Disease diagnosis in horses involves the identification and characterization of illnesses through various diagnostic methods and tools. This process is essential for effective veterinary care and management of equine health. Techniques used in diagnosing diseases in horses include clinical examinations, laboratory tests, imaging modalities such as ultrasonography and radiography, and molecular diagnostics. Blood tests are frequently utilized to assess parameters such as complete blood count and biochemical profiles, which can indicate underlying health issues. Additionally, advancements in genetic testing and biomarker identification have enhanced the ability to detect specific diseases early. This page aggregates peer-reviewed research studies and scholarly articles that explore diagnostic methodologies, their applications, and their impact on equine health management.
Wamsley HL, Alleman AR, Porter MB, Long MT.To evaluate CSF in horses with confirmed West Nile virus encephalomyelitis. Methods: Retrospective study. Methods: 30 horses. Methods: Results of CSF analyses from horses with acute neurologic signs attributed to West Nile virus infection that was confirmed by immunoglobulin M antibody capture ELISA were reviewed and analyzed. Results: Among 30 CSF samples, findings in 8 (27%) were within reference ranges and in 22 (73%) were abnormal. Among the 22 abnormal samples, mononuclear pleocytosis was found in 16 (73%) and high protein concentration with nucleated cell count within reference range was...
Hosaka Y, Kirisawa R, Yamamoto E, Ueda H, Iwai H, Takehana K.Although inflammatory activation of cytokines have been analyzed in various tissues, there have only been a few and as-yet-inconclusive studies on cytokines in equine tendons. In this study, the localizations of 4 cytokines (IL-1alpha, IL-1beta, TNFalpha and IFNgamma) in tendinocytes of the equine superficial digital flexor tendon (SDFT) were analyzed by the use of an immunohistochemical method. In inflamed tendons positive staining for all 4 cytokines antibodies were detected in endotedinieum cells and vascular epithelial cells. In contrast, negative or trace immunoreactions were obtained in ...
Parente EJ, Martin BB, Tulleners EP, Ross MW.To evaluate the occurrence of dorsal displacement of the soft palate (DDSP) during high-speed treadmill (HSTM) exercise in racehorses, and determine treatment efficacy relative to the endoscopic findings observed during resting and HSTM endoscopic examination. Methods: Retrospective study. Animals-Ninety-two racehorses (74 Thoroughbreds, 18 Standardbreds). Methods: The signalment, history (clinical and race), treatments, and video recordings made during resting and HSTM endoscopy were reviewed in 92 racehorses that developed DDSP during HSTM exercise. Only horses that completed 3 starts before...
Carneiro GF, Liu IK, Hyde D, Anderson GB, Lorenzo PL, Ball BA.In vitro fertilization (IVF) is being routinely used in humans and several domestic species, however, limited success has been achieved in the horse. Although immature equine oocytes are capable of completing meiosis in vitro, subsequent fertilization, and embryonic development of those oocytes are questionable. The lack of development of these oocytes could be attributed to an impaired cytoplasmic maturation. In the horse, the study of oocyte cytoplasmic maturation and post-fertilization development has been hindered by the lack of progress in IVF. In mammalian oocytes, migration of cortical ...
McGorum BC, Anderson RA.To test the hypothesis that equine grass sickness may be associated with the ingestion of cyanogenic glycosides from white clover (Trifolium repens), the concentrations of whole blood cyanide, and plasma and urinary thiocyanate, the main metabolite of cyanide, were measured in 12 horses with acute grass sickness and 10 horses with subacute grass sickness, and in 43 control horses, of which 21 were co-grazing with cases of acute grass sickness, 12 grazed pastures where grass sickness had not been reported, and 10 were stabled horses. The healthy horses which grazed with cases of acute grass sic...
Durando MM, Martin BB, Hammer EJ, Langsam SP, Birks EK.The primary goal was to investigate the relationship between dynamic upper airway abnormalities and arterial blood gas tensions during exercise. Horses that completed a high-speed treadmill examination consisting of upper-airway videoendoscopy, blood gas evaluation and electrocardiogams and, postexercise, echocardiograms and tracheal washes, were included. An age-matched group of fit, healthy Thoroughbreds, trained to run on a high-speed treadmill, served as controls for blood gas values at specific exercise speeds. One hundred and nineteen horses completed the treadmill examination. Sixty (50...
