Pathology in horses involves the study of diseases and abnormalities affecting equine health, encompassing a range of conditions that can impact various systems within the horse's body. This field examines the causes, mechanisms, and effects of diseases, as well as the structural and functional changes they induce in equine tissues and organs. Common pathological conditions in horses include laminitis, colic, equine infectious anemia, and respiratory disorders. Understanding these diseases involves evaluating clinical signs, diagnostic methods, and treatment options. This page compiles peer-reviewed research studies and scholarly articles that explore the etiology, pathogenesis, and clinical implications of pathological conditions in horses.
Schrock P, Lüpke M, Seifert H, Staszyk C.This study investigated the hypothetical contribution of biomechanical loading to the onset of equine odontoclastic tooth resorption and hypercementosis (EOTRH) and to elucidate the physiological age-related positional changes of the equine incisors. Based on high resolution micro-computed tomography (μCT) datasets, 3-dimensional models of entire incisor arcades and the canine teeth were constructed representing a young and an old incisor dentition. Special attention was paid to constructing an anatomically correct model of the periodontal ligament (PDL). Using previously determined Young's m...
Wijnberg ID, van der Ree M, van Someren P.Short-duration electroencephalography (EEG) recordings in horses are helpful in diagnosing intracranial disorders. Potentially, long-duration ambulatory EEG (AEEG) recordings in horses will enhance the chance of detecting abnormal brain activity independent of the presence of an insult. Objective: The objective of this study was to test if AEEG recordings in unsedated horses can be acquired and benefit diagnosing abnormal brain activity. Methods: Recordings were taken from 8 adult control horses and 10 patients suspected of intracranial abnormalities. Self-adhesive electrodes and the 'Porti-5'...
Psalla D, Rüfenacht S, Stoffel MH, Chiers K, Gaschen V, Doherr MG, Gerber V, Welle MM.Equine pastern vasculitis is clinically challenging and the underlying aetiopathogenesis is unclear. The aims of this retrospective study were to establish histopathological criteria for pastern vasculitis, to look for an underlying cause, to investigate whether the histopathological lesions are associated with a distinct clinical picture, to assess if and how the clinical picture varies, and to determine the treatment response. Skin biopsies and clinical data from 20 horses with a diagnosis of vasculitis of the distal extremities were investigated and histology was compared to biopsies from h...
Kuemmerle JM, Berchtold S.This study compared the areas of cartilage accessible for curettage in arthrodesis of the equine proximal interphalangeal joint using the conventional and collateral ligament sparing approaches. For this purpose, forelimbs and hindlimbs of six equine cadavers without radiographic evidence of proximal interphalangeal joint disease were used. One limb of each pair of limbs was randomly assigned to a dissection using a standard approach to the proximal interphalangeal joint including transection of the collateral ligaments, while each contralateral limb was exposed using the same approach but lea...
Reed SM, Howe DK, Morrow JK, Graves A, Yeargan MR, Johnson AL, MacKay RJ, Furr M, Saville WJ, Williams NM.Recent work demonstrated the value of antigen-specific antibody indices (AI and C-value) to detect intrathecal antibody production against Sarcocystis neurona for antemortem diagnosis of equine protozoal myeloencephalitis (EPM). Objective: The study was conducted to assess whether the antigen-specific antibody indices can be reduced to a simple serum : cerebrospinal fluid (CSF) titer ratio to achieve accurate EPM diagnosis. Methods: Paired serum and CSF samples from 128 horses diagnosed by postmortem examination. The sample set included 44 EPM cases, 35 cervical-vertebral malformation (CVM) ca...
Dixon PM, du Toit N, Staszyk C.There have been many significant and interesting developments in equine dental anatomy during the past 20 years that are of major clinical significance in better understanding the physiology of equine mastication, the etiopathogenesis of some dental disorders, and their safe treatment. The many recent significant developments include descriptions of the enamel infolding of cheek teeth and of infundibular anatomy, including the frequent absence of cementum infilling in many infundibulae, which can lead to infundibular caries. Many important developments in equine dental anatomy are summarized i...
