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.
Menzies-Gow NJ, Bailey SR, Berhane Y, Brooks AC, Elliott J.To determine the effect of endotoxin (lipopolysaccharide [LPS]) on vasoactive mediator production by cultured equine digital vein endothelial cells (EDVECs). Methods: EDVECs obtained from forelimb digital veins of 7 healthy adult horses. Methods: EDVECs were incubated with or without LPS (1 microg/mL) for 0, 2, 4, 6, 22, and 24 hours. The EDVECs were incubated for 18 hours with LPS (10 pg/mL to 1 microg/mL) with or without ibuprofen, cycloheximide, or L-nitroarginine methyl ester. Medium concentrations of prostacyclin, cyclic guanosine monophosphate, endothelin-1, and thromboxane A(2) were det...
Johns IC, Sweeney RW.Liver biopsy is useful in the diagnosis of liver disease in horses. However, bleeding is the major complication. Liver dysfunction can result in abnormalities in coagulation, although there is no definitive association between risk of hemorrhage after biopsy and coagulopathy in humans. Frequency of coagulopathies in horses with liver disease and the nature and frequency of complications after liver biopsy are not reported. Objective: To determine whether there is an association between coagulopathy and hemorrhage after liver biopsy in horses. Methods: Horses with suspected liver disease from w...
Ferreira JC, Gastal EL, Ginther OJ.Transrectal color and power Doppler ultrasonography was used to study uterine blood flow and perfusion in mares with and without uterine cysts. Vascular perfusion of the uterus and blood flow velocities, vascular perfusion, diameter, circumference, and area of a cross section of the mesometrial attachment were evaluated. To study the effect of internal cysts, two matched groups (cystic and control, n=21 mares/group) were used. Uterine vascular perfusion in mares with cysts was less (P<0.0001) in the cystic than the noncystic region and less (P<0.0009) than that for controls. Mares with c...
Hanche-Olsen S, Teige J, Skaar I, Ihler CF.Cases of hindlimb digital extensor weakness of unknown etiology have been observed in Norway since 1995. Objective: We hypothesized that the observed bilateral extensor weakness was attributable to neuropathy of the distal nerves and that this was related to environmental factors, possibly dietary. Methods: Seventy-five horses with digital extensor weakness occurring from 1995 to 2004 are described. Methods: Eleven horses were examined at The Norwegian School of Veterinary Science, and the medical records of 64 horses seen in ambulatory practice were reviewed. Results: There was no apparent se...
Wernery U, Knowles NJ, Hamblin C, Wernery R, Joseph S, Kinne J, Nagy P.A virus was isolated from aborted dromedary (Camelus dromedarius) fetuses during an abortion storm in Dubai, United Arab Emirates. Laboratory investigations showed the causative agent to be indistinguishable from equine rhinitis A virus (ERAV), a picornavirus. Two pregnant dromedaries experimentally infected with the camel virus isolate both aborted and an identical virus was reisolated from both fetuses, thus confirming the diagnosis. The extremely high prevalence of antibody (>90 %) and the high titres recorded against ERAV in the dromedary herd clearly showed that ERAV does infect dromedari...
van Galen G, Cassart D, Sandersen C, Delguste C, Nollet H, Amory H, Ducatelle R.Polyneuritis equi (PNE) is a rare neurological disease in the horse. Because of the suspicion in PNE of a T-lymphocyte mediated immune response against the myelin, the objective of this study was to determine the composition of the inflammatory infiltrate in the involved nerves of 3 horses with PNE, studied retrospectively. T-lymphocytes were demonstrated in the lesions, which suggests a T-lymphocyte mediated immune response against myelin. In addition, the presence of B-lymphocytes indicated a local production of antibodies. More research, involving a prospective study, is needed to determine...
