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.
Edington N, Wright JA, Patel JR, Edwards GB, Griffiths L.Equine adenovirus 1 was recovered after four to six passages from two out of three cases of cauda equina neuritis (CEN) using kidney monolayers. Similar treatment of lumbo-sacral spinal cord from six normal horses did not yield adenovirus. All three cases of CEN had antibodies to the neuritogenic myelin protein P2 while immunofluorescence demonstrated that autologous IgG bound to the myelin of affected nerves. Adenovirus was not detected in neural tissue by immunofluorescence.
Hildreth SW, Beaty BJ, Maxfield HK, Gilfillan RF, Rosenau BJ.Enzyme immunoassays (EIAs) for eastern equine encephalomyelitis (EEE) and Highlands J (HJ) virus antigens were compared in a retrospective study with standard virus isolation procedures (VIP) for detection of alpha virus-infected mosquito pools. The original VIP was a plaque assay in chick embryo cell culture, and was performed in the years from 1979 to 1981. Using the original VIP as the reference standard, the sensitivity rate of the EIA was 0.7674 and the false negative rate was 0.2326. However, when the storage age and the initial virus titer of the sample were considered, the sensitivity ...
Montelaro RC, Parekh B, Orrego A, Issel CJ.The recurrent nature of equine infectious anemia has been attributed to relatively rapid antigenic variations in equine infectious anemia virus (EIAV) during persistent infection under selective immune pressures. This model was tested by serological and biochemical analysis of virus isolates recovered from separate febrile episodes in two experimentally infected ponies. Neutralization assays employing immune sera from the experimentally infected ponies demonstrated that distinct antigenic strains of virus predominate during sequential febrile episodes in a single pony. Analysis of the test str...
Shen DT, Gorham JR, McGuire TC.An indirect enzyme-linked immunosorbent assay (ELISA) was developed for the detection of equine infectious anemia (EIA) antibody in horse sera. Purified P26 viral protein was the antigen; alkaline phosphatase linked to rabbit anti-horse immunoglobulin G was the conjugate. The ELISA detected EIA antibodies in horse sera as early as 11 to 14 days after experimental inoculations. There was full agreement between the results of ELISA and the agar-gel immunodiffusion tests on EIA proficiency test sera. The ELISA readily detected EIA antibody in horse sera that had weak positive reactions on agar-ge...
Payne S, Parekh B, Montelaro RC, Issel CJ.The unique periodic nature of equine infectious anaemia (EIA) is believed to result from the ability of the infecting virus. EIAV, to undergo relatively rapid antigenic variations which circumvent host immune responses resulting in distinct virus populations in sequential clinical episodes in the persistently infected horse. This model was examined by oligonucleotide mapping comparisons of the RNA genomes of selected isolates of EIAV. Variations in oligonucleotide maps could be reproducibly demonstrated (i) after adaptation of the laboratory strain of EIAV to replication in a pony, (ii) after ...
Montelaro RC, West M, Issel CJ.The immunogenic contributions of the carbohydrate and peptide portions of the major envelope glycoprotein of equine infections anemia virus, EIAV gp90, were analyzed by measuring the effects of specific glycosidase and protease digestions on the reactivity of the glycoprotein with immune sera from infected horses. The results of both direct and competitive radioimmunoassay demonstrated that immune sera contained antibodies reactive with both the carbohydrate and protein moieties of EIAV gp90, with the predominant reactivity apparently against the gp90 peptide epitopes. These results contrast w...
Timoney PJ, Geraghty VP, Harrington AM, Dillon PB.A microneutralization test in PK(15) cells was developed to measure the neutralizing antibody response of a group of ponies experimentally challenged with louping ill virus. Viral cytopathic effect was maximal after 6 days of incubation, at which point titration endpoints were clear-cut and readily determinable. The assay compared favorably with the mouse neutralization test for accuracy and ease of performance.
Coignoul FL, Cheville NF.Six pregnant mares were given equine viral arteritis virus intravenously. Tissues from genital tracts, placentae, and fetuses were examined by light and electron microscopy to study the mechanism of abortion. Four mares which died with acute disease had diffuse vacuolation of endometrial epithelium and systemic necrotizing vasculitis. Two of these mares had dead fetuses and two had live fetuses; virus was isolated from tissues of one live fetus. Placentae of mares dying from acute disease did not have lesions attributable to infection; virus was isolated from two of these placentae. One of the...
Bouillant AM, Becker SA.The successive steps of maturation of seven retroviruses from five species of farm animals and one retrovirus from a mouse were compared in cell cultures. The viruses included three type C oncoviruses, one spumavirus, and three lentiviruses. Although members of the 3 subfamilies shared some gross morphologic features such as budding on plasma membranes, core, and surface projections, differences were noted in the ultrastructural detail of these features. Type C oncoviruses did not show any structural differentiation in identifiable form in the cytoplasm as opposed to characteristic features ob...
Caughman GB, Staczek J, O'Callaghan DJ.Enveloped virions and nucleocapsids of equine cytomegalovirus (ECMV; equine herpesvirus type 2) have been purified from the supernatants and the nuclear extracts of infected rabbit kidney (RK) cells, respectively, and their structural protein compositions have been analyzed. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis revealed that ECMV nucleocapsids were composed of nine proteins (average molecular weights = 148K, 52K, 49.5K, 46K, 43.5K, 38.5K, 27K, 20K, and 18K), which together constituted 89% of the total nucleocapsid protein on the basis of incorporated 3H-labeled am...
Burrows R, Goodridge D, Denyer MS.Vaccinated yearