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.
Zientara S, Sailleau C, Moulay S, Wade-Evans A, Cruciere C.The development of a coupled reverse transcriptase-polymerase chain reaction assay (RT-PCR) is described for the detection of African horse sickness virus (AHSV) double-stranded RNA. Genome segments 7 and 10 were chosen as target templates for primers selected for use in the RT-PCR. Using these AHSV-specific primers all 9 serotypes were detectable. The sensitivity and specificity of the RT-PCR results were compared to those obtained by competition ELISA.
Davis EO, Curran GE, Hetherington WT, Norris DA, Wise GA, Roth IJ, SeaWright AA, Bryden WL.Flood plain staggers, a corynetoxicosis of grazing livestock, occurred on flood plains of the Darling river in northern New South Wales between spring 1990 and autumn 1991, associated with the grazing of Agrostis avenacea with diseased inflorescences. Over this period 1722 cattle, 2466 sheep and 11 horses died on 31 farms. Clinical signs were similar in sheep and cattle, being characterised by intermittent episodes of cerebral convulsion superimposed on varying degrees of cerebellar dysfunction. Pathological changes were variable and non-specific, principally reflecting trauma and the generali...
Woods PR.Skin lesions can be associated with many internal diseases. Most organ systems seem to have conditions in which skin lesions can develop. Treatment of the skin lesions in such a situation is palliative. The underlying internal disease must be addressed for resolution of the skin lesions to occur. It is important to view the skin as an integral communicating part of the body and not just as the skin.
Fadok VA.Pruritus is a common complaint associated with equine dermatoses. Self-mutilation results in alopecia, excoriations, scaling, and crusting; the aesthetic appearance of the horse is often ruined and the horse may be unfit for riding or showing. This article specifically addresses those pruritic dermatoses caused by allergies, including food allergy/intolerance, atopy and contact allergy, as well as by two ectoparasites, stick-tight fleas and rhabditic mange. The clinical signs, diagnostic tests, and treatment recommendations are discussed for each disorder. Insect hypersensitivity and pruritus ...
Fadok VA.Papules and nodules are common lesions on horses and have a variety of underlying causes. This article addresses inflammatory and congenital nodules primarily, including urticaria, erythema multiforme, those nodules caused by infectious agents, epidermoid and dermoid cysts, and the uniquely equine skin tumor, the sarcoid. The eosinophilic nodules and other tumors are covered elsewhere in this issue. Diagnostic and therapeutic approaches to each of the diseases are emphasized.
Cohen ND, Wallis DE, Neibergs HL, Hargis BM.Salmonella was identified in feces from horses, using the polymerase chain reaction (PCR) and genus-specific oligonucleotide primers. Feces from healthy horses were determined to be culture negative and PCR negative for Salmonella. Fecal samples were inoculated with known numbers of colony-forming units (CFU) of S. enteritidis. The fecal samples were enriched overnight in tetrathionate broth, and then DNA was extracted and amplified by PCR using genus-specific primers. Sensitivity of the assay extended to 10 degrees CFU Salmonella enteritidis/g feces; sensitivity of microbiologic culture with ...
Greiner EC.Potential methods of incriminating insects as the cause of insect hypersensitivity are presented. A listing of the biting midges known to attack horses in North America is presented also. An example of how species may be determined to be the cause of the hypersensitivity is given using data from a recent study in Florida. Light trap collections indicated the temporal and geographic distribution of potential contributing species and collections made by vacuuming horses further delineated species by proving they feed on horses and the correct locations on the horses to match lesion distribution....
Thompson JC, Ellison R, Gillett R, Badcoe L.Thyrotropin releasing hormone (TRH) stimulation tests were carried out on a number of horses, including one clinically affected horse whose age and clinical signs suggested that a pituitary adenoma was most unlikely. The results of these tests indicated that, according to criteria published overseas, the majority of these horses had pituitary adenomas. The fact that clinically normal or affected horses may have marked increases in cortisol concentrations indicates that the TRH stimulation test is not suitable for the diagnosis of pituitary adenoma. Other tests, including alterations in glucose...
