Disease etiology in horses refers to the study of the causes and development of diseases within equine populations. It encompasses various factors, including genetic predisposition, environmental influences, infectious agents, and nutritional imbalances, that contribute to the onset and progression of diseases in horses. Understanding disease etiology is essential for identifying risk factors and implementing preventative measures in equine health management. This topic includes research on pathogen-host interactions, the impact of management practices on disease incidence, and the role of genetic and environmental factors in disease susceptibility. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, contributing factors, and implications of disease etiology in horses.
Jenkinson DM, Montgomery I, Elder HY, Mason DK, Collins EA, Snow DH.The ultrastructure of sweat glands from the skin of free sweating horses was compared with that of glands from anhidrotic cases. Evidence of atrophied and abnormal sweat glands in the anhidrotic horses indicates that the condition involves progressive failure of the glandular mechanism of sweat production.
Nimmo Wilkie JS, Yager JA, Nation PN, Clark EG, Townsend HG, Baird JD.A generalized, chronic, progressive, exfoliative dermatitis in five horses is described. Histologically, the lesion is characterized by a superficial and deep perivascular dermatitis which is eosinophil-rich with a marked lymphocytic and plasmacytic component, accompanied by marked acanthosis and hyperkeratosis. More severe cases progress to a lichenoid pattern with the same cellular composition with focal eosinophilic spongiosis and eosinophilic subcorneal pustules. Clinically, the disease is associated with chronic, severe weight loss and is fulminating. The skin lesions are accompanied by l...
Cahill JI, Goulden BE, Pearce HG.A review of the literature on stringhalt in horses is presented, including the aetiology, clinical signs, pathology and treatment of this disease. Three New Zealand outbreaks of stringhalt are reported and discussed. The occurrence of these (and most previously reported outbreaks) in the late summer and autumn, and the association of the disease with various weeds, indicates a likely toxic aetiology.
Ginther OJ, Bergfelt DR, Leith GS, Scraba ST.Pregnancy was determined by ultrasound on Days 11, 15, 20, 25, 30, 35, 40, 45, and 50 in 154 ponies and 27 horses. In ponies, the embryonic loss rate for Days 11 to 15 (28 154 , 18.2%) was greater (P<0.01) than for any of the subsequent five-day intervals (0% to 3.3%). There were no losses during Days 11 to 15 in horses (0 27 ), and the difference between ponies and horses was significant. The loss rates for the seven periods encompassing Days 15 to 50 were not significantly different among periods. Pseudopregnancy occurred more frequently (P<0.01) following embryonic loss after Day 20 (...
Wyn-Jones G, Peremans KY, May SA.The management of a case of quadrilateral flexural contracture in a 10-year-old pony is described. The animal was restored to normal appearance and function through a combination of surgical desmotomy and management techniques; the importance of analgesia and exercise as adjuncts to surgery is emphasised. The aetiology and pathogenesis of the condition in the immature animal and the adult is compared and a possible association is made between this condition and palmar fibromatosis (Dupuytren's contracture) occurring in man.
Cummings E, James ER.Of 664 horses reported to have originated in southeastern and midwestern United States, 341 (51.4%) were positive for Onchocerca cervicalis cutaneous microfilariasis. The highest prevalence of 68.8% was recorded for horses from Virginia. Horses with the highest concentrations of microfilariae (as high as 19,770 microfilariae/mg in 1 horse) were from the Southeast (Georgia, Florida, Tennessee, and Alabama). For horses from South Carolina, the prevalence of infection was 57.1%; from the Midwest (Kentucky, Illinois, Ohio, and Indiana), 54.4%; from North Carolina, 45.5%; from Pennsylvania, 7.7%; a...
Zamora CS, Vitums A, Foreman JH, Bayly WM, Weidner JP.On the basis of clinical and laboratory examinations, a ventricular septal defect or a variant of the tetralogy of Fallot was suspected in a 3-year-old filly with a history of poor growth rate and exercise intolerance. The filly was euthanatized and found to have a 3-chambered heart (cor triloculare biatriatum). The heart had 2 normally formed atria and a large common ventricle into which the right and left atrioventricular orifices opened and from which the aorta arose. There was a small separate chamber from which the pulmonary trunk originated. This chamber communicated with the common vent...