Tewari D, Del Piero F, Cieply S, Feria W, Acland H.Equine herpesvirus-1 (EHV-1) strains with a single point mutation at the 2254 nucleotide position with a G2254 constitution within the DNA polymerase gene are associated strongly with equine myeloencephalopathies. Infections with non-neuropathogenic EHV-1 strains without the G2254 nucleotide but with an A2254 nucleotide are associated less frequently with equine neurologic disease. A retrospective study utilizing DNA extracted from formalin fixed paraffin embedded tissues was conducted with real time PCR and pyrosequencing, to determine the infecting EHV-1 strains. Infection with EHV-1 A2254 a...
Navas de Solis C, Slack J, Boston RC, Reef VB.To describe the prognosis and clinical, echocardiographic, and pathological features of hypertensive cardiomyopathy in horses. Methods: Retrospective case series. Methods: 5 horses with cardiac hypertrophy and systemic hypertension. Methods: Demographics, history, physical and cardiological examination findings, diagnosis, clinical progression, prognosis, and pathological findings were obtained from medical records. Results: The primary diagnosis was chronic laminitis in 3 horses and chronic renal failure in 2. Persistent tachycardia, hypertension, chronic laminitis, or a combination of these ...
Clarke L, Simon A, Ehrhart EJ, Mulick J, Charles B, Powers B, Duncan C.Mast cell tumors are uncommon in horses and typically have a benign clinical course, but there are occasional reports of more aggressive behavior. The objective of this study was to review histologic features and KIT expression patterns of 72 previously diagnosed equine cutaneous mast cell tumors to determine if either is associated with clinical outcomes. Biopsy specimens were reviewed using histologic criteria derived from grading schemes, and KIT antibody expression patterns used in canine tumors and surveys were sent to referring veterinarians for follow-up clinical data. Arabians were ove...
Knight CG, Dunowska M, Munday JS, Peters-Kennedy J, Rosa BV.Equus caballus papillomavirus type 2 (EcPV-2) infection has been associated with equine genital squamous cell carcinomas (SCCs). However, quantitative PCR (qPCR) has not been performed to determine viral copy numbers within these lesions. Additionally, the frequency with which EcPV-2 can be detected in other common sites of equine SCC development remains uncertain. The aim of this study was to develop a qPCR assay to estimate the viral load in a variety of equine tissue samples. These included 40 SCC lesions, 19 penile non-SCC or precursor disease lesions, and 222 tissues without observable le...
Shon W, Folpe AL.Cartilaginous tumors of soft tissue are uncommon, with benign chondromas of soft parts greatly outnumbering rare soft-tissue chondrosarcomas. Over the past several years, we have seen in consultation a distinctive, benign-appearing chondroid soft-tissue lesion of the plantar foot that differs in a number of respects from chondroma of soft parts. Herein we report our experience with this distinctive lesion. A retrospective review of all cases from the foot in our soft-tissue consultation and institutional surgical pathology archives identified 9 similar cases, most often previously coded as 'fi...
Pessoa CR, Pessoa AF, Maia LA, Medeiros RM, Colegate SM, Barros SS, Soares MP, Borges AS, Riet-Correa F.The effects and susceptibility of donkeys to Crotalaria juncea and Crotalaria retusa poisoning were determined at high and low doses. Seeds of C. juncea containing 0.074% of dehydropyrrolizidine alkaloids (DHPAs) (isohemijunceines 0.05%, trichodesmine 0.016%, and junceine 0.008%) were administered to three donkeys at 0.3, 0.6 and 1 g/kg body weight (g/kg) daily for 365 days. No clinical signs were observed and, on liver and lung biopsies, the only lesion was a mild liver megalocytosis in the donkeys ingesting 0.6 and 1 g/kg/day. Two other donkeys that received daily doses of 3 and 5 g seed/...
Tóth P, Horváth C, Ferencz V, Tóth B, Váradi A, Szenci O, Bodó G.Despite the fact that bone mineral density (BMD) is an important fracture risk predictor in human medicine, studies in equine orthopedic research are still lacking. We hypothesized that BMD correlates with bone failure and fatigue fractures of this bone. Thus, the objectives of this study were to measure the structural and mechanical properties of the proximal phalanx with dual energy X-ray absorptiometry (DXA), to correlate the data obtained from DXA and computer tomography (CT) measurements to those obtained by loading pressure examination and to establish representative region of interest (...
Diab SS, Rodriguez-Bertos A, Uzal FA.Clostridium difficile is commonly associated with diarrhea and colitis in humans and other mammals, including horses. To this date, the epidemiologic, microbiologic, clinical, and diagnostic aspects of C. difficile-associated disease (CDAD) in horses have been thoroughly described. However, reports describing the enteric pathology of this disease in horses are limited. This study presents a comprehensive description of the pathologic characteristics of CDAD in 21 horses and discusses the criteria for the diagnosis of the disease. Case selection was based on C. difficile A/B toxins detection (e...
Walker WT, Kawcak CE, Hill AE.To characterize medial femoral condyle (MFC) morphometrics and subchondral bone density patterns in Thoroughbred racehorses and to determine whether these variables differ between left and right limbs. Methods: Stifle joints harvested from 6 Thoroughbred racehorses euthanized for reasons other than hind limb lameness. Methods: The distal portion of the left and right femurs of each cadaver was scanned via CT. Hounsfield units were converted to dipotassium phosphate equivalent densities through use of a phantom on each specimen. Medial femoral condyle width, length, height, and curvature; subch...
Sasani F, Javanbakht J, Ghamsari M, Hassan MA.We report one such case which was diagnosed intraoperatively as left dorsal colon volvulus due to multiple mesenteric abnormalities. A 17-year-old castrated male horse was taken to the Tehran University Veterinary Hospital for treatment of metacarpal wound accompanied by severe abdominal distension and acute colic. The treatment and measurement were taken for a month, and the prepared biopsy indicated that the healing trend was obvious. Unfortunately, prior to discharge, the clinical colic manifestations emerged and the animal suddenly died. Dilated large intestine was palpated per rectum and ...
Kapoor A, Simmonds P, Cullen JM, Scheel TK, Medina JL, Giannitti F, Nishiuchi E, Brock KV, Burbelo PD, Rice CM, Lipkin WI.The recent identification of nonprimate hepaciviruses in dogs and then in horses prompted us to look for pegiviruses (GB virus-like viruses) in these species. Although none were detected in canines, we found widespread natural infection of horses by a novel pegivirus. Unique genomic features and phylogenetic analyses confirmed that the tentatively named equine pegivirus (EPgV) represents a novel species within the Pegivirus genus. We also determined that EPgV causes persistent viremia whereas its clinical significance is undetermined.
Baccarin RY, Pereira MA, Roncati NV, Bergamaschi RR, Hagen SC.This study aimed to detect, by radiographic examination, the evolution of osteochondral lesions in the tarsocrural and femoropatellar joints of Lusitano foals. Within 1 month of age, 76.08% of foals had radiographic signs of osteochondrosis, but only 16.20% had lesions at 18 months. The radiographic signs resolved by 5 mo of age in most foals, but some cases that involved either joint, were not resolved until 12 mo of age. It is thought that the "age of no return" is 5 mo for the tarsocrural and 8 mo for the femoropatellar joint but this study demonstrated regression of osteochondral lesions i...
Crişan MI, Damian A, Gal A, Miclăuş V, Cernea CL, Denoix JM.The purpose of this study was to provide a detailed description of the vascular changes in the distal part of deep digital flexor tendon (DDFT). Eight isolated forelimbs were collected from 8 horses with DDF tendinopathy diagnosed post-mortem by ultrasound and gross anatomopathological examination. The samples were fixed in 10% neutral buffered formalin, softened in 4% phenol and dehydrated with ethylic alcohol. Goldner's Trichrome staining method was used. The histopathological examination revealed vascular proliferation associated with structural disorders of blood vessels. Angiogenesis, fib...
Smiet E.Lately there has been a tendency to discuss Equine Cushing's disease and its related phenomena, due to the amount of recently acquired research data. The author has composed a brief overview of the present situation emphasizing relevance for practitioners.
Kelly PG, Reardon RJ, Johnston MS, Pollock PJ.Endoscopic examination of Thoroughbred (TB) yearlings is performed routinely to determine the suitability of horses for racing and to ensure that the conditions of sale are satisfied. However, previous research has demonstrated that resting endoscopic examination can be inaccurate in the diagnosis of functional pathology of the upper portion of the respiratory tract (URT). Objective: To investigate the feasibility of performing dynamic overground endoscopy in a group of TB yearlings and to compare the results of resting and dynamic endoscopic examination of the URT. Methods: Prospective cohort...
