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Topic:Virology
Virology in horses encompasses the study of viruses that affect equine species, including their biology, transmission, and impact on horse health. This field investigates viral pathogens that can lead to a range of diseases, from respiratory infections to neurological disorders. Common viruses affecting horses include equine influenza virus, equine herpesvirus, and West Nile virus. Understanding these viruses involves examining their genetic makeup, modes of transmission, and interactions with the equine immune system. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, pathogenesis, and control measures of viral infections in horses.
Influenza virus ISCOMs: antibody response in animals. A monovalent experimental ISCOM vaccine has been prepared with the envelope glycoproteins haemagglutinin and neuraminidase of the equine virus strain A/Solvalla/79 (H3N8). In vaccination trials on BALB/c mice the ISCOM vaccine induced more than ten times higher serum antibody titres measured in ELISA than a corresponding experimental micelle vaccine. Similarly, in guinea-pigs the ISCOMs induced about tenfold higher haemagglutination inhibition (HI) and neuraminidase inhibition (NI) titres than a micelle vaccine or a conventional killed influenza whole virus vaccine. Horses vaccinated with a di...
Propagation and quantitation of animal herpesviruses in eight cell culture systems. A comparative study was carried out to determine the relative sensitivities of eight different cell culture systems to six different herpesviruses of animals. The cells used were: OFL (ovine fetal lung), ML (mink lung), FK (ferret kidney), PTK-2 (potoroo kidney), TEK (turkey embryo kidney), ED (equine dermal), BT (bovine turbinate), and PK15 (porcine kidney). The viruses tested were: PRV (pseudorabies) of swine, CPHV (caprine herpesvirus), IBRV (infectious bovine rhinotracheitis virus), DN-599 strain of bovine herpesvirus type 4, EHV-1 (equine herpesvirus), and CHV (canine herpesvirus). On the...
[Infection with equine herpesvirus and its manifestation in the central nervous system of the horse]. Infections with EHV1 can lead to manifestation at the CNS of horses followed by encephalomyelitis and "equine stroke". Horse experiments could confirm the clinical picture and gave links to the potential pathogenesis of the disease. We also have been in the position to isolate and characterize an EHV4 virus out of the brain of a horse with CNS disorders. The two viruses carry different biological properties which obviously dominate the pathogenesis. These properties as well as experimental and field cases are described and different diagnostic tests are discussed.
Asinine herpesvirus genomes: comparison with those of the equine herpesviruses. Two previously unknown and distinct herpesviruses were isolated from donkeys. One, with the characteristics of a betaherpesvirus, was isolated from the leukocytes of an apparently healthy donkey, while the second, an alphaherpesvirus, was recovered from the nasal cavity of donkeys given high doses of corticosteroids, and caused rhinitis in two seronegative weanling donkeys when they were intranasally infected. Few, if any, restriction endonuclease fragments were shared by the donkey betaherpesvirus, equine herpesvirus 2 (EHV 2) or EHV 5, a second distinctly different equine betaherpesvirus, no...
Difference in growth behavior of human, swine, equine, and avian influenza viruses at a high temperature. Growth characteristics of a wide range of influenza A viruses from different mammals and bird species were examined in an established line of canine kidney (MDCK) cells at an ordinary (37 degrees C) and a high temperature (42 degrees C). Although all viruses employed in the present study possessed a capability of replicating at 37 degrees C, virus growth at 42 degrees C showed considerable variation and reflected differences in the natural hosts of the isolates. All reference strains and isolates from bird species grew well in the MDCK cells maintained at 42 degrees C, but human viruses did no...
Antigenic variation of equine infectious anemia virus as detected by virus neutralization. Brief report. The antigenic structure of 16 viruses isolated from four horses which were inoculated with a clone of equine infectious anemia (EIA) virus was compared by the neutralization test. The antigenic structure of viruses isolated after development of neutralizing antibody differed from virus to virus. Back mutation of the antigenic structure was also demonstrated by serial passage of the virus in horses. These results suggest that EIA virus is subject to multidirectional antigenic variation. The possibility that the variants originated in the heterologous virus population in the inoculum seems to be...