Sims LD, Tzipori S, Hazard GH, Carroll CL.Two foals aged 35 and 48 h from 2 Thoroughbred studs died several hours after developing clinical signs of depression, severe haemorrhagic diarrhoea and dehydration. Both foals had an acute haemorrhagic enteritis extending from the anterior jejunum to the terminal ileum which was characterised histologically by villus necrosis. Necrotic villi were surrounded by large numbers of rod-shaped Gram positive bacteria. Clostridium perfringens was recovered from the intestines of both foals and the isolates were considered to be C. perfringens type C. Other cases of diarrhoea were also observed in foa...
Van der Lugt JJ, Coetzer JA, Jordaan P, Marlow CH.Tyzzer's disease was diagnosed histologically in two foals, a 4-week-old Thoroughbred cross and a 6-week-old Arabian foal. Clinically both foals were in good health prior to a short illness lasting only a few hours. The liver lesions in both foals were characterized microscopically by multiple foci of necrosis. Variable numbers of elongated slender intracytoplasmic bacilli resembling Bacillus piliformis were demonstrated within hepatocytes bordering the necrotic foci.
Hurtig MB, Farrow CS, Fretz PB.The radial carpal and intermediate carpal bones were found to be fused in a four year old Quarterhorse stallion having a subtle forelimb lameness. Clinical examination, diagnostic local anesthesia, radiography and arthroscopy were used to arrive at the diagnosis. A cause could not be established, although perinatal deformation of cartilagenous carpal bone templates is suspected. A similar case of carpal bone fusion was found among carpi collected for an anatomical study, indicating this condition may be more common than expected. Clinicians should carefully evaluate the flexed lateral view of ...
French DD, Haynes PF, Miller RI.A horse had severe granulomatous lesions of the upper airways that were attributable to Conidiobolus coronatus. Therapeutic success was documented by clinical examination of the horse 4 years after treatment by surgical extirpation and intralesional and topical use of amphotericin B.
Sohrabi Haghdoost I, Zakarian B.THE results of a 20 year retrospective study of the tumours diagnosed in all equine cases referred to the Faculty of Veterinary Medicine, University of Teheran, for surgical treatment or post mortem examination are reported here.
Chan CW, Collins EA.An angiosarcoma involving the right frontal and maxillary sinuses in a nine-year-old Thoroughbred mare was studied post mortem by light and electron microscopy. Important diagnostic features included malignant endothelial cells lining ill-defined vascular spaces, supported by other vasoformative elements. Rhabdomyoblasts were also found. The tumour is apparently rarely seen in the nasal passages of the horse.
Foil L, Stage D, Adams WV, Issel CJ.The occurrence of tabanid feeding between mares and foals was observed. When mares and foals were observed freely moving within a pasture situation, foals had 2.43% (4 flies in 77 observations vs 297 flies in 139 observations) of the tabanid feeding occurrences of the mares. This difference in tabanid burden varied due to herd size, herd location, and tabanid species. Lower tabanid burden of foals was indicated as a practical protective mechanism against pathogenic agents mechanically transmitted by tabanids, such as equine infectious anemia virus.
Johnson P.An unusual compound of small molecular weight has been detected in serum from horses with acute grass sickness by solvent extractions and thin-layer chromatography. The substance has not been detected in the serum of normal horses or cases of equine colic and apparently disappears from grass sickness serum after two to three days of clinical illness. Although this compound is found in sera which are known to possess in vivo neurotoxicity, this property could not be demonstrated in either the total chloroform extract which contains the compound or in the hydrophilic serum components remaining a...
Leid RW, Coley SC, Blanchard DP, Perryman LE.The equine alternative complement pathway has been partially characterized and compared to the equine classical activation pathway. A dose-dependent lysis of RbRBC was observed with peak lytic values noted within 10 minutes at 37 degrees C when rabbit red blood cells (RbRBC) were used as an alternative pathway activator. Sheep red blood cells (SRBC) sensitized with rabbit hemolysin or partially purified equine IgM antibodies were equally sensitive to lysis. Dilution of the commercial hemolysin by 1/5 reduced lysis from 90% to 38% in the presence of constant cell numbers. Hemolysis of SRBC peak...