Tacchio G, Davies HM, Morgante M, Bernardini D.The aim of this study was to validate a radiographic technique to measure objectively the longitudinal hoof balance in the horse. Ten left third phalanges (P3) obtained from front hooves and 19 left front hooves were used in order to assess the reliability of the radiographic technique and to identify any effect of rotation or alignment of specimens or distance between the X-ray machine and the radiographic cassette, in measuring P3s structures and balance related parameters. A rotational support was made to hold specimens in order to standardise some of the conditions of X-raying. The main ax...
Menzies-Gow NJ, Patterson-Kane JC, McGowan CM.The clinical signs of chronic nodular panniculitis in a three-year-old mare were consistent with a diagnosis of sterile nodular panniculitis, but the mare had histopathological signs of both generalised steatitis and sterile nodular panniculitis. The mare was deficient in vitamin E and selenium.
Dunnett M, Harris RC, Dunnett CE, Harris PA.This study was undertaken as part of a larger investigation into carnosine metabolism and function in the Thoroughbred horse. More specifically, we wished to evaluate plasma carnosine concentration as a potential indicator of muscle carnosine status. In contrast to man, carnosine is present in equine plasma where its presence is consistent with the absence of plasma carnosinase. A significant effect of age on plasma carnosine concentration in resting Thoroughbred horses was observed. Values in horses age 3 years and older were 113-14.1 micromol/l, whereas concentrations in foals and yearlings ...
Newton JR, Wood JL.In an epidemiological study of risk factors for exercise-induced pulmonary haemorrhage (EIPH) in young Thoroughbreds in the UK, in which 148 horses contributed 1614 horse-months of data, there were 64 (4%) episodes of endoscopically visible tracheal bleeding and 824 (51%) episodes of increased quantities of haemosiderophages in tracheal washes. There were increases in prevalence and risk of EIPH by both definitions with age from or = 4 years, season of sampling from winter (Nov-Jan) to autumn (Aug-Oct) and several different measures of airway inflammation, including tracheal mucus, neutrophil...
Harmegnies NF, Duvivier DH, Vandenput SN, Art T, Lekeux PM, Votion DM.This study aimed to compare exercise-induced pulmonary perfusion redistribution in healthy vs. 'heavey' horses using scintigraphy, a minimally invasive technique. Six healthy (A) and 5 'heavey' horses in remission (B(I)) and during clinical signs of disease (B(II)) were investigated. Dimensions of the exercising pulmonary perfusion (QE) images were expressed in percent of the resting perfusion (QR) images. Computed QE to QR ratios (QE/QR) images enabled the definition of the region more perfused at exercise than at rest (R1). In all groups, exercise induced a major enlargement of the Q image b...
Parente EJ, Russau AL, Birks EK.Mild lameness is considered a performance-limiting problem that may escape detection until it worsens, and is considered the primary reason for reduced racing performance. The kinematics changes associated with a lame horse at the trot have been demonstrated previously, but the metabolic cost of these alterations in their gait have not been demonstrated. Six fit Thoroughbred horses with an established VO2max participated in 4 trials using a randomised cross-over design study, separated by 10-14 days. The horses were tested with one of 4 trial conditions: lead forelimb lameness (LL); off-lead f...
Franklin SH, Naylor JR, Lane JG.Dorsal displacement of the soft palate (DDSP) is one of the most common obstructive conditions of the upper respiratory tract in the racehorse. The present study was conducted to determine the effects of intermittent dorsal displacement of the soft palate (DDSP) on ventilation and respiratory airflow during high intensity exercise. Videoendoscopic recordings were made of the nasopharynx and larynx simultaneously with measurements of airflow and respiratory gas exchange, during high-speed treadmill exercise in 9 horses with confirmed intermittent DDSP admitted for clinical investigation of poor...
Smith RK, Gerard M, Dowling B, Dart AJ, Birch HL, Goodship AE.Over-strain injury of the superficial digital flexor tendon (SDFT) is a common injury in the horse. Tendon appears to adapt to loads placed on it during development, but fatigue damage accumulates after skeletal maturity, which is inadequately repaired and predisposes to clinical tendinitis. In any population of horses, there is a wide variation in SDFT mechanical properties. A noncollagenous protein, cartilage oligomeric matrix protein (COMP), is particularly abundant during growth in the equine SDFT and has been proposed to have an organisational role in the formation of collagenous matrices...