Faleiros RR, Macoris DG, Alves GE, Souza DG, Teixeira MM, Moore RM.The purpose of this study was to observe and characterize colonic and lung lesions in horses subjected to experimental distension and decompression of the small colon. Sixteen healthy adult horses were divided into 2 groups: 9 horses that were subjected to distension of the small colon by means of a latex balloon surgically implanted in the lumen and inflated to a pressure of 40 mm Hg for 4 h, and 7 horses in which the balloon was implanted but not inflated. Colonic biopsy specimens were collected before balloon implantation, at the end of the period of obstruction, and 1.5 and 12 h after deco...
Sturgeon BP, Milne EM, Smith KC.A 20 x 10 cm, lobulated mass was present in the perianal region of a 4-year-old Dales pony. Histopathology revealed an unencapsulated, loose arrangement of sheets and whorls of narrow mesenchymal cells, situated in the deep dermis. Intervening areas had a myxomatous appearance. The whorls were often arranged around a central structure resembling an axon or a vascular structure. Immunohistochemistry revealed that the elongated mesenchymal cells and central axon-like structures expressed vimentin, S-100, and neuron-specific enolase, but not pancytokeratin, glial fibrillary acid protein, and the ...
Jacobsen B, Venner M, Gerdwilker A, Wohlsein P.A ventral meningomyelocele was found in a five week old, male German warmblood foal which exhibited central nervous symptoms. This rare malformation in horses may be caused by absent or defective fusion of vertebral bodies leading to herniation of the spinal cord and meninges with subsequent degenerative alterations of the spinal cord.
Muller S, Grzybowski M, Sager H, Bornand V, Brehm W.This report describes a case of nodular posthitis caused by Halicephalobus gingivalis in a 24-year-old warmblood horse. Macroscopic examination revealed a multinodular, partially ulcerated mass on the external lamina of the prepuce. Nematode migration from unfixed biopsy material in phosphate-buffered saline revealed adult nematodes with the typical morphological features of H. gingivalis: distinctive rhabditiform oesophagus with corpus, isthmus and bulb and the dorsoflexed ovary. The main histopathological features consisted of submucosal confluent granulomatous foci containing cross- and tan...
Allen GP, Bolin DC, Bryant U, Carter CN, Giles RC, Harrison LR, Hong CB, Jackson CB, Poonacha K, Wharton R, Williams NM.An emerging problem of equine herpesvirus-1 (EHV-1) infection in horses in the USA is a high-mortality myeloencephalopathy that commonly occurs where large numbers of horses are stabled. EHV-1 isolates recovered from recent neurological outbreaks represent a mutant virus strain that possesses enhanced neuropathogenicity. A central question of EHV-1 myeloencephalopathy is the latency carriage rate for these mutants of EHV-1 in USA horse populations. Objective: To estimate the prevalence of neuropathogenic strains of EHV-1 as latent infections in the Thoroughbred broodmare population of central ...
Divers TJ, Irby NL, Mohammed HO, Schwark WS.Information on antibiotic concentrations in the equine eye following systemic therapy is limited. Reports that Leptospira spp. are frequently present in the eyes of horses with recurrent uveitis, emphasises a need for studies on ocular concentrations of specific antibiotics. Objective: 1) Enrofloxacin, administered i.v. at 7.5 mg/kg bwt q. 24 h, results in aqueous humour concentrations greater than the reported minimum inhibitory concentration (MIC) for Leptospira pomona. 2) Aqueous humour paracentesis sufficiently disrupts the blood-aqueous humour barrier (BAB) to cause an increase in aqueous...
Hahn CN, Matiasek K, Syrja P, Jokinen TS, Macintyre N, Tulamo RM.A neurological disorder characterised by pelvic limb metatarsophalangeal joint extensor paresis has been observed in numerous horses in Scandinavia for the last decade. Very little has been formally reported and there have been no detailed assessments of the neurological signs or neuropathological lesions. Objective: To describe the epidemiological and pathological features of an outbreak of 'Scandinavian knuckling syndrome' in a riding stable in southern Finland. Methods: Clinical neurological examination of 4 cases and neuropathological assessment of tissues of one case were performed. Resul...
