The study of diseases in horses encompasses a wide range of conditions affecting equine health, including infectious diseases, metabolic disorders, and genetic abnormalities. These diseases can impact various systems within the horse, such as respiratory, gastrointestinal, and musculoskeletal systems, and can lead to significant health challenges. Research in this area focuses on understanding the pathophysiology, diagnosis, prevention, and treatment of equine diseases. Common diseases studied include equine influenza, equine herpesvirus, and laminitis. This page provides access to peer-reviewed research studies and scholarly articles that explore the etiology, clinical presentation, and management strategies of diseases in horses, contributing to the advancement of equine veterinary medicine.
Dahlgren LA, DeBowes RM, Gift LJ, Veatch JK.Heterotopic salivary tissue was diagnosed in a 7-month-old Quarter Horse colt with a history of a draining wound in the left temporal region from time of birth. Surgical excision of the tract was performed for diagnosis and treatment. Histologically, tissues were compatible with a mixed-type salivary gland, most likely of parotid salivary gland origin. Complete resolution of the drainage was achieved after surgical removal of the ectopic tissue.
Kerkvliet NI, Wagner SL, Schmotzer WB, Hackett M, Schrader WK, Hultgren B.Investigations into the cause of health problems on a horse-breeding farm led to the discovery of high concentrations (630 to 9,810 mg/kg of bedding) of pentachlorophenol in wood shavings used as bedding for horses over a period of 2 to 4 years. Toxicologic signs in the horses were characteristic of toxic effects associated with exposure of polychlorinated dibenzo-p-dioxins and dibenzofurans. Tissue residue analysis confirmed presence of toxic polychlorinated dibenzo-p-dioxin and dibenzofuran isomers known to be in pentachlorophenol, substantiating the bioavailability of polychlorinated dibenz...
Knottenbelt DC, Harrison LJ, Peacock PJ.Three foals under four weeks old and two under six months old with a history of oesophageal obstruction, had oesophageal strictures of different characters in the rostral cervical oesophagus. One case, which was complicated by severe inhalation pneumonia, was euthanased without any treatment and in another initial treatment by bougienage under general anaesthesia was attempted without success. The four surviving cases were provided with progressively firmer and coarser food, starting with liquid only, over a period of three to four weeks. The treatment is recommended in the early stages of str...
Geor RJ, Becker RL, Kanara EW, Hovda LR, Sweeney WH, Winter TF, Rorick JK, Ruth GR, Hope E, Murphy MJ.Fever, limb edema, and laminitis were observed in horses 18 to 36 hours after they consumed hoary alyssum (Berteroa incana) under field and experimental conditions. Clinical signs were not observed in all horses that had ingested the plant. Diagnosis in the field cases was limited to observation of clinical signs and evidence of plant ingestion in hay or on pasture. In most cases, clinical remission was observed 2 to 4 days after empirical treatment, removal of the plant source, or both.
O'Donohue DD, Smith FH, Strickland KL.A two part survey was carried out in Irish Thoroughbred horses in 1988 and 1989 to establish the incidence and prevalence of developmental skeletal problems, particularly possible manifestations of developmental orthopaedic disease (DOD). Survey One was a retrospective study based on a questionnaire involving the foal crops of 46 stud farms for 3 successive seasons; the 1711 animals initially documented represented 10.46% of Irish foal registrations. The second survey involved repeated monitoring of the 1988 foal crop from birth to 18 months of age on 17 stud farms. The 248 foals initially exa...
Ekfalck A, Rodriguez H, Obel N.LAMINITIS after abdominal surgery is a well known
complication that may occur after the horse has recovered from
colic (McIlwraith and Turner 1987). We had the opportunity to
examine a horse with post-surgical laminitis with a peracute
course whose early death made it possible to gain material from
the acute stage for histopathological investigations. We consider
that our observations may be of some value for colleagues
interested in the pathogenesis of laminitis.
Ball MA, Weldon AD.A 5-year-old Appaloosa gelding was presented with a history of intermittent multiple joint swelling, weight loss, and anemia. Physical examination and clinical pathology revealed a grade IV/VI holodiastolic murmur, louder on the left, and a marked hyperproteinemia. Echocardiography of the heart demonstrated a large vegetative lesion on one of the aortic valve cusps. Blood cultures did not elucidate the causative organism, and the disease was refractory to empiric antibiotic therapy. The horse was euthanized after approximately 2 months of therapy.
Logas D, Kunkle G, Calderwood-Mays M, Frank L.An 8-year-old gelding, with a 1-year history of intense pruritus only after exercise, was diagnosed as having cholinergic pruritus. Provocative testing, using exercise and hot-water baths to increase core body temperature, assisted in the diagnosis. Cholinergic pruritus in human beings is a variant of the more common syndrome, cholinergic urticaria, which is characterized by intense pruritus and pinpoint urticaria. With cholinergic pruritus, intense itching results without urticaria. Specific diagnostic laboratory tests have not been developed.
