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.
Kim DY, Taylor HW, Moore RM, Paulsen DB, Cho DY.Osteoarthritis (OA) is the most common joint disease in horses. Chondrocyte apoptosis has been implicated as a major pathological OA change in humans and experimental animals but no studies have been performed on equine OA. Articular cartilage was collected from three normal and five OA horses. Histopathological changes were scored by a modified Mankin grading system. A terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay was performed to identify chondrocyte apoptosis. Nitric oxide (NO) production from chondrocytes was indirectly evaluated by immunohistochemistr...
Textor JA, Nixon AJ, Fortier LA.To develop a tenoscopic method to divide the carpal flexor retinaculum and decompress the carpal canal. Methods: Cadaver specimen study and prospective trial. Methods: Twelve cadaveric limbs, 4 clinically normal horses, and 2 clinically affected horses. Methods-A tenoscopic approach to the proximolateral aspect of the carpal sheath was used to identify and facilitate endoscopic division of the inner and outer layers of the carpal flexor retinaculum in cadaver limbs. The technique was further evaluated in 4 normal and 2 clinically affected horses. Results: Anatomic dissection, intraoperative ob...
Malone ED, Les CM, Turner TA.To report a severe form of carpometacarpal osteoarthritis (CMC-OA) affecting primarily older Arabian horses. Methods: Retrospective study. Methods: Thirty-one horses with CMC-OA. Methods: Carpal radiographs (405 sets) from 3 hospitals were evaluated to identify horses with marked osteoproliferative reaction across the medial aspect of the CMC joint. Owners were contacted to obtain detailed histories and status updates. Necropsy specimens of the CMC joint were evaluated at 2 hospitals to determine the prevalence of 2 variations in the articulation between the proximal second and third metacarpa...
Rampersad J, Cesar E, Campbell MD, Samlal M, Ammons D.We report on a study that evaluated the usefulness of PCR for the routine detection of Babesia equi in horses. The blood from a total of 105 horses comprising both sick and apparently healthy animals were examined for the presence of B. equi using both Wright-Giemsa-stained blood smears and PCR. Microscopic analysis of Giemsa-stained blood smears revealed 10/105 animals positive for Babesia, compared to 16/105 for the primary PCR and 36/105 for the nested PCR. Three of the 10 samples positive by Wright-Giemsa-stain were negative by PCR for B. equi. However, evidence is presented that these sam...
van der Linden MA, Laffont CM, Sloet van Oldruitenborgh-Oosterbaan MM.A retrospective study was performed on 649 horses admitted to the Clinic of Equine Internal Medicine (Utrecht University) for gastrointestinal colic. The aim of this study was to provide a better guideline for determining prognosis in horses with colic. Short- and long-term survival were evaluated, and Cox regression analysis was performed to identify the clinical and clinicopathologic variables usable to predict survival. Intestinal displacements and strangulations were the most frequently diagnosed causes of colic. Regarding the surgically treated horses, 54% were discharged and 88% of these...
Corley KT, Donaldson LL, Durando MM, Birks EK.Critical illness, anesthesia, primary cardiovascular disease, and exercise may result in marked hemodynamic alterations. Measuring cardiac output (CO) is central to defining these alterations for both clinician and researcher. In the past 10 years, several new methods of measuring CO have been developed for the human medical market. Some of these methods are now validated in the horse and are in clinical use. The Fick method has been used in equine research for more than a century. It depends on simultaneous measurement of mixed venous (pulmonary arterial) and peripheral arterial oxygen conten...
Naylor JM, Wolker RE, Pharr JW.Twenty students and 16 diplomates listened to 7 recordings made from 7 horses with either aortic (n = 3) or mitral valve (n = 4) regurgitant murmurs. A total of 30 different terms were used to describe the character of these murmurs. However, only 4 terms were used in a repeatable and consistent manner. Most people described the character of a given mitral or aortic valve murmur with 1 or 2 terms. Diplomates drew from a pool of terms that was about half the size of that used by students--8.1 +/- 2.0 terms for diplomats (mean +/- 1 SD) versus 13.1 +/- 1.8 terms for students (P > .001). Only blo...