Giles CJ, Urquhart KA, Longstaffe JA.Clinical and laboratory findings are recorded from a series of 15 cases (aged one to 16 years) of sudden-onset chronic diarrhoea with weight loss, progressing in many cases to emaciation and death, associated with the emergence of fourth stage cyathostome (trichoneme) larvae in large numbers through the colonic and caecal mucosae. Apart from a single incident in mid-October, disease only occurred in winter and spring (January to May). Characteristic features included hypoalbuminaemia, increased alpha and beta plasma globulin levels and neutrophilia without left shift. Faecal egg counts were fr...
de Oliveira AC, Rosenbruch M, Schulz LC.The morphology of asteroid bodies in equine arteries is demonstrated by light microscopy as well as by scanning and transmission electron microscopy combined with chemical analysis. Asteroid bodies first occur in horses at four weeks of age in all investigated tissues except the esophagus and always are located in the subendothelial space. The number, shape, ultrastructure and chemical composition of asteroid bodies differ markedly--depending on the age of the horse. Asteroid bodies are round and smooth in foals, but are shaped irregularly and have several projections and marked stratified cal...
Clarke AF.Exercise induced pulmonary haemorrhage (EIPH) is a condition of uncertain aetiology. This article reviews the evidence relating to its incidence, clinical findings, radiological observations, histopathology and certain aspects of respiratory physiology. It is proposed that EIPH is primarily caused by mechanical stress in the dorsocaudal region of the lung.
Davies JV, Gerring EL.Small intestinal ischaemia is a cause of pain in man and horses. Occlusion of the vascular supply to Thiry loops in experimental ponies caused severe discomfort and loss of motility within a few minutes but these effects could not be reproduced by a similar procedure in intact gut preparations. However, embolisation of the mural vascular network produced ischaemia of the small intestine of anaesthetised ponies which led to a cessation of motility in the affected segments, though unaffected segments became hypermotile with a characteristic motility pattern. These results suggest the need for re...
Widders PR, Stokes CR, Newby TJ, Bourne FJ.This study identifies nonimmune binding of equine immunoglobulin by the causative organism of contagious equine metritis. Immunoglobulin binding to the bacterium was strongest for immunoglobulin G (IgG) and less for IgM; IgA was not bound. Binding of equine IgG was inhibited by human IgG, but not by IgG of domestic animals. Immunoglobulin binding by the bacterium appeared to be directed towards an epitope in the hinge region of the immunoglobulin molecule.
Rawlinson RJ, Jones RT.The history and clinical findings of 1 horses with guttural pouch mycosis referred to us are described. The salient features of the history and clinical signs common to both cases were profuse spontaneous nasal haemorrhage, partial pharyngeal paralysis; subsequently bilateral nasal discharge containing food material, inability to drink and parotid pain became evident. One case made a gradual recovery with conservative medical treatment while the second case was destroyed and submitted for post-mortem, histopathological and microbiological examination. This examination failed to establish the i...
Lacombe VA.Seizures are a diverse and very common set of chronic neurologic disorders in humans and dogs but are less common in horses. Seizures refer to a specific clinical event (described as sudden and severe) regardless of the etiology, which includes both intracranial and extracranial causes. Therefore, after briefly reviewing some definitions, this article aims to describe the use of a standardized classification, which could facilitate a logical approach for the clinician to establish a diagnosis, as well as to use a consistent mode of communication. For instance, seizures can be classified by typ...
van Dixhoorn ID, Meershoek LS, Huiskes R, Schamhardt HC.Motion of the navicular bone might play a role in the development of navicular disease in horses but is difficult to asses. In the present study, 3-dimensional motion of this bone was determined using roentgen stereophotogrammetric analysis. Tantalum pellets were inserted, in vitro, in the bones of 6 forelimbs of mature Shetland ponies and kinematics were measured during vertical loading up to 2 kN. The motions of the navicular bone and coffin joint were limited to flexion/extension, there were no substantial out-of-plane motions. There was only little flexion between the navicular bone and th...
