Histopathology in horses involves the microscopic examination of tissue samples to study the manifestations of disease. This field provides insights into the structural and cellular changes that occur in equine tissues as a result of various pathological conditions. Common applications of histopathology in equine medicine include the diagnosis of neoplastic, inflammatory, and degenerative diseases. Techniques such as tissue staining and immunohistochemistry are employed to identify specific cellular components and pathological markers. This page aggregates peer-reviewed research studies and scholarly articles that explore the methodologies, findings, and implications of histopathological investigations in equine health.
Celik F, Karabulut B, Uslug M, Cankaya E, Eroksuz Y, Simsek S. is a parasitic cestode primarily maintained within an equine-canine life cycle, with horses, donkeys, mules, and other ungulates serving as intermediate hosts. Although has historically been considered non-zoonotic, recent molecular studies suggest that this assumption may need to be reevaluated. This study aimed to investigate the presence and molecular characterization of in equids from Türkiye. A retrospective analysis of 52 equine necropsies performed between 2020 and 2025 identified hydatid cysts in one Arabian horse and two donkeys. Gross and histopathological examination confirmed t...
Souto EPF, Dantas VW, Oliveira AM, Garcia DS, Vilela VLR, Neto EGM, Mota RA, Dantas AFM.Strongylus vulgaris remains a significant cause of disease in equids, especially in regions with insufficient deworming practices. Objective: To describe the epidemiological, clinical, pathological, and parasitological findings of vascular and extravascular lesions associated with S. vulgaris in equids. Methods: A retrospective analysis was conducted on necropsy reports from equids examined at the Animal Pathology Laboratory, Federal University of Campina Grande (2000-2024), targeting cases of vascular lesions associated with S. vulgaris. Epidemiological, clinical, and pathological findings we...
Mathys RA, Schmitz TR, Geyer H, Borel N, Hilbe M, Ohlerth S, Bischofberger AS.This study described, assessed and correlated ultrasonographic, computed tomographic, and histological findings in the sacroiliac joints of adult Warmblood horse cadavers. In total, 25 joints from 15 horses were examined post-mortem using transrectal ultrasonography and helical computed tomography. Findings on computed tomography were graded in the caudal joint third (caudally) and for the entire joint as mild, moderate, or severe. In total, 11 joints from nine horses were evaluated histologically. All joints (100%) showed abnormalities on computed tomography, and 92% (23/25) displayed abnorma...
Nieman RT, Lamim LI, Del Fava C.Fetal loss in mares can result from a range of causes, including infectious agents or noninfectious conditions such as neoplasia, which may originate from either the fetus or the dam. Among neoplastic conditions, teratomas are rarely reported and, to date, have not been described in the equine fetal testis. Teratomas arise from the partial differentiation of pluripotent germ cells and may occur in young and adult horses, typically in cryptorchid testes. Their gross and histopathological features vary widely between cases. This report describes a rare case of bilateral fetal testicular teratoma...
Pimenta J, Cotovio M.This study explores equine veterinarians' clinical practices regarding mucocutaneous tumors, based on a survey conducted among members of the Portuguese Association of Equine Veterinarians, and examines their perceptions of owner and buyer concerns regarding these tumors. Veterinarians expressed significantly greater concern about squamous cell carcinoma (SCC) during routine examinations ( < 0.001) compared to sarcoids and melanomas. Concern over sarcoids was significantly greater during pre-purchase evaluations compared to routine clinical exams ( = 0.03). For melanomas, a trend toward increa...
Martano M, Montagnaro S, Power K, Cuccaro B, Cutarelli A, Maiolino P, Restucci B.This study investigated the presence of δ bovine papillomaviruses (BPV-1, BPV-2, BPV-13, BPV-14) in equine skin lesions from Southern Italy, focusing on equine sarcoids and their histopathological correlations. 63 equine skin samples were analysed using PCR and sequencing for BPV detection, and their histopathological features were assessed. BPV DNA was detected in 69.84% of the samples, with BPV-1 and BPV-2 being the most prevalent genotype, followed by BPV-13, while BPV-14 was not detected. BPV DNA was also found in non-sarcoid tumours and non-neoplastic conditions. Histopathological analys...
Zamboulis DE, Thorpe CT.The high stresses and strains experienced by the superficial digital flexor tendon (SDFT) make it prone to age-related injury. The SDFT exhibits cellular and structural specializations, localized to the interfascicular matrix (IFM), enabling it to resist its extreme mechanical environment. With aging, these specializations are lost, impacting the ability of the tendon to withstand repeated loading. Within the IFM, there is loss of mechanical properties and organization accompanying cell senescence and a decreased resolution of inflammation. Developing therapeutics to reverse these changes may,...
Maeda Y, Kanno C, Sugiyama M, Yamamoto R, Sato S, Ando R, Noda R, Kawaguchi H, Takahashi F.A 17-year-old Thoroughbred stallion died suddenly after grazing. Necropsy revealed massive hemorrhage in the pericardial sac, suggesting cardiac tamponade. Aortic perforation was observed at the aortic origin, and hemorrhage was observed in and around the epicardium. Superficial observation of the aortic lumen revealed a transverse tear of the aortic wall at the bases of the right semilunar valve and septal semilunar valve. Fibro-osseous changes with calcification were histopathologically observed at the site of the rupture. A nodular goiter was observed in the left thyroid gland. The horse di...
Schollmeyer M, Liebler-Tenorio EM, Felton C, Kohl S, Ulrich R.A 34-year-old Haflinger gelding presented with a unilateral, expansile, intranasal mass that regrew after partial excision. After euthanasia, a large pedunculated mass that originated from the left caudal maxillary sinus and obliterated the left nasal cavity was seen by radiological and macroscopic examination. Histopathology revealed a poorly cellular, expansile, well-vascularized neoplasm composed of a loosely arranged meshwork of spindle cells and collagen fibres. Spindle cells were immunopositive for alpha-smooth muscle actin and occasionally for vimentin, whereas endothelial cells immunol...
Al-Hammadi MA.Equine papillomavirus type 1 (EcPV-1) causes cutaneous papillomatosis in horses, which is characterized by benign, proliferative epithelial lesions. Despite its global presence, the prevalence and characterization of EcPV-1 in Arabian horses in Saudi Arabia have not been previously reported. Unassigned: This study is the first to identify and comprehensively analyze EcPV-1 in four Arabian horses presenting with multiple raised, verrucous lesions around the muzzle and lips. Unassigned: This study involved clinical examination, skin biopsy collection, histopathological examination, and molecular...
Hansen S, Hopster-Iversen C, Berg L, Fjeldborg J, Massey C, Piercy RJ, Carstensen H.Exertional myopathies are recognised as a cause of poor performance in equines. In Icelandic horses presenting reduced performance and/or multi-limb lameness, no specific myopathy has been identified. Objective: To characterise the clinical presentation and histopathological findings in muscle biopsy samples from Icelandic horses demonstrating poor performance. Methods: Case series. Methods: Phenotypic characteristics, clinical examination and diagnoses of 17 Icelandic horses were studied. All horses had a resting serum creatine kinase (CK) and aspartate transaminase activities measured, and C...
Gómez-Torres F, Ballesteros-Acuña L, Ruíz-Sauri A.Arrhythmic sudden cardiac death in dogs and horses often results from ventricular arrhythmia secondary to myocardial damage. Despite this, limited data exist on the histomorphometric changes in cardiac conduction fibers (CCFs) and cardiac conduction cells (CCCs) following spontaneous myocardial infarction (MI). This study aimed to characterize morphometric and histological alterations in conduction fibers and their junctions with cardiomyocytes in infarcted hearts of horses and dogs. Unassigned: Ten hearts from horses and 10 from dogs that had died suddenly were examined. Histological and immu...
Dimuccio MM, Ceci E, Bonerba E, Celentano FE, De Marzo P, Leone R, Sportelli S, Bozzo G.The aim of this study was to evaluate cadmium (Cd) concentrations in horses imported from various European Union countries and slaughtered in Italy. In addition, we assessed the potential correlation between Cd levels in tissues and organs, and Cd-related gross and histological lesions. The animals were divided into six groups based on age and geographical origin. Among the 430 animals examined, gross renal lesions were observed in only two kidney samples from Polish horses, which also had the highest Cd concentrations: 9.1 mg/kg w/w and 8.23 mg/kg w/w, respectively. Further histological a...
Sinovich M, Monné Rodriguez J, Pieńkowska-Schelling A, Schelling C, Kelly PG.Introduction Monorchidism is a rarely described condition in the horse and is not to be confused with cryptorchidism. The diagnosis is challenging and confirmed by surgery and histology in combination with hormonal assays. This report describes, to the best of the author's knowledge, the first case of monorchidism and abdominal cryptorchidism of the developed testicle in a horse. Methods An Irish Cob underwent laparoscopic castration for removal of bilateral cryptorchid testicles. At surgery the horse was diagnosed as a monorchid with the testicle retained intra-abdominally. Histopathological,...