Perkins GA, Nydam DV, Flaminio MJ, Ainsworth DM.The purposes of this study were to (1) prospectively establish serum IgM and IgG concentrations in normal, fit, adult horses over time and (2) determine the accuracy of serum IgM concentrations for diagnosing lymphoma. Serial IgM and IgG concentrations were measured with a radial immunodiffusion assay in 25 regularly exercised horses at 6-week intervals. Horses had serum IgM concentrations ranging from 50 to 242 mg/dL over 5 months, with 20% of horses having IgM < or = 60 mg/dL. The normal range for IgM in fit horses should be considered 103 +/- 40 mg/dL and a cut-point for an IgM deficiency, ...
Stevenson RA, Hartley CA, Huang JA, Studdert MJ, Crabb BS, Warner S.Equine rhinitis A virus (ERAV) is an important respiratory pathogen of horses and is of additional interest because of its close relationship and common classification with foot-and-mouth disease virus (FMDV). As is the case with FMDV, the VP1 capsid protein of ERAV has been shown to be a target of neutralizing antibodies. In FMDV VP1, such antibodies commonly recognize linear epitopes present in the betaG-betaH loop region. To map linear B cell epitopes in ERAV VP1, overlapping fragments spanning its length were expressed in Escherichia coli as glutathione S-transferase (GST) fusion proteins....
The Journal of parasitologyMay 23, 2003
Volume 89, Issue 2 309-314 doi: 10.1645/0022-3395(2003)089[0309:POSNIN]2.0.CO;2
Chapman MR, French DD, Klei TR.One hundred and seventeen ponies were surveyed for the seasonal prevalence of strongyloid parasites, particularly cyathostomes, and for host- and age-related differences in these infections. For 56 ponies, all stages of the cyathostome life cycle, both mucosal and luminal, were enumerated. Total numbers of cyathostomes and percentage of developing larvae (DL) encysted in the mucosa remained constant in all 4 seasons of the year, whereas a significant increase in the percentage of adults in the cyathostome population occurred in fall. In yearling ponies, encysted early third-stage larvae consti...
Lewis S.A 24-hour-old colt presented with clinical signs consistent with gastric ulceration. Treatment was initiated with a histamine type-2 receptor antagonist and clinical signs resolved. Gastroscopy at 16 d confirmed the presence of a gastric ulcer. Although gastric ulceration is common in foals, it is rarely reported in foals this young.
Ducharme NG, Hackett RP, Woodie JB, Dykes N, Erb HN, Mitchell LM, Soderholm LV.Contributes to the understanding of the pathogenesis of dorsal displacement of the soft palate during exercise so that management of this condition could be enhanced. Objective: That the thyrohyoid muscles play an important role in the stability of the laryngo-palatal relationship and that dysfunction of these muscles leads to dorsal displacement of the soft palate (DDSP) during exercise. Methods: Ten horses were exercised on a high-speed treadmill under 4 different treatment conditions: control conditions (n = 10), after resection of thyrohyoid muscles (TH, n = 10), after sham-treatment (n = ...
Guérin G, Bailey E, Bernoco D, Anderson I, Antczak DF, Bell K, Biros I, Bjørnstad G, Bowling AT, Brandon R, Caetano AR, Cholewinski G, Colling D....A low-density, male-based linkage map was constructed as one of the objectives of the International Equine Gene Mapping Workshop. Here we report the second generation map based on testing 503 half-sibling offspring from 13 sire families for 344 informative markers using the CRIMAP program. The multipoint linkage analysis localized 310 markers (90%) with 257 markers being linearly ordered. The map included 34 linkage groups representing all 31 autosomes and spanning 2262 cM with an average interval between loci of 10.1 cM. This map is a milestone in that it is the first map with linkage groups ...