Scorpio DG, Leutenegger C, Berger J, Barat N, Madigan JE, Dumler JS.Anaplasma phagocytophilum causes human granulocytic anaplasmosis by inducing immunopathologic responses. Its immunodominant Msp2 protein is encoded by a family of >100 paralogs. Msp2 (msp2) expression modulates in the absence of immune pressure, and prolonged in vitro passage modulates in vivo virulence. Because programmed MSP2 expression occurs in Anaplasma marginale, we hypothesized a similar event in A. phagocytophilum in vivo, with specific Msp2 expression triggering immunopathologic injury or clinical manifestations of disease. We examined msp2 transcripts in 11 B6 mice and 6 horses inocu...
Cheetham J, Radcliffe CR, Ducharme NG, Sanders I, Mu L, Hermanson JW.Studies are required to define more accurately and completely the neuroanatomy of the equine dorsal cricoarytenoid muscle as a prerequisite for developing a neuroprosthesis for recurrent laryngeal neuropathy. Objective: To describe the anatomy, innervation, fibre types and function of the equine dorsal cricoarytenoid muscle. Methods: Thirty-one larynges were collected at necropsy from horses with no history of upper airway disease and 25 subjected to gross dissection. Thereafter, the following preparations were made on a subset of larynges: histochemical staining (n = 5), Sihler's and acetylch...
Wilson ME.Pathologic conditions of the urinary tract may produce specific clinical signs, but they are more than likely to be nonspecific clinical signs, which often occur with chronic renal disease in addition to countless other diseases. Further, clinical signs that may seem to be directly related to the urinary tract may be the result of other systemic diseases. Thus, before embarking on diagnostics, it is important to obtain a thorough history and physical examination.
Arroyo LG, Stämpfli HR.Renal tubular disorders have been sporadically reported in horses. Only three types of tubular defects have been recognized: (1) nephrogenic diabetes insipidus, attributable to unresponsiveness of the renal tubules to antidiuretic hormone; (2) distal renal tubular acidosis (RTA; type I); and (3) proximal RTA (type II). The following review focuses on RTA and nephrogenic diabetes insipidus.
Schmitz DG.Many different substances can induce toxic damage to various structural components of the equine kidney, and most lack pathognomonic signs. Some of these agents have specific treatments, although many do not. Supportive and symptomatic therapy is an important aspect of treatment of most cases of equine nephrotoxicosis. Regardless of cause, if the toxic substance is removed or neutralized before significant renal damage, full recovery of renal function may occur. Many horses already have significant renal damage before a definitive diagnosis is made, and the prognosis for full recovery thus rem...
Williams KJ, Maes R, Del Piero F, Lim A, Wise A, Bolin DC, Caswell J, Jackson C, Robinson NE, Derksen F, Scott MA, Uhal BD, Li X, Youssef SA, Bolin SR.Pulmonary fibrosis and interstitial lung disease are poorly understood in horses; the causes of such conditions are rarely identified. Equine herpesvirus 5 (EHV-5) is a gamma-herpesvirus of horses that has not been associated with disease in horses. Pathologic and virologic findings from 24 horses with progressive nodular fibrotic lung disease associated with EHV-5 infection are described and compared with 23 age-matched control animals. Gross lesions consisted of multiple nodules of fibrosis throughout the lungs. Histologically, there was marked interstitial fibrosis, often with preservation ...
Warhonowicz M, Staszyk C, Gasse H.The hypsodont equine cheek tooth erupts continuously throughout life. The collagen fibers of the periodontal ligament (PDL) have to remodel constantly to allow the tooth to move in an occlusal direction. Remodeling of the collagen fiber bundles needs to be well-coordinated in order to maintain functional tooth support. The aim of this study was to examine the role of matrix metalloproteinase-1 (MMP-1) in the collagen remodeling of the equine PDL under physiological conditions. Specimens containing the PDL interposed between the dental cementum and the alveolar bone were taken from nine Warmblo...
van Brantegem L, de Cock HE, Affolter VK, Duchateau L, Govaere J, Ferraro GL, Ducatelle R.Early diagnosis and monitoring progression of chronic diseases in elastin-rich tissues, such as chronic progressive lymphoedema in draught horses and chronic obstructive pulmonary disease (COPD) is still a real challenge in the horse. Use of an enzyme-linked immunosorbent assay (ELISA) to detect anti-elastin antibody (AEAb) levels might be useful to assess the status of such diseases. Baseline levels, representing physiological breakdown of elastin in normal horses, are not available at present. Objective: Levels of AEAb in healthy horses are generally low and follow the same age-related patte...