Azari O, Ghamsari SM, Roustaei A, Golchin D, Baharloo F, Javaheri M, Valizadeh N.This report describes a case of massive renal cell carcinoma (RCC) causing mild chronic colic in a 20-day-postpartum Arabian mare. The mare presented with deteriorating abdominal pain following normal parturition. Clinical examination revealed tachycardia, tachypnoea, weak intestinal motility and pale mucosal membranes. Rectal examination identified a very large mass in the caudal part of the abdominal cavity, and abdominal ultrasound examination revealed a huge space-occupying mass with renal architecture. During midline exploratory laparotomy, a massive tumour was observed in the anatomical ...
Abdelnaby EA, ElKader NAA, Yehia SG, Salem NY, Ramadan ES, Khattab MS, Farghali HA, Emam IA.This study aimed to demonstrate the vaginal tissue alterations via vaginal biopsy and hemodynamic alterations by introducing chromoendoscopy to analyse the effect of equine vaginitis on the oxidative and hormonal profile. Mares were divided into normal mares (N = 10) and affected mares (N = 10). Animals were subjected to Doppler ultrasonographic evaluation, endoscopic examination, oxidative stress was estimated, and biopsy samples were taken for histopathology and immunohistochemistry. Uterine body (UB) thickness (mm), circumference (mm) and area (mm) elevated significantly in infected...
Holz N, Suárez J, Hetzel U, Rampazzo A, Stoppini R.A 15-year-old Swiss Warmblood gelding was presented to the ophthalmology service of Zurich University due to severe visual impairment. Ophthalmic and neurologic examinations were performed, raising suspicion of post-retinal blindness. Standing contrast computed tomography (CT) of the head revealed a partially calcified, soft tissue attenuating mass in the sphenopalatine sinus with concurrent compression of the optic nerves and chiasm. Differential diagnosis included neoplasia and granulomatous disease. The horse was euthanized, and the head was subsequently examined by magnetic resonance imagi...
Trauner AM, McCoski SR, Satterfield MC, Bradbery AN.Reproductive health of male offspring following perturbations in maternal nutrition is not well-described in the horse; therefore, the objective of this study was to determine the effects of maternal overnutrition on neonatal foal testicular development. Sixteen Quarter Horse mares were used in a completely randomized design and stratified by expected foaling date, body weight, and body condition score into 1 of 2 dietary treatments beginning on gestational day 235: control (CON; n = 8) fed to meet nutrient requirements and overfed (HIGH; n = 8) fed 40% above CON. At 5 h postpartum, f...
Fernandes T, Robin MG, Oikawa MA, Alexander GR, Pompermayer E, Uberti B.Tracheal congenital defects are infrequent but serious findings in animals. Tracheal diverticula are congenital air-filled cystic lesions, a sub-type of paratracheal air cyst mainly found extra-thoracically in foals. We describe a case in a twelve-day old show Arabian colt with right sided unilateral cervical swelling since birth. Percutaneous ultrasound revealed a heterogeneously air- and fluid-filled spheroid mass, and upper airway endoscopy confirmed luminal communication to the trachea. Contrasted computed tomography showed a narrow isthmus originating between two proximal tracheal rings a...
Gillen A, Archer D, Ireland J, Rocchigiani G.Strangulating lipomata are the most common cause of small intestinal strangulating obstruction. Evaluation of histological features of pathological and non-pathological lipomata, and the histological properties of omental and retroperitoneal fat have not been described. Objective: To characterise histological features of equine abdominal lipomata, omental and retroperitoneal adipose tissue, and associations between them. Methods: Prospective observational anatomic (gross and histological). Methods: Horses undergoing emergency laparotomy for management of abdominal pain in a single hospital wer...
Engiles JB, Stefanovski D, van Eps A.To examine the effects of prolonged preferential weight bearing (PWB) and reduced ambulation (RA) on hoof lamellae using a nonpainful in vivo experimental model. Unassigned: 12 healthy Standardbred horses were housed in stocks continuously for 92 hours. A platform shoe was placed on 1 forelimb in the PWB group (n = 6) to increase the load on the supporting limb (SL) by approximately 10% bodyweight, whereas the RA group (n = 6) had normal weight bearing. Archived healthy horse (n = 8) samples were used as controls. Histomorphometry and histochemistry (terminal deoxynucleotidyl transferase dUTP ...
Guo W, Li Z, Mao W, Liu X, Yang Y, Yu J, Yang H, Gao R.Flunixin meglumine (FM) is commonly used in painful conditions in horses; however, it may contribute to equine gastric ulcer syndrome (EGUS). Some veterinarians combine omeprazole (OME) and FM to reduce EGUS risk. However, the efficacy and safety of this combination in Mongolian horses with chronic lameness remain unknown. Objective: To investigate the changes in lameness and EGUS scores in Mongolian horses through the comparison of three treatment strategies: FM, FM + OME and placebo treated control (CON) and to assess the effects of these treatments on gastric fluid pH, serum total prote...
de Moura Alonso J, Apolonio EVP, Teng FS, Perandré PI, Amorim RL, Mazaro RD, Watanabe MJ, Alves ALG, Hussni CA.In horses, basal cell neoplasms are uncommon benign tumors with slow growth mostly reported in the skin and eyelid. Malignant presentation is even more uncommon. This report describes a basal cell carcinoma (BCC) in the periocular region of a 10-year-old donkey. The animal presented good body condition and a neoformation in the right eye, noted 3 months prior to hospital admission. At the ophthalmological examination, the mass was identified above and adhered to the cornea, measuring 3.0 × 2.5 × 1.5 cm. Cytology revealed a suspicion of a malignant epithelial neoplasm, characterized ...
Campebell RC, Oliveira AB, Fagundes JLA, Fortes BNA, Veado HC, Macedo IL, Dallago BSL, Barud HS, Adorno J, Salvador PAV, Santos PS, Castro MB.This study evaluates the wound-healing process in horses following the application of two treatment modalities: bacterial cellulose hydrogel with alginate (BCAW) and frog skin (FSW) dressings on experimentally induced skin wounds. Throughout the experiment, no clinical abnormalities were noted in the horses, although initial wound assessments indicated edema and sensitivity. Local hemorrhage was observed in some cases on Day 0, with granulation tissue formation evident by Day 14. Epithelialization began around Day 14 but did not reach complete healing in any group by Day 28. The analysis showe...
Luedke LK, Seabaugh KA, Cooper BG, Snyder BD, Wimmer MA, McIlwraith CW, Barrett MF, Kawcak CE, Grinstaff MW, Goodrich LR.Post-traumatic osteoarthritis (PTOA) is a common cause of lameness in the horse. There is no cure, therefore treatments are aimed at reducing pain and improving the joint environment by modifying inflammatory pathways or by viscosupplementation. Here, we report the safety and efficacy of the biolubricant (poly(2-methacryloyloxyethyl phosphorylcholine; pMPC) to mitigate the physical, gross, histological, and biochemical effects of arthritis. We created an osteochondral fragment in the middle carpal joint of one limb in 16 horses to induce PTOA; the contralateral limb served as a sham-operated j...
Carvalho Serena G, Marchezan Piva M, Viezzer Bianchi M, Fernandes da Fonseca HC, Chitolina Pupin R, Martins Basso R, Secorun Borges A....In horses, systemic calcinosis is a rare syndrome characterised by muscle lesion associated with the mineralisation of large muscle groups or other organs, in the absence of an alternative cause for the calcification, such as toxic, enzootic or metabolic. Molecular and histopathological aspects of the disease are still poorly elucidated. Objective: To describe the epidemiological, pathological and molecular aspects of systemic calcinosis in a convenience sample of six horses submitted to necropsy in the Southern and Midwestern regions of Brazil. Methods: Retrospective exploratory study. Method...
Nassar AFC, Chiebao DP, Fava CD, Miyashiro S, Castro V, Ogata RA, Yamamora JM, Monteiro CAS, Monteiro EJB.Glanders is a zoonotic disease of equids caused by the bacterium Burkholderia mallei, responsible for considerable economic loss. This study aimed to describe the clinical manifestations, pathological findings, and also bacteriological and molecular methods for agent detection in naturally infected animals (16 adult horses and one fetus) detected by serological survey from three glanders outbreaks. Of the 16 horses, 6 (37.5%) did not show clinical signs. After necropsy,samples of organs, lymph nodes, lesions and secretions were collectedfor histopathology, bacterial isolation, and PCR. The cli...
Charles A, Kerckhove HV, De Maré L, Cassart D, Ficheroulle J, Pouyade GR, Tosi I.A Standardbred racehorse was presented for exercise intolerance, weight loss, pyrexia and facial deformity. Radiography and ultrasonography revealed periostitis and regional soft tissue swelling of maxillary bones. Computed tomography excluded any dental or sinus origin of these abnormalities. Further deformities on distal limbs and skin lesions appeared during hospitalization. Radiography identified bilateral periostitis and soft tissue swelling in the distal radius and metatarsal bones, as observed in the head, suggestive of hypertrophic osteopathy (HO). Skin biopsies revealed granulomatous ...