Batson EL, Paramour RJ, Smith TJ, Birch HL, Patterson-Kane JC, Goodship AE.Injury to the superficial digital flexor tendon (SDFT) is common in competition horses. The SDFT contributes to locomotory efficiency by storing energy; such tendons have low safety margins. Tendons which merely position the limb, including the opposing common digital extensor tendon (CDET), are rarely injured. The current failure of strategies to prevent or effectively treat injury to the SDFT indicates the importance of understanding how it differs from tendons which are not injury-prone. Objective: That the structural and material properties and matrix composition of the SDFT and CDET diffe...
Franklin SH, Usmar SG, Lane JG, Shuttleworth J, Burn JF.It has long been recognised that the production of abnormal respiratory sounds by horses during exercise is frequently associated with upper airway obstructions. Respiratory acoustic measurements have shown promise in investigation of upper airway disorders in man and, more recently, in horses with experimentally-induced obstructions. Objective: To evaluate sounds from exercising horses with naturally occurring dynamic obstructions of the upper respiratory tract and to compare these with those from normal horses in order to determine whether different obstructions produce characteristic spectr...
Little D, Flowers JR, Hammerberg BH, Gardner SY.Possible anthelmintic resistance on a breeding farm where a rapid rotation anthelmintic programme had been implemented for 9 years was investigated. Cyathostomins resistant to fenbendazole and pyrantel were documented by faecal worm egg count reduction test (FWECRT). Objective: To 1) manage small strongyle transmission in a herd of horses in which resistance to both pyrantel pamoate and fenbendazole was identified and thereby reduce the risk of clinical disease in the individual animal, 2) monitor the change in resistance patterns over time and 3) monitor the efficacy of ivermectin over the st...
Dyson S, Murray R, Branch M, Harding E.Sacroiliac (SI) joint disease is difficult to diagnose definitively on clinical grounds. Objective: Lameness not attributable to SI joint pain may result in asymmetrical uptake of radiopharmaceutical in the tubera sacrale and SI joints; and that horses with clinical signs suggestive of sacroiliac joint disease would have differences in the ratios of radiopharmaceutical uptake between the fifth lumbar vertebra (L5) and either the tubera sacrale or SI joints compared with normal horses. Objective: To determine whether differences in radiopharmaceutical activity could identify individuals with pr...
Estepa JC, Garfia B, Gao PR, Cantor T, Rodriguez M, Aguilera-Tejero E.Parathyroid hormone (PTH) plays a critical role in the regulation of mineral metabolism in mammals. Until recently, the standard method for PTH measurement has been the 2nd generation intact-PTH (I-PTH) assay. Current evidence indicates that the I-PTH assay binds to the PTH molecule and to an inactive N-terminally truncated PTH fragment that tends to accumulate in the blood of uraemic patients. Therefore, a new 3rd generation PTH assay that detects only the whole PTH molecule (W-PTH; cyclase-activating PTH [CAP]) has been developed. Objective: To validate this more specific W-PTH assay for mea...
Johnson PJ, Messer NT, Ganjam VK, Thompson DL, Refsal KR, Loch WE, Ellersieck MR.There exists a need for better diagnostic tests to characterise thyroid disease in horses. Currently available diagnostic tests fail to differentiate between thyroid gland disorders and thyroid abnormalities resulting from pituitary or hypothalamic problems. Objective: To evaluate the effects of treatment with propylthiouracil (PTU) and bromocryptine (BROM) on serum concentrations of triiodothyronine (T3), thyroxine (T4), reverse T3 (rT3) and equine thyroid-stimulating hormone (e-TSH, thyrotrophin) in mature horses. Methods: Healthy mature horses were treated using either PTU or BROM for 28 da...