Simhofer H, Riedelberger K.A 6 year old Haflinger gelding was presented to the reporting clinics with a history of chronic dysuria. A large cystic calculus (12 x 9 x 9 cm) was diagnosed cystoscopically. Lithotripsy was carried out endoscopically in the standing, sedated patient with a Holmium:YAG surgical laser (2100 nm, 0.5-3.5 J/pulse, 3-60 pulses/sec.). The endoscope was inserted into the bladder via perineal urethrostomy. Fragmentation of the urolith was carried out with a laser fiber (core diameter 600 microns) in contact mode. Healing proceeded uneventfully. On follow up examination 8 weeks post surgery, no signs ...
Kaplan RM.Suppressive anthelmintic treatment strategies originally designed to control Strongylus vulgaris in horses were extremely successful in reducing morbidity and mortality from parasitic disease. Unfortunately, this strategy has inadvertently resulted in the selection of drug-resistant cyathostomes (Cyathostominea), which are now considered the principal parasitic pathogens of horses. Resistance in the cyathostomes to benzimidazole drugs is highly prevalent throughout the world, and resistance to pyrantel appears to be increasingly common. However, there are still no reports of ivermectin resista...
Koehler K, Stechele M, Hetzel U, Domingo M, Schönian G, Zahner H, Burkhardt E.This report describes a case of cutaneous leishmaniosis in a horse in southern Germany. Diagnosis is based on histopathology, immunohistochemistry and electron microscopy. The protozoan was identified as Leishmania infantum via PCR and restriction fragment length polymorphism. The horse did not show specific Leishmania antibodies. The lesions healed completely within 6 months without any specific treatment. Since neither the infected horse nor its dam had ever left their rural area, autochthonous infection in Germany cannot be excluded. Factors possibly influencing the epidemiological situatio...
McCluskey BJ, Mumford EL, Salman MD, Traub-Dargatz JJ.Approximately 20 sentinel premises in Colorado were visited quarterly during a 3-year prospective study to investigate the persistence of VS viruses in horses. A survey to assess management practices, health events, animal movements and environmental data was completed at each visit. Collection of serum samples and oral swabs along with a clinical examination of sentinel horses were performed at each visit. Serum samples were tested by 2 or more of 4 available serological tests. The data collected for two years (August 1998 to August 2000) are reported here. During this period there was seroco...
Bhuyan AK, Kumar R.To determine the kinetic barrier in the folding of horse cytochrome c, a CO-liganded derivative of cytochrome c, called carbonmonoxycytochrome c, has been prepared by exploiting the thermodynamic reversibility of ferrocytochrome c unfolding induced by guanidinium hydrochloride (GdnHCl), pH 7. The CO binding properties of unfolded ferrocytochrome c, studied by 13C NMR and optical spectroscopy, are remarkably similar to those of native myoglobin and isolated chains of human hemoglobin. Equilibrium unfolding transitions of ferrocytochrome c in the presence and the absence of CO observed by both e...
Bindeus T, Vrba S, Gabler C, Rand T, Stanek C.Major advantages of computed radiography are the potential reduction of dose and the possibility of postprocessing. In our study, we compared conventional radiographs to digital radiographs of the equine stifle by subjective evaluation of diagnostic quality when using a decreasing photon flux (mAs). Twelve equine stifle joints from horses of different weight and size were examined. Conventional and digital radiographs were performed identically in a caudocranial projection with the tube angled 15 degrees. A series of four radiographs was performed in each technique with an increasing photon fl...
Daft BM, Barr BC, Gardner IA, Read D, Bell W, Peyser KG, Ardans A, Kinde H, Morrow JK.To determine sensitivity and specificity of western blot testing (WBT) of CSF and serum for diagnosis of equine protozoal myeloencephalitis (EPM) in horses with and without neurologic abnormalities. Methods: Prospective investigation. Methods: 65 horses with and 169 horses without neurologic abnormalities. Methods: CSF and serum from horses submitted for necropsy were tested for Sarcocystis neurona-specific antibody with a WBT. Results of postmortem examination were used as the gold standard against which results of the WBT were compared. Results: Sensitivity of WBT of CSF was 87% for horses w...