Valberg SJ, Porter A.Muscle biopsy is often required to provide a definitive diagnosis for neuromuscular disorders and can be performed using open surgical or percutaneous needle biopsy techniques. Fresh samples that are subsequently frozen in the laboratory are preferred by laboratories engaged in research, whereas formalin-fixed muscle is processed by diagnostic laboratories with specialized tinctorial and immunohistochemical techniques. Interpretation by an experienced histopathologist, combined with the signalment, history, and clinical input, is essential for establishing a diagnosis. This article outlines be...
Morris JM, Lassaline ME, Nunnery CM, Teixeira LBC, Martins BC, Moore BA, Knickelbein KE, Scherrer NM, Plummer CE.Little information describing the biologic behaviour and therapies for corneal lymphoma exist. Objective: To characterise histologically confirmed equine corneal lymphoma considering breed, age or sex predisposition, histologic and immunologic features, therapies and outcomes. Methods: Retrospective case series. Methods: A multicentre retrospective medical record review was used to identify horses that presented with corneal disease confirmed morphologically as corneal lymphoma from 2012 to 2022. Results: Mean age at diagnosis was 10.5 years. Males represented 18/26 cases. Warmblood (14) and...
Theoret CL, Olutoye OO, Parnell LK, Hicks J.To compare histopathologic features of a fibroproliferative disorder in horses (exuberant granulation tissue-EGT) and people (keloid). Methods: Archival tissue samples of EGT (n = 8) and keloid (12). Methods: After automated hematoxylin and eosin, histochemical (Gomori trichrome, Verhoeff-van Gieson elastin) and immunohistochemical (vimentin, α-smooth muscle actin, CD34, CD68, CD117) stainings, tissue sections were evaluated using a semi-quantitative grading scale for presence or absence of ulceration, keloidal collagen, myofibroblasts, and elastic fibers as well as degree of inflammation, fi...
Deeg CA, Ehrenhofer M, Thurau SR, Reese S, Wildner G, Kaspers B.Equine recurrent uveitis (ERU) is the most serious eye disease in horses worldwide. Despite the fact that ERU is generally considered to be immune mediated, a detailed description of the histopathology of the posterior part of ERU eyes is lacking. Here, we examined sections of paraffin-embedded eyes using histological and immunhistological methods. Twenty seven eyes of 20 horses with ERU and 30 eyes of 15 healthy control horses were included in this study. We could consistently demonstrate an involvement of the retina and the choroid in all examined eyes of horses with spontaneous ERU. In eyes...
Rikihisa Y, Pretzman CI, Johnson GC, Reed SM, Yamamoto S, Andrews F.Ehrlichia risticii has a close antigenic relationship to E. sennetsu. Sera of ponies experimentally infected with E. risticii, the etiologic agent of Potomac horse fever, consistently reacted with E. sennetsu, a human pathogen, in indirect fluorescent-antibody (IFA) testing, while human E. sennetsu convalescent serum reacted with E. risticii by IFA testing and immunoferritin labeling of cells infected in vitro. Two ponies injected intravenously with live E. sennetsu did no develop clinical illness. Subsequent injection with live E. sennetsu did not develop clinical illness. Subsequent injectio...
Chang YF, Novosol V, McDonough SP, Chang CF, Jacobson RH, Divers T, Quimby FW, Shin S, Lein DH.Seven specific-pathogen-free (SPF) ponies, 1-5 years old, were exposed to Borrelia burgdorferi-infected adult ticks while being treated with dexamethasone over 5 consecutive days. One SPF pony (pony No. 178) was first exposed to laboratory-reared nymphs without B. burgdorferi infection and 3 weeks later was exposed to B. burgdorferi-infected adult ticks with concurrent dexamethasone treatment for 5 consecutive days. Four uninfected ponies treated with dexamethasone, exposed to laboratory-reared ticks without B. burgdorferi infection served as uninfected controls. Clinical signs, bacteriologic ...
Lehmann J, Ellenberger C, Hoffmann C, Bazer FW, Klug J, Allen WR, Sieme H, Schoon HA.The aim of the present study was to characterize the morpho-functional features of endometrosis in barren and foaling mares, using both conventional histopathological and immunohistochemical methods. Endometrial biopsy samples were collected during the physiological breeding season from 159 estrous, clinically healthy mares (mean age 12 years), and the quality and degree of endometrosis was histomorphologically defined. The mares were bred and those that foaled were put in the foaling group whereas those that did not foal were placed in the barren group. Foaling mares were then compared with b...
Monthoux C, de Brot S, Jackson M, Bleul U, Walter J.Skin malformations that resembled manifestations of Ehlers-Danlos-Syndrome were described in a variety of domestic animals during the last century as cutis hyperelastica, hyperelastosis cutis, dermatosparaxis, dermal/collagen dysplasia, dermal/cutaneous asthenia or Ehlers-Danlos-like syndrome/s. In 2007, the mutation responsible for Hereditary Equine Regional Dermal Asthenia (HERDA) in Quarter Horses was discovered. Several case reports are available for similar malformations in other breeds than Quarter Horses (Draught Horses, Arabians, and Thoroughbreds) including four case reports for Warmb...