Antigenic mapping of the envelope proteins of equine infectious anemia virus: identification of a neutralization domain and a conserved region on glycoprotein 90. Monoclonal antibodies (MCAbs) were used to dissect the antigenic sites of the surface glycoproteins of the prototype cell-adapted Wyoming strain of equine infectious anemia virus (EIAV). Serologic reactivities of these MCAbs were determined by ELISA, additive ELISA, competitive ELISA, and Western blot assays. The results indicated that antigenic reactivity of gp90 was localized on at least four distinct epitopes, two of which were important in neutralization. Our studies also revealed that these epitopes were localized on overlapping antigenic sites on gp90. On the other hand, only two distinc...
Rapid detection of viral-specific antibodies by enzyme-linked immunosorbent assay (ELISA). The development of three separate rapid ELISAs for detecting antibodies in host serum to three different viruses is described. These include: 1. A direct antigen assay using enzyme labelled anti-canine Ig for detecting antibodies to canine parvovirus, 2. A competitive ELISA using a feline infectious peritonitis virus-specific monoclonal antibody labelled with enzyme, and 3. A competitive ELISA using an equine infectious anemia virus-specific monoclonal antibody and enzyme labelled antigen, p. 26. The utility and benefits of each of the three approaches is emphasized.
Role of the host immune response in selection of equine infectious anemia virus variants. Equine infectious anemia virus was isolated from peripheral blood leukocytes collected during two early febrile cycles of an experimentally infected horse. RNase T1-resistant oligonucleotide fingerprint analyses indicated that the nucleotide sequences of the isolates differed by approximately 0.25% and that the differences appeared randomly distributed throughout the genome. Serum collected in the interval between virus isolations was able to distinguish the isolates by membrane immunofluorescence on live cells. However, no neutralizing antibody was detected in the interval between virus isola...
Antigenic variation and lentivirus persistence: variations in envelope gene sequences during EIAV infection resemble changes reported for sequential isolates of HIV. The extent and nature of genomic variation among nine antigenically distinct EIAV isolates recovered during sequential clinical episodes from two experimentally infected ponies were examined by restriction fragment analysis and nucleotide sequencing. Only minor variations in restriction enzyme patterns were observed among the viral genomes. In contrast, env gene sequences of four isolates from one pony revealed numerous clustered base substitutions. Divergence in env gene nucleotide and deduced amino acid sequences between pairs of virus isolates ranged from 0.62 to 3.4% env gene mutation rate...
Serum neutralizing antibody titers in dairy cattle administered an inactivated vesicular stomatitis virus vaccine. Two doses of a formalin-killed, cell culture-derived vesicular stomatitis virus (vsv)-New Jersey serotype vaccine were administered intramuscularly, 30 days apart, to all lactating and nonlactating cows in a 350-cow dairy herd. Serum specimens were obtained serially from 96 cows before vaccination and at 30, 52 and 80 days after vaccination and from 24 of these cows 175 days after vaccination. Serum neutralizing antibody titers to vsv-New Jersey serotype were determined from serum-dilution, plaque-reduction tests. Serum neutralizing antibody titers also were determined during the same period f...
Equine viral encephalomyelitis in Canada: a review of known and potential causes. Rabies, equine herpesvirus type I, and eastern and western encephalomyelitis viruses, known causes of equine neurological disease, are reviewed with emphasis on epidemiology, pathogenesis, clinical signs, and diagnosis.Several arboviruses known to be active in Canada and capable of producing neurological disease in humans (Powassan, St. Louis encephalitis, snowshoe hare, and Jamestown Canyon viruses) are discussed as potential causes of encephalomyelitis in horses.
Vesicular exanthema of swine virus: isolation and serotyping of field samples. Virus isolation was attempted from 262 field samples of vesicular material collected during the outbreaks of vesicular exanthema of swine in the U.S.A. from 1952-54. Using primary swine kidney culture, viral cytopathogenic agents were isolated from 76.3% of the samples. However, an overall recovery rate of 82.1% was obtained after samples negative in tissue culture were inoculated intradermally in susceptible swine. All vesicular exanthema of swine virus isolates were identified as serotype B51 using complement fixation and serum neutralization tests. Two isolates did not react with antisera t...
Regulation of equine herpesvirus type 1 gene expression: characterization of immediate early, early, and late transcription. The regulation of equine herpesvirus type 1 (EHV-1) transcription was examined in infected rabbit kidney cells using metabolic inhibitors. In order to map EHV-1 immediate early, early, and late transcripts, viral RNA was 32P-labeled in vivo and hybridized to EHV-1 DNA restriction fragments immobilized on nitrocellulose filters. Immediate early viral RNA was mapped to one region of the viral genome within the inverted repeat DNA sequences (map units 0.78-0.83 and 0.95-1.0). Northern blot hybridization analysis using a 32P-labeled cloned DNA probe from this region identified a single immediate e...