Schaudien D, Müller JM, Baumgärtner W.A well-circumscribed mass 70 x 35 x 28 cm in size and 41 kg in weight was detected at necropsy in a male adult horse within the omentum major without any association to the gastrointestinal tract. The tumor consisted of multiple white-to-yellow lobules and displayed a firm consistency. In addition, multiple cysts filled with blood-like fluid, and multifocal areas of necrosis were observed. Histologically, the mass consisted of slightly pleomorphic spindloid-shaped cells arranged in interlacing bundles containing elongated nuclei with blunt ends. The majority of tumor cells revealed a positive ...
Heim A, Passos LM, Ribeiro MF, Costa-Júnior LM, Bastos CV, Cabral DD, Hirzmann J, Pfister K.Blood samples were collected from 487 adult horses, including 83 pregnant mares, at a slaughterhouse located in Araguari, Minas Gerais State, Brazil. For each blood sample, the packed cell volume (PCV) was determined, and Giemsa-stained smears were microscopically examined for the presence of hemoparasites. The plasma was examined by the indirect fluorescent antibody test for detection of antibodies against Babesia caballi and Theileria equi. In addition, DNA was extracted and analyzed by a multiplex real-time polymerase chain reaction (PCR), specific for B. caballi and T. equi. Products of PC...
Abraham G, Kottke C, Ungemach FR.In recurrent airway obstruction (RAO) or heaves, bronchospasm has been attributed to enhanced cholinergic activity. However, the expression and function of muscarinic acetylcholine receptors (mAChR) and their signaling components are not yet known. Thus, we examined the expression, subtype distribution and postreceptor signaling pathways of mAChR in the peripheral lung, bronchial and tracheal epithelia with the underlying smooth muscle from nine horses with RAO and 11 healthy control horses. In RAO horses, no significant segment-dependent alteration in mAChR density and subtype distribution (a...
Moyaert H, Decostere A, Pasmans F, Baele M, Ceelen L, Smits K, Ducatelle R, Haesebrouck F.A novel urease-negative Helicobacter species has been isolated from faecal samples of clinically healthy horses, but no information is available about the main sites of colonisation in the equine gastrointestinal tract nor is the pathogenic potential of this microorganism known. An experimental infection in horses was therefore carried out. Methods: Four horses were infected with H. equorum strain CCUG 52199T and subjected to euthanasia at 10 (n = 2) and 30 days (n = 2) post inoculation. A fifth animal was inoculated with phosphate buffered saline and used as control. Gastrointestinal samples ...
Charman RE, Vasey JR.Chronic facial defects extending into the sinuses of two mares were repaired using periosteal flaps. Partial osseous bridging was established over the defects following repair. Previous attempts to close the defects with skin alone had failed. A periosteal flap is a simple surgical technique that provides the foundations for successful repair, despite the chronicity of some fistulae.
Desjardins MR, Hurtig MB.The clinical, radiographic, arthrographic, arthroscopic, and pathological findings of three horses with femorotibial joint injuries are presented. Overall diagnostic accuracy is improved when clinical signs, arthrography, and arthroscopy are combined. Treatment of these injuries remains limited. One horse was euthanized, and two were treated by stall rest after diagnosis. Of the two surviving horses, one became a successful breeding animal, and the other was unable to perform as a pleasure horse.