Ferris RA, McCue PM, Borlee GI, Glapa KE, Martin KH, Mangalea MR, Hennet ML, Wolfe LM, Broeckling CD, Borlee BR.Bacteria in a biofilm community have increased tolerance to antimicrobial therapy. To characterize the role of biofilms in equine endometritis, six mares were inoculated with -engineered strains isolated from equine uterine infections. Following establishment of infection, the horses were euthanized and the endometrial surfaces were imaged for luminescence to localize adherent -labeled bacteria. Samples from the endometrium were collected for cytology, histopathology, carbohydrate analysis, and expression of inflammatory cytokine genes. Tissue-adherent bacteria were present in focal areas bet...
Schramme M, Hunter S, Campbell N, Blikslager A, Smith R.Tendon injuries are common in all athletic activities in both humans and horses. Research of treatment modalities for this disease has typically been performed on a model of collagenase-induced tendonitis. This model has several disadvantages. Our hypothesis was that a reproducible core lesion could be created surgically in superficial digital flexor tendons (SDFT), which could then be evaluated consistently using ultrasonography. Methods: Four horses free of forelimb lameness were used in this study. Each horse underwent general anaesthesia and a synovial resector was used to create a core le...
Teifke JP, Kidney BA, Löhr CV, Yager JA.We examined 12 formalin-fixed paraffin-embedded feline skin tumours which had the histopathological features of fibropapillomas for the presence of papillomavirus (PV) DNA using touchdown polymerase chain reaction (PCR), DNA sequencing and nonradioactive in situ hybridization. Nine of the tumours contained a 102-bp PCR product demonstrated using consensus PV primers that amplify a portion of the L1 gene. The nucleotide sequences are closely related, but not identical to that of ovine PV type 2, rabbit oral PV and reindeer PV. The deduced amino acid sequences had strong homologies with the majo...
Wong DM, Belgrave RL, Williams KJ, Del Piero F, Alcott CJ, Bolin SR, Marr CM, Nolen-Walston R, Myers RK, Wilkins PA.5 horses were evaluated because of decreased appetite, weight loss, fever, cough, tachypnea, and respiratory distress. Results: Tachycardia, tachypnea, increased respiratory effort, lethargy, fever, poor body condition, and nasal discharge were detected in various combinations on initial physical examination. Evaluation of the lower portion of the respiratory tract via radiography and ultrasonography revealed a severe nodular interstitial pattern. Histologic examination of lung tissue revealed interstitial expansion of alveolar parenchyma with collagen, intraluminal accumulation of neutrophils...
Meyer J, Delay J, Bienzle D.Clinical, laboratory and tissue findings from 37 horses with lymphoma were investigated. Horses ranged in age from 0.3 to 20.5 years (median 5.0 years) and included 18 females and 19 males. Weight loss (n = 25) and ventral edema (n = 21) were the most common historical and physical abnormalities. The most common laboratory abnormalities were hyperfibrinogenemia (n = 26), hypoalbuminemia (n = 19), anemia (n = 19), leukemia (n = 14), hyperglobulinemia (n = 13), and thrombocytopenia (n = 13). Thirty-four tumors involved multiple lymphoid tissues and abdominal or thoracic organs, and 3 tumors were...
Rodrigues A, Fighera RA, Souza TM, Schild AL, Barros CS.The clinical signs and pathology of the central nervous system in 9 horses with naturally occurring neurologic disease due to Trypanosoma evansi are described. The clinical course was 2 to 20 days; clinical signs included marked ataxia, blindness, head tilt and circling, hyperexcitability, obtundity, proprioceptive deficits, head pressing, and paddling movements. Grossly, asymmetric leukoencephalomalacia with yellowish discoloration of white matter and flattening of the gyri were observed in the brain of 7 of 9 horses. Histologically, all 9 horses had necrotizing encephalitis that was most sev...
