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Topic:Disease
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.
Examination of the foal. Recent advances in veterinary diagnostics have improved our ability to diagnose and treat foal diseases. However, these advances do not replace the physical examination as the most valuable diagnostic aid available to the equine practitioner. The basic physical examination provides the majority of information needed to make a presumptive diagnosis, provide a direction for ancillary tests, and formulate a plan for emergency therapy if needed.
Leishmaniasis disseminated by Leishmania braziliensis in a mare (Equus cabalus) immunotherapy and chemotherapy assays. Cutaneous disseminated lesions caused by Leishmania sp. were found in a pregnant mare (Equus cabalus) from a rural city in the State of Rio de Janeiro, Brazil. Before delivering, treatment was undertaken by immunotherapy followed by chemotherapy. Histopatology and serology were performed during treatment, as well as the biochemical characterization of the parasite (L. braziliensis) that was isolated from one of the lesions.
The cytology of squamous cell carcinomas in domestic animals. A series of 40 tumors with a proven diagnosis of squamous cell carcinoma for which both histology and cytology were available were classified according to their histologic appearance as well differentiated, moderately differentiated, and poorly differentiated. The Romanowsky-stained cytology specimens were reviewed. When available, Papanicolaou-stained smears were included. The cytologic findings for each of the 3 groups are described, and the most significant findings are photographically illustrated.
The validity of swimming training for two-year-old thoroughbreds. To investigate the validity of swimming training, the following matters were considered: 1) changes in the performance capacity, 2) changes in the constitution and 3) frequency of locomotor diseases. These were evaluated during a training program including both conventional exercise on a track and swimming. In this study, 24 two-year-old thoroughbred horses were studied, and divided into the following three groups: Group A, trained by only running; Group B, trained by running plus a gradual increase in swimming; Group C, trained by running plus constant swimming. As a result of standardized ex...
In vivo replicative status and envelope heterogeneity of equine infectious anemia virus in an inapparent carrier. The distribution and replicative status of equine infectious anemia virus (EIAV) DNA in the tissues of a well-characterized inapparent carrier horse were established by using the PCR technique. The EIAV pol region could be amplified in all of the tissues tested, including the cerebellum and periventricular tissue, at concentrations approximately 10(5)-fold less than in the same tissue from an acutely infected horse. Further analysis of the EIAV genome, with primer pairs diagnostic for sequential stages of reverse transcription, suggests that EIAV DNA in the brain, liver, and lymph nodes was in...
Babesia equi erythrocytic stage continuously cultured in an enriched medium. Babesia equi was continuously cultured through 90 passages in an enriched chemically defined basal medium (HL-1) supplemented with 20% fetal bovine serum and serum replacement factors, including lipid-rich bovine serum albumin, bovine insulin, and human transferrin. Cryopreservation and subsequent recovery of B. equi were easily achieved. Inoculation of a splenectomized and an intact horse with cultured infected erythrocytes resulted in parasitemias and B. equi in vitro reisolation from both animals. In vitro forms of the parasite resembled in vivo forms. After establishment, parasitemias of 1...
Relationships between radiography of cervical vertebrae and histopathology of the cervical cord in wobbling 19 foals. Nineteen wobbling foals (17 males and 2 females) showing lameness of hindlimbs at 6 to 21 months of age were investigated radiographically and histopathologically. Minimum sagittal diameter (MSD), minimum flexion diameter (MFD) and minimum dural sagittal diameter (MDD) were measured on plain radiograms or myelograms taken at neutral and flexed positions as indicators of narrowed vertebral canal. After necropsy, the cervical spines and the spinal cord were examined macroscopically and respectively the relationships between radiographic findings and the corresponding morphological lesions were e...
Toxigenic strains of Stachybotrys atra associated with poisonous straw in Morocco. From 10 moldy straw samples collected in a Moroccan area with an apparent equine stachybotryotoxicosis outbreak in November 1991, 8 isolates of Stachybotrys atra were obtained. They all showed toxigenesis, however they were variable in nature and intensity. While 1 isolate had only mild toxicity when fed to mice as moldy barley, another revealed very high toxicity to Artemia saline larvae, or rat skin, and to mice. The toxicity of the other 6 isolates were between these 2 limits. This study indicates that the November 1991 outbreak was due to toxigenic strains of Stachybotrys atra.