Cohen ND, Mackay RJ, Toby E, Andrews FM, Barr BS, Beech J, Bernard WV, Clark CK, Divers TJ, Furr MO, Kohn CW, Levy M, Reed SM, Seahorn TL, Slovis NM.To identify risk factors for equine protozoal myeloencephalitis (EPM) among horses examined at 11 equine referral hospitals. Methods: Case-control study. Methods: 183 horses with EPM, 297 horses with neurologic disease other than EPM (neurologic controls), and 168 horses with non-neurologic diseases (non-neurologic controls) examined at 11 equine referral hospitals in the United States. Methods: A study data form was completed for all horses. Data were compared between the case group and each of the control groups by means of bivariate and multivariate polytomous logistic regression. Results: ...
Hansen S, Olsen E, Raundal M, Agerholm JS.Cerebellar abiotrophy (CA) is an uncommon hereditary neurodegenerative disorder affecting the cerebellar Purkinje cells. Equine CA has been reported in several breeds, but a genetic etiology has only been confirmed in the Arabian breed, where CA is caused by an autosomal recessive mutation. Methods: Clinical and histological findings consistent with CA are reported in an 8.5-month-old Icelandic filly. The filly showed a perceived sudden onset of marked head tremor, incoordination, ataxia, lack of menace response and a broad-based stance. Cerebrospinal fluid, hematological and biochemical findi...
Rose RJ.Complications from neurectomy have been well known for many years. A 16-year-old mare suffered bilateral luxation of the coffin joints following palmar neurectomy and was destroyed. Autopsy showed complete rupture of the deep flexor tendons, and the supporting ligaments of the coffin joints. Arthritis of the coffin joints, with erosion of articular cartilage was evident.
Mouithys-Mickalad A, Storms N, Franck T, Ceusters J, de la Rebière de Pouyade G, Deby-Dupont G, Serteyn D.Experimental laminitis, characterized by a failure of the dermal-epidermal interface of the foot, can be induced in horses by the oral administration of a black walnut extract (BWE). In the early phase of this severe and painful disease, an activation of neutrophil occurs, with the release of myeloperoxidase (MPO), a pro-oxidant enzyme of neutrophils, in plasma, skin, and laminar tissue. Juglone, a naphthoquinone derivative endowed with redox properties, is found in walnuts and has been incriminated in this neutrophil activation. We report for the first time the inhibitory activity of juglone ...
Scott ML, John EE, Bellone RR, Ching JC, Loewen ME, Sandmeyer LS, Grahn BH, Forsyth GW.Congenital stationary night-blindness (CSNB) is a recessive autosomal defect in low-light vision in Appaloosa and other horse breeds. This condition has been mapped by linkage analysis to a gene coding for the Transient Receptor Potential cation channel Member 1 (TRPM1). TRPM1 is normally expressed in the ON-bipolar cells of the inner nuclear layer of the retina. Down-regulation of TRPM1 expression in CSNB results from a transposon-like insertion in intron 1 of the TRPM1 gene. Stop transcription signals in this transposon significantly reduce TRPM1 primary transcript levels in CSNB horses. Thi...
Reubel GH, Studdert MJ.Based on sequence homology with human adenovirus 2 (HAdV2), the hexon gene of equine adenovirus 1 (EAdV1) was identified. HindIII restriction fragments containing the hexon and other viral genes were cloned into the plasmids pUC19 and pBlueScript SK(-) and sequenced. The nucleotide sequence of the hexon gene was completely determined and partial sequence data were obtained for seven other EAdV1 genes. Amino acid (aa) sequence comparison with published adenovirus (AdV) proteins identified the genes for the IIIa, penton, pVII, PVI, 23K proteinase, DNA binding and 100K proteins. The eight EAdV1 g...
Hryhorczuk DO, Withrow WA, Hesse CS, Beasley VR.The authors investigated an outbreaks of unusual illnesses in humans and horses residing within 1.3 km of a wire reclamation incinerator. The study included site visits; medical and veterinary examinations; analyses of furnace ash, fly ash, soil, and biologic samples for air residues. Tetrachlorodibenzo-p-dioxins (TCDDs) and tetrachlorodibenzofurans (TCDFs) were discovered in furnace ash, fly ash, soil, horse fat, and horse liver samples.
