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.
Mazan MR.The airways are the first part of the pathway in the oxygen transport chain that is critical to excellent athletic performance, and the lower airways are considered the final gatekeeper before oxygen enters the blood and carbon dioxide exits. Horses are blessed with large airways and lungs that allow them to be superb athletes, but the down side of this largesse on the part of evolution is that unless they are truly elite athletes they may withstand noninfectious disease of the lower respiratory tract for months to years before the owner or trainer notices. The two conditions of the lower resp...
Cohen ND, Carey VJ, Donahue JG, Seahorn JL, Brown SE, Riddle TW.To characterize the temporality of dates of breeding and abortion classified as mare reproductive loss syndrome (MRLS) among mares with abortions during early gestation. Methods: 2,314 mares confirmed pregnant at approximately 28 days after breeding from 36 farms in central Kentucky, including 515 mares that had early-term abortions. Methods: Farm veterinarians and managers were interviewed to obtain data for each mare that was known to be pregnant to determine pregnancy status, breeding date, last date known to be pregnant, and date of abortion. Results: Mares bred prior to April 1, 2001, app...
Ryan AD, Gerberich SG, Alexander BH, Renier CM.Working with animals on agricultural operations is hazardous for youths. This study evaluated the associations between activities and injuries related to specific animal types. A case-control study within the Regional Rural Injury Study II included 425 youths (less than 20 years of age) with injuries related to their operation and 1,886 controls (randomly selected youths). Exposures of interest were collected for the months prior to injury events for cases and randomly selected months for controls, based on an injury incidence algorithm. Multivariate logistic regression characterized associati...
Kondo T, Mashimo Y, Sato F, Tsuzuki N, Yamada K.Thoroughbred horses appear to be particularly predisposed to cervical vertebral stenotic myelopathy (CVSM), also known as wobbler syndrome. We hypothesized that variations in the cervical vertebral volumes can affect the dynamic instability of the cervical vertebrae. This observational study aimed to clarify whether cervical vertebral volume could be considered as a contributing factor in CVSM in Thoroughbred horses. Computed tomography (CT) was used to investigate a total of 21 male Thoroughbred horses (age range, 217-1,002 days; mean, 542.3 days). The study population comprised 17 CVSM horse...
D'Anza E, Buono F, Albarella S, Castaldo E, Pugliano M, Iannuzzi A, Cascone I, Battista E, Peretti V, Ciotola F.The Pony of Esperia is an Italian autochthonous horse breed reared in the wild on the Aurunci and Ausoni Mountains. Currently, it is considered an endangered breed, as its population consists of 1623 animals. It is therefore essential to identify all aspects that can improve the management and economy of its breeding, favoring its diffusion. In this paper, the effects of intestinal strongyle infection on the chromosome stability of peripheral blood lymphocytes (PBLs) was evaluated through aneuploidy and chromosome aberration (gap, chromatid and chromosome breaks, and the number of abnormal cel...
Forster HV, Pan LG, Flynn C, Bisgard GE.The purpose of this study was to determine whether there was any recovery of the Hering-Breuer inflation reflex in ponies between 2-4 wk and 3-4 yr after hilar nerve denervation (HND). Under anesthesia and before HND, airway occlusion after a 3-liter lung inflation lengthened the subsequent occluded breath by nearly 10 times the control breath duration. Between 2 wk and 3-4 yr after HND, this maneuver increased the duration of the occluded breath by only 2.5 times the control breath duration. Also under anesthesia, the airway was occluded at end expiration. This maneuver increased the duration...
Archer RM, Lindsay WA, Smith DF, Wilson JW.The vasculature of 22 small colons from dead adult ponies was perfused with latex or barium sulphate solution. The vascular anatomy was studied by use of dissection and alkali digestion of the latex specimens and microangiography of the barium sulphate-perfused specimens. The small colon is supplied by the caudal mesenteric artery. The left colic artery arises from the caudal mesenteric artery, which then becomes the cranial rectal artery. Branches from the left colic and cranial rectal arteries form anastomosing arcades that become narrower distally along the length of the small colon. From t...
