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Topic:Infectious Disease
Infectious diseases in horses encompass a range of illnesses caused by bacteria, viruses, fungi, or parasites. These diseases can affect various systems within the equine body, leading to symptoms that range from mild discomfort to severe systemic illness. Common infectious diseases in horses include equine influenza, strangles, equine herpesvirus, and West Nile virus. These diseases can be transmitted through direct contact with infected animals, contaminated surfaces, or vectors such as insects. Understanding the mechanisms of transmission, pathogenesis, and immune response is essential for effective prevention and control. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, diagnosis, treatment, and management of infectious diseases in horses.
Viral DNA in horses infected with equine infectious anemia virus. The amount and distribution of viral DNA were established in a horse acutely infected with the Wyoming strain of equine infectious anemia virus (EIAV). The highest concentration of viral DNA were found in the liver, lymph nodes, bone marrow, and spleen. The kidney, choroid plexus, and peripheral blood leukocytes also contained viral DNA, but at a lower level. It is estimated that at day 16 postinoculation, almost all of the viral DNA was located in the tissues, with the liver alone containing about 90 times more EIAV DNA than the peripheral blood leukocytes did. Assuming a monocyte-macrophage ...
[Detection of streptococci from various serological groups in animals]. During the period from 1985 to 1988 we determined 228 strains of streptococci isolated from samples of various sorts of biomaterials, mainly animals. From this set of streptococci we classified 207 strains into serological groups according to the Lancefield classification and about 30% strains into species by means of serological and biochemical methods. Most of the strains were allocated to group C (37.28%) and group Q (17.39%). 89 streptococci strains originated from pigs, 40 strains from horses, 13 from cattle, 12 from dogs, 9 from poultry and 8 from coypu. The other streptococci strains or...
The management of open joint injuries. The prognosis for returning horses with open joint injuries to athletic function is most closely related to the duration of the injury prior to treatment. Prompt diagnosis and appropriate therapy should yield a favorable result. Delayed diagnosis or inappropriate therapy that allow the wound to progress to an infected state makes the likelihood of return to athletic function poor. Refractory joint infection can occur despite early diagnosis and prompt appropriate therapy. The development of these infections is undoubtedly increased by tissue loss and gross contamination. Appropriate antibiotic...
Influence of technical parameters on the in vitro motility of equine neutrophils in the presence of streptococcal culture supernatant. To identify the influence of technical factors on the in vitro motility of equine neutrophils towards streptococcus culture supernatant in an under-agarose assay, we studied the changes in eight cell migration parameters. The distances the phagocytes travelled by directed, random and spontaneous migration increased with incubation time, cell concentration and the gelatin and serum contents of the migration plates. The contribution of chemotaxis to the phagocyte migrations, however, decreased simultaneously. The directed and random, though not the spontaneous, migrations of the phagocytes incre...
Cross-neutralizing and subclass characteristics of antibody from horses with equine infectious anemia virus. Antibody responses in horses with equine infectious anemia virus (EIAV) were examined to determine their cross-neutralizing capacity. Antibodies induced by infection with any of six biologically cloned variants of EIAV cross-neutralized multiple variants from the group. Anti-EIAV antibody was found in both the IgG and IgG(T) subclasses in plasmas with virus-neutralizing activity and the majority of antiviral antibody was of the IgG(T) subclass. Depletion of IgG(T) did not increase the neutralization indexes of either neutralizing or non-neutralizing plasma samples.
Class-specific and polyvalent enzyme-linked immunosorbent assays for detection of antibodies to Borrelia burgdorferi in equids. Class-specific and polyvalent ELISA were developed to detect IgM antibody or total immunoglobulins to Borrelia burgdorferi in equine sera. Analyses of 122 serum specimens, collected during 1985 from horses and ponies in tick-infested areas of Connecticut, revealed IgM antibody in 41 (34%) samples; titration end points ranged from 1:160 to 1:2,560. In polyvalent ELISA, 73 (16%) of 454 serum specimens contained IgM and/or IgG antibody. Seropositivity was highest (32%) for blood samples collected during May. Both ELISA procedures had comparable sensitivities.
Monthly prevalence (in 1986) of antibody titers against equine monocytic ehrlichiosis in apparently healthy horses in Illinois. The seroprevalence and seasonal trend of antibody titers against equine monocytic ehrlichiosis (Potomac horse fever) were determined in apparently healthy horses in selected areas of Illinois in 1986. Sera from 1,367 horses (6 months to 29 years old) were evaluated for the presence of antibodies against Ehrlichia risticii with indirect immunofluorescence. The majority (88%) of the horses were Thoroughbred or Standardbred racehorses. The number of horses with antibodies against E risticii was 229/1,367 (16.75%). The titers in these horses ranged from 1:10 to 1:640. As the year progressed, the n...