Dyson S, Murray R, Branch M, Whitton C, Donovan T, Harding E.Sacroiliac (SI) disease is recognised as a cause of poor hindlimb action but differential diagnosis is often difficult. Objective: That in clinically normal horses there would be a significant difference in the ratio of radiopharmaceutical uptake (RU) between the fifth lumbar vertebra (L5) and each tuber sacrale (TS) and between L5 and each SI joint; and that these ratios would alter with age, but ratios would be bilaterally symmetrical. Methods: Dorsal scintigraphic images of the SI region of 15 horses, selected randomly from the clinic database, were analysed by 2 of the authors, comparing n...
Robinson NE, Berney C, Eberhart S, deFeijter-Rupp HL, Jefcoat AM, Cornelisse CJ, Gerber VM, Derksen FJ.To investigate relationships between cough frequency and mucus accumulation, airway obstruction, and airway inflammation and to determine effects of dexamethasone on coughing and mucus score. Methods: 13 horses with recurrent airway obstruction (RAO) and 6 control horses. Methods: 6 RAO-affected and 6 control horses were stabled for 3 days. Coughing was counted for 4 hours before and on each day horses were stabled. Before and on day 3 of stabling, tracheal mucus accumulation was scored, airway obstruction was assessed via maximal change in pleural pressure (deltaPpl(max)), and airway inflamma...
Kelly G, Lumsden JM, Dunkerly G, Williams T, Hutchins DR.Mucosal ulcers and, occasionally, small granulomas on the axial surface of one or both arytenoid cartilages have been found in TB yearlings presented for post sale endoscopic examination. Objective: To determine the incidence, endoscopic characteristics and outcome of a group of Thoroughbred yearlings affected with mucosal ulcers and granulomas of the arytenoid cartilage. Objective: The incidence of mucosal ulceration of the arytenoid cartilages of yearling Thoroughbreds is relatively high compared to other upper airway abnormalities; and that the majority of mucosal ulcers heal uneventfully, ...
Gerber V, Robinson NE, Venta RJ, Rawson J, Jefcoat AM, Hotchkiss JA.Increased mucin gene expression may be an important cause of mucus accumulation observed in recurrent airway obstruction (RAO)-affected horses. To date, however, no mucin gene sequences are available for the horse. Objective: To identify equine homologues of gel-forming mucins and investigate their expression at different airway generations of healthy and RAO-affected horses. Methods: Two equine homologues were identified by cloning and sequencing fragments of equine (eq)MUC5AC and eqMUC2. Results: Semiquantitative RT-PCR on RNA from airways (generations 1, 5, 10, 15; small airways and parench...
Kaps S, Richter M, Spiess BM.To determine corneal sensitivity in healthy adult horses in order to establish reference values. Methods: One hundred eyes of 50 healthy adult horses. Methods: Corneal sensitivity was determined by evaluating the corneal touch threshold (CTT) in five different corneal regions using a Cochet-Bonnet esthesiometer. Results: Comparing CTT values (in mm filament length) of the five prescribed corneal regions revealed regional variations in corneal sensitivity, with the central region (21.15 +/- 6.23 mm) being the most sensitive, followed by the nasal (20.75 +/- 5.14 mm), temporal (20.70 +/- 5.37 mm...
Pirie RS, Collie DD, Dixon PM, McGorum BC.Equine heaves is a naturally occurring organic dust-induced asthma characterized by airway neutrophilia, mucus hypersecretion and obstructive lung dysfunction. However, the relative role of different dust components in disease severity remains unclear. Objective: This study investigated the relative contribution of inhaled endotoxin and organic dust particulates (mainly mould spores) in inducing heaves in heaves-susceptible horses. Methods: Control and heaves-susceptible horses received inhalation challenges with hay dust suspension (HDS) before and after lipopolysaccharide (LPS) depletion. He...