Goehring LS, van Maanen C, Berendsen M, Cullinane A, de Groot RJ, Rottier PJ, Wesselingh JJ, Sloet van Oldruitenborgh-Oosterbaan MM.Equid herpesvirus type 1 (EHV-1)-associated myeloencephalopathy (EHM) may follow an infection with the virus in horses. This study tested three hypotheses: (1) a large inhaled dose of a neuropathogenic EHV-1 strain would induce a cell-associated viraemia in all infected horses; (2) neurological disease will only occur in viraemic horses, and (3) the cerebrospinal fluid (CSF) composition following EHV-1 viraemia will be an indicator for EHM. Four EHV-1 seronegative horses were inoculated with EHV-1 by inhalation. Three developed clinical signs of neurological disease, which were mild in two hor...
de Laat MA, Sillence MN, McGowan CM, Pollitt CC.Endocrinopathic laminitis is frequently associated with hyperinsulinaemia but the role of glucose in the pathogenesis of the disease has not been fully investigated. This study aimed to determine the endogenous insulin response to a quantity of glucose equivalent to that administered during a laminitis-inducing, euglycaemic, hyperinsulinaemic clamp, over 48 h in insulin-sensitive Standardbred racehorses. In addition, the study investigated whether glucose infusion, in the absence of exogenous insulin administration, would result in the development of clinical and histopathological evidence of ...
Staszyk C, Bienert A, Kreutzer R, Wohlsein P, Simhofer H.A poorly described, painful disorder of incisor and canine teeth, variably causing periodontitis, with resorptive or proliferative changes of the calcified dental tissues, has recently been documented in aged horses. No plausible aetiopathogenesis for this syndrome has been recorded. Eighteen diseased teeth from eight horses were examined grossly and microscopically and showed the presence of odontoclastic cells by tartrate resistant acid phosphatase (TRAP) staining. A chronological sequence of odontoclastic resorption followed by hypercementosis was demonstrated and, consequently, the term eq...
Cnudde V, Masschaele B, De Cock HE, Olstad K, Vlaminck L, Vlassenbroeck J, Dierick M, Witte YD, Van Hoorebeke L, Jacobs P.Micro-CT is a non-destructive technique for 3D tomographic investigation of an object. A 3D representation of the internal structure is calculated based on a series of X-ray radiographs taken from different angles. The spatial resolution of current laboratory-used micro-CT systems has come down over the last years from a few tens of microns to a few microns. This opens the possibility to perform histological investigations in 3D on a virtual representation of a sample, referred to as virtual 3D histology. The advantage of micro-CT based virtual histology is the immediate and automated 3D visua...
Ricketts SW, Alonso S.The results of a retrospective analysis of 3,804 endometrial biopsy specimens collected from non-pregnant mares during the course of routine equine stud farm practice demonstrates a significant and practically useful correlation between the severity of chronic degenerative endometrial disease (CDE) diagnosed and age of mare at the time of examination. There were significant correlations between the number of foals born and the mares' barren years prior to biopsy and the severity of CDE, but the differences were not sufficiently large to be useful. Correlations between the severity of chronic i...
Ludwig H, Thein P.From 18 horses with clinical symptoms of an affection of the central nervous system and with histopathologic alterations in the brain, four were demonstrated to have Bornavirus-specific antibodies. The antibodies are monospecific, recognizing identical antigens from infected brains of different animal species as well as from persistently infected tissue culture cells. Discrete immunoglobulin species (oligoclonal IgG) can be demonstrated in concentrated horse cerebrospinal fluid; they carry Bornavirus antibody specificity. Their presence, together with the higher antibody titers in the cerebros...
Turley SM, Thambyah A, Riggs CM, Firth EC, Broom ND.The palmar aspect of the third metacarpal (MC3) condyle of equine athletes is known to be subjected to repetitive overloading that can lead to the accumulation of joint tissue damage, degeneration, and stress fractures, some of which result in catastrophic failure. However, there is still a need to understand at a detailed microstructural level how this damage progresses in the context of the wider joint tissue complex, i.e. the articular surface, the hyaline and calcified cartilage, and the subchondral bone. MC3 bones from non-fractured joints were obtained from the right forelimbs of 16 Thor...
Hurtig MB, Fretz PB, Doige CE, Schnurr DL.The mechanisms and completeness of equine articular cartilage repair were studied in ten horses over a nine month period. Large (15 mm square) and small (5 mm square) full-thickness lesions were made in weight bearing and nonweight bearing areas of the radiocarpal, middle carpal and femoropatellar joints. The horses were euthanized in groups of two 1, 2.5, 4, 5 and 9 months later. Gross pathology, microradiography, and histopathology were used to evaluate qualitative aspects of articular repair. Computer assisted microdensitometry of safranin-O stained cartilage sections was used to quantitate...
Tham HL, Linder KE, Olivry T.Autoimmune dermatoses targeting melanocytes have gained attention in human medicine due to their progressive nature and the social impact suffered by affected individuals. In veterinary medicine, vitiligo and the uveodermatological syndrome are the two autoimmune diseases that are known to affect skin melanocytes.In the first part of this article, we will review the signalment, clinical signs, histopathology and the treatment outcome of vitiligo in dogs, cats and horses; where pertinent, we compare the animal diseases to their human homologue. In a similar fashion, the information on the uveod...