Comparison of bacteria isolated from specimens obtained by use of endoscopic guarded tracheal swabbing and percutaneous tracheal aspiration in horses. Results of bacteriologic culture of specimens obtained from 14 horses with pneumonia and from 15 horses that were clinically healthy (nonpneumonia group) were compared. Specimens were obtained by use of an endoscopic guarded tracheal swabbing method and percutaneous tracheal aspiration. The percentage of agreement between the 2 tracheal specimens for the horses of the pneumonia group was 79% for aerobic isolates and 100% for anaerobic isolates. The percentage of agreement between results of the 2 tracheal specimens for horses of the nonpneumonia group was 80% for aerobic organisms and 93% for ...
Surgical treatment of septic pedal osteitis in horses: nine cases (1980-1987). Over an 8-year period, 9 horses with septic pedal osteitis were admitted to the New York State College of Veterinary Medicine. Septic pedal osteitis was defined by the presence of purulent exudate combined with radiographic evidence of lysis of the distal phalanx. The condition described involved only the distal phalanx, the laminae and hoofwall, and the soft tissues of the sole. Treatment included curettage and removal of the affected portion of the distal phalanx through a ventral approach to the foot, combined with systemic administration of antibodies. Of the 9 horses, 7 returned to soundn...
Susceptibility of erythrocytes from several animal species to Vibrio vulnificus hemolysin. The hemolytic activity of Vibrio vulnificus hemolysin (VVH) against erythrocytes from several animal species (sheep, horse, cow, rabbit, chicken) was investigated. VVH was active against erythrocytes from all species, but the amount of VVH causing 50% hemolysis under identical conditions (hemolytic susceptibility to VVH) differed. The degree of 125I-labeled VVH (125I-VVH) binding to each erythrocyte species correlated with the susceptibility of the cells to hemolysis. However, marked differences in the binding ability of 125I-VVH were not observed against liposomes constructed with lipids from...
Molecular confirmation of an abortigenic strain of equine herpesvirus 1 (subtype 1) in a pregnant mare study. Four pregnant mares were inoculated intranasally and/or intravenously with equine herpesvirus 1 (EHV-1), subtype 1 during the third trimester of gestation. One mare aborted on postinfection day 15, one mare delivered a sick, weak full term foal, and two mares delivered healthy, full term foals. EHV-1, subtype 1 was isolated from several tissues of the aborted fetus and from the thymus of the sick foal. DNA restriction endonuclease patterns of the recovered EHV-1 viruses were identical to those of the EHV-1 challenge strain, documenting the origin of the abortigenic viruses.
Antibody response to Ehrlichia risticii and antibody reactivity to the component antigens in horses with induced Potomac horse fever. The antibody response and the antibody reactivity to component antigens of Ehrlichia risticii were studied in horses with induced Potomac horse fever. These horses had no detectable antibodies to E. risticii in their preinoculation (PrI) sera by indirect fluorescent-antibody assay and enzyme-linked immunosorbent assay (ELISA). All the horses exhibited typical disease features following experimental infection and responded with specific antibodies, as measured by ELISA and indirect fluorescent-antibody assay. A primary antibody response was detected in 70% of the horses, while a secondary-type ...
Leptospira abortion in horses. Leptospira infection was diagnosed as the cause of 4 late-term equine abortions/stillbirths and 1 neonatal death in Louisiana. The most consistent gross and microscopic lesions were icterus and interstitial nephritis, respectively. Diagnoses were based on visualization of compatible spirochetes in Warthin-Starry-stained sections of kidney, liver, and placenta. Confirmation by immunofluorescence was made in 2 cases.
Localization of conserved and variable antigenic domains of equine infectious anemia virus envelope glycoproteins using recombinant env-encoded protein fragments produced in Escherichia coli. Previous characterizations of equine infectious anemia virus (EIAV) glycoprotein variation by DNA sequence analysis and epitope mapping using monoclonal antibodies (MAbs) have revealed the presence of conserved and variable regions within the EIAV env gene. To extend these studies, fragments of the EIAV envelope proteins gp90 and gp45 were expressed in Escherichia coli and used in Western blot analysis with a diverse panel of equine immune sera to identify antigenic segments. All sera from EIAV-infected animals reacted with the carboxyl terminal portion of gp90 and the amino terminal portion o...