Johnson GC, Kohn CW, Johnson CW, Garry F, Scott D, Martin S.Ultrastructural examination of a mechanobullous disease of probable hereditary nature in Belgian foals, confirmed light microscopic findings that separation of the dermo-epidermal junction occurred through the lamina lucida of the basement membrane, leaving the intact lamina densa adherent to the dermis and the plasmalemma of the basal epithelial cells intact. The location of the cleft and the presence of small hemidesmosomes in adjacent intact skin are additional characteristics which make this condition similar to junctional epidermolysis bullosa of man.
Velie BD, Smith PM, Fjordbakk CT, Solé M, Jäderkvist Fegraeus K, Rosengren MK, Røed KH, Ihler CF, Lindgren G, Strand E.Dynamic laryngeal collapse (DLC) associated with poll flexion is the most common disorder of the upper respiratory tract (URT) in the Norwegian-Swedish Coldblooded Trotter (NSCT). The disorder, which has also been diagnosed in other breeds of trotters and gaited horses, appears to be related to anatomic phenotypes and only occurs during poll flexion when the horse is exercised 'on the bit'. Objective: Identify genomic regions associated with DLC in the NSCT by combining a rigorous phenotyping protocol with genomic data from a high-density equine genotyping array. Methods: Prospective case/cont...
Morris DD, Whitlock RH, Corbeil LB.An equine antiserum to core lipopolysaccharide was produced by inoculation of 6 horses with a boiled cell bacterin made from the J-5 mutant of Escherichia coli O111:B4. The antiserum immunoglobulin G titer to J-5 mutant E coli, as determined by enzyme-linked immunosorbent assay, was 1:15,006. Pooled serum prepared before inoculation (preimmune serum) had a J-5 immunoglobulin G titer of 1:350. The J-5 antiserum was tested for its protective efficacy in sublethal endotoxemia in 14 horses. Four horses served as nontreated controls and were given nothing before endotoxin challenge exposure (10 mic...
Macpherson ML.Equine placentitis is a complex disease that has devastating consequences for horse owners. Placentitis is a significant cause of foal loss annually. Prompt diagnosis and treatment of the disease are paramount for survival of the affected neonate. This article discusses current information on pathogenesis of the disease as well as diagnostic and therapeutic options.
Fedorka CE, Ball BA, Wynn MAA, McCormick ME, Scoggin KE, Esteller-Vico A, Curry TE, Kennedy LA, Squires EL, Troedsson MHT.Preterm labor and/or abortion causes considerable economic impact on the equine industry. Unfortunately, few experimental models exist for the induction of various pregnancy-related complications, and therefore extrapolations are made from the experimental model for ascending placentits, although inferences may be minimal. Certain steroid hormones (progestogens, estrogens) and fetal proteins (alpha-fetoprotein; AFP) might improve the diagnostics for abnormal pregnancy, but the utility of these markers in the field is unknown. To assess this, thoroughbred mares (n = 702) were bled weekly begi...
Dyson SJ, Kidd L.The normal gastrocnemius tendon may contain some muscular tissue proximally. This results in a patchy echogenicity ultrasonographically where it lies caudal or lateral to the superficial digital flexor tendon (SDFT). When it has assumed a position dorsal (cranial) to the SDFT the gastrocnemius tendon has a more uniform echogenicity and its margins are well defined. Five horses had lameness associated with lesions identified ultrasonographically in the gastrocnemius tendon in the latter region. Lameness ranged from mild to severe and was characterised by reduced hock flexion, lowered arc of foo...
Magnarelli LA, Bushmich SL, Anderson JF, Ledizet M, Koski RA.A polyvalent ELISA and plaque reduction neutralization tests (PRNTs) were used to measure serum antibodies to West Nile virus (WNV) in horses naturally exposed to or vaccinated against this flavivirus in Connecticut and New York State, USA. Relying on a PRNT as a 'gold standard', the main objective was to validate a modified ELISA containing a recombinant WNV envelope protein antigen. It was also important to assess specificity by testing sera from horses that had other, undiagnosed illnesses. Sera for the latter study were obtained from 43 privately owned horses during 1995-1996. Analyses by ...