Siger L, Bowen R, Karaca K, Murray M, Jagannatha S, Echols B, Nordgren R, Minke JM.Efficacy of the Recombitek Equine West Nile Virus (WNV) vaccine was evaluated against a WNV intrathecal challenge model that results in WNV-induced clinical disease. Ten vaccinated (twice at days 0 and 35) and 10 control horses were challenged 2 weeks after administration of the second vaccine with a virulent WNV by intrathecal administration. After the challenge, eight of 10 controls developed clinical signs of encephalomyelitis whereas one vaccinate exhibited muscle fasciculation only once. Nine controls and one vaccinate developed a fever. Histopathology revealed mild to moderate nonsuppura...
McCue ME, Valberg SJ, Lucio M, Mickelson JR.A missense mutation in the GYS1 gene was recently described in horses with polysaccharide storage myopathy (PSSM). Objective: The first objective was to determine the prevalence of the GYS1 mutation in horses with PSSM from diverse breeds. The second objective was to determine if the prevalence of the GYS1 mutation differed between horses diagnosed with PSSM based on grade 1 (typically amylase-sensitive) or grade 2 (typically amylase-resistant) polysaccharide. Methods: Eight hundred and thirty-one PSSM horses from 36 breeds. Methods: Horses with PSSM diagnosed by histopathology of skeletal mus...
Ortega J, Daft B, Assis RA, Kinde H, Anthenill L, Odani J, Uzal FA.Omphalitis and the resulting septicemia contribute to perinatal mortality in several animal species. In foals, the most important causes of omphalitis are Escherichia coli and Streptococcus zooepidemicus. However to date, no information has been published about the role of Clostridium sordellii in these infections. In this paper, we describe 8 cases of perinatal mortality in foals associated with internal umbilical remnant infection by C. sordellii. The foals studied were between 12 and 21 days old at the time of death, and various breeds were represented in the group. Five of the foals were m...
Contreras M, Morales A, García-Amado MA, De Vera M, Bermúdez V, Gueneau P.To assess the presence of Helicobacter DNA in the gastric mucosa Thoroughbred horses. Results: Squamous and glandular mucosa samples were collected from 20 Thoroughbreds. None of these horses had shown any clinical symptoms of gastrointestinal disease. Necropsy tissues were analysed using histopathological techniques and a Helicobacter genus-specific PCR assay followed by sequencing of the amplicons. Seven horses were diagnosed with gastric ulceration, five with gastritis and six with both pathologies. Only two horses had a healthy gastric mucosa. Helicobacter-like DNA was detected in two out ...
Bischofberger AS, Dart CM, Horadagoda N, Perkins NR, Jeffcott LB, Little CB, Dart AJ.To investigate the effect of 66% Manuka honey gel on the concentrations of transforming growth factor (TGF)-β1 and TGF-β3, bacterial counts and histomorphology during healing of contaminated equine distal limb wounds. Methods: In this experimental study of 10 Standardbred horses, five full-thickness skin wounds (2 × 1.5 cm) were created on one metacarpus and six similar wounds were created on the contralateral metacarpus. Wounds were assigned to three groups: non-contaminated control wounds; contaminated control wounds; contaminated wounds treated daily with 1 mL Manuka honey gel to...
Sponseller BT, Valberg SJ, Schultz NE, Bedford H, Wong DM, Kersh K, Shelton GD.Seasonal pasture myopathy (SPM) is a highly fatal form of nonexertional rhabdomyolysis that occurs in pastured horses in the United States during autumn or spring. In Europe, a similar condition, atypical myopathy (AM), is common. Recently, a defect of lipid metabolism, multiple acyl-CoA dehydrogenase deficiency (MADD), has been identified in horses with AM. Objective: To determine if SPM in the United States is caused by MADD. Methods: Six horses diagnosed with SPM based on history, clinical signs, and serum creatine kinase activity, or postmortem findings. Methods: Retrospective descriptive ...
Timoney JF, Kumar P.Little is known about entry and subsequent multiplication of Streptococcus equi following exposure of a susceptible horse. This information would have value in design of intranasal vaccines and understanding of shedding and protective immune responses. Objective: To determine entry points and sites of subsequent replication and dispersion of S. equi at different times after intranasal infection or commingling exposure. Methods: Previously unexposed horses and ponies were subjected to euthanasia 1, 3, 20 or 48 h following intranasal inoculation with biotin labelled or unlabelled S. equi CF32. S...