Greet TR.Thirty eight horses with epiglottal entrapment were examined. In 29 the dorsally displaced mucosa was split axially with a curved hook knife, per nasum. The condition was also treated by subepiglottal mucosal resection (4 horses) and solely by the administration of an anti-inflammatory throat spray (4 horses). All surgical cases were treated with an anti-inflammatory throat spray and parenteral phenylbutazone. Those horses treated via a laryngotomy incision were box rested until the laryngotomy incision healed. The other horses were restricted to walking and trotting exercise for 10 days befor...
van Rensburg IB, Jardine JE, Carstens JH, van der Walt ML.Specimens from the ileum, colon and rectum were aseptically collected from 50 consecutive horse carcases submitted for necropsy to the Department of Pathology, Faculty of Veterinary Science, University of Pretoria. These were bacteriologically examined for the presence of Salmonella. Seventeen of these were positive for Salmonella at one or more sites. Serotyping of the isolates revealed a dominance of Salmonella Hayindogo in these horses.
McCann SH, Mumford JA, Binns MM.A search for variable restriction sites has been carried out for equine herpesvirus-1 (EHV-1) in an attempt to develop markers which can be used to group epidemiologically related viruses into groups, and to learn more about the dynamics of EHV-1 disease. Crude viral DNA extracts of EHV-1, prepared by Hirt extraction, were digested with AluI, HaeIII, or RsaI, and Southern blotted following electrophoresis. DNA fingerprints, produced by probing the Southern blots with the EHV-1 EcoR1-I fragment, separated 56 isolates into 16 groups. The variable sites within the EcoR1-I fragment were mapped app...
Causey RC, Paccamonti DL, Todd WJ.A total of 22 clinical streptococcal isolates, predominantly Streptococcus zooepidemicus, associated with endometritis in horses were tested for their ability to withstand the natural bactericidal properties of freshly obtained blood. During a 3-hour incubation in blood from a single horse, 8 of these isolates survived and grew, the remainder were killed. To determine whether this ability to grow extended to blood of other horses, 5 of these growing isolates were tested for their ability to grow in the blood of 5 additional horses. The same 5 horses were used for each isolate. The isolates gre...
Wang ZW, Yu MF, Robinson NE, Derksen FJ.The present study was conducted to determine if acetylcholine (ACh) release from airway cholinergic nerves is increased and if modulation of ACh release by prejunctional receptors is altered in horses with heaves, an obstructive airway disease characterized by airway inflammation and bronchospasm. Trachealis strips and bronchial segments of normal horses and horses affected with heaves were suspended in 2-ml tissue baths. ACh release was induced by electrical field stimulation and the bath ACh content was measured by high performance liquid chromatography (HPLC) with electrochemical detection....
Moens Y, Lagerweij E, Gootjes P, Poortman J.The distribution of inspired gas to each lung, time constants of the lungs and parameters of gas exchange were studied in 2 groups of horses (mean bwt 606 kg), anaesthetised using thiopentone and chloral hydrate and breathing room air. One group (n = 4) had a downward curved abdominal contour (round-bellied) and the other group (n = 4) had an upward curved abdominal contour (flat-bellied). An equal distribution of inspired gas between the lungs existed in both groups in dorsal recumbency. Flat-bellied horses maintained this equal distribution in lateral recumbency whereas in round-bellied hors...
Pavlásek I, Hess L, StehlÃk I, Stika V.The first occurrence of Giardia spp. in horses in the Czech Republic is reported. During preventive examination of 360 five-month up to 14-year horses from various parts of the region of Central Bohemia carried out from January 1993 to June 1994 in the parasitological laboratory of the State Veterinary Institute in Prague, the Giardia cysts were detected in the excrements of 18 (5%) horses, mostly 2-4 years of age, and in two foals 3 and 6 weeks old. During the period between March 1993 and June 1994, systematic and repeated observation was aimed at a group of 38 racing horses two up to four y...
Joost RE.Acremonium coenophialum Morgan-Jones and Gams, an endophytic fungus commonly found in tall fescue (Festuca arundinacea Schreb.), has been identified as the cause of poor performance of beef cattle and horses on tall fescue. Ryegrass staggers, a neurological disorder of sheep, has been linked to the presence of a similar fungus, A. lolii Latch, Christensen and Samuels, in perennial ryegrass (Lolium perenne L.). Renovation of endophyte-infected (E+) pastures with endophyte-free (E-) cultivars of tall fescue or perennial ryegrass has resulted in improved animal performance, but productivity and s...