Howe L, Leroux C, Issel CJ, Montelaro RC.Equine infectious anemia virus (EIAV) infection of horses is characterized by well-defined waves of viremia associated with the sequential evolution of distinct viral populations displaying extensive envelope gp90 variation; however, a correlation of in vivo envelope evolution with in vitro serum neutralization phenotype remains undefined. Therefore, the goal of the present study was to utilize a previously defined panel of natural variant EIAV envelope isolates from sequential febrile episodes to characterize the effects of envelope variation during persistent infection on viral neutralizatio...
Milenkovic D, Oustry-Vaiman A, Lear TL, Billault A, Mariat D, Piumi F, Schibler L, Cribiu E, Guérin G.The aim of this study was to increase the number of type I markers on the horse cytogenetic map and to improve comparison with maps of other species, thus facilitating positional candidate cloning studies. BAC clones from two different sources were FISH mapped: homologous horse BAC clones selected from our newly extended BAC library using consensus primer sequences and heterologous goat BAC clones. We report the localization of 136 genes on the horse cytogenetic map, almost doubling the number of cytogenetically mapped genes with 48 localizations from horse BAC clones and 88 from goat BAC clon...
Christensen H, Bisgaard M, Olsen JE.Members of Bisgaard taxon 11 have been isolated from horses. These bacteria are of importance in the veterinary clinic and also to the medical profession, since they may be isolated from infected wounds of humans bitten by horses. Six strains from different continents were identified as taxon 11, with 16S rRNA similarities between 98.0 and 99.7%. A single isolate that represented the so-called (+)L-arabinose-positive Actinobacillus equuli isolated from a diseased foal showed 99.9% 16S rRNA similarity to the type strain of A. equuli. DNA-DNA hybridizations showed that (+)L-arabinose-positive st...
Goff LM, Jeffcott LB, Jasiewicz J, McGowan CM.Pain originating from the sacroiliac joint (SIJ) in horses has long been associated with poor performance, yet specific diagnosis of sacroiliac dysfunction (SID) has been difficult to achieve. Clinical presentation of SID appears to fall into two categories. The first, presenting as pain and poor performance, is responsive to local analgesia of periarticular structures with poorly defined pathology. The second presents primarily as poor performance with bony pathological changes as a result of chronic instability. Diagnostic tests based on biomechanics as well as manual provocation for SIJ pai...
Gerring EL, Webbon PM.Restriction of free movement of the flexor tendons through the fetlock canal results in lameness. The commonest cause was chronic synovitis of the digital sheath. The condition is characterised by an unremitting lameness, synovial distension and a notch on the caudal aspect of the limb. The condition can be relieved by section of the annular ligament of the fetlock. In a series of 24 cases 16 horses returned to work with no recurrence of lameness, three cases were lost to follow up and five animals remained lame; three of these had intercurrent disease.
Krüger MU, Wünschmann A, Ward C, Stauthammer CD.Pulmonary atresia with intact ventricular septum, rudimentary tricuspid valve, hypoplastic right ventricle, and right-to-left atrial shunting were identified in a four-day-old, male Arabian foal with clinical signs of cyanotic heart disease. Pulmonary blood flow was apparently derived from a ductus arteriosus. Echocardiographic evaluation revealed the majority of cardiac abnormalities and also findings compatible with right-sided congestive heart failure. Congenital cardiac defects have a high incidence in this breed, and this is the first description of this combination of congenital cardiac ...
Drudge JH, Lyons ET.This review cites recent advances in the knowledge pertaining to infections of large strongyles in equids. Emphasis is placed on Strongylus vulgaris and attention is focused on pathogenesis of clinical manifestations of infections and treatment and control, including chemotherapy of migrating larvae and drug resistance.
Richards AJ, Kelly DF, Knottenbelt DC, Cheeseman MT, Dixon JB.This report summarises clinical and pathological observations on Fell pony foals with a range of signs that included ill thrift, anaemia, respiratory infection, glossal hyperkeratosis and diarrhoea. Some of the foals had normochromic, normocytic anaemia and some had low levels of plasma proteins, including immunoglobulin G. Antibiotic and supportive treatment was ineffective and all affected foals died or were killed on humane grounds. Postmortem examination of 12 foals and tissues from 2 other foals revealed a range of lesions that included glossal hyperkeratosis, typhlocolitis, intestinal cr...