Freese S, Sheats MK.A 20-year-old Paint gelding was evaluated for fever of unknown origin. History and clinical signs were consistent with potential tick-borne disease. Samples were collected and submitted for tick-borne disease panel, herpes virus, complete blood count, and serum biochemistry. Based on physical examination findings and vaccination history, the gelding was treated for suspected tick-borne disease with oxytetracycline (8 mg/kg intravenously BID) for 5 days, followed by doxycycline (10 mg/kg PO BID) for an additional 5 days. Although titers to Borrelia burgdorferi, Anaplasma phagocytophilum, an...
Allen D, White NA, Tyler DE.The morphologic effects of induced intraluminal hydrostatic pressures (IHPs) of 0, 9, and 18 cm H2O were evaluated in 33 isolated equine jejunal segments. Fifteen segments were distended with Tyrode's solution for 1 hour and nine segments for 4 hours. Tyrode's solution was added as needed to maintain the prescribed pressures. Nine other segments were left undisturbed for 4 hours after the initial distention period. On decompression of the intestinal segments, progressive peristaltic contractions resumed in all segments. Evaluation of intestinal sections by light microscopy and transmission ele...
Spoormakers TJ, Ensink JM, Goehring LS, Koeman JP, Ter Braake F, van der Vlugt-Meijer RH, van den Belt AJ.The occurrence of unexpectedly high numbers of horses with neurological signs during two outbreaks of strangles required prompt in-depth researching of these cases, including the exploration of magnetic resonance imaging (MRI) as a possible diagnostic technique. Objective: To describe the case series and assess the usefulness of MRI as an imaging modality for cases suspected of space-occupying lesions in the cerebral cavity. Methods: Four cases suspected of suffering from cerebral damage due to Streptococcus equi subsp. equi infection were examined clinically, pathologically, bacteriologically...
Heales CJ, Summers IR, Fulford J, Knapp KM, Winlove CP.The aetiology of bone marrow oedema-like abnormalities (BMOA) seen on magnetic resonance imaging (MRI) is as yet not fully understood. The current study aimed to investigate the potential of projection radiography and Raman microspectroscopy to provide information regarding the underlying physiological changes associated with BMOA in equine bone samples. Methods: MRI was used to assess 65 limbs from 43 horses. A subset of 13 limbs provided 25 samples, 8 with BMOA present and 17 as controls; these were examined with projection radiography to assess bone mineral density and Raman spectroscopy to...
Beard W.The respiratory system is a frequent cause of exercise intolerance in performance horses. Labored breathing, fatigue during performance, and prolonged recovery after exercise are common complaints. Inadequate fitness level and diseases of the cardiovascular system are differential diagnoses that share these complaints and should be ruled out. Generation of increased airway noise is a clinical sign that implicates the upper respiratory system. A careful history from the owner and endoscopy of the upper airway are the most useful diagnostic tools. Endoscopy during exercise on a treadmill is indi...
Pearce DJ, Hitchens PL, Malekipour F, Ayodele B, Lee PVS, Whitton RC.Fatigue-induced subchondral bone (SCB) injury is common in racehorses. Understanding how subchondral microstructure and microdamage influence mechanical properties is important for developing injury prevention strategies. Mechanical properties of the disto-palmar third metacarpal condyle (MCIII) correlate poorly with microstructure, and it is unknown whether the properties of other sites within the metacarpophalangeal (fetlock) joint are similarly complex. We aimed to investigate the mechanical and structural properties of equine SCB from specimens with minimal evidence of macroscopic disease....
Kitamura H, Okumura M, Sato F, Kimoto K, Kohama M, Hashimoto Y, Tagami M, Iwanaga T.Our previous study established protein gene product 9.5 (PGP 9.5), a ubiquitin C-terminal hydrolase, as a specific cytochemical marker of synovial lining cells (type B synoviocytes) in the horse joint. The present study aimed to detect PGP 9.5 in the synovial fluid and shows that PGP 9.5 is a valuable marker of osteoarthritis in the horse. Immunohistochemical staining confirmed rich and consistent localization of PGP 9.5 immunoreactivity in the cytoplasm of synovial lining cells in the normal horse joint. Western blot analysis of synovial fluid from normal joints could detect a significant ban...