Gauff F, Patan-Zugaj B, Licka TF.Insulin leads to overexpression of endothelin-1 (ET-1) in the endothelium of insulin-resistant rodents. If this is also the case in equine laminar tissue, this could explain the predisposition of insulin-resistant horses to laminitis. Objective: To investigate the effect of hyperinsulinaemia on metabolism and vascular resistance of the isolated equine digit in a model of extracorporeal perfusion. Methods: Randomised, controlled study with interventional group, with blinded evaluation of histology results. Methods: After exsanguination, equine digits (n = 11) and autologous blood were collected...
Compostella F, Tremaine WH, Franklin SH.To investigate causes of respiratory noises in horses following prosthetic laryngoplasty (with or without a ventriculocordectomy) and to examine potential associations between degree of arytenoid abduction and the presence of other upper respiratory tract (URT) abnormalities, including right-sided collapse. Methods: Clinical records and dynamic videoendoscopic recordings were examined from horses presented between 1995 and 2010 for investigation of respiratory noise during exercise, following a prosthetic laryngoplasty (+/- a ventriculocordectomy). Relationships between the degree of left aryt...
Yamout SZ, Nieto JE, Anderson J, De Cock HE, Vapniarsky N, Aleman M.Definitive ante mortem diagnosis of pancreatitis in horses is difficult. Reports summarising the most common clinical signs, clinicopathological features and concurrent disorders in horses with a definitive diagnosis of pancreatitis that may aid in the recognition of disease are lacking. Objective: To describe case details, clinical signs, clinicopathological data and necropsy findings in horses with a definitive diagnosis of pancreatitis. Methods: This was a retrospective study (1986-2011) and inclusion criteria consisted of horses with a definitive diagnosis of pancreatitis. A medical record...
Cadby JA, David F, van de Lest C, Bosch G, van Weeren PR, Snedeker JG, van Schie HT.Injuries in energy-storing tendons are common in both horses and man. The high prevalence of reinjury and the relatively poor prognosis for returning to preinjury performance levels warrant further research, for which well characterised models would be very helpful. Objective: Given the clinical similarities in tendinopathy of energy-storing tendons, we hypothesised that a recently developed experimental model of equine tendon injury would display many of the characteristics of clinical tendinopathy and could therefore be of use for both species, thus providing comparative insight to the human...
Pinchbeck GL, Clegg PD, Boyde A, Barr ED, Riggs CM.Palmar/plantar osteochondral disease (POD) is a common, debilitating condition in Thoroughbred racehorses; however, training- and racing-related factors associated with this disease are unknown. Objective: To determine horse-, racing- and training-related risk factors for POD. The general hypotheses were that early training and racing, and increased intensity of racing and training, lead to increased severity of POD. Methods: The metacarpo/metatarsophalangeal joints of 164 Thoroughbred racehorses were examined at post mortem and graded for third metacarpal and metatarsal POD. The relationships...
de Laat MA, Pollitt CC, Kyaw-Tanner MT, McGowan CM, Sillence MN.The reason why a sustained high concentration of insulin induces laminitis in horses remains unclear. Cell proliferation occurs in the lamellae during insulin-induced laminitis and in other species high concentrations of insulin can activate receptors for the powerful cell mitogen, insulin-like growth factor (IGF)-1. The first aim of this study was to determine if IGF-1 receptors (IGF-1R) are activated in the hoof during insulin-induced laminitis. Gene expression for IGF-1R and the insulin receptor (InsR) was measured using qRT-PCR, in lamellar tissue from control horses and from horses underg...
Votion DM.Atypical myopathy (AM) is a frequently fatal seasonal pasture myopathy that emerges in Europe. Outbreaks are of an acute and unexpected nature and practitioners should be prepared to handle these critically ill patients. This review retraces the history of AM and describes results of epidemiological investigations that were conducted to raise hypotheses concerning the etiology of this devastating disease as well as to be able to suggest potential preventive measures. Also, clinical studies have contributed to a better definition and recognition of the syndrome, whereas elucidation of the patho...