Bergfelt DR, Woods JA, Ginther OJ.Characteristics of spontaneous embryonic loss in 21 mares were compared with those of 52 contemporary mares that maintained pregnancy. Embryonic losses were, in retrospect, grouped according to day of loss and length of the interovulatory interval, respectively, as follows: group 1, less than or equal to day 20 and less than or equal to 30 days (n = 10); group 2, less than or equal to day 20 and greater than 30 days (n = 3); and group 3, greater than day 20 and greater than 30 days (n = 8); ovulation was day 0. Mean diameter of the embryonic vesicle in group 1 was smaller (P less than 0.05) on...
Oladosu LA, Olufemi BE.An investigation was carried out to study the haematology of steroid immunosuppressed horses experimentally infected with Babesia equi and Ehrlichia equi, separately or simultaneously. Horses infected with both pathogens showed less marked changes in their haematology than those inoculated with either pathogen separately. This appeared to result from early elimination of the more pathogenic Babesia as Ehrlichia spread through the granulocytes. The apparent suppression of Babesia by Ehrlichia is of field clinical importance and merits further investigation for its apparent useful potentials in ...
Folz SD, Hanson BJ, Griffin AK, Dinvald LL, Swerczek TW, Walker RD, Foreman JH.Ceftiofur sodium was evaluated as a therapy for respiratory infections in horses. This cephalosporin antimicrobial was administered intramuscularly every 24 h and at a dose of 2.2 mg/kg (1.0 mg/lb) of body weight. The efficacy of ceftiofur sodium was compared with that of a positive control drug, ampicillin sodium (recommended dose of 6.6 mg/kg [3 mg/lb], given every 12 h). Both treatments were continued for 48 h after clinical symptoms were no longer evident (maximum of 10 days). Fifty-five (55) horses with naturally acquired respiratory infections were included in the study; 28 were treated ...
Sweeney CR, Humber KA, Roby KA.Tracheobronchial aspirates obtained from 66 healthy Thoroughbred racehorses in training at the same track were examined. Twenty-seven percent of the horses had greater than 20% neutrophils in the aspirate. Eosinophils, mast cells, giant cells, and Curschmann's spirals of mucus were observed in 94, 83, 65, and 42% of the horses, respectively. Hemosiderophages were observed in 86% of the horses, half of which had previous confirmation of exercise-induced pulmonary hemorrhage. Although fungal elements were seen in 70% of the horses, bacteria were detected in only 3% of the horses. The authors con...
Vacek JR, Macharg MA, Phillips TN, Foerner JJ, Everett KA.A 3-month-old Thoroughbred colt was presented with signs of colic. Findings from physical examination, abdominal paracentesis, abdominal radiographs and clinical pathology revealed uroperitoneum secondary to a calculus obstructing the urethra and causing subsequent urinary bladder rupture. Analysis of the calculus demonstrated a tissue center with outer concretions composed primarily of struvite.
Mayhew IG, Washbourne JR.The Brainstem Auditory Evoked Potential (BAEP) is a recording of the electrical activity of the brainstem following an acoustic stimulation. Up to seven peaks may be identified within 10 ms, and are labelled I to VII. The first five of these peaks are of most clinical importance, and in normal horses, peaks I, III and V are always present at stimulus intensities of 70-100 dB. Repeated sampling of clinically normal subjects at different stimulus intensities has enabled mean latency values to be determined for the ipsilateral and contralateral peaks I, III and V, and also for the interpeak laten...
Vice JD, Shoemaker RS, Cho DY.A 2-year old Thoroughbred filly was examined for a 1-month history of persistent nasal discharge. Contrast radiography revealed a circumscribed mass within the right maxillary sinus which extended to the frontal sinus and ethmoid labyrinth. A discrete attachment of the mass to the ethmoid labyrinth was identified at surgery. Surgical removal of the mass eliminated the nasal discharge. On gross examination, the external structure of the mass was similar to a turbinate with a thin bony wall covered by a smooth mucosal membrane. The internal structure of the lesion had a lining membrane with mult...
Gibson JS, Slater JD, Field HJ.The sequencing of the genome of equine herpesvirus-1 (EHV-1) is reported in Elizabeth A. R. Telford, Moira S. Watson, Kathryn McBride, and Andrew J. Davison, 1992, Virology, 189, 304-316. The sequence was derived using a plaque-purified clone of EHV-1 strain Ab4 (designated Ab4p). To ensure that Ab4p shares the pathogenic characteristics of parental Ab4 (hereafter Ab4), both were inoculated intranasally into foals, specifically free from EHV-1 and EHV-4. Clinical signs, including rectal temperature, were similar for both viruses. In addition, nasal shedding of virus was observed over a 1- to 2...
