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.
Toombs-Ruane LJ, Riley CB, Rosanowski SM, Kendall AT, Benschop J.Decreased efficacy of veterinary antimicrobials and increased prevalence of multi-drug resistance (MDR) is of concern, but little is known of antimicrobial resistance encompassing the New Zealand (NZ) equine population. Recent concerns have arisen over the emergence of multi-resistant bacteria [1], especially on NZ stud farms where antibiotics are frequently used for respiratory disease without veterinary input [2]. Objective: To describe bacterial culture and antimicrobial sensitivity results from respiratory samples submitted of young horses (4 weeks to 3 years old). Methods: Retrospective s...
Littlejohn A.Twenty cases of chronic cough originating in the lung and associated with loss of performance were clinically examined. The physical signs observed were compared with those observed in a control series of 38 clinically normal horses. Reduced work tolerance, coughing for more than 3 months and abnormal pulmonary sounds (râles) were primary signs of chronic obstructive pulmonary disease (COPD). Forced abdominal expiratory efforts and pumping of the anus were regarded as confirmatory signs. Neither nasal discharge nor increased marginal distance was found to be a reliable sign of COPD. The mean ...
Dik KJ, Németh F, Merkens HW.The radiological and clinical interpretation of alterations of the navicular bone, the interaction of radiological and clinical symptoms in relation to the age of the animal, the influence of work-load on this interaction and the possibility of predicting navicular disease at an early stage are discussed. The discussion is based on experience in a study of 130 horses.
Friesen KM, Johnson GD.Reproductive potential was assessed for stable fly cohorts fed cattle, chicken, or horse blood. Flies provided chicken blood oviposited 20% more eggs per day than did those fed cattle or horse blood. However, flies provided cattle or horse blood were fecund 50% longer. When both egg viability and number of eggs produced were considered, lifetime reproductive potential was almost twice as high for flies fed cattle or chicken blood than for flies fed horse blood. Maternal investment, which took egg production and volume into account, was higher in cohorts fed cattle blood (70 mm3) when compared ...
Giri DK, Quist EM, Ambrus A, Gold J, Porter BF, Bratton GR, Storts RW.A 5-day-old quarter horse colt with a history of hypothermia, agonal breathing, and diarrhea was euthanized. At necropsy, numerous slightly raised, discrete, closely approximated submucosal nodules were observed in the colon and small intestine. Histologically, these nodules were composed of expanded submucosal mesenchyme that contained numerous neurons either individually or in ganglia. Thirty-two percent of these ganglia included 8 or more neurons, in contrast to 6% in an age-matched foal. Some nodules had necrosuppurative inflammation with vasculitis, thrombosis, and bacterial colonization....
Slocombe JO, McCraw BM.Sixteen pony foals were reared worm-free and inoculated with Strongylus vulgaris. On day 7 after inoculation, 12 ponies were given a fenbendazole 10% suspension at dose rate of 50 mg/kg of body weight by stomach tube. On day 8 after inoculation, 8 of these ponies were given the 2nd treatment of the anthelmintic and on day 9, 4 of these ponies were given the 3rd treatment. (The other 4 of the 16 ponies were given only tap water, as controls.) The ponies were necropsied at death or on day 28 after inoculation. Fenbendazole was effective in minimizing the appearance of clinical signs associated w...
Moll HD, Schumacher J, Dabareiner RM, Slone DE.Three horses underwent exploratory celiotomy because of signs of acute abdominal pain. At surgery, all horses were diagnosed as having left dorsal displacement of the large colon. Each surgery was complicated by fibrous adhesions of the spleen to the body wall. All horses had previously undergone abdominal surgery for colic. In these cases, it appeared that the left large colon displaced cranially and then entered the renosplenic space from a cranial to caudal direction. Adhesions of the spleen to the body wall would prevent correction of left dorsal displacement of the large colon by the roll...
Bauer C, Bürger HJ.A paste formulation containing 14.3 per cent of oxibendazole and 44 per cent of trichlorfon was administered to 33 ponies and horses. The dose rate used was equivalent to 10 mg and 30 mg/kg bodyweight, of oxibendazole and trichlorfon respectively. After treatment 25 animals passed between one and 82 third stage larvae of Gasterophilus intestinalis in their faeces. Dosing with 0.2 mg ivermectin/kg bodyweight three weeks later resulted in six animals expelling between one and four bots. The efficacy of the oxibendazole-trichlorfon paste was on average 96.2 per cent. This drug combination given t...