Blikslager AT, Wilson DA, Constantinescu GM, Miller MA, Corwin LA.A 1-year-old half-Arabian colt was referred for evaluation of a cranial cervical abnormality. Physical examination revealed the left wing of the atlas to be more ventral than the right wing. A head tilt, with the pole deviated to the left, was present because of the malpositioned atlas. Neurologic examination identified symmetrical weakness, ataxia, and proprioceptive deficits in all four limbs. Radiographs of the cranial cervical region revealed fusion of the atlas and axis, and deviation of the atlantoaxial joint to the left of the median plane. Euthanasia was elected. Necropsy confirmed the...
Della Tommasa S, Winter K, Seeger J, Spitzbarth I, Brehm W, Troillet A.Horses are a widely accepted model for osteoarthritis (OA) research. Synovial tissue sampling is commonly used in studies to evaluate and grade the progress of OA or to assess treatment effects. Synovial explants play an important role in ex-vivo studies, increasingly replacing the use of living animals. To understand histomorphological changes in the process of joint-related diseases such as OA, detailed information about histomorphometric parameters of unaffected synovial villi is necessary. The objective of the present study was to evaluate the mean width of the intimal synovial lining and ...
Pointelli E, Santa-maria MA, Caretta G.A total of 1267 microfungi, including 35 Myxomycetes, were recorded from the fecal samples of the 60 horses; of these 395 were found on 20 saddle-horse feces, 363 on 20 race-horses and 509 on 20 working horses. Eighty two species representing 53 genera were recorded; of these 7 were Zygomycetes, 18 Ascomycetes, 1 Basidiomycetes and 25 Fungi Imperfecti: 2 Myxomycetes. Common coprophilous fungi are in decreasing order Pilobolus kleinii, Saccobolus depauperatus, Mucor hiemalis, Lasiobolus ciliatus, Podospora curvula, Petriella guttulata, M. circinelloides, Coprinus radiatus, Dictyostelium mucoroi...
Doxey DL, Pearson GT, Milne EM, Gilmour JS, Chisholm HK.A study of myenteric and submucosal plexuses was undertaken in the jejunum and ileum of horses and ponies in which no clinical or pathological evidence of intestinal abnormality was apparent. Complete transverse sections of the intestine, stained by a modified haematoxylin and eosin method, were examined using up to 20 sequential sections per animal. Information was gathered from adult, juvenile and fetal equidae. In adults, the longitudinal muscle layers were thinner than the circular muscle layers and the ileum had thicker layers compared to the jejunum. In adults, the submucosal plexus had ...
Eysker M, Jansen J, Mirck MH.Inhibited early third stage larvae of Cyathostominae were found in the digested mucosa of the large intestine of 12 yearling, female Shetland ponies, which were used in two grazing experiments. The ponies were killed in late autumn. In some ponies the inhibited larvae were very abundant and in most animals the majority of the Cyathostominae populations consisted of these early third stage larvae, suggesting that the phenomenon has an epidemiological significance.
Trachsel DS, Calloe K, Mykkänen AK, Raistakka P, Anttila M, Fredholm M, Tala M, Lamminpää K, Klaerke DA, Buhl R.Exercise-associated sudden deaths (EASDs) are deaths occurring unexpectedly during or immediately after exercise. Sudden cardiac death (SCD) is one cause of EASD. Cardiac arrhythmias caused by genetic variants have been linked to SCD in humans. We hypothesize that genetic variants may be associated with SCD in animals, including horses. Genetic variants are transmitted to offspring and their frequency might increase within a family. Therefore, the frequency of such variants might increase with the inbreeding factor. Higher inbreeding could have a negative impact on racing performance. Pedigree...
Dyson S, Pool R, Blunden T, Murray R.There is limited knowledge about the interpretation of alterations in the distal sesamoidean impar ligament (DSIL) detected using magnetic resonance imaging (MRI) and their correlation with histopathology. Objective: There would be: 1) a correlation between histopathology and MRI findings; and 2) a relationship between MR abnormalities at the origin and the insertion of the DSIL, between insertion and body; and origin and body. Methods: Fifty limbs from 28 horses were examined using high-field MRI and histopathology. MR abnormalities of the DSIL, its origin on the navicular bone and its insert...
