T, Saito S, Haga T.Bovine papillomavirus types 1 and 2 (BPV1/2) infection in horses has been associated with the development of equine sarcoids. Previous findings revealed the presence of sarcoid-associated BPV sequence variants that have been proposed as a key factor of cross-species infection in horses. To verify this hypothesis, sarcoid-associated BPV variants should be identified regardless of geographic location. Objective: Sequence analyses of BPV1/2 derived from both horses and cattle were conducted to clarify the sarcoid-associated sequence variants. The aim of this study was to clarify the correlation b...
Gleeson LJ, Coggins L.Twenty-one pregnant mares were inoculated with EHV1. Nineteen became infected as evidenced by clinical signs and/or viremia but only one mare aborted a virus-infected fetus. The viremias were leukocyte-associated and appeared to be non-productive, latent infections of these cells. Infectivity, detectable by cocultivation, persisted in the circulating leukocytes for as long as 9 days without resulting in abortion. The data suggest that it is extremely difficult to evaluate the efficacy of vaccines in preventing EHV1 (Rhinopneumonitis) abortion due to the paucity of non-exposed mares, lack of te...
Donoghue EM, Lyons ET, Bellaw JL, Nielsen MK.Parascaris spp. infects foals worldwide and may cause airway inflammation in addition to small intestinal impaction and rupture. It is observed that acquired immunity eliminates ascarid burdens beginning at about 6 months of age, and current evidence suggests that a single parasite generation propagates in each foal crop. The purpose of this study was to monitor natural parasitic infections in untreated mixed breed horse foals over the course of 0-300 days of age. Fecal samples were collected monthly from all foals born in 2014 (n=13), beginning July 2014 through February 2015. Fecal egg count...
Foote CE, Love DN, Gilkerson JR, Whalley JM.Equine herpesvirus 1 (EHV-1) is a major cause of respiratory disease and abortion in horses worldwide. Although some vaccines have been shown experimentally to reduce disease, there are few reports of the responses to vaccination in the field. This study measured antibody responses to vaccination of 159 mares (aged 4-17 years) and 101 foals (aged 3-6 months) on a large stud farm with a killed whole virus EHV-1/4 vaccine used as per the manufacturer's recommendations. Using an EHV glycoprotein D (gD)-specific ELISA and a type-specific glycoprotein G (gG) ELISA, respectively 13.8 and 28.9% of ma...
Yamate J, Izawa T, Ogata K, Kobayashi O, Okajima R, Kuwamura M, Kotani T, Aoki M.An 11-year-old thoroughbred gelding was euthanatized because of right nasal cavity tumor. The tumor consisted of round to oval cells with a scanty cytoplasm and hyperchromatic nuclei. Homer-Wright rosettes and pseudorosettes, as well as microcysts were seen. Neoplastic cells were immunoreactive to vimentin, S-100 protein, and neuron-specific enolase, glial fibrillary acidic protein and microtube-associated protein in varying degrees, indicating neurogenic nature. Based on these findings, this tumor was diagnosed as an olfactory neuroblastoma. Since this type is an uncommon tumor showing histol...
Bjorneby JM, Leach DR, Perryman LE.Cryptosporidial infections were established in five young foals with severe combined immunodeficiency following oral administration of 10(8) Cryptosporidium parvum oocysts. All foals shed oocysts (average of 8 x 10(6) to 2 x 10(8)/g of feces) until death. Inflammation and C. parvum organisms were observed in the common bile duct, duodenum, jejunum, and ileum. Since foals with severe combined immunodeficiency lack functional T and B lymphocytes and are incapable of antigen-specific immune responses, they are well suited for evaluating the pathogenesis and treatment of persistent cryptosporidios...
Fielding CL, Magdesian KG.Sepsis and septic shock represent a major cause of morbidity and mortality in equine neonates and in all species. Early recognition of the condition is important, but definitive examination and laboratory variables to predict equine neonatal sepsis are lacking. Early and aggressive treatment should include broad-spectrum antimicrobial coverage, source control, and hemodynamic support. Field practitioners and intensive care clinicians work together in the management of this condition because the recognition and initial treatment should begin as early as possible.