Pasteurella caballi, a new species from equine clinical specimens. The name Pasteurella caballi is proposed for a group of organisms represented by 29 strains isolated from respiratory and other infections in horses. P. caballi strains are gram-negative, oxidase-positive, nonmotile, fermentative rods with the key characteristics of the genus Pasteurella. These strains differed from other Pasteurella species in that all were aerogenic and catalase negative, and some strains produced acid from myo-inositol and L-rhamnose. The levels of DNA relatedness of 28 P. caballi strains with labeled DNA from the proposed type strain averaged 91 and 85% (hydroxyapatite met...
Cross-protective immunity between equine encephalomyelitis viruses in equids. Eighteen equids were inoculated with eastern equine encephalomyelitis (EEE) and 18 equids with western equine encephalomyelitis (WEE) viruses to produce EEE virus- and WEE virus-immunized equids. Twelve surviving EEE virus-seropositive equids, 15 surviving WEE virus-seropositive equids, and 10 nonimmunized, seronegative equids (controls) were subsequently inoculated with an equine pathogenic (epizootic) strain of Venezuelan equine encephalomyelitis (VEE) virus to determine cross-protective immunity. Challenge infection produced 90% mortality in control (nonimmunized) equids, and 40% mortality ...
Pseudallescheria boydii keratomycosis in a horse. The fungal organism Pseudallescheria boydii was isolated from the cornea of a Quarter Horse with ulcerative keratitis. Despite aggressive hourly medication through a subpalpebral lavage system, with drugs including miconazole and natamycin, the cornea developed a stromal abscess. Orbital exenteration was performed after 3 weeks. The fungal isolate was later determined to be resistant to all 8 antifungal drugs tested. Microscopic examination of the cornea revealed fungal hyphae throughout the corneal stroma and penetrating the Descemet membrane. Pseudallescheria boydii has not been implicated p...
The influence of corticosteroids on sequential clinical and synovial fluid parameters in joints with acute infectious arthritis in the horse. Infectious arthritis was induced experimentally in one tarsocrural joint of six horses by intra-articular injection of 1 ml Staphylococcus aureus-saline suspension with the addition of 200 mg methylprednisolone acetate. The corresponding contralateral joint was injected with 1 ml of saline with the addition of 200 mg methylprednisolone acetate, and served as a control. The purpose of the experiment was to examine the effect of corticosteroids on the acute clinical signs of infectious arthritis, and the associated changes in synovial fluid, to separate the effects of a steroid injection from th...
Sequential clinical and synovial fluid changes associated with acute infectious arthritis in the horse. Infectious arthritis was induced experimentally in one tarsocrural joint of six horses by intra-articular injection of 1 ml Staphylococcus-saline suspension containing 9 x 10(4) to 3 x 10(6) organisms. The corresponding contralateral joint was injected with 1 ml of saline and served as a control. The progression of the induced infectious arthritis was assessed over a nine-day period by clinical examination and sequential synovial fluid analysis with pH and lactate measurements. Changes in synovial fluid were present before clinical signs of infectious arthritis were manifested. The diagnostic ...
DNA sequence and comparative analyses of the equine herpesvirus type 1 immediate early gene. The immediate early (IE) proteins of herpesviruses are important regulatory factors which control the expression of genes at the transcriptional level. We report the DNA sequence of the immediate early gene of the alphaherpesvirus equine herpesvirus type 1 (EHV-1). This sequence is shown to be extremely rich in guanine and cytosine, resulting in a highly biased codon usage. The IE gene region possesses 38 open reading frames (ORFs) greater than 300 bp in length, 11 of which have coding regions of at least 100 amino acids (aa) following potential translation initiator codons. The largest ORF co...
Viral transcripts in cells infected with defective interfering particles of equine herpesvirus type 1. Equine herpesvirus type 1 (EHV-1) preparations enriched in defective interfering particles (DIPs) have previously been demonstrated to mediate the coestablishment of persistent infection and oncogenic transformation in primary hamster embryo fibroblasts. In this study, it was demonstrated that infection of a rabbit kidney (RK) cell line with EHV-1 DIP-enriched preparations also results in the establishment of persistent infection. Viral transcription was characterized in RK cells infected with DIP-enriched stocks and compared to viral transcription in RK cells infected with standard (STD) EHV-...