Page AE, Loynachan AT, Bryant U, Stills HF, Adams AA, Gebhart CJ, Pusterla N, Horohov DW.Lawsonia intracellularis is the etiological agent of infectious intestinal hyperplasia for which several clinical diseases have been described including proliferative enteropathy (PE), intestinal adenomatosis, and ileitis. While initially recognized as the causative agent of PE in pigs, L. intracellularis is now viewed as an emerging cause of intestinal hyperplasia in a wide range of mammalian species, including horses. Equine proliferative enteropathy (EPE) has been reported worldwide though definitive diagnosis is difficult and the epidemiology of the disease remains poorly understood. Weanl...
Nieto JE, Snyder JR, Kollias-Baker C, Stanley S.To determine effects of cisapride and 5-hydroxytryptamine (5-HT) on the jejunum of horses. Methods: Jejunal muscle strips from 8 horses. Methods: Muscle strips were suspended in isolated muscle baths. Isometric stress responses to 5-HT and cisapride, with and without specific antagonists, were determined. Results: Muscle strips incubated with atropine and tetrodotoxin responded to 5-HT and cisapride with an increase in contractile force. The 5-HT caused a concentration-dependent increase in contractile amplitude, with a maximum response (Emax) of 1,151+/-214 g/cm2 and a molar concentration tha...
Heath SE, Peter AT, Janovitz EB, Selvakumar R, Sandusky GE.A 2-year-old Standardbred gelding was examined because of prolapse of the third eyelid; myoclonus of the muscles of the head, neck, and forelimbs; and persistent tail swishing. The horse had a high plasma sodium concentration but was not drinking water. The hypernatremia could not be corrected by means of IV administration of fluids, and the horse became worse and, 6 days later, died. At necropsy, a tumor was found to be compressing the neurohypophysis and the area in the brain in which the thirst centers are believed to be located. It is believed that hypernatremia in this horse was a result ...
Marinkovic D, Aleksic-Kovacevic S, Plamenac P.Chronic obstructive pulmonary disease (COPD) is an inflammatory obstructive disease of the airways characterized with hypersensitivity of the airway tissues to various allergens, most commonly the fungi contained in the poor-quality hay and straw bedding-Saccharopolyspora rectivirgula, Aspergillus fumigatus, and Thermoactinomyces vulgaris. It is manifested clinically in middle-aged horses with recurrent episodes of dyspnea, chronic cough, and their reduced athletic and working capacity. Pulmonary emphysema and lack of pulmonary collapse are the most common gross lesion. Pathohistological findi...
Martel G, Crowley D, Olive J, Halley J, Laverty S.Extensive osteochondritis dissecans (OCD) lesions of the lateral ridge of the trochlea of the femur (LRTF), the most common OCD-affected site in the stifle, have a poor outcome with surgical debridement and can be career ending. The early detection of osteochondrosis lesions and their conservative management holds the promise to enhance outcome. We hypothesise that ultrasonography is a valuable field screening tool to detect and monitor early subclinical LRTF osteochondrosis. Objective: The goals were to 1) describe the normal ultrasonographic features of the LRTF in foals of different ages an...
Stewart AJ, Pettigrew A, Cochran AM, Belknap JK.The liver and lung are not only described as "target organs" in sepsis in most species, but are purported to be sources of circulating inflammatory mediators central to the systemic inflammatory response syndrome (SIRS). As we have recently reported an inflammatory response in the laminar tissue in laminitis similar to that described in "target organs" in human sepsis, we investigated the inflammatory response of the lung and liver in the black walnut extract (BWE) model of equine laminitis to determine (1) if a similar systemic inflammatory response occurs in this laminitis model as described...
Wilson AD.Horses are affected by a wide variety of arthropod ectoparasites, ranging from lice which spend their entire life on the host, through ticks which feed over a period of days, to numerous biting insects that only transiently visit the host to feed. The presence of ectoparasites elicits a number of host responses including innate inflammatory responses, adaptive immune reactions and altered behaviour; all of which can reduce the severity of the parasite burden. All of these different responses are linked through immune mechanisms mediated by mast cells and IgE antibodies which have an important ...
White SD, Affolter VK, Schultheiss PC, Ball BA, Wessel MT, Kass P, Molinaro AM, Bannasch DL, Ihrke PJ.A Quarter horse filly bred from two horses affected with HERDA (hereditary equine regional dermal asthenia) was observed clinically and its skin histologically for the 1.5 years of its life. Severe signs of the disease did not manifest until 1.5 years of age, and were not temporally related to saddling. Histological comparison to an age-, breed- and sex-matched control did not show any consistent diagnostic features. Monitoring of the proband substantiated previous reports of (i) the autosomal recessive nature of the disease, (ii) mares affected with HERDA being able to foal without damage to ...