Gleeson LJ, Studdert MJ.Intrauterine infection of pregnant mare with equine herpesvirus type 2 (EHV 2) did not result in foetal abortion, stillbirth or recognisable disease. Collection of uterine fluid by allantocentesis or amniocentesis 107 days after inoculation confirmed that intrauterine infection was established. EHV 2 was isolated from both allantoic and amniotic fluid separately collected at the time of elective Caesarean section 156 days after inoculation and virus neutralising antibody to EHV 2 was present in the foal's presuckle serum at birth. A very mild clinical disease, characterised by a scant, mucous ...
Hall TL, Tell LA, Wetzlich SE, McCormick JD, Fowler LW, Pusterla N.Ceftiofur, a third generation cephalosporin, demonstrates in vitro efficacy against microorganisms isolated from septicemic neonatal foals. This pharmacokinetic study evaluated the intravenous and subcutaneous administration of ceftiofur sodium (5 mg/kg body weight; n = 6 per group) and subcutaneous administration of ceftiofur crystalline free acid (6.6 mg/kg body weight; n = 6) in healthy foals. Plasma ceftiofur- and desfuroylceftiofur-related metabolite concentrations were measured using high performance liquid chromatography following drug administration. Mean (±SD) noncompartmental pharma...
Harrison IW.The average age of 122 horses with ascending colon volvulus was 6.6 +/- 0.4 years. Gastric reflux was a presenting sign in 35% of the cases. Peritoneal fluid protein levels had a mean of 2.54 +/- 0.14 g/dl and 20 horses had grossly normal peritoneal fluid at the time of presentation. Ascending colon volvulus was most commonly found at the level of the cecocolic fold with the initial ventral colon movement in a dorsomedial direction about the ascending mesocolic axis. The overall survival rate was 34.7% with a recurrence rate of only 4.9%.
Kirkpatrick CE, Skand DL.Giardia infection was believed responsible for chronic diarrhea, weight loss, lethargy, inappetence, and dermatitis in a 4-year-old Thoroughbred horse. Fecal cysts were detected by the zinc sulfate centrifugal flotation method. All clinical signs resolved upon treatment with metronidazole suspension (5 mg/kg body weight per os, TID for 10 days).
McGovern KF, Lascola KM, Smith SA, Clark-Price SC, Wilkins PA, Schaeffer DJ, Foreman JH.Hyperglycemia and endotoxemia have been associated with coagulation abnormalities in horses. Studies in humans suggest greater disturbances in coagulation with hyperglycemia and concurrent endotoxemia. Objective: To compare coagulation parameters in horses administered with lipopolysaccharide (LPS) with and without concurrent hyperglycemia. Methods: Twelve healthy adult horses. Methods: Hyperglycemia (180-240 mg/dL) was maintained for 6 hours in 6 horses (GLU-LPS) using 140 mg/kg IV bolus of dextrose followed by a 20% dextrose constant rate infusion. A similar volume of saline was administe...
Brooks MB.The most common cause of hemorrhage is vascular injury; however, the possibility of hemostatic failure should be considered in the initial differential diagnosis. This article provides an overview of preliminary screening and definitive tests to identify hemostatic defects in horses.
Embertson RM.This article discusses selected urogenital surgeries. The discussion focuses on perioperative concerns and complications. The ideal approach to addressing complications resulting from disease processes or surgery is to avoid them. This approach requires knowledge of what can go wrong, gained by personal experience and that shared by others. The better one is able to anticipate potential complications, the more likely complications can be avoided.
Voynick BT, Sweeney CR.Philippine polo and racing horses were examined for exercise-induced pulmonary hemorrhage after their competitive exercise. Exercise-induced pulmonary hemorrhage occurred in 11.1% of the polo horses and 64% of the racing horses. None of the horses had blood at the nostrils.
Chiewsilp D, McCown JM.Repeated clot formation in mouse ascitic fluids containing antiviral antibody was eliminated by acid precipitation of the fibrinogen.