Hargis AM, Clark EG, Duclos DD, Leclerc S, West K.Over a 6-year period seven adult horses of different breeds and genders developed multifocal, exudative, oozing dermatitis characterized histologically by epidermal spongiotic vesicles and perivascular eosinophilic, neutrophilic and mixed mononuclear inflammation. Three horses were pruritic. Systemic disease was not noted. Two horses had a history of recurrent urticaria (hives) and one horse had nodules or welt-type lesions that progressed to exudative, oozing lesions. Interepithelial immunoglobulin (Ig)G was detected by avidin-biotin complex-peroxidase staining, but the pattern of staining wa...
Zynda HM, Scare JA, Steuer AE, Anderson HP, Nielsen MK.Cyathostomins are pervasive equine parasites in horses across the world, and larval stages are known to cause the deadly disease larval cyathostominosis. The mucosal digestion technique is widely used for enumeration of encysted larval stages. Previous studies have investigated the spatial variation of encysted larvae, however current protocols lack a description of a standardized area from which to take the tissue sample. This study sought to evaluate spatial variation in encysted cyathostomin larval counts among the large intestinal organs and their subsections. Following humane euthanasia, ...
BOYD WL, BOYD JW.Boyd, William L. (Ohio State University, Columbus) and Josephine W. Boyd. Viability of coliform bacteria in antarctic soil. J. Bacteriol. 85:1121-1123. 1963.-The distribution of coliform bacteria in soils of Ross Island and the nearby mainland was studied. None was found in almost all of the samples collected, including some from the Adelie penguin rookeries at Cape Royds and Cape Crozier and in soil at the McMurdo Base which had been recently contaminated by human sewage. Samples of pony manure left from previous expeditions were also negative, with one exception where Escherichia coli were p...
Nyack B, Padmore CL, Dunn D, Kufuor-Mensan E, Mobini S.A 10-year-old Tennessee Walker gelding, with a history of progressive weight loss, intermittent colic and lethargy, had a slight fever, tachycardia, tachypnea, pallor, ascites and marked ventral edema. Blood analyses revealed anemia, leukocytosis, neutrophilia with a left shift, lymphopenia, monocytosis, hypoproteinemia and a slightly increased SDH level. Abdominocentesis produced red-orange fluid with many RBC and an increased fibrinogen content. Rectal palpation revealed a large mass in the left caudal abdominal quadrant. The animal died shortly after resection of the mass. The histopatholog...
McClure SR, Hooper RN, Watkins JP.A 13-month-old Quarter Horse colt sustained a puncture wound to the frog region of the foot, which penetrated the navicular bursa and distal interphalangeal joint, 7 days prior to examination. A street-nail procedure was performed to debride the tract and provide drainage of the navicular bursa and distal interphalangeal joint. An indwelling lavage system was placed through the dorsal aspect of the joint and antimicrobials were infused intermittently to supply a high local concentration of drug and to frequently lavage the distal interphalangeal joint and navicular bursa.
Herb VM, Zehetner V, Blohm KO.This is the first description of Multiple Congenital Ocular Anomalies (MCOA) in a silver coat Missouri Fox Trotter determined to be heterozygous for the Silver PMEL17 missense mutation associated with MCOA and a silver coat in other breeds. The stallion was treated for meningoencephalitis and bilateral uveitis of unknown origin. A complete ophthalmic examination and ocular ultrasonography were performed. As an incidental finding, the patient exhibited bilateral cystic lesions restricted to the temporal anterior uvea consistent with the Cyst phenotype and was genotyped heterozygous for the Silv...
Collins ND, LeRoy BE, Vap L.Extremely high bicarbonate (HCO3-) and anion gap values were measured in two horses and a calf using the Hitachi 911 automated serum biochemistry analyzer. All three animals had severe muscle disease as evidenced by markedly increased aspartate aminotransferase and creatine kinase activities. Laboratory error was suspected as the source of the increased HCO3- because values calculated from blood gas analysis were normal. It was hypothesized that increased serum lactate dehydrogenase (LDH) activity and pyruvate concentration overwhelmed the oxamate LDH inhibitor in the enzymatic HCO3- assay, re...