Rapid, single-step differentiation of equid herpesviruses 1 and 4 from clinical material using the polymerase chain reaction and virus-specific primers. Sets of primers were designed which enabled specific amplification of homologous regions of the glycoprotein C and gene 76 genetic loci of equine herpesviruses 1 and 4 (EHV-1 and EHV-4). The resultant virus-specific polymerase chain reaction (PCR) products arising from each loci could be discriminated easily on the basis of size on an agarose gel, allowing rapid differentiation of the two equine herpesviruses. Specificity of the amplifications were confirmed by Southern hybridization and restriction endonuclease digestion. The PCR test was applied to nasal swab samples from weanling foals and ...
Characterization of a red blood cell antigen in donkeys and mules associated with neonatal isoerythrolysis. A red cell antigen of donkeys and mules was identified using antibodies in serum from a mare which produced a mule foal affected with neonatal isoerythrolysis (NI). Subsequently antibodies with similar activity were identified in the sera of other mares which had produced mule foals and were produced by immunization of horses with blood from donkeys. The antigen detected by these antibodies does not correspond to any recognized horse red cell alloantigen. This may be a xenoantigen since all donkeys (and mules) tested have shared this antigen and all horses tested have lacked the antigen. The r...
Peripartum asphyxia. The abysmal survival rates for the first barking foals described more than 60 years ago were probably due to the cumulative effects of asphyxia on multiple organ systems. Successful treatment of asphyxiated foals requires recognition of periparturient conditions associated with the syndrome and appreciation of the spectrum of clinicopathologic complications that can ensue.
Hepatic cirrhosis and hemochromatosis in three horses. Hemochromatosis, an iron storage disease, was diagnosed in 3 horses with hepatic cirrhosis. Each horse had bridging portal fibrosis and abundant iron deposits in the cytoplasm of hepatocytes. Serum concentrations of liver-derived enzymes and total bile acids were high. However, serum iron concentration was not high, and iron binding capacity was only 46% saturated in the 1 horse in which it was measured. However, the concentration of iron in the liver of this horse was 20 times the reference limits. Hemochromatosis is common in mynah birds and human beings. There are several types of this iron...
Pneumocystis carinii pneumonia in foals. Pneumocystis carinii pneumonia was diagnosed in 3 foals. In 2 foals (No. 1 and 2), diagnosis was by histologic evaluation of pulmonary tissue. On retrospective evaluation, P carinii cysts were found on sediment smears of bronchoalveolar lavage fluid in 1 foal (No. 1). A different foal (No. 3) was diagnosed as having pneumocytosis by finding P carinii cysts in bronchoalveolar lavage fluid, and was treated successfully. Definitive diagnosis of pneumocytosis in animals is usually made at necropsy. However, careful cytologic evaluation in bronchoalveolar lavage fluid sediment can provide a diagnos...
Blood cell deformability in horses with intestinal colic. Hematologic and rheologic variables were examined in a group of 13 horses with intestinal colic and a control group of 6 horses. All horses had been recently transported to the veterinary teaching hospital, and blood samples were obtained during initial examination. There were no significant differences in blood neutrophil count or plasma fibrinogen concentration between the groups, and PCV was significantly increased in horses with intestinal colic. Cell filterability was measured by passing uniform concentrations of blood, erythrocytes, and neutrophils through micropore filters. There were n...
Studies on oral transmission of Potomac horse fever. Eight normal ponies placed in direct contact with ponies experimentally infected with Ehrlichia risticii for 30 to 90 days did not develop signs of Potomac horse fever. They also did not seroconvert, and they remained susceptible to IV infection. One of 8 ponies that were force fed fresh feces from infected ponies while in direct contact with ponies experimentally infected with E. risticii developed Potomac horse fever and seroconverted. The other 7 remained asymptomatic, did not seroconvert, and were susceptible to IV infection. Six of 9 ponies inoculated with E. risticii via nasogastric intu...
Cutaneous hemangiosarcoma with pulmonary metastasis in a horse. A 6-year-old Thoroughbred mare had a 7-cm ulcerated mass on the cranial aspect of the left cervical area. Ultrasonography revealed the mass to be < 1 cm thick and composed of small lobules that were filled by material hypoechoic to the surrounding muscle tissues. Fine-needle aspiration of the mass yielded blood, and cytologic examination revealed a few epithelial cells with neoplastic changes. Thoracic radiography revealed an interstitial pattern with several disseminated nodules. A diagnosis of cutaneous hemangiosarcoma with pulmonary metastases was made. The diagnosis was confirmed at necrop...
Lentivirus cross-reactive determinants present in the capsid protein of equine infectious anaemia virus. In this study we used immune sera from equine infectious anaemia virus (EIAV)-infected horses which uniquely display broad reactivity with different lentivirus capsid proteins (CA) to characterize the cross-reactive determinants of lentivirus CA proteins. In particular, the role of the major homology region (MHR) of lentivirus CA proteins in this serological cross-reactivity was evaluated using both equine immune serum and murine monoclonal antibodies (MAbs) directed against the MHR segment of different lentiviruses. The results of our studies indicate that about 80% of sera from long-term exp...