Lowden S, Heath T.In the horse ileum, lacteals in the villi are continuous with prelymphatic intercellular channels and a plexus of lymphatic sinuses in the lamina propria that encircle the domes of the follicle/dome structures and proprial follicles. These sinuses may act as the major entry site for many of the lymphocytes migrating from gut-associated lymphoid tissue via the lymphatic system. Vessels from this plexus penetrate the muscularis mucosae and lymph flows into lymphatic vessels within the interfollicular tissue between the follicles of both follicle/dome structures and lymphoglandular complexes (LGC...
Valberg SJ, Williams ZJ, Finno CJ, Schultz A, Velez-Irizarry D, Henry ML, Gardner K, Petersen JL.Both type 1 (PSSM1) and type 2 polysaccharide storage myopathy (PSSM2) are characterised by aggregates of abnormal polysaccharide in skeletal muscle. Whereas the genetic basis for PSSM1 is known (R309H GYS1), the cause of PSSM2 in Quarter Horses (PSSM2-QH) is unknown and glycogen concentrations not defined. Objective: To characterise the histopathological and biochemical features of PSSM2-QH and determine if an associated monogenic variant exists in genes known to cause glycogenosis. Methods: Retrospective case control. Methods: Sixty-four PSSM2-QH, 30 PSSM1-QH and 185 control-QH were identifi...
Cedrola F, Bordim S, D'Agosto M, Dias RJP.The aims of this study were to identify and quantify the gastrointestinal ciliates from Brazilian domestic horses, to compare the data obtained with previous studies and to review data on ciliate communities associated with horses around the world. We used eight domestic horses, kept under extensive management. Fecal samples were obtained immediately after defecation of animals and fixed in 18.5% formaldehyde. We identify 24 species of endosymbiotic ciliates, distributed in two subclasses, two orders, five families and 13 genera. The ciliate composition was similar among the animals analyzed. ...
Martín-Cuervo M, Gracia LA, Vieitez V, Jiménez J, Durán E, Ezquerra LJ.A 16-year-old, Lusitanian stallion was admitted to the Veterinary Teaching Hospital with a 12-hour history of signs of abdominal pain. Exploratory celiotomy was performed due to an inguinal hernia, and a second celiotomy was performed in response to the abdominal pain. The horse was euthanized and mesenteric venous thrombosis was diagnosed and considered likely due to peritonitis and systemic inflammatory response syndrome (SIRS). Un étalon Lusitanien âgé de 16 ans a été admis à l’hôpital d’enseignement vétérinaire avec une anamnèse de 12 heures de douleurs abdominales. Une coel...
Carneiro FP, Alonso MA, Redoan MA, Henriques DA, Lima FM, Oliveira RM, Cogliati B, Canisso IF, Fernandes CB.Nocardioform placentitis is a pathologically unique form of placental disease first diagnosed in central Kentucky in the mid-80s. Since then, the occurrence of nocardioform placentitis in the region has varied over the years, from sporadic cases to outbreaks. The disease has been sporadically detected in other countries and has not been confirmed in South America. A 13-year-old multiparous Mangalarga delivered a healthy filly at 340d gestation. The mare passed the fetal membranes 33 minute after foaling. Gross examination of the fetal membranes identified two focal lesions on the chorionic sur...
Nunn FG, Pirie RS, McGorum B, Wernery U, Poxton IR.There is much evidence to suggest that group III Clostridium botulinum (types C and D) are involved in the aetiology of equine grass sickness (EGS). Antibodies have been detected previously in the blood and high levels associated with resistance to disease. Specific mucosal antibodies in the gastrointestinal (GI) tract are likely to be important in protection, and this study was performed to ascertain if such antibodies could be detected and if their levels were related to disease state. Objective: To develop a method for quantifying IgA antibodies to C. botulinum types C and D in the GI tract...
