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.
Levine JF, Levy MG, Nicholson WL, Gager RB.Larval Dermacentor variabilis (Say) (n = 327) were fed on Balb/C mice inoculated with Ehrlichia risticii, the etiologic agent of equine monocytic ehrlichiosis (Potomac horse fever). All mice displayed clinical signs of E. risticii infection at the time of feeding. After molting, resulting nymphs (n = 74) were fed on susceptible mice. No clinical signs were observed, and the mice remained seronegative for 6 wk after feeding.
Groschup M, Müller HP, Weiss R, Schliesser T.For the determination of a species-specific antigen of Streptococcus (S.) equi, acid extracts of group C streptococcal strains from horses (S. equi, S. zooepidemicus, S. equisimilis) were investigated using polyacrylamide gel electrophoresis and the immunoblotting technique. Using sera of horses suffering from strangles as well as sera from horses with respiratory infection of unknown etiology, Western blotting yielded more or less multiple banding reactions with bands in the 70, 54, 42, 40, and 31-28 kd molecular weight ranges against extracts of all of the 3 different bacterial species. Howe...
Burg JG, Roberts AW, Williams NM, Powell DG, Knapp FW.Experimental transmission of Ehrlichia risticii, the causal agent of Potomac horse fever, was attempted with adult stable flies, Stomoxys calcitrans, (L.) using two feeding schedules. In schedule A, a set of 140 flies was allowed to feed once on an experimentally infected donor pony and once 24 h later on a recipient pony. A different set of flies was used each day for a 12-d period. In schedule B, 240 flies were allowed to feed once daily for 12 consecutive d on the donor pony followed by five consecutive daily feedings on the recipient pony. E. risticii was isolated from the blood of the exp...
Lindsay WA.Three clinical cases are presented to illustrate some of the problems that may complicate the treatment of wounds in horses. The three examples are a lower limb laceration, a chronic draining chest wound, and complications associated with a fiberglass cast. The use of ancillary diagnostic aids such as arthrocentesis, diagnostic nerve blocks, radiographs, and ultrasonography are indicated to assess change to deeper structures.
Tate LP, Sweeney CL, Bowman KF, Newman HC, Duckett WM.Transendoscopic neodymium:yttrium-aluminum-garnet (Nd:YAG) laser was used to treat 12 standing horses with epiglottic entrapment (EE) or dorsal displacement of the soft palate (DDSP), or both. In four horses, transendoscopic laser staphylectomy was performed. The most common presenting complaints were respiratory stridor, cough, and exercise intolerance. Ten horses with EE healed without epiglottic complications; in one horse, partial adhesion of the aryepiglottic fold to one side of the epiglottis was corrected surgically through a laryngotomy incision. One horse with DDSP had no further sign...
De Geest JP, Lauwers H, Simoens P, De Schaepdrijver L.The present investigation of 20 equine eyes shows that the iridocorneal angle of the horse is characterised by a very distinct pectinate ligament and a large ciliary cleft. The pectinate ligament consists of long and broad pigmented trabeculae which form a firm, flat and dense network that encircles the eye. On meridional sections, the ciliary cleft is visible as a wide triangular space comprising the trabecular meshwork which consists of two parts. The inner part is the larger and forms a three-dimensional network of large pigmented trabeculae with very wide intertrabecular spaces. The outer ...
Thaker SR, Dutta SK, Adhya SL, Mattingly-Napier BL.A gene bank of Ehrlichia risticii was constructed in plasmid vector pUC13. Five clones representing discrete regions of the E. risticii genome were tested for their ability to hybridize specifically to E. risticii DNA. None of the clones cross-hybridized with Ehrlichia equi DNA, whereas four of these clones cross-hybridized with Ehrlichia canis and Ehrlichia sennetsu DNAs. However, one clone carrying a 1-kilobase HindIII fragment of E. risticii DNA failed to cross-react with the genomes of E. sennetsu, E. canis, and E. equi in dot blot hybridization assays. The sensitivity of this probe for th...
Mironneau J, Martin C, Arnaudeau S, Jmari K, Rakotoarisoa L, Sayet I, Mironneau C.Saturable, high-affinity binding sites for [3H]saxitoxin were identified in equine portal vein smooth muscle membranes. These sites had a dissociation constant of 0.29 nM and a maximal binding capacity of 115 fmol.mg-1 of protein. A similar dissociation constant was obtained with cells prepared from rat portal vein. Specific binding of [3H]saxitoxin was completely displaced by unlabelled saxitoxin and tetrodotoxin, with inhibition constants of 0.42 and 2.10 nM, respectively. Tetrodotoxin blocked the fast Na+ current in single cells of rat portal vein in a concentration-dependent manner, with a...
Holt PE, Mair TS.Bladder paralysis and sabulous urolithiasis were diagnosed in 10 horses with urinary incontinence. Additional neurological deficits in the hindquarters were detected in five of them. Treatment by catheter drainage and bladder lavage was unsuccessful, and all the horses were destroyed within 14 months of presentation. Neuritis of the cauda equina was diagnosed post mortem in one horse, but the cause of the paralysis was not identified in the others, although radiography revealed abnormal lumbosacral vertebral angulation in one case.