Yamamoto K.Monospecific (MSp-) antisera against E1 and E2 glycoproteins of western equine encephalitis (WEE) virus were prepared and examined for binding activities to whole virions, hemagglutination-inhibition (HI), neutralization (NT) and protection. Both anti-E1 and anti-E2 MSp-Abs protected mice against WEE virus challenge. A competition experiment with monoclonal antibodies showed that these MSp-antisera appear to lack the antibody population for some epitopes involved in viral neutralization.
Scilimati N, Pepe M, Pressanto MC, Angeli G, Beccati F.A 4-month-old Thoroughbred filly was referred for evaluation of severe left forelimb lameness of 24 hours duration. Radiographic projections of the shoulder revealed mild irregularity and sclerosis of the proximal humeral apophysis. Ultrasonographic examination showed a moderate increase in the amount of anechogenic synovial fluid within the intertubercular bursa and scapulohumeral joint, and irregularity of the ossifying bone surface of the intermediate tubercle of the humerus. Computed tomographic (CT) examination revealed a circular hypoattenuating area at the level of the proximal apophysi...
Cole R, Chesen AB, Pool R, Watkins J.Equine mast cell tumors are typically benign solitary growths of the head, neck, trunk, or limbs. When involving the limbs, these masses tend to be adjacent to joints without involving them. In radiographs there is often a well-circumscribed soft tissue mass with granular mineralization. The Arabian breed appears to be over represented. Surgical removal is usually curative. In this report, we describe the diagnosis, clinical features, and management of mast cell tumors in the rear limb of a horse.
García-Tamayo J.Clinical findings on Venezuelan Equine Encephalitis virus infection and the teratogenic effects of several Togaviruses are described. Similarities between the intrauterine alterations induced by Venezuelan Equine Encephalitis virus and rubella virus are pointed out. Findings described by Wenger in 1967 were those of massive cerebral necrosis in fetuses of women presumably suffering of encephalitis and they are commented along with the development of an animal experimental model at the end of 1970-1980. Pathogenesis of the intrauterine infection seemed to be related to changes in the placental ...
Allen WE.The situations and conditions that can disrupt the mares normal oestrous cycle are described. Season of the year is a major influence; maximum reproductive efficiency does not totally coincide with the artificially defined "breeding season". Other abnormalities are associated with spontaneously persistent luteal function, psychological influences over behavioural activity, the presence of endometritis, multiple ovulation, reproductive behavior after pregnancy failure and granulosa cell tumours.
Page AE, Adam E, Stewart JC, Gonzales C, Barker V, Horohov DW.While the use of lipopolysaccharide (LPS) to induce inflammation has been well described in the horse, the object of this study was to evaluate the effect of repeated intra-articular LPS injections and determine whether this method may be of use to assess changes in gene expression related to inflammation. Six mixed breed horses were utilized for this study, with three horses aged 10-17 years (older group) and three horses aged 3 years (younger group). One milliliter of phosphate-buffered saline containing 3 μg of LPS from Escherichia coli O111:B4 was aseptically injected into either the radi...
Seide RK, Kehoe JM.Studies of the molecular biology of lymphoid cells have markedly increased our understanding of how millions of different antibodies can be synthesized by a single animal. To date, the most detailed understanding has been achieved for the mouse, primarily because of the relatively greater experimental availability of this species. These studies, as well as those involving other species, have shown that the complete genes for antibody polypeptide chains are assembled from disparate genetic elements which are originally widely separated in the genome. The assembly process itself, together with t...
DiPietro JA, Paul A, Todd KS.Forty horses from a herd known to have benzimidazole-resistant small strongyles were treated with mebendazole (8.8 mg/kg) or combinations of mebendazole and piperazine monohydrochloride (25, 40, or 55 mg of piperazine base/kg). Pretreatment and 7-day posttreatment fecal examinations were done. Fecal cultures and strongyle egg per gram (epg) counts, and in vitro testing for benzimidazole resistance were performed. Results of fecal examinations prior to treatment were similar in all horses, and results of testing were positive for benzimidazole resistance. Horses treated with mebendazole and pip...