Wilcox AL, Calise DV, Chapman SE, Edwards JF, Storts RW.Hypoxic/ischemic encephalopathy in a cloned American Quarter horse foal was initially associated with placental insufficiency and exacerbated by protracted hypotension during anesthesia for a surgical procedure. The foal, born at the Texas A&M Veterinary Medical Center, was diagnosed at birth with neonatal maladjustment syndrome that was accompanied by dysmaturity, muscle contracture of the front limbs, and a blood clot within the lumen of the urinary bladder. Seizures that developed after anesthesia were attributed to hypoxia/ischemia during anesthesia and culminated in death. Macroscopically...
van Wuijckhuise-Sjouke LA.Meconium constipation is observed in a number of foals during every foaling period. The literature on the clinical picture, methods of treatment and complications, is reviewed in the present paper. In addition, the cases of seventy-five foals are reviewed, in which meconium constipation was suspected and which were submitted to the Internal Disease Department of Large Animals during the period from 1972 to 1982. The clinical picture was found to be due to another disorder in nine cases. Treatment with castor oil and alcohol resulted in discharge of the meconium in fifty-eight cases. Complicati...
Green SL, Cochrane SM, Smith-Maxie L.Ten cases of equine Horner's syndrome were reviewed. None of the clinical signs in this series were transient (<48 hours). Sweating and ptosis were consistently observed by the attending clinician in over half of the affected horses. Enophthalmos and prolapse of the third eyelid were not reported consistently. The average duration of the clinical signs was 4.94 months and ranged from 14 days to 15 months. Eight of the ten horses developed associated complications, some of which affected performance. Airway obstruction and impedance of passage of a fiberoptic endoscope due to nasal mucosal e...
Björnsdóttir S, Ekman S, Eksell P, Lord P.Osteoarthrosis (OA) in the distal tarsal joints, bone spavin, is a well known condition which is common in Icelandic horses age 6-12 years. Objective: To determine the nature, location and age of appearance of early radiographic and histological changes in the centrodistal tarsal joint (CD) of young Icelandic horses. Methods: Slab sections from the CD of young Icelandic horses were examined by high detail radiography (age 6 months to 6 years, n = 111) and histology (age 6 months to 4 years, n = 82) to detect and describe the early changes indicative of OA. Horses younger than 5 years were unri...
Mohan K, Muvavarirwa P, Pawandiwa A.Among the Actinobacillus spp. only A. lignieresii represents a homogenous and well studied taxon. However, haemolytic and non-haemolytic strains of A. equuli and A. suis are also isolated from a wide range of diseases in a variety of hosts. These isolates often pose problems in definitive identification. Consequently, several studies have been published, emphasizing the need for detailed studies to reclassify various members of this genus and also to assess their disease significance. We isolated 48 strains of Actinobacillus from clinical cases in horses, cattle, sheep, cat, pigs and ostrich. ...
Marr KA, Lees P, Cunningham FM.Adherence to vascular endothelium and extracellular matrix proteins is a pre-requisite for neutrophil accumulation at sites of inflammation. In this study, equine neutrophil adherence to fibronectin and autologous serum-coated plastic in response to PAF, hrIL-8, hrC5a and PMA has been measured. In addition, the mechanisms involved have been investigated using monoclonal antibodies (MoAbs) against the beta2 integrin CD18. PAF and hrC5a caused similar, concentration dependent, increases in adherence to fibronectin- and serum-coated plastic (maximum responses 19 +/- 4% and 19 +/- 3% for PAF and 1...
Kurotaki T, Narayama K, Oyamada T, Yoshikawa H, Yoshikawa T.An immunohistochemical study was carried out on the kinetics of Langerhans cells (LCs) at various pathological stages of "Kasen". Skin lesions of "Kasen" that were collected by biopsy from May to October were classified histopathologically into three stages: initial (Group I, 31 cases), developing (Group II, 50 cases) and regressing (Group III, 13 cases). LCs showed a positive reaction with anti-equine thymocytes (EqT6) monoclonal antibody (MoAb) and anti-major histocompatibility complex (MHC) class II MoAb by immunohistochemical staining. The anti-EqT6 MoAb was intensely positive along the cy...