Inui T, Yamada K, Itoh M, Yanagawa M, Higuchi T, Watanabe A, Imamura Y, Urabe M, Sasaki N.Temporohyoid osteoarthropathy (THO) is characterized by progressive osseous proliferation of the stylohyoid and petrous temporal bones. Generally, diagnosis is confirmed by guttural pouch endoscopy and skull radiography. In the present case, computed tomography (CT) and magnetic resonance imaging (MRI) were performed in a 6-month-old Thoroughbred foal showing signs of head tilt and unilateral ear droop, consistent with the presence of a vestibular disease and unilateral facial paralysis. CT revealed bony fusion and proliferation of the right temporohyoid joint, while MRI revealed that otitis m...
Lu KG, Morresey PR.Diagnosis, treatment, and, ultimately, prevention of reproductive disease are vital components of equine veterinary medicine. A thorough understanding of anatomy and physiology is necessary to reconcile the pathologic findings of disease. Only then can a rational treatment plan be formulated. Many recent advances in knowledge about the reproductive system of multiple species have application to the mare and stallion.
Moens Y, Gootjes P, Lagerweij E.The tube-in-tube technique for the functional separation of the lungs in intact anaesthetised adult horses is based on fibre-optic-guided left-sided endobronchial intubation avoiding tracheostomy. It facilitates a valid separation of the two lungs despite variability in bronchial and carinal anatomy. No clinical complications that could be related to its use have been seen.
Escande F, Vallee E, Aubart F.The isolation of Pasteurella caballi from an horse-bite wound in a 56-year-old man is reported. Biochemical characteristics are described and compared with the other species representing the genus Pasteurella. This strain probably represents the first human isolate of P. caballi in France.
Mair TS, de Westerlaken LV, Cripps PJ, Love S.Samples of faeces and blood were obtained from 66 adult horses with diarrhoea. The results of routine bacteriological, parasitological, haematological and biochemical tests were correlated with the outcome of the cases. Twenty-two (33 per cent) of the horses died or were destroyed as a consequence of the diarrhoea. A diagnosis was reached in only 23 cases (35 per cent), and in nine of them only at post mortem examination. Salmonella typhimurium was isolated from five cases. Statistical analysis revealed significant differences between the horses which survived and those which died in their pac...
Davies JV, Gerring EL.The effect of acepromazine, Buscopan (Crown Chemicals), pethidine and methadone was evaluated in ponies prepared with Thiry-Vella (T-V) loops. Motility was assessed by electrophysiological means (bipolar electrodes and strain gauge transducers) and by the passage through the T-V loop of a fluid test meal. Results were obtained from 26 experiments in three ponies and compared with six control experiments, in which saline had been administered to the same ponies. Each pony acted as its own control in each experiment and pre and post treatment values for slow wave frequency, spiking activity, del...
Reeves HJ, Lees R, McGowan CM.A high basal plasma or serum insulin concentration is commonly accepted as an indicator of Cushing's disease in horses. The results of the combined dexamethasone suppression test and thyrotropin-releasing hormone stimulation test were compared with the basal insulin concentrations and insulin response tests of eight hyperinsulinaemic and insulin-resistant ponies with clinical histories of chronic or recurrent laminitis that were suspected of having Cushing's disease. Seven of the eight ponies had normal responses to the combined test indicating that basal insulin concentrations are not a speci...
Socha W, Rola J, Żmudziński JF.The genetic stability of ORF1a encoding non-structural proteins nsp1, nsp2, nsp3 and nsp4 of equine arteritis virus (EAV) has been analysed for nearly seven years in a persistently infected stallion of the Malopolska breed. Between November 2004 and June 2011, 11 semen samples were collected. Viral RNA extracted from semen of this carrier stallion was amplified, sequenced and compared with the sequences of the other known strains of EAV. Sequence analysis of ORF1a showed 84 synonymous and 16 non-synonymous mutations. The most variable part of ORF1a was the region encoding nsp2 protein with 13 ...