Latimer FG, Blackford JT, Valk N, Wan P, Patton S.To use gastrointestinal linear stapling instrumentation to perform a closed one-stage functional end-to-end jejunojejunostomy in adult horses as an alternative to a stapled side-to-side jejunojejunostomy. Methods: Clinical outcome, anatomic and histological architecture, and anastomotic dimensions were determined at 2, 4, 8, 16, and 24 weeks postoperatively. Methods: 18 adult horses. Methods: The anastomosis and peritoneal cavity were inspected for adhesions. The diameter and circumference of the anastomosis and jejunum oral and aboral to the anastomosis were determined from digitized contrast...
van Zadelhoff C, Schwarz T, Smith S, Engerand A, Taylor S. To describe detectable and non-detectable naturally occurring cartilage damage of the equine distal interphalangeal (DIP) joint using plain magnetic resonance (MR) imaging and gadolinium and saline MR arthrography. The second objective was to quantify the sensitivity, specificity and accuracy in detection of cartilage damage. In a pilot study, the distal limbs of two horses with confirmed osteoarthritis of the DIP joint were imaged with low-field MR. Magnetic resonance images were assessed in consensus by three observers and compared to gross pathological findings. Subsequently, a prospectiv...
Harrison GD, Duncan ID, Clayton MK.The age of onset of equine recurrent laryngeal neuropathy has not been ascertained, although the clinical condition of left laryngeal hemiplegia ("roaring") has been recognized for centuries. The purpose of this study was to evaluate the laryngeal muscles of draft horse foals for the presence of fiber-type grouping, indicating denervation and reinnervation, and to determine if histological evidence of recurrent laryngeal neuropathy was present. Abductor and adductor laryngeal muscles from the left and right sides were collected immediately after euthanasia from male draft horse foals, six less...
Richards KS, Riley EM, Taylor DH, Morris DL.Protoscoleces of Echinococcus granulosus were subjected to high concentrations of praziquantel (10-1000 micrograms/ml medium or cyst fluid) for a short, 10 min duration in vitro or in situ within cysts. Drug efficacy was then monitored either by in vitro culture in drug-free medium and/or by passage into rodents. The in vitro test of effectiveness suggested that ovine-derived protoscoleces were more sensitive than those of equine origin, and that the in vitro method of treatment was more successful than that performed in situ. However, the subsequent passage of treated protoscoleces, whether i...
Dakin SG, Dyson SJ, Murray RC, Tranquille C.Osseous abnormalities associated with collateral ligament (CL) injury of the distal interphalangeal (DIP) joint have been documented using magnetic resonance imaging (MRI) but there is currently limited information about the frequency of osseous pathology associated with CL injury. Objective: To determine the frequency of occurrence of osseous abnormality coexistent with CL injury of the DIP joint and describe the distribution and character of osseous lesions; and to establish if there was an association between osseous abnormality and increased radiopharmaceutical uptake (IRU). Objective: The...
Ramsay JD, Evanoff R, Mealey RH, Simpson EL.In racehorses, serum gamma-glutamyltransferase (GGT) activity is positively correlated with cumulative days in training and, when ≥100 IU/L, has been associated with poor performance. The prevalence of increased GGT activity in North American Thoroughbreds and its aetiopathogenesis are unknown. Four emerging viruses, pegivirus E (PgV E; equine pegivirus), hepacivirus A (HcV A; equine hepacivirus), pegivirus D (PgV D; Theiler's disease virus), and equine parvovirus-hepatitis (EqPV-H) have been identified in horses with clinical and subclinical hepatopathy. Available prevalence data indicate ...
Simeonova GP, Krastev SZ, Simeonov RS.The pathogenic mechanism of equine recurrent uveitis (ERU) is still poorly defined and many variations between experimental animal models and spontaneous disease exist. Objective: The aim of our study was to investigate if Th17 cell-mediated response plays role in the pathogenesis of the used experimental model in horses and to reveal its pathological findings. Methods: Experimental uveitis was induced in 6 healthy horses. The concentrations of retinal autoantigen CRALBP and IL-17 were measured using ELISA in aqueous humor and vitreous body of the 12 inflamed eyes as well as in 12 control non-...