Gericota B, Aleman M, Kozikowski TA, Pesavento P, Bollen AW, Madigan JE, Higgins RJ.A 4-year-old Dutch warmblood mare was presented with a 10-month history of ataxia and proprioceptive deficits. Computed tomography defined a large, non-contrast enhancing mass in the left cerebral hemisphere. Necropsy examination revealed a tumour that effaced much of the piriform and temporal lobes. Microscopically the lesion was classified as a grade IV glioblastoma with an oligodendroglial component (GBM-O). The tumour was composed of highly pleomorphic cells organized in different patterns within a fibrillary stroma. There were multiple foci of necrosis. At the periphery of the tumour neop...
Vallance SA, Vidal MA, Whitcomb MB, Murphy BG, Spriet M, Galuppo LD.To evaluate use of a diode laser to induce tendinopathy in the superficial digital flexor tendon (SDFT) of horses. Methods: 4 equine cadavers and 5 adult horses. Methods: Cadaveric SDFT samples were exposed to a diode laser at various energy settings to determine an appropriate energy for use in in vivo experiments; lesion size was assessed histologically. In vivo experiments involved laser energy induction of lesions in the SDFT (2 preliminary horses [0, 25, 75, and 87.5 J] and 3 study horses [0 and 125 J]) and assessment of lesions. Study duration was 21 days, and lesions were assessed clini...
Wilson DG, Cooley AJ, MacWilliams PS, Markel MD.In six horses, a 0.05% solution of chlorhexidine diacetate was used to lavage one tarsocrural joint; the contralateral control joint was lavaged with lactated Ringer's solution. Horses were evaluated daily for lameness. Synovial fluid samples were collected on days 1, 4, and 8 for determination of protein concentration, total and differential leukocyte counts, and mucin clot formation. After death on day 8, synovium and osteochondral samples were collected from the tarsocrural joints for examination of morphology and proteoglycan staining. Lavage with chlorhexidine solution caused lameness tha...
Hahn CN, Matiasek K, Syrja P, Jokinen TS, Macintyre N, Tulamo RM.A neurological disorder characterised by pelvic limb metatarsophalangeal joint extensor paresis has been observed in numerous horses in Scandinavia for the last decade. Very little has been formally reported and there have been no detailed assessments of the neurological signs or neuropathological lesions. Objective: To describe the epidemiological and pathological features of an outbreak of 'Scandinavian knuckling syndrome' in a riding stable in southern Finland. Methods: Clinical neurological examination of 4 cases and neuropathological assessment of tissues of one case were performed. Resul...
Niebauer GW, Wolf B, Yarmush M, Richardson DW.Thirty-one horses with secondary osteoarthritis as a sequel of trauma (chip fractures) or osteochondritis dissecans were screened for immune complexes (IC) and anticollagen antibodies. Eighty-two percent of horses with joint disease had circulating C1q-binding IC; 77% of those horses had IC in synovial fluids of affected joints. Although only a few horses had anticollagen type-II antibodies, anticollagen type-I antibodies were found in sera of 25% of the horses and in 41% of their synovial fluids. This correlated well with the clinical data and suggested that antibodies might have been elicite...
Hopster K, Jacobson B, Hopster-Iversen C, Rohn K, Kästner SBR.Inappropriate mechanical ventilation can lead to ventilator-induced lung injury (VILI). Aim of this study was to evaluate the effects of inhalation anaesthesia and ventilation with and without recruitment (RM) and PEEP titration on alveolar integrity in horses. Twenty-three horses were divided into 4 groups (group OLC ventilated with OLC, group IPPV ventilated with intermittent positive pressure ventilation, group NV non-ventilated, and group C non-anaesthetized control group). After sedation with xylazine and induction with diazepam and ketamine anaesthetized horses were under isoflurane anae...