Genomic heterogeneity of equine betaherpesviruses. The genomes of 51 isolates of slowly cytopathic equine herpesviruses were examined by digestion with restriction endonucleases. Forty-seven of the isolates showed considerable fragment pattern heterogeneity although common fragments were evident, especially when any two isolates were compared or when they were digested with SalI. Fifteen of the 47 viruses, selected for their diverse fragment patterns, showed a high degree of homology in Southern blot hybridization. In contrast, four viruses, representing three epidemiologically distinct isolations, shared few, if any, comigrating fragments wit...
An equine rotavirus (FI-14 strain) which bears both subgroup I and subgroup II specificities on its VP6. An equinine rotavirus FI-14 strain, originally isolated from a diarrheic foal in New York state, was shown to belong to serotype 3 by neutralization assay. In addition, it was found to react with both subgroup I and subgroup II monoclonal antibodies by enzyme-linked immunosorbent assay (ELISA), thus representing the first rotavirus strain to exhibit both subgroup specificities. By using hybridoma technology, we successfully produced monoclonal antibodies directed against the major inner capsid protein VP6 (the sixth gene product) of FI-14 virus. Such monoclonal antibodies reacted specifically ...
Course and extent of variation of equine infectious anemia virus during parallel persistent infections. Comparisons of peptide and oligonucleotide maps of glycoproteins and RNA from nine isolates of equine infectious anemia virus (EIAV) that were generated during parallel infections of two Shetland ponies revealed that each isolate was structurally unique. Each EIAV isolate contained a unique subset of variant peptides, oligonucleotides, or both, indicating that structural variation in EIAV is a random and noncumulative process and that a large spectrum of possible EIAV variants can be generated in infected animals.
Comparison of naturally occurring poliovirus-reactive immunoglobulins in bovine and equine sera. Bovine and equine sera were screened for poliovirus-reactive immunoglobulins (PRIgs) by means of neutralization and precipitation reactions with type 1 poliovirus. Bovine serum B1826 and B36 were found to contain such PRIgs from their reactivity to various PRIgs-resistant mutants of type 1 poliovirus origin. Neutralization and precipitation reactions with six mono-specific antibodies obtained by absorbing antiserum with each of the six different PRIgs-resistant virus mutants revealed that three antibodies were active in precipitation reaction while the others were substantially ineffective. On...
Characterization of equine infectious anemia virus long terminal repeat. The long terminal repeats (LTRs) of equine infectious anemia virus (EIAV) were examined with respect to their ability to function as transcriptional promoters in various cellular environments. Nucleotide sequence analyses of the LTRs derived from two unique proviral clones revealed the requisite consensus transcription and processing signals. One of the proviruses possessed a duplication of a 16-base-pair sequence in the CCAAT box region of the LTR which was absent in the other provirus. To assess its functional activity, each LTR was coupled to the bacterial chloramphenicol acetyltransferase ...
Infection of a poikilothermic cell line (XL-2) with eastern equine encephalitis and western equine encephalitis viruses. Eastern Equine Encephalitis (EEE) was in Cuba before the 1940s; the virus has been isolated from horses, birds, and rodents during epizootic as well as interepizootic periods. The only isolation of Western Equine Encephalitis (WEE) virus was from a sick pigeon found in the vicinity of Havana University. Both viruses can cause human disease; the isolation of WEE virus from the centre of an urban area emphasises the need for the prompt isolation and rapid identification of these agents. The object of this work was to compare the sensitivity of a continuous cell line (XL-2) from the toad, Xenopus...
Hybridoma cell lines secreting monoclonal antibodies against equine infectious anemia virus. A monoclonal anti-equine infectious anemia virus (anti-EIAV) antibody (1B15) has been generated by fusion of X63 Ag 8.653 myeloma cells and spleen cells from mice hypersensitized with viral antigen p29. Ouchterlony double-diffusion analysis indicated that antibody 1B15 is of the IgG class. The specificity of the immune reaction for p29 was confirmed by cross-over immunoelectrophoresis and disc-gel electrophoresis. MAb 1B15 was used to devise a solid-phase 'capture' RIA for EIAV-p29 antigen. The antigen, bound by 1B15 adsorbed onto wells of flexible microtitre plates, was detected using a rabbi...