Santschi EM, Adams SB, Robertson JT, DeBowes RM, Mitten LA, Sojka JE.Six mares had ovariohysterectomy performed for chronic pyometra associated with cervical abnormalities, uterine neoplasia, or removal of a macerated fetus. Ovariohysterectomy was performed through a ventral midline incision with access to the ovarian and uterine vessels aided by traction on the uterus and retraction of abdominal viscera. Abdominal pain, the most common complication after surgery, occurred in four mares but resolved within 36 hours. Peritonitis occurred in two mares; one mare was subsequently euthanatized. Other complications that resolved with treatment included infection of t...
Ladefoged O, Stürup S.A case of copper deficiency or molybdenum toxicosis in cattle, sheep and horses after heavy pollution of a pasture with fly ash is described. If the pastures had not been grazed by cattle and sheep as well as the horses, it would have been difficult to identify the reason for the intoxication in the horses. It is argued that molybdenum intoxication, although seldom seen in non-ruminants, was the cause of the deaths of the horses. It is suggested that the bioavailability of molybdenum in fly ash is high and therefore can cause equine intoxication.
Madison JB, Reid BV, Raskin RE.Infectious arthritis caused by Candida spp was diagnosed in 2 horses. Source of infection was by direct inoculation in 1 horse and was presumed to be hematogenous in the other horse. On microbial culturing of synovial fluid and synovial membrane specimens, the organisms were isolated in both horses. In both horses, the joint infections resolved after i.v. administration of amphotericin B and joint drainage; however, 1 horse was eventually euthanatized because of signs of cervical pain and progressively worsening ataxia. Fungal organisms isolated on microbial culturing of joint specimens in hor...
Doxey DL, Milne EM, Gilmour JS, Pogson DM.An attempt has been made to assess the diagnostic value of clinical features seen at initial examination of horses with grass sickness, colic cases and cases submitted as possible grass sickness but diagnosed subsequently as some other condition. There appears to be no single pathognomonic sign for grass sickness. A range of signs has been associated with grass sickness but these are of value only when related to the length of illness and the history. Biochemical tests related to intestinal tissue damage, stress and dehydration were evaluated and most were found to be of value in diagnosing ac...
Noll CV, Kilcoyne I, Nieto JE, Thio T, Byrne BA.To determine the ability of 0.2% polyhexamethylene biguanide (PHMB)-impregnated gauze to inhibit the growth of bacteria isolated from equine infected sites. Methods: In vitro study. Methods: Nine bacterial isolates were obtained from cultures submitted from equine patients presenting with penetrating injuries of the hoof (n = 4), septic osteitis (n = 1), synovial sepsis (n = 1), wounds (n = 2), and incisional infection following laparotomy (n = 1). Two standardized strains were also included. A standard inoculum of each isolate was placed on 12 Muller-Hinton agar plates. Squares (2.5 cm ×â€...
Brook D.A case of what can be presumed to be secondary nutritional hyperparathyroidism, due to high phosphorus diet, in a six year old pony is discussed. The findings are compared to those found when the disease occurs in young growing horses.
Cross DL, Reinemeyer CR, Prado JC, Donnell RL, Bond KG, Farr H, Longhofer SL.The objective was to evaluate the efficacy of domperidone in the prevention of reproductive complications of fescue toxicosis in periparturient mares. Pregnant mares at ≤310 days of gestation were fed ≥200 μg ergovaline per kg diet daily in endophyte-infected fescue hay and seed, starting ≥30 days before their expected foaling date (EFD: 340 days after breeding). Thirty-five mares were randomized to a treatment group to receive either domperidone gel (n = 20, 1.1 mg/kg, PO, once daily) or placebo (n = 15). Treatment was initiated 10 to 15 days before the EFD and continued for 5 days aft...
Böhnel H.The laboratory diagnosis of C. botulinum is described for cattle and horses in the years 1995-1998. Out of 122 cases 66 were positive. All types of toxins were identified; in cattle mainly types C and D. In 9 cases typing was not conclusive. The results of an enquiry of afflicated animal owners showed, that modern agricultural technology has an important impact on toxinogenesis in feed stuff. Possibilities to prevent the disease and to reduce economic losses are discussed; a solution cannot be presented.