Nikles SA, Heath TJ.In the horse, several thousand lymph nodes receive lymph from the intestine, part of which is very large and contains microorganisms that enable the animal to utilize refractory dietary constituents such as cellulose. The aim of this study was to describe the pathways by which lymph is delivered into, traverses, and is drained from these lymph nodes. These pathways were studied with either Microfil or methacrylate casting materials and with light and electron microscopy. The afferent lymphatic vessel delivering lymph into one of the nodes divides over the capsular surface and within trabeculae...
White NA.Intestinal infarction associated with cranial mesenteric artery thrombosis, without strangulation obstruction of the intestine, was studied in 18 horses. Findings normally of value in evaluating horses with acute abdominal pain (heart rate, rectal palpation findings, gastric reflux) or classification of the degree of pain were not helpful in diagnosing the problem. Similarly, packed cell volume, plasma total protein, circulating white blood cell count, peritoneal white blood cell count, and peritoneal fluid total protein were not of value in predicting severity of the intestinal damage, locati...
Brounts SH, Rashmir-Raven AM, Black SS.This case report describes a distinctive deep cutaneous lesion in a 1-year-old Quarter Horse filly with hyperelastosis cutis. The horse had a typical clinical presentation of hyperelastic skin associated with a 6-month history of cutaneous wounds that developed following minor cutaneous trauma. Punch biopsies of skin from the affected horse were thinner than similar biopsies from an age- and breed-matched control. Significant microscopic lesions were not seen in cutaneous punch biopsies stained with haematoxylin and eosin and Masson's trichrome stains, but the ultrastructure of the dermis from...
Pedersen HG, Watson ED, Telfer EE.Follicular atresia has been examined previously by various biochemical and histological methods. The aim of this study was to compare, for the first time, detection of granulosa cell apoptosis by biochemical DNA analysis and microscopic examination of fresh granulosa cell morphology with the established method of detecting atresia by histology in equine follicles. DNA extracted from granulosa cells was examined by staining with ethidium bromide and end-labelling with [(32)P]dideoxy-ATP, which labels the free 3'-end of DNA fragments. In 25 of 26 follicles (96%) there was agreement between end-l...
Wisner ER, O'Brien TR, Lakritz J, Pascoe JR, Wilson DW, Tyler WS.Complete thoracic radiographic examinations were performed on 7 horses ranging in age from 24 to 60 months, followed by in-situ lung fixation. Radiographs were examined by 3 radiologists for the presence, degree and distribution of generalised pulmonary patterns within a region of interest in the caudodorsal lung. Pulmonary tissue was obtained from 12 sites within a designated volume of interest in the caudodorsal lung, corresponding to the area of interest evaluated radiographically, and examined for the presence, character and severity of microscopic lesions. Radiographic findings within the...
Kuwamura M, Shirota A, Yamate J, Kotani T, Ohashi F, Sakuma S.A thyroid gland tumor, showing unusual histology, was identified in a 13-year-old male Andalusian horse. Microscopically, the tumor consisted of neoplastic proliferation of C-cell (parafollicular cell) with cytoplasmic fine granules, containing diffusely distributed, variously sized colloid-containing follicles. Immunohistochemically, the neoplastic C-cell were positive for calcitonin and follicleforming epithelial cells showed a positive reaction for thyroglobulin. Ultrastructurally, membrane-bound secretory granules up to 250 nm in diameter were found in the cytoplasm of the parafollicular c...
Breider MA, Kiely RG, Edwards JF.A generalized debilitating disease in a horse was believed to be related to hypersensitivity to migrating strongyle larvae. The clinical signs included weight loss, diarrhea, and ulcers on all 4 coronary bands. The mare's condition deteriorated rapidly, so the mare was euthanatized and necropsied. The major histopathologic findings were chronic multifocal eosinophilic pancreatitis, hepatic portal fibrosis, biliary hyperplasia, and chronic ulcerative eosinophilic colitis. This case was similar to previously reported cases of chronic eosinophilic gastroenteritis in horses. Although the etiologic...