Dunkel B, Shokek AB, Wilkins PA.A neonatal foal with signs of rectal bleeding was diagnosed with an intraluminal rectal mass and intussusception on surgical exploration of the abdomen. Histologically, the mass consisted of cystic spaces lined by simple columnar epithelium with numerous goblet cells and was surrounded by thin bands of smooth muscle in a myxomatous stroma. Although the mass shared similarities with retrorectal cystic hamartoma (tailgut cyst) and juvenile polyps, described in human medicine, location and histologic findings were not entirely consistent with either condition.
Fox-Clipsham LY, Brown EE, Carter SD, Swinburne JE.The Fell and Dales are UK pony breeds that have small populations and may be at risk from in-breeding and inherited diseases. Foal immunodeficiency syndrome (FIS) is a lethal inherited disease caused by the recessive mutation of a single gene, which affects both Fell and Dales ponies and potentially other breeds that have interbred with either of these. FIS, previously known as Fell pony syndrome, is characterised by progressive anaemia and severe B lymphocyte deficiency. The identification of the causal mutation for this disease led to the recent development of a DNA-based carrier test. In th...
Fenger CK, Bertone JJ, Biller D, Merryman J.Generalized medullary infarction of the long bones was diagnosed in a 12-year-old Tennessee Walking Horse mare. The mare was referred after a 6-week course of shifting weight on her hind limbs, and kicking. Physical examination revealed mild stifle joint distention and withdrawal reactions to digital pressure over the long bones. Radiography revealed patchy areas of medullary sclerosis in the distal portion of each femur and proximal portion of each tibia. A full-thickness cortical and cancellous tibial biopsy revealed infarcted bone marrow, with cortical and periosteal osteonecrosis. The caus...
Zoll WM, Prakoso D, Dark M, Liu J, Stockdale-Walden H, Long MT.Eosinophils within the central nervous system are abnormal and are usually associated with fungal or parasitic infections in horses. Causative agents include Halicephalobus gingivalis, Sarcocystis neurona, and Neospora hughesi. Confirmation of these organisms via specific testing is typically not performed, and final diagnoses are often presumptive. With molecular technology, many of these organisms can now be confirmed. This is important for emerging and zoonotic pathogens, including Angiostrongylus cantonensis, an emerging parasite of interest in the southeastern United States. We retrospect...
Peham C, Schobesberger H.Knowledge of load effects is crucial for the understanding of the aetiology and pathogenesis of equine back problems. Objective: To investigate different load scenarios of the equine back, such as being ridden or increased muscle tone, using biomechanical simulations. Methods: Kinetic and kinematic data of 15 sound horses and the electromyelograph of their long back muscles were recorded. A biomechanical simulation model was used for simulations under different biomechanical scenarios (ridden/unridden, localised increased stiffness) using ADAMS. Results: The vertical forces acting through a ri...
Hébert L, Rincé I, Sanna C, Laugier C, Rincé A, Petry S.The genus Taylorella is composed of two species: (i) Taylorella equigenitalis, the causative agent of CEM, a venereally transmitted infection of Equidae and (ii) Taylorella asinigenitalis, a closely related species considered to be nonpathogenic, although experimental infection of mares with this bacterium resulted in clinical signs of vaginitis, cervicitis or endometritis. Currently, there is a need for an alternative host model to further study the taylorellae species. In this context, we explored Galleria mellonella larvae as potential alternative model hosts for taylorellae. Our results sh...
Valentine BA, Flint TH, Fischer KA.Serial sections of formalin-fixed, paraffin-embedded muscle biopsy specimens from 28 Quarter Horse, Paint, and draft-related breeds, aged 0.5-23 years, were treated with periodic acid-Schiff (PAS) stain for glycogen and were immunostained to detect ubiquitin expression. On the basis of findings in PAS-stained sections, a diagnosis of equine polysaccharide storage myopathy (EPSSM) was made in 22 horses aged 2-23 years (mean, 9.4 years); samples from 6 horses aged 0.5-15 years (mean, 7.3 years) had a normal PAS staining pattern, with no relevant lesions. Ubiquitin expression was detected in all ...