Elce YA, Laverty S, Almeida da Silveira E, Piat P, Trencart P, Ruzickova P, Reardon RJ.To estimate the frequency of undetected perforations in surgical gloves during equine surgery and to identify risk factors associated with occurrence. Methods: Observational cohort study. Methods: Surgical gloves-292 pairs. Methods: Water leak tests were performed on gloves after equine surgery to detect perforations. Fifty pairs of unused gloves were also tested. Potential risk factors were recorded. Logistic regression was used to explore associations between putative risk factors and perforation. Results: No perforations were detected in the unused gloves. Of 292 pairs of used gloves tested...
Wallace KD, Selcer BA, Tyler DE, Brown J.Ninety-one equine aortic and cranial mesenteric arterial segments were evaluated ultrasonographically in a water bath. On the basis of pathologic evidence of verminous arteritis, arterial segments were classified into 4 categories, and the ultrasonographic characteristics of each group were evaluated. Normal arteries (class 1) were ultrasonographically characterized by a smooth luminal surface layer and uniform wall thickness and echogenicity. Arteries with only histopathologic evidence of verminous arteritis (class 2) were ultrasonographically characterized by a smooth luminal surface layer, ...
Irwin CF.A total of 487 Standardbred and Thoroughbred mares at two studs were manually tested for pregnancy at 20 to 24, 30 to 34, and greater than 42 days after service and the abortion rate compared to that obtained in previous years when only the greater than 42-day test was performed. The results indicated that early manual pregnancy testing does not increase the abortion rate if undertaken carefully and enables non-pregnant mares to be re-mated earlier in the same season.
Van Pelt RW, Langham RF, Gill HE.A 2-year-old Standardbred colt with a history of intermittent lameness of the left hindlimb had hemangiosarcomatous involvement of the tarsal synovial sheath. Tibiotarsal and proximal intertarsal synovial sacs were visibly distended and there was pronounced distension of the tarsal synovial sheath. A large, firm mass was palpable in the sheath at about the level of the tuber calcis. Three circumscribed sessile growths were surgically excised from the sheath. The growths were lobulated, moderately vascular, and of fibrotic consistency. Microscopically, the pattern of the hemangiosarcomas appear...
MartÃn-Cuervo M, Gracia-Calvo LA, MacÃas-GarcÃa B, Ezquerra LJ, Barrera R.Systemic inflammatory response syndrome (SIRS) is a very common finding in critically ill patients. To accurately identify patients with SIRS and those who need intensive care, several markers have been evaluated, including cortisol, WBC or lactate. It is widely known that a stress leukogram includes eosinopenia as one of its main markers (neutrophilia, eosinopenia, lymphopenia and mild monocytes). It is known that cortisol concentration in plasma is the main stress biomarker and is strongly correlated with the severity of disease in horses. However, it is not possible to measure this paramete...
Mortola E, Miceli G, Alarcon L, Azcurra M, Larsen A.In newborn foals the absorption of colostrum immunoglobulins in the small intestine is maximal up to 8Â hours after birth and then progressively decreases to become null after 24Â hours post-partum. Thus, equine practitioners need a simple, quick, inexpensive and reliable field test to identify foals affected by failure of passive transfer rather than an accurate method yielding quantitative results within the whole range of immunoglobulin concentrations. Objective: As the validity of the immunocrit method to detect failure of passive transfer in foals had not been evaluated before, the object...
Coignoul FL, Bertram TA, Roth JA, Cheville NF.Neutrophils from 4 pony foals, 3 lactating pony mares, and 3 nonlactating mares were evaluated ultrastructurally and by in vitro function tests. Neutrophils from foals had significantly (P = 0.05) less random migration than neutrophils from mares; values in tests for iodination and Staphylococcus aureus ingestion were also lower with foal neutrophils. Neutrophils from lactating mares had lower responses to iodination, antibody-dependent cell-mediated cytotoxicity, and random migration tests than did neutrophils from nonlactating mares. Ultrastructurally, granule concentration did not differ si...