Smith KC, Whitwell KE, Binns MM, Dolby CA, Hannant D, Mumford JA.From 1988 to 1991, 51 pregnant pony mares were challenged intranasally or by aerosol with an isolate of EHV-1 (AB4) originally recovered from a quadriplegic mare. This resulted in 32 abortions, occurring from 9 to 29 days after infection. In 14 of the early abortions (Days 9-14), EHV-1 was not demonstrated in the foetal tissues by virus isolation or immunostaining despite no other non-viral cause for the abortion being evident. Application of the polymerase chain reaction to foetal tissues from 9 of these cases also proved negative. One of the 14 mares was destroyed immediately after abortion,...
Boy MG, Zhang C, Antczak DF, Hamir AN, Whitlock RH.A 10-month-old Arabian foal was evaluated for a suspected immunoglobulin (Ig) M deficiency. Decreased to nondetectable concentrations of IgM, IgA, and IgG (T), and a normal concentration of IgG, were present. Results of in vitro testing of the blood lymphocyte blastogenesis showed a weak response to the B-cell mitogen, lipopolysaccharide (LPS), but normal responses to T-cell mitogens. Results of postmortem examination showed synovitis of the left tibiotarsal and both scapulohumeral joints. Atrophy and edema of the lymph nodes and lymphocyte depletion in the thymus and spleen were seen. A subac...
Catlin BW.The clinical significance, Gram stain reaction, and genus affiliation of Gardnerella vaginalis have been controversial since Gardner and Dukes described the organism as the cause of "nonspecific vaginitis," a common disease of women which is now called bacterial vaginosis. The organism was named G. vaginalis when taxonomic studies showed that it was unrelated to bacteria in various genera including Haemophilus and Corynebacterium. Electron microscopy and chemical analyses have elucidated the organism's gram-variable reaction. Controversy over the etiology of bacterial vaginosis was largely res...
Parker JL, White KK.A complete search of the literature concerning Lyme borreliosis as it relates to horses and cattle was done. The epidemiology, pathogenesis, immunological response to the disease, diagnosis and treatment are discussed. A review of clinical cases in horses and cattle is presented. Clinical signs of Lyme borreliosis in horses include: chronic weight loss, sporadic lameness, laminitis, low grade fever, swollen joints, muscle tenderness, and anterior uveitis. In addition to those clinical signs, neurological signs such as depression, behavioral changes, dysphagia, head tilt and encephalitis can be...
Whitehair KJ, Adams SB, Parker JE, Blevins WE, Fessler JF.Antibiotics were delivered to chronically infected tissues by regional limb perfusion in three horses with osteomyelitis associated with orthopedic implants. Two infections were resolved with implants in place; in one, a sequestrum was resorbed. In one horse, regional antibiotic perfusion was applied to treat progressively worsening bone infection after initial implants loosened and were removed.
Seahorn TL, Sams AE, Honnas CM, Schmitz DG, McMullan WC.Ultrasonography was used to confirm the tentative diagnosis of keratoma in a horse admitted for chronic progressive lameness. A definitive diagnosis of keratoma traditionally has been diagnosed by history, clinical findings, and radiographic evaluation. Confirmation of the keratoma by use of ultrasonography facilitated the formulation of a treatment plan that resolved the condition.
Sheppard M, Drysdale SM, Studdert MJ.Physical maps were constructed for the genome of equine adenovirus 1 (EAV1) using the restriction enzymes; DraI, EcoRV, NotI and SfiI. The total size of the EAV1 genome was 34.4 kb estimated by comparison with known DNA standards and the polarity of the fragment order, with respect to the left and right molecular ends, was determined by hybridization with known regions of the human adenovirus 2 (HAV2) genome.
Hance SR, Robertson JT, Bukowiecki CF.Two horses were examined for compression of the pharynx from the dorsal pharyngeal wall. Neither horse had a patent opening of 1 of the guttural pouches. Radiography of the guttural pouch region revealed a retropharyngeal opacity that occluded 1 guttural pouch. Organisms were not isolated on bacteriologic culture of fluid obtained from the affected guttural pouch. Surgical exploration of the guttural pouch revealed the lining to be easily removeable by blunt dissection in 1 horse; however, the lining was more firmly attached and removal was not attempted in the second horse. A fenestration bet...
Rodríguez A, Peña L, Flores JM, González M, Castaño M.This study was undertaken to investigate the presence of neuroendocrine cells (N.E.C.) by immunocytochemical means in equine lungs during three distinct evolutionary periods: fetal, neonatal and adult. The authors identified bombesin, somatostatin and calcitonin secretory cells. In the fetal lungs the N.E.C. were located in the interstitial tissue and exhibited greater immunoreactivity to bombesin than to the other two neuropeptides studied. A large number of calcitonin-producing cells and a smaller number of bombesin-positive cells were seen in the bronchial and bronchiolar epithelium of newb...