Bentinck-Smith J, Tasker JB.The following topics are discussed in this presentation: A. Recent advances in the use and interpretation and methodology of antibiotic susceptibility testing. B. Improvements in sample submittal to obtain accurate results from your laboratory. C. Staining blood, bone marrow, and cytology specimens in the office laboratory. D. Pathogenesis and differential diagnosis of lipemia. E. Differential diagnosis of abdominal effusions.
Labruna MB, Amaku M.The present study evaluated the engorgement and drop-off rhythms of Anocentor nitens females feeding on horses. Drop-off rhythm was evaluated at 6h-intervals (06:00, 12:00, 18:00, and 00:00 h) on horses held in stalls or in a pasture. A new method of marking feeding female ticks (the bowknot technique) was developed to evaluate ticks on horses in pasture that attached to different parts of the horse's body. This technique was highly successful, indicating no significant interference on tick engorgement rate or final tick weight, length and reproductive capability. Horses held in the pasture du...
Charlton C, Tulleners E.Two male racehorses (1 Standardbred, 1 Thoroughbred) were examined because of intraluminal cervical tracheal lesions, located 60 to 70 cm from the nares. A contact neodymium:yttrium aluminum garnet laser with a chisel probe attached to the fiber end was used to transendoscopically debride a nonhealing tracheal ulcer and to excise a pyogranulomatous mass. In both horses, the surgical sites healed quickly and the lesions did not redevelop.
Kearns CF, Lenhart JA, McKeever KH.Erythropoietin (EPO) is the primary hormone of erythropoiesis. Administration of recombinant human erythropoietin (rhuEPO) to improve racing performance in the horse represents a new form of blood doping, which has been associated with increased mortality. While immunoassay kits have become plentiful, very few commercial hormone assays are made specifically for equine research. There is a strong degree of sequence homology reported for EPO among species, which has allowed antibodies designed for human EPO research to be used to determine EPO concentration in other species. The objective of the...
Quieroz AO, Nehme-Russell NS, Brandão A, Jansen AM.'Mal de Cadeiras' is a disease which causes great mortality in horses in the Pantanal Matogrossense region, Brazil. The agent of this disease is Trypanosoma evansi, a kinetoplastid flagellate which belongs to the Trypanosomatidae family, classified into the Salivarian section. Transmission occurs mechanically by haematophagous Diptera, mainly by Stomoxys sp. and Tabanus sp. and vampire bats. Outbreaks of Mal de Cadeiras in horses result in economic losses, thus limiting their use in cattle raising. Ten isolates of T. evansi recently derived from coati (Nasua nasua, Carnivora, Procyonidae), hor...
Tomizawa N, Nishimura R, Sasaki N, Kadosawa T, Senba H, Hara S, Takeuchi A.Cervical myelography and survey radiography was performed on 12 light breed wobbling foals and a new radiographic measurement method was applied for more accurate diagnosis of cervical vertebral instability. Ratios of stenosis of the spinal canal on survey radiography and myelography using relative values in an individual foal were defined on radiograms of lateral flexed position of mid-cervical region, and coincidence between the ratios and histopathological lesions in the cervical spinal cord was investigated. Five of 6 foals had ratios of stenosis on myelography more than 40% at the interve...
Fukunaga Y, Wada R, Sugita S, Fujita Y, Nambo Y, Imagawa H, Kanemaru T, Kamada M, Komatsu N, Akashi H.Equine arteritis virus (EAV) was readily isolated in RK-13 cell monolayers by plaque assay from seminal plasma of experimental carrier stallions when they contained high titers of virus regardless of the presence of non-viral cytotoxicity in the seminal plasma. The cytotoxicity interfered with virus isolation from seminal plasma which contained virus at titers less than 10 PFU/ml. However, it was possible to detect the virus in seminal plasma pretreated with PEG (#6000). EAV was consistently identified by RT-PCR from crude seminal plasma which contained virus at titers of more than 10(2.7) PFU...
