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Topic:Virus
The study of viral infections that affect equine species assesses the relationship between viruses and horses. Infections can lead to a range of clinical symptoms and may impact the health and performance of horses. Common equine viruses include Equine Influenza Virus, Equine Herpesvirus, and West Nile Virus, among others. Understanding the mechanisms of viral transmission, pathogenesis, and host immune responses is essential for developing effective prevention and treatment strategies. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, molecular biology, and clinical management of viral infections in horses.
A comparison of horse, cow, and sheep blood in NYC medium: effect on recovery of N. gonorrhoeae and urogenital mycoplasmas. NYC medium supplemented with cow blood (NYC-C) and sheep blood (NYC-S) were tested for the growth of N. gonorrhoeae and urogenital mycoplasma in comparison with standard NYC medium which contains horse blood. In situations where horse blood is not available, cow blood could be substituted in NYC standard medium, whereas the use of sheep blood was found unsuitable.
Search for epizootic-like Venezuelan encephalitis virus at enzootic habitats in Guatemala during 1969-1971. Seventy-four strains of Venezuelan encephalitis (VE) virus recovered from sentinel hamsters or mosquitoes at enzootic habitats in Guatemala in the two years following the 1969 epidemic-equine epizootic were examined for ability to produce small plaques in Vero African green monkey kidney cell cultures, like isolates obtained during the epizootic. (a) One strain recovered from a sentinel hamster in late October 1969 at an enzootic habitat near the epicenter of the hemagglutination-inhibition (HI) and equine-virulence properties like epizootic virus; this strain retained its small plaque charact...
[FAB immunoglobulin fragments. I. The comparative characteristics of the serological and virus-neutralizing properties of a gamma globulin against tick-borne encephalitis and of the FAB fragments isolated from it]. A comparative study was made of the serological properties and virus-neutralizing activity of antiencephalitis gamma-globulin and Fab-fragments isolated from it by gel-filtration. Horse immunoglobulins against the autumno-summer tick-borne encephalitis virus could be disintegrated with the aid of papaine to monovalent Fab-fragments which (according to the complement fixation reaction, the test of suppression of the complement fixation, and the HAIT) retained the serological activity whose level was compared with that of the serological activity of gamma-globulin. Fab-fragments possessed a mark...
Venezuelan equine encephalitis virus: comparison of infectivity and virulence of strains V-38 and P676 in donkeys. Two strains of Venezuelan equine encephalitis (VEE) virus were examined for the ability to replicate in, as well as to produce death among donkeys. One, a low passage strain known as strain P676 was originally isolated from mosquitos in Venezuela. The other, strain V-38 was isolated from a horse brain in 1938 and had undergone an unknown number of laboratory passages; it is used extensively for the preparation of inactivated VEE vaccine. Both strains were found to be approximately equal in their ability to infect donkeys. However, a quantity as small as 50% hamster intraperitoneal infectious u...
Equine herpesviruses. 6. Sequential infection of horses with types 2, 3 and 1. The immunological and virological status of 3 foals in respect of equine herpesviruses (EHV) was established and the foals were sequentially infected with EHV2, EHV3 and EHV1. Following experimental infection with EHV2, no clinical signs of disease were observed in any foal. The inoculation of EHV3 into the genital tract resulted in lesions of the mucous membrane and perineal skin that were considered typical of equine coital exanthema. Following intransal inoculation of EHV3 extensive ulceration and pustule formation on the nasal mucosa was observed by day 5 accompanied at day 7 by a profuse,...
Immunity to equine herpesvirus type 1 (rhinopneumonitis): in vitro lymphocyte response. Twenty-two ponies were examined for serum-neutralizing (SN) antibody to equine herpesvirus type 1 and for in vitro lymphocyte transformation in the presence of viral antigen. Six ponies had undetectable levels of neutralizing antibody (titer less than 1:2) and had lymphocytes which did not respond in culture with viral antigen (stimulation index less than 2.0). Four ponies which had SN antibody to equine herpesvirus type 1 did not manifest lymphocyte transformation in vitro. The 12 remaining seropositive ponies had lymphocyte transformation with viral antigen in vitro (stimulation indexes from...
Serological detection of equid herpesvirus 1 infections of the respiratory tract. An investigation was made of 3 serological tests (virus neutralization, complement fixation and indirect immunofluorescence), which are applicable to epidemiological studies of infections by Equid herpesvirus 1 (EHV-1). Sera from gnotobiotic foals inoculated intranasally with various strains of EHV-1 were unable in some cases to neutralize heterologous strains and these results were not consistent with the existence of clearly-defined subtypes of EHV-1, as previously proposed. The cross-reactions in complement-fixation tests paralleled those with neutralization but immunofluorescence tests wer...
