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.
Development of an equine herpesvirus in two cell culture systems: light and electron microscopy. Development of equine herpesvirus strain 82A was studied in cells from primary horse kidney (HOK) cultures and an equine dermis (ED) cell strain. HOK and ED cells are equally susceptible to the 82A virus infection and yield about the same amount of infectious virus. Intranuclear inclusions were present in both cell systems, but a ring-shaped syncytial formation was observed only in infected ED cells. Ultrastructural studies revealed the presence of dense granules 30 nm in diameter and characteristic star-like clusters of granules in the infected HOK cells, but these granules were rarely seen i...
Elimination of repeated clot formation in mouse ascitic fluid containing arbovirus antibodies. Repeated clot formation in mouse ascitic fluids containing antiviral antibody was eliminated by acid precipitation of the fibrinogen.
The fluorescent antibody technique in the diagnosis of equine rhinopneumonitis virus abortion. Using two known positive equine viral rhinopneumonitis (EVR) sera, conjugates were prepared with fluorescein isothiocyanate and tested for specificity using EVR infected tissue culture cells. The conjugate was then applied to selected tissues from 32 aborted fetuses and foals submitted during a natural outbreak of EVR. Antigen was detected in various tissues by immunofluorescence in 20 cases (62.5%). In 24 cases bovine fetal kidney cell monolayers were inoculated with a pool of lung and liver and EVR virus was isolated from 15 (62.5%). Histological examination of various tissues from 29 cases ...
Preparation and evaluation of inactivated Venezuelan equine encephalitis vaccines. No abstract available
Equine abortion (herpes) virus: strain differences in susceptibility to inactivation by dithiothreitol. The infectivity of equine abortion (herpes) virus (EAV) was inactivated by treatment with reduced dithiothreitol (DTT). According to their susceptibility to DTT, the EAV strains could be divided into three groups. The vaccine strain RAC-H (419) proved to be more resistant to DTT than all of the other 14 strains tested. The hemagglutinin of EAV was also inactivated by DTT; no strain differences were observed in this respect.
Study of the one-step growth curve of equine infectious anemia virus by immunofluorescence. Primary horse leukocyte cultures were inoculated with 2 or 10 50% tissue culture infective doses (TCID(50)) of equine infectious anemia (EIA) virus per cell, and the titer of cell-associated and fluid-phase virus was determined from 1 to 72 hr postinoculation (PI). Cover slips were collected from 4 to 72 hr PI and stained for EIA viral antigen by the indirect immunofluorescent (FA) technique. Viral replication was detected after a latent period of approximately 18 to 24 hr and reached peak titers of approximately 10(4.5) to 10(6) TCID(50)/0.5 ml from 48 to 72 hr PI. The fluid phase contained 1...
Experimental infection of horses with an attenuated Venezuelan equine encephalomyelitis vaccine (strain TC-83). Ten horses (Equus caballus) were vaccinated with strain TC-83 Venezuelan equine encephalomyelitis (VEE) virus vaccine. Febrile responses and leukopenia due to a reduction of lymphocytes and neutrophils were observed in all animals. Viremias were demonstrable in eight horses, with a maximum of 10(3.5) median tissue culture infectious dose units per ml of serum in two horses. Clinical illness with depression and anorexia were observed in five horses. Neutralizing (N), hemagglutination-inhibiting, and complement-fixing antibodies to the vaccine virus were demonstrable by 5, 6.5, and 7 days, respe...
Stability of live attenuated Venezuelan equine encephalitis vaccine. Reconstituted Venezulean equine encephalitis vaccine was found to retain significant titers of plaque-forming virus after storage at 4 or 22 C for 24 hr.
Field studies of an attenuated Venezuelan equine encephalomyelitis vaccine (strain TC-83). A series of field studies using strain TC-83 attenuated Venezuelan equine encephalomyelitis vaccine in horses was made to determine the rate of seroconversions, the postvaccination viremia, and the possibility of adverse reactions to the vaccine. The rate of seroconversions varied from 50% in one study to 91 and 100% in two others. The highest level of viremia measured was 7 x 10(3) to 8 x 10(3) plaqueforming units per ml. No adverse reactions to the vaccine were observed in any horses, including 42 pregnant mares and their resulting foals.
Antigenic variation of equine (Heq2Neq2) influenzavirus. Influenza equine (Heq2Neq2) strains isolated during the course of epizootics observed in Guanabara (Rio de Janeiro) and São Paulo, Brazil, in July-October 1969 were shown to differ antigenically from earlier strains of the same subtype (A/equine/Miami/1/63 (Heq2Neq2)). The difference could be clearly demonstrated in haemagglutination inhibition tests performed with postinfection horse or ferret sera but not with hyperimmune rooster sera. Antibody responses of diseased horses were higher and more frequent against current isolates than against strain equine/Miami/1/63. Some animals also showed ...