Srihakim S, Swerczek TW.Parasite-free pony foals (n = 10) were infected orally with 1000,000 Parascaris equorum embryonated eggs. One pony foal each was euthanatized on days 1, 3, 5, 7, 11, 16, 23, 27, 42, or 80 after infection. Foals infected for more than 7 days showed signs of coughing, anorexia, rough coat, and weight loss. Cellular changes in the blood were mild anemia, marked eosinophilia, and leukopenia. Gross postmortem lesions included hemorrhage, edema, and white-to-yellow necrotic foci (0.5 to 1.00 mm) in lungs, liver, and bronchial and hepatic lymph nodes. Microscopically, the liver was hemorrhagic and ha...
Headley SA, de Carvalho PH, Cunha Filho LF, Yamamura AA, Okano W.The cause of the death of a 16-month-old Brasileiro-de-Hipismo filly and a 3-year-old male Paint Horse with clinical manifestations of anemia and apathy from southern Brazil was investigated. These horses were maintained at the same stable; received hay as part of their diet and were submitted for routine necropsy evaluations. Significant gross findings included several nodules randomly distributed throughout the pulmonary lobes of both horses, and the kidneys, myocardium, and the frontal lobes of the cerebrum of the filly. Histopathological evaluation revealed pyogranulomatous bronchopneumoni...
Gaughan EM, Gift LJ, Frank RK.Tubular duplication of the cervical portion of the esophagus was diagnosed in a 10-day-old female Quarter Horse. The foal was examined because of the development of a 12- to 15-cm diameter mass at the caudal aspect of the mandible after suckling. The foal was dyspneic when in lateral recumbency. Radiography and ultrasonography revealed a fluid- and gas-filled mass. Endoscopy revealed a normal-appearing upper airway and esophagus. Complete surgical resection of the mass was successful. The mass had a 3-mm diameter communication with the esophageal lumen at the pharyngoesophageal oriface. Histol...
Rowe EL, White NA, Buechner-Maxwell V, Robertson JL, Ward DL.To identify apoptosis in equine intestines and determine whether apoptosis is associated with gastrointestinal tract disease or a specific tissue layer of intestine. Methods: 38 horses that underwent surgery or were euthanatized for small or large intestine obstruction, strangulation, or distension and 9 control horses euthanatized for reasons other than gastrointestinal tract disease or systemic disease. Methods: Specimens were collected at surgery from intestine involved in the primary lesion and distant to the primary lesion site or at necropsy from several sites including the primary lesio...
Lowe J, Clifford L, Julian A, Koene M.The data presented in this paper are derived from an in vivo study performed to characterize the nature of the synovial integration process of a 2.5% synthetic cross-linked injectable polyacrylamide hydrogel (2.5 iPAAG) injected IA in horses. Methods: 10 healthy horses not suffering from OA or signs of joint disease were administered 50 or 100 mg 2.5 iPAAG in a total of 13 metacarpophalangeal or middle carpal joints. Methods: Injected joints were examined at 0, 14, 42, and/or 90 days postinjection. Parameters investigated included clinical examination, synoviocentesis, gross pathology, histolo...
Andersen C, Walters M, Bundgaard L, Berg LC, Vonk LA, Lundgren-Åkerlund E, Henriksen BL, Lindegaard C, Skovgaard K, Jacobsen S.Osteoarthritis (OA) remains a major cause of lameness in horses, which leads to lost days of training and early retirement. Still, the underlying pathological processes are poorly understood. MicroRNAs (miRNAs) are small non-coding RNAs that serve as regulators of many biological processes including OA. Analysis of miRNA expression in diseased joint tissues such as cartilage and synovial membrane may help to elucidate OA pathology. Since integrin α10β1-selected mesenchymal stem cell (integrin α10-MSC) have shown mitigating effect on equine OA we here investigated the effect of integrin α10...
is one of the most pathogenic nematodes affecting equids. Larval migration through the cranial mesenteric artery (CMA) with attendant arteritis and thromboembolism can result in fatal non-strangulating intestinal infarction. Once considered a historical disease, recent studies have described the reemergence of this pathogen in several European countries; however, little is known of the current prevalence of in the Canadian horse population. Unassigned: To determine the prevalence of active cranial mesenteric arteritis in horses submitted for postmortem examination to the Diagnostic Services...