Practical aspects of equine virus abortion in the United Kingdom. The current knowledge of the clinical signs, epidemiology and pathogenesis of abortion due to the equid herpesvirus (EHV 1) is reviewed. The relationship between the respiratory and abortigenic forms of the disease is discussed as well as the low incidence of virus abortion in the UK compared to some other parts of the world. Some practical aspects of the disease as they affect stud management are considered including methods of diagnosis, prophylaxis and the necessary action to be taken to prevent spread of infection.
Effects of crude extracts of various plants on infectious bovine rhinotracheitis virus-plaque production. Extracts of 28 plants were tested without demonstable antiviral activity in an agar-overlay plaque-reduction antiviral assay system, using infectious bovine rhinotracheitis virus and bovine endocardial cell cultures. Ethanolic extract of Narcissus tazetta L bulb elicited antiviral activity by inhibition of viral plaque formation. Antiviral activity was demonstrated against infectious bovine rhinotracheitis and equine rhinopneumonitis viruses. Narcissus tazetta L bulb did not directly inactivate the virus extracellularly. The extract exhibited only limited toxicity to rapidly multiplying bovine...
Studies of possible movement of Venezuelan encephalitis virus from an enzootic focus in Guatemala during 1971-1974. During the wet seasons of 1972 and possibly 1971, sentinel horses became infected by Venezuelan encephalitis (VE) virus in a temporally and geographically progressive manner inland from an enzootic marsh focus of virus on the Pacific couast of southeastern Guatemala. During the wet seasons of 1972 and 1973, VE virus was detected by sentinel horses (and a sentinel hamster in 1972) in a small woods 10 km north of the marsh, but virus was undetectable there during the dry seasons of 1973 and 1974 and the wet season of 1974. Culex (Melanoconion) mosquitoes were found in this woods and at the marsh...
Meningoencephalomyelitis in horses associated with equine herpesvirus 1 infection. During an outbreak of abortion caused by equine herpesvirus 1, a neurologic disease characterized clinically by dullness and ataxia occurred in several mares. Equine herpesvirus 1 was isolated from brain and lung of two severely affected mares. Histologically, both mares had disseminated meningoencephalomyelitis characterized by necrotizing arteritis, focal malacia in grey and white matter of brain and spinal cord, and accumulation of lymphocytes and neutrophils in paravertebral ganglia. Eosinophilic intranuclear inclusion bodies occurred in foci of necrosis in thyroid adenomas of both mares.
Transmission of equine infectious anemia virus by Tabanus fuscicostatus. The mechanical transmission of equine infectious anemia (EIA) virus by Tabanus fuscicostatus was investigated. In 1 of 7 transmission trials, a single horsefly transmitted EIA virus from an acutely infected pony to a susceptible pony. Groups of horseflies isolated for 3, 10, or 30 minutes before refeeding transmitted EIA virus, whereas those isolated for 4 or 24 hours did not. Data from field studies indicate that the home range or flight distance of horseflies may exceed 4 miles. That information together with our observations suggest that segregation of infected horses (usually defined as at...
Purification and characterization of equine infectious anemia virus. EIA virus was purified from equine fetal kidney cell cultures by PEG-precipitation, two sucrose-gradient sedimentations (5-30 per cent) and (25 to 60 per cent) centrifugation, using the immunodiffusion test to follow the procedure. Purified EIA virus had a density (20 degrees C) of 1.162 and a sedimentation constant of S20w=656. electron microscopy revealed a particle of about 100 nm in diameter with a very flexible but usually spherical shape. The dense core may be at various locations inside the membrane bound particle.
Vaccination by the non-parenteral route of virus disease in the veterinary field. After a brief reference to the importance of the non-parenteral route of vaccination of domestic animals in general, the author deals, for each animal species separately, with the most important vaccines utilised by this method of administration. On the basis of bibliographical data, he describes the history of this use, discusses the results of the application in the field and draws the relative conclusions.
Immunization of man and animals against influenza by oral and intranasal routes. Live human and equine influenza virus strains modified by serial passage on allantois-on-shell system (AOS) in the presence of normal horse serum were administered orally or intranasally to volunteers or horses. Mostly mild clinical short-lasting reactions, replication in nasal mucosae, transmission to placebo recipients and significant local or circulating antibody rises were observed following administration to volunteers of strains modified by five or less serial passages on AOS in the presence of normal horse serum (NHS). Milder clinical reactions, no replication, no viral transmission and...