[The isolation of hyperimmune horse serum to the Ebola virus]. Immunization of horses with Ebola virus resulted in the production of specific virus-neutralizing antibody with maximum titres at 28-42 days. Repeated cycles of immunization led to a rise in antibody titres to 1:4096.
Posttranscriptional effector domains in the Rev proteins of feline immunodeficiency virus and equine infectious anemia virus. By systematically dissecting the Rev proteins of feline immunodeficiency virus (FIV) and equine infectious anemia virus (EIAV), we have identified within each a short peptide that is functionally interchangeable with the effector domains found in Rev-like proteins from other retroviruses. The active sequences from FIV and EIAV differ in several respects from other known effectors and may represent a distinct class of effector domain.
Epidemiologic and immunologic characteristics of Streptococcus equi infection in foals. A 2-phase study was performed to characterize the effects of Streptococcus equi infection in unexposed and previously exposed foals. In phase I, 22 weanling foals involved in a naturally occurring S equi epizootic were studied, along with a comparison group of 11 unexposed foals, matched for age, sex, and breed. Six months later (phase II), an epizootic was experimentally induced in previously exposed and unexposed foals from phase I. The prevalence and duration of clinical signs, the relative risk of developing disease, bacteriologic culture results, hematologic responses, and mucosal and ser...
Investigation of association between alpha-1 proteinase inhibitor haplotype and endometritis in the thoroughbred mare. Failure to inhibit proteinases can lead to excessive tissue damage. The possibility that the severity of endometritis in Thoroughbred mares correlates with the haplotypes of plasma alpha 1-proteinase inhibitor (alpha 1-PI) expressed was investigated in two groups of mares. In mares with pyometritis before treatment, the frequency of the N haplotype, which is already high in the Thoroughbred population, was significantly increased when compared with that in a large published population. In mares with acute endometritis which persisted after treatment followed by sexual rest, the absence of S an...
Detection of African horse sickness virus by reverse transcription-PCR. Reverse transcription-PCR (RT-PCR) was used to detect African horse sickness virus (AHSV). A single primer pair which amplified a 423-bp fragment of the S8 gene which encodes the NS2 protein of AHSV was identified. Amplification of this fragment from all nine serotypes of AHSV was achieved with these primers. Between 10(1) and 10(2) copies of AHSV genomic double-stranded RNA could be detected by RT-PCR followed by agarose gel electrophoresis and ethidium bromide staining. Application of RT-PCR to blood samples from AHSV-infected horses resulted in earlier detection of viremia than virus isolat...
Tetanus in the horse: a review of 20 cases (1970 to 1990). The case records of 20 horses with tetanus referred to the Ontario Veterinary College-Veterinary Teaching Hospital between 1970 and 1990 were reviewed. The fatality rate was 75%. There was a strong association with previous vaccination and survival (P = .03). Most of the animals had been injured an average of 9 days (range 2 to 21 days) prior to development of clinical signs. Hyperesthesia and prolapse of the third eyelid were the most common clinical signs. Treatment regimens varied during hospitalization; however, all horses received parenteral penicillin, tranquilizers, tetanus toxoid, and ...
Skeletal muscle mitochondrial myopathy as a cause of exercise intolerance in a horse. Although exertional myopathies are commonly recognized in horses, specific etiologies have not been identified. This is the first report in the horse of a deficiency of Complex I respiratory chain enzyme associated with profound exercise intolerance. Physical examination, routine blood tests, endoscopy, and ultrasonograms of the heart and iliac arteries were unremarkable. With slow, incremental exercise (speeds 1.5-7 m/s), the Arabian mare showed a marked lactic acidosis, increased mixed venous PVO2, and little change in oxygen consumption. Muscle biopsies contained large accumulations of mito...
Enhancement of EIAV replication and disease by immunization with a baculovirus-expressed recombinant envelope surface glycoprotein. The potential for antibody-dependent enhancement of replication of macrophage/monocyte tropic viruses has posed a significant problem in the development of vaccines for several animal and human viruses and has raised significant concern in the design of potential AIDS vaccines. Using the previously described equine infectious anemia virus/Shetland pony system as a model for HIV-1 vaccine development, we have evaluated the efficacy of a recombinant subunit vaccine containing a baculovirus-expressed envelope surface glycoprotein (gp90) of EIAV. The results of these trials demonstrate not only th...