Sigurdsson SF, Olstad K, Ley CJ, Björnsdóttir S, Griffiths DJ, Fjordbakk CT.Osteochondrosis occurs due to failure of the blood supply to growth cartilage. Osteochondrosis lesions have been identified in small tarsal bones and suggested to cause distal tarsal osteoarthritis; however, it has not been determined whether distal tarsal osteochondrosis lesions were the result of vascular failure. Objective: To perform post-mortem arterial perfusion and micro-computed tomography (CT) of the central (CTB) and third tarsal bones (TIII) of fetuses and foals up to 5 months old, to describe tarsal development and any lesions detected. Methods: Descriptive, nonconsecutive case se...
Stünzi H, Ehrensperger F, Wild P, Leemann W.A 9-year-old horse had numerous firm, painless nodules of the skin and subcutis. Moderately vascular granulation tissue with numerous uni- or multinuclear reticuloendothelial cells was in the nodules and the regional lymph nodes but not in the viscera. By using special stains and electron microscopy, widespread amyloid deposits, mainly in the cytoplasm of reticuloendothelial cells, were identified. Amyloid was probably produced within the reticuloendothelial cells, then expelled from the dying cell and deposited in the intercellular space.
Cardwell JM, Christley RM, Gerber V, Malikides N, Wood JL, Newton JR, Hodgson JL.The term 'inflammatory airway disease' (IAD) is often used to describe the syndrome of lower airway inflammation that frequently affects young racehorses in training around the world. In practice, this inflammation is generally diagnosed using a combination of endoscopic tracheal examination, including grading of amounts of mucus present and tracheal wash sampling. However, a recent consensus statement from the American College of Veterinary Internal Medicine concluded that bronchoalveolar lavage (BAL) sampling, rather than tracheal wash (TW) sampling, is required for cytological diagnosis of ...
Fisher RA, Scott AM.A new method for separating the isozymes of horse serum esterase is described. The improved resolution has enabled us to detect several previously undescribed phenotypes. This method has also been used to detect two different apparently 'silent' alleles.
Ramirez S, Sedrish SA, Paccamonti DL, French DD.This report describes two mares presented for evaluation of anorexia, fever of unknown origin, and weight loss. Clinical examination, laboratory findings, and transrectal ultrasonographic images suggested ovarian abscessation. One mare was successfully treated medically. Because of financial considerations, the second mare was euthanatized and a postmortem examination was performed. At necropsy, there was an enlarged right ovary with an adhesion to the large colon. Microscopic findings were characteristic of an ovarian abscess.
Estberg L, Case JT, Walters RF, Cardiff RD, Galuppo LD.The objectives of the current project were to: (1) identify limitations of search sensitivity and positive predictive value (PPV) for free-text surgical diagnoses included in electronic patient records maintained at the University of California, Davis, Veterinary Medical Teaching Hospital (VMTH), (2) develop procedural or programmable recommendations for removing these limitations, and (3) provide guidelines for effective search strategies for users performing aggregate searches using the VMTH clinical information system. Search sensitivity corresponds to detection sensitivity (the capacity of...
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.
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...
Garma-Aviña A, Valli VE, Lumsden JH.Four cases of equine congenital cutaneous papillomatosis were found during a review of 555 cutaneous tumours received at the pathology department, Ontario Veterinary College, during a 10-year period. A fifth case received after that period was also included. Two of the tumours were found in Thoroughbreds, one in a Standardbred, one in an Arabian and in one case the breed was not specified. The anatomical locations were the rib cage, head, hind leg and 2 on the forehead.
Zhang M, Wei K, Wu Z, Sun J, Hu J, Deng S, Tao J.There is considerable confusion concerning the relationships among species of Sarcocystis found in donkeys and horses. Here, we describe a Sarcocystis species in Chinese donkeys (Equus asinus). Sarcocysts were found in 12 of 32 (37.5%) adult donkeys. By light microscopy, they were divided into two types, thin-walled and thick-walled. The thin-walled were macroscopic (up to 320 μm wide) and had short club-like protrusions (up to 2.7 μm long); the thick-walled were microscopic (up to 135 μm wide) and had villar protrusions (up to 5.4 μm long). Ultrastructures of the two types exhibited s...