Serag RM, Abu-Seida AM, Abdelrahman HA, Samir A, Ibrahim IM, AbdElkader NA.Orodental disorders are common in equidae and can lead to serious clinical complications. This study determines the prevalence rate (PR) of orodental disorders in working donkeys in Egypt and their potential risk factors. During 4 years, 3,791 donkeys were examined in six Egyptian governorates. Full case history and thorough clinical and oral examinations were performed. Radiography and oroendoscopy were undertaken whenever possible. All data were statistically analyzed using Poisson generalized linear models to compare PR among governorates, sex, years, body condition score, and age groups an...
Ogorevc J, Poklukar K, Dovč P.Skin-derived tissue cultures are a useful model to study molecular mechanisms of skin renewal and pathogenesis of dermal diseases. Horses often suffer from skin diseases, skin trauma and problems with proper wound healing, which could be improved by in vitro grown keratinocyte grafts. Herein we describe establishment and characterization of equine skin-derived primary cell cultures, using enzymatic and explant methods. The established cell lines of primary equine keratinocytes (peK) maintained high proliferative capacity for over five passages and expressed different epithelial/keratinocyte-s...
Grulke S, Gangl M, Deby-Dupont G, Caudron I, Deby C, Serteyn D.Gastrointestinal disorders in horses leading to endotoxic shock could have further consequences on other splanchnic organs such as the pancreas, as can be seen in humans suffering from septic shock. In this study, the range of enzymatically active trypsin (EAT) in healthy horses was established and is similar to the range observed in healthy humans. EAT values were determined in horses with acute abdominal crises on admission as well as during anaesthesia and in the postoperative phase. A significant increase in plasma EAT was found in 59% of the horses with surgical colic when compared to our...
Mendoza L, Franck T, Lejeune JP, Caudron I, Detilleux J, Deliège B, Serteyn D.Osteochondrosis (OC) disease appears to be multifactorial in origin, including skeletal growth rates, nutrition, endocrinological factors, exercise, biomechanics, and other environmental factors. Endocrinological and metabolic factors seem to have an important role in the pathogeny of OC like the Wnt signaling pathway. One of the regulators in the Wnt signaling pathway is the sclerostin glycoprotein. The aim of this study was to investigate the sclerostin blood concentration according to the evolution of the disease, the environment, and the age but also its use as a possible biomarker for OC ...
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...
Brown DR, Forster HV, Lowry TF, Forster MA, Forster AL, Gutting SM, Erickson BK, Pan LG.Breathing, diaphragmatic and transversus abdominis electromyograms (EMGdi and EMGta, respectively), and arterial blood gases were studied during normoxia (arterial PO2 = 95 Torr) and 48 h of hypoxia (arterial PO2 = 40-50 Torr) in intact (n = 11) and carotid body-denervated (CBD, n = 9) awake ponies. In intact ponies, arterial PCO2 was 7, 5, 9, and 11 Torr below control (P less than 0.01) at 1 and 10 min and 5 and 24-48 h of hypoxia, respectively. In CBD ponies, arterial PCO2 was 3-4 Torr below control (P less than 0.01) at 4, 5, 6, and 24 h of hypoxia. In intact ponies, pulmonary ventilation, ...
Merlin A, Foucher N, Linster M, Cazeau G, Marsot M, Delerue M, Sala C, Schneider J, Ferry B, Amat JP, Tapprest J.There is limited evidence regarding the proportion of dead equids in France that were euthanized and the factors influencing the decision-making of euthanasia. The better understanding of which could facilitate research on improvement of welfare, especially on end of life issues. The aim of this study was to estimate the proportion of euthanasia and identify associated factors in equids in France. A web-based survey was created and distributed by the French horse and riding institute to owners who reported an equine death between April 2017 and April 2018 (n = 5 158). Factors associated with...
Richards B, Sage Jacobson S, James Aquino YS.The introduction of Artificial Intelligence (AI) into health care has been accompanied by uncertainties and regulatory challenges. The establishment of a regulatory framework around AI in health is in its infancy and the way forward is unclear. There are those who argue that this represents a concerning regulatory gap, while others assert that existing regulatory frameworks, policies and guidelines are sufficient. We argue that perhaps the reality is somewhere in between, but that there is a need for engagement with principles and guidelines to inform future regulation. However, this cannot be...