Nath LC, Saljic A, Buhl R, Elliott A, La Gerche A, Ye C, Schmidt Royal H, Lundgren Virklund K, Agbaedeng TA, Stent A, Franklin S.Approximately 1-2 per 100,000 young athletes die from sudden cardiac death (SCD) and extreme exercise may be associated with myocardial scar and arrhythmias. Racehorses have a high prevalence of atrial fibrillation (AF) and SCD but the presence of myocardial scar and inflammation has not been evaluated. Cardiac tissues from the left (LAA) and right (RAA) atrial appendages, left ventricular anterior (LVAPM) and posterior (LVPPM) papillary muscles, and right side of the interventricular septum (IVS-R) were harvested from racehorses with sudden cardiac death (SCD, n = 16) or other fatal injur...
Bishop SP, Cole CR, Smetzer DL.Twelve horses and 3 mules with grade II or louder prolonged diastolic murmurs were selected for functional and histopathologic study. Aortic insufficiency was demonstrated in all mules and in all except two horses on the basis of murmurs, jet lesions and/or pathologic and incompetent valve cusps. In 15 control animals lesions resulting in aortic insufficiency were not found.
A thick fibrous band was present on all aortic valve cusps judged to be definitely insufficient. This band occurred at the line of valvular closure, parallel to the free edge, and allowed eversion of the peripheral portio...
Pandey VS.The lungs and livers of 429 adult donkeys from different parts of Morocco were examined for hydatid cysts; 4·2% of lungs were infected and 2·1% of livers. Most of the cysts were small and had very hard thick walls; 61% of the donkeys had only one hydatid cyst; 78·5% of them were sterile and 29% caseated or calcified.
Cho DY, Leipold HW.The report describes a case of myelodysplasia involing spinal cord segments C7 to T8 of a 5 month old part-Thoroughbred foal. There was a single extensive syringomyelic and hydromyelic cavity which extended from the seventh cervical segment (C7), to the seventh thoracic segment (T7), abnormal size and shape of central canal, and disorderly differentiation of the grey and white matter. The cause of the defect is unknown.
Proctor-Brown L, Hicks R, Colmer S, Guilfoyle D, Dallap-Schaer B, Johnson AL, Tomlinson J.Digital cryotherapy (DC) is frequently used as laminitis prophylaxis for horses. While DC with ice-water slurries is reported to be safe for up to 48 h, the safety of sleeve-style digital cryotherapy (SSDC) with ice in direct contact with the distal limb has not been evaluated. Our objective was to determine the incidence of distal limb pathologic conditions (DLPC) among horses treated with SSDC. A retrospective study of cases from 2011 to 2015 identified 285 horses treated with SSDC for a minimum of 12 h. Data collected from medical records included demographic, treatment, diagnostic, and...
Ramsauer AS, Wachoski-Dark GL, Fraefel C, Ackermann M, Brandt S, Grest P, Knight CG, Favrot C, Tobler K.There is growing evidence that equine papillomavirus type 2 (EcPV2) infection is etiologically associated with the development of genital squamous cell carcinoma (SCC) and precursor lesions in equids. However, the precise mechanisms underlying neoplastic progression remain unknown. To allow the study of EcPV2-induced carcinogenesis, we aimed to establish a primary equine cell culture model of EcPV2 infection. Three-dimensional (3D) raft cultures were generated from equine penile perilesional skin, plaques and SCCs. Using histological, molecular biological and immunohistochemical methods, rafts...
Thomas HL, Livesey MA, Caswell JL.Multiple aneurysmal bone cysts (ABCs) are previously unreported in horses. An ABC was diagnosed in the left 3rd metacarpal of a Thoroughbred foal, which partially resolved following surgical curettage. A 2nd ABC developed in the left tibia, 7 wk postoperatively, and the foal was euthanized.