Mfitilodze MW, Hutchinson GW.A postmortem survey of 57 horses in tropical northern Queensland revealed 41 (89%) infected with intestinal strongyles. Thirty-five strongyle species (8 large strongyles and 27 small strongyles [Cyathostominae]) were recorded of which 9 species are reported from Australia for the first time. The 14 most prevalent small strongyles were Cyathostomum catinatum (in 76% of horses), Cyathostomum coronatum (65%), Cyathostomum pateratum (33%), Cyathostomum labiatum (30%), Cylicostephanus calicatus (70%), Cylicostephanus longibursatus (67%), Cylicostephanus goldi (43%), Cylicostephanus minutus (26%), C...
Seethanathan P, Bottoms GD, Schafer K.Direct effects of endotoxin (lipopolysaccharide [LPS]) on equine WBC are known to stimulate the release of a variety of mediators including thromboxane, prostacyclin, and leukotrienes. In this study, 0.1 microgram of LPS/ml stimulated an early increase in tumor necrosis factor, succeeded by an increase in interleukin-1, but concentrations of LPS up to 5.0 micrograms/ml caused no significant increase in superoxide anion release. The concentration of LPS (0.1 microgram/ml) used in this experiment was in the range of concentrations measured in plasma of some horses with gastrointestinal problems....
Schryver HF.Horses are subject to poisoning from many sources. This article considers poisonings from minerals and vitamins of nutritional significance and from minerals as environmental contaminants.
Clarke LL, Roberts MC, Argenzio RA.The association of feeding practices with the development of digestive disorders in horses has long been recognized, although the underlying mechanisms had been barely considered. The physiologic consequences of meal frequency may help to explain the relationship and prove to be of major significance in the induction of many conditions. Many Equidae kept for performance and leisure activities are fed high-energy, low-forage rations twice daily, with limited access to hay or grazing. Rapid ingestion of such meals stimulates a copious outpouring of upper alimentary secretions and results in tran...
Houpt KA, Zahorik DM, Swartzman-Andert JA.The ability of ponies to learn to avoid a relatively novel food associated with illness was tested in three situations: when illness occurred immediately after consuming a feed; when illness occurred 30 min after consuming a feed; and when illness was contingent upon eating one of three feeds offered simultaneously. Apomorphine was used to produce illness. The feeds associated with illness were corn, alfalfa pellets, sweet feed and a complete pelleted feed. The ponies learned to avoid all the fees except the complete feed when apomorphine injection immediately followed consumption of the feed....
Bürki F, Rossmanith E.Selected sets of serum samples of horses were tested blindly in a comparative investigation for antibodies against Equine Infectious Anemia (EIA) virus. Three commercial kits were used, a well-established agar-gel immuno-diffusion kit which our laboratory has been using routinely for 14 years on one hand, a competitive ELISA kit (CELISA) and a non-competitive ELISA kit on the other hand. The American EIA Reference Laboratory in Ames cotested 56 serum samples with the same 3 products, with highest-level correlation, thereby ascertaining full dependability of our own results. Five EIA experts su...
Dill SG, Correa MT, Erb HN, deLahunta A, Kallfelz FA, Waldron C.A case-control study was done to identify factors associated with the development of equine degenerative myeloencephalopathy (EDM). Questionnaires were mailed to the owners of 146 horses admitted to the New York State College of Veterinary Medicine between November 1978 and June 1987 and diagnosed as having EDM by histologic examination. Questionnaires also were sent to owners of 402 clinically normal horses admitted to the college during the same period. Data were compared between the EDM-affected and control groups (56 and 179 questionnaires returned, respectively). Risk factors identified i...
Furr MO, Tyler RD.The CSF creatine kinase (CK) activity was determined in 70 CSF samples from 69 horses with CNS disease. Abnormal values (greater than or equal to 1 IU/L) were determined from 32 CSF samples, and normal values (less than 1 IU/L) were found in 38 samples. Increased CK activity was most frequently associated with a diagnosis of equine protozoal myelitis; CK activity was not increased in 11 horses with cervical compressive myelopathy. Other diagnoses, in which CSF CK activity was increased included trauma (n = 1), idiopathic epilepsy (n = 2), botulism (n = 2), articular facet fracture (n = 1), int...
Allison CJ.A chronic wasting disease in a 16 month old Welsh pony filly is described. The animal died 26 days after the onset of illness which commenced with a sub-acute colic and was characterised by progressive loss of appetite and weight. Post-mortem examination revealed a total invagination of the caecum into the colon and it seemed logical to assume this invagination occurred at the start of the illness. A review of the literature showed that total caecal invagination produces 2 distinct clincal syndromes. It can occur either as an acute illness characterised by severe colic and death after about 10...
Meek LA.A 40-mm intraocular silicone prosthesis was placed in a horse's globe to control glaucoma. The glaucoma was suspected to be associated with a lens subluxation, but primary glaucoma could not be ruled out. Medical treatment and cyclocryotherapy had been attempted, but failed to decrease the intraocular pressure to a normal value. The prosthesis was placed, via a dorsal scleral incision, after removal of the intraocular contents. The size of the prosthesis was estimated from measurements of the horse's normal left globe and an enucleated, age-matched globe. Silicone prostheses offer a cosmetic a...