Bastianello SS, Nesbit JW.The pathological features of biliary atresia in a foal are described. A 4-week-old American Saddler foal was presented for autopsy following an illness characterised by clinical features indicative of hepatic failure. The significant macroscopical lesions occurred in the liver which was extremely enlarged, mottled in appearance and indurated. Bile stasis was evident. Lobular distinction was absent and on sectioning, large bile ducts were absent. A moderate ascites, hydrothorax and hydropericardium and a mild anasarca and intermuscular oedema accompanied the hepatic lesion. The diagnosis of bil...
Biros DJ, Brooks DE, Brown MP, Merritt KA, Kubilis PS.To determine regional and zonal variation in sulfation patterns of chondroitin sulfate in normal equine corneal stroma. Methods: 22 normal eyes from 11 horses. Methods: Corneas were collected within 24 hours of death from equine necropsy specimens. After papain-chondroitinase digestion of corneal tissue, disaccharides deltaDi4S and deltaDi6S were quantified by use of capillary zone electrophoresis in the superficial, middle, and deep zones of central and peripheral regions of the cornea. Results: For the 2 regions combined, deltaDi6S/deltaDi4S values were significantly lower in the deep and mi...
Saadi A, Dalir-Naghadeh B, Akbari H, Rashedi M, Mohammadi R.An 11-year-old Hanoverian gelding used for jumping was evaluated for gait abnormalities and hoof problems in the hindlimbs. Clinical examinations revealed signs consistent with shivers. A thyroid gland enlargement was noticed, baseline serum thyroid hormone (TH) concentrations were low, and a low response to thyrotropin-releasing hormone administration was observed. Hypothyroidism was suspected. The horse was treated with levothyroxine for 1 year. TH concentrations returned to the normal range by week 4 of treatment. Thirty weeks after the initiation of levothyroxine therapy, the gait abnormal...
Freeman DE, Pearn AR.Epiploic foramen entrapment (EFE) is a common cause of colic in horses and available anatomical descriptions of this foramen and the associated vestibule of the omental bursa tend to be inconsistent, contradictory and inaccurate. Objective: To describe the anatomy of the vestibule of the omental bursa and epiploic foramen. Methods: Dissection of 21 fresh equine cadavers shortly after euthanasia. Methods: The anatomy of the vestibule of the omental bursa, epiploic foramen and related structures in the cranial abdomen were examined in situ and after removal from the abdomen. Photographs were tak...
Inoue OJ, Freeman DE, Wallig MA, Clarkson RB.To determine effects of reactive oxygen metabolites (ROMs), with and without flunixin meglumine, on equine right ventral colon (RVC) in vitro. Methods: 18 healthy horses and ponies. Methods: In 3 groups of 6 animals each, short-circuit current and conductance were measured in RVC mucosa in Ussing chambers. The 3 groups received physiologic saline (0.9% NaCl) solution, IV, 10 minutes before euthanasia and tissue incubation in Krebs-Ringer-bicarbonate (KRB) solution; flunixin meglumine (1.1 mg/kg, IV) 10 minutes before euthanasia and tissue incubation in KRB solution; or physiologic saline solut...
Nielsen MK, Leathwick DM, Sauermann CW.Over the past three decades, equine strongylid egg reappearance periods (ERPs) have shortened substantially for macrocyclic lactone anthelmintics. The ERPs of ivermectin and moxidectin were originally reported in the 8-10 and 12-16 week ranges, respectively, but several recent studies have found them to be around 4-5 weeks for both actives. This loss of several weeks of suppressed strongylid egg output could have substantial implications for parasite control. This study made use of a computer simulation model to evaluate the impact of shortened ERPs on the anthelmintic performance of ivermecti...
Paradis MR, Breeze RG, Laegreid WW, Bayly WM, Counts DF.Eight ponies were allotted to 2 groups of 4. Group-1 ponies (1-4) were given 0.2 g of indole/kg of body weight orally and group-2 ponies (5 to 8) were given 0.1 g of indole/kg. Various physical, hematologic, and physiologic measurements were obtained after administration of indole. Intravascular hemolysis and hemoglobinuria were detected in both groups within 24 hours of dosing. Hemolysis was reflected by decreases in PCV, hemoglobin concentration, and RBC count, and an increase in indirect bilirubin. Erythrocyte fragility appeared to increase in both groups at 8 hours after dosing and peaked ...