Arko RJ, Wong KH.An infection model in laboratory mice for studying the bacterium (proposed name Haemophilus equigenitalis) causing contagious equine metritis is described. Small porous chambers were implanted subcutaneously into mice and after 1 to 3 weeks were inoculated with H equigenitalis. Infections that persisted for > 30 days were established by direct transfer of infective chamber fluid or by injection of laboratory-grown cultures. Immunization of mice with formaldehyde-treated cells induced significant, strain-related immunity to infection and did not appear to require complement as a protection medi...
Berezowski C.A 14-year-old quarter horse mare had a 2-year history of infertility and the presence of a mass in the right uterine horn. Prior to surgery, the mass was determined to be invasive by using ultrasonography and hysteroscopy. A partial ovariohysterectomy was performed. The mass was diagnosed histologically as a uterine leiomyoma.
Sanmartí J, Armengou L, Viu J, Alguacil E, Civit S, Ríos J, Jose-Cunilleras E.Sparse information regarding plasma iron concentration in neonatal foals and its utility as an inflammatory marker in this population has been published. Objective: To determine the physiologic plasma iron concentration in neonatal foals. To assess its utility as an inflammatory marker to predict systemic inflammatory response syndrome (SIRS) and as a prognostic marker. Methods: Forty-seven ill neonatal foals admitted to a referral equine hospital were divided in 2 groups based on the SIRS criteria (24 SIRS and 23 non-SIRS). Two control groups of 43 hospital and 135 stud farm healthy neonatal ...
Firth EC, Poulos PW.Examination of growth plate defects in the distal radial physis of 13 foals three to 70 days of age revealed lesions in the lateral and medial aspects of the distal radial physis; the lateral defects were more numerous and obvious. Lesions consisted of widening of the zone of hypertrophying cells of the metaphyseal growth plate (retained cartilage), retained cartilage with discontinuity of cartilage and primary spongiosa, and microfracture of the primary spongiosa. In some foals, the cartilage retention was thought to be due to primary spongiosa microfracture, although fracture subsequent to c...
Sanz MG, Bradway DS, Horohov DW, Baszler TV. is the most common cause of pneumonia in young foals. Pneumonic foals are an important source of environmental contamination as they shed higher amounts of in their faeces than unaffected foals. As -specific hyperimmune plasma (HIP) lessens clinical pneumonia, we hypothesise that its use would result in decreased faecal shedding of by foals. Neonatal foals were either given HIP (n=12) or nothing (n=9, control) shortly after birth and were then experimentally infected with Faeces were collected before and on weeks 2, 3, 5 and 7 after infection. Presence of virulent was tested using qPCR. T...
Blevins WE, Widmer WR.This article focuses on the principles involved in making radiographs of equine limbs; understanding radiographic anatomy, including normal variations; and principles of radiographic interpretation. The influence of pathogenesis of disease on the radiographic image is considered. Diseases associated with racing as well as the developing racehorse are discussed.
Appleton JA, Gagliardo LF.A large panel of mouse monoclonal antibodies was produced and tested against field isolates of the equine H7N7 influenza A virus subtype. Only a limited degree of H7 haemagglutinin variation was detected. At least four antigenic sites were identified by selecting variant viruses in eggs. The limited variation in the field did not correlate with the frequency of variant viruses detected in eggs; this frequency was similar to those reported for other influenza viruses. We sought to determine whether the limited amount of variation could be correlated with an epitope-restricted antibody response ...
Warko G, Bostedt H.Eight vital, new-born foals were additionally administered a non-species-specific colostrum-substitute via stomach-tube within the first 18 hours of their life. The substitute had been made of cattle-colostrum. These foals as well as a control-group of eight foals constantly had free access to maternal colostrum. Object of measurement was GGT-activity in the blood-serum. The increase of GGT-activity within the first 24 hours after birth was very low in the control-group (up to 25 U/l), and very high in the tested animals (418 +/- 182 U/l). Obviously there is a direct connection between this ri...
Dwyer RM, Garber LP, Traub-Dargatz JL, Meade BJ, Powell D, Pavlick MP, Kane AJ.To identify factors associated with excessive proportions of early fetal losses associated with mare reproductive loss syndrome in central Kentucky during 2001. Methods: Case-control study. Methods: Questionnaires were used to collect information on farm-, pasture-, and individual animal-level factors purportedly associated with mare reproductive loss syndrome. Data were collected for 133 farms (97 with excessive proportions of early feta losses and 36 control farms) representing 6,576 mares. Results: Factors significantly associated with an increased risk of excessive early fetal losses were ...