Traub-Dargatz JL.This article is a review of reports on neoplasia of the equine urinary tract. Clinical signs associated with equine patients with urinary tract neoplasia are summarized along with a description of diagnostic methods used in such patients. The prognosis for treatment of urinary tract neoplasia is guarded. A review of the limited treatments that have been reported to date are also provided in this article.
Lunn DP, Peel JE.A five-year-old standardbred mare suffered a cervical oesophageal rupture subsequent to a kick. Marked cellulitis and extensive soft tissue damage resulted. Treatment consisted of creating an oesophageal fistula, local debridement and systemic antibiotics. The mare made a long but successful recovery. Treatment of oesophageal rupture in the horse is discussed.
Humber KA, Sweeney RW, Saik JE, Hansen TO, Morris CF.Bacillus piliformis infection (Tyzzer's disease) in foals is rarely observed clinically because of the peracute course of the disease. Clinical and clinicopathologic findings as well as information on therapeutic attempts in two foals are described. Clinicopathologic abnormalities common to both cases included leukopenia, hyperfibrinogenemia, metabolic acidosis, and hypoglycemia. Treatment was unsuccessful in both cases.
Carmalt JL, Baptiste KE, Chirino-Trejo JM.A 10-year-old pregnant Norwegian Fjord horse was examined for gross swelling of the muzzle of 2 years' duration. Examination of biopsy specimens revealed diffuse dermal fibrosis, micropustule formation, and vascular thrombosis; large numbers of Actinobacillus lignieresii were isolated in pure culture. Prolonged treatment with i.v. administration of sodium iodide and oral administration of trimethoprim-sulfamethoxazole caused regression of the swelling and did not induce abortion. A 5-month-old American Paint filly was examined for swelling in the udder region. Bacteriologic culture of purulent...
Deacon LJ, Navas de Solis C, Richardson DW, Polkes A, Reef VB.• An ACF developed in a hospitalized horse following orthopedic surgery. • Spontaneous closure of the ACF occurred 6 weeks after initial diagnosis. • Echocardiography is the primary imaging modality to confirm the presence of ACF in equids. [Figure: see text]
Robinson CS, Wylie CE, Compston PC, Payne RJ.To describe a technique of canaliculosinostomy into the caudal maxillary sinus to alleviate epiphora secondary to nasolacrimal duct obstruction and to report the long-term outcome in 5 horses. Methods: Case series. Methods: Five client-owned horses. Methods: Case records of all horses presented for chronic epiphora to a single equine hospital that underwent surgical treatment were reviewed. All included horses had a Jones test or dacryocystography to confirm nasolacrimal duct obstruction. All horses were anesthetized and canaliculosinostomy was created from the medial canthus of the eye into t...
van der Velden MA, Rutgers LJ.During a 10 year period, 18 horses were treated surgically because of visceral prolapse after castration. Surgery was successful in six cases of omental prolapse and in eight out of 12 cases of intestinal prolapse. To minimise the risk of visceral prolapse, the authors prefer half-closed castration, with proper ligation of the parietal vaginal tunic, to open castration. If adequate treatment is started promptly, prognosis in cases of visceral prolapse is favourable.
Heath SE, Bell RJ, Chirino-Trejo M, Schuh JC, Harland RJ.Four horses from the same farm developed clinical signs of botulism during the winter months; three of these horses died. One horse survived an initial attack and recovered over a three-week period, but died during a second attack. The horse that survived took six weeks to recover. Clinical and postmortem examination ruled out other causes of disease. Confirmation of the diagnosis was made by isolation of Clostridium botulinum type C toxin from the dirt in the bottom of an oak feedtrough used by all horses, and from the colonic contents of one of the horses that died. To our knowledge, this is...
Donahue JM, Williams NM, Sells SF, Labeda DP.Over the course of the past decade, actinomycetes have been isolated from the placentas of horses diagnosed with nocardioform placentitis. The incidence of this infection has generally been low, with typically no more than 30 animals affected in most years, but the incidence increased through 1999, with placentas from 144 mares found to be infected. Approximately half of the cases result in loss of the foal. A typical actinomycete with branching mycelium was isolated from placental lesions, and a comparison of the sequence of the 16S rDNA gene against the public databases indicated a relations...
Birch-Machin I, Ryder S, Taylor L, Iniguez P, Marault M, Ceglie L, Zientara S, Cruciere C, Cancellotti F, Koptopoulos G, Mumford J, Binns M....Three filamentous phage random peptide display libraries were used in biopanning experiments with purified IgG from the serum of a gnotobiotic foal infected with equine herpesvirus-1 (EHV-1) to enrich for epitopes binding to anti-EHV-1 antibodies. The sequences of the amino acids displayed were aligned with protein sequences of EHV-1, thereby identifying a number of potential antibody binding regions. Presumptive epitopes were identified within the proteins encoded by genes 7 (DNA helicase/primase complex protein), 11 (tegument protein), 16 (glycoprotein C), 41 (integral membrane protein), 70 ...