Campagnolo ER, Trock SC, Hungerford LL, Shumaker TJ, Teclaw R, Miller RB, Nelson HA, Ross F, Reynolds DJ.Dermatitis consisting of blisters on the nose and other parts of the body was reported among horses at a Midwestern horse show. Some horses also had jaundice, hematuria and anorexia. An outbreak investigation was initiated, and of 239 horses for which information could be obtained, 58 (24%) were found to have been affected. Median duration of illness was 5 days, and all horses recovered. Age, sex, water source, grain source, and stabling location were not associated with illness. The use of wood shavings bedding obtained at the show grounds was the factor most strongly associated with the deve...
Gonzlez CR, Elgueta M, Krolow TK, Henriques AL.A catalog of the Tabanidae from Chile is provided. All valid names and synonyms for the 116 species and 25 genera known for the country including information about name, author, year of publication, page number, type species, type locality and references are listed. The species Dasybasis albohirta (Walker) is cited for the first time for Chile. The type locality of Dasybasis nigrifrons (Philippi) is corrected to Chile (Todos Los Santos Lake). The dates of the description of Tabanus nigrifrons Philippi (now Dasybasis), and Pangonia australis Philippi (now Pseudoscione) are corrected from their ...
Lapan G, Awad-Masalmeh M, Hartig A, Silber R.In this study 55 strains of Taylorella equigenitalis isolated from horses of four different studs in Austria, and a comparative strain from the Federal Republic of Germany were investigated by different methods. These investigations were carried out with the help of SDS-PAGE, immunoblotting, the analyses of genomes and by proof of plasmids. Furthermore, pathogenic mechanisms such as adhesion or the formation of toxins were investigated in vitro. On the basis of the results carried out by means of SDS-PAGE and immunoblotting all tested strains of Taylorella equigenitalis were alike, whereas by ...
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...
Sponseller BA, Clark SK, Friedrich RA.Determining mechanisms of viral escape to particular epitopes recognized by virus-neutralizing antibody can facilitate characterization of host-neutralizing antibody responses as type- versus group-specific, and provides necessary information for vaccine development. Our study reveals that a single N-glycan located in the 5' region of the Wyoming wild-type equine infectious anemia virus (EIAV) principal neutralizing domain (PND) accounts for the differences in neutralization phenotype observed between PND variants, while variations in charged amino acids within the PND do not appear to play a ...
Williams MR.Rats were injected intradermally with rabbit anti-ovalbumin serum and 3 hours later were challenged intravenously with ovalbumin and Evans Blue dye. Inflammatory lesions were produced within 20 minutes and their size was markedly dose-dependent. Attempts were made to interfere with this passive cutaneous anaphylaxis (PCA) by admixture of normal IgG with the rabbit anti-ovalbumin to measure the relative tissue binding affinities of IgG from various species. It was found that normal IgG from any of the species tested had an enhancing effect on PCA in rats. These immunoglobulins serially arranged...
Gilbert RO, Marlow CH.Records of 1,009 pregnancies in 574 foaling, barren and maiden Thoroughbred mares on a single stud farm, over a period of 12 years were examined. The farm is situated in the eastern Cape Province of South Africa, at an elevation of 1,800 m, and in an area of climatic extremes. Records of 604 pregnancies in 249 foaling Thoroughbred mares were examined. For these purposes, those pregnancies in which a mare conceived in the same breeding season during which she had foaled were considered as pregnancies in foaling mares. Pregnancy was confirmed by rectal palpation by a single experienced practitio...
van Weeren PR, Morales JA, Rodríguez LL, Cedeño H, Villalobos J, Poveda LJ.This article describes a case of massive mortality among horses which was probably due to intoxication by pyrrolizidine alkaloids from Heliotropium indicum. Over 4 years more than 75% of a population of about 110 horses on a farm in Costa Rica died after showing nervous neurological symptoms. Two clinical manifestations were encountered, an acute and a chronic one, both with a fatal outcome. Pathological findings in 2 horses coincided with those reported in the literature for intoxication by pyrrolizidine alkaloids and were not specific for VEE. However Venezuelan equine encephalitis (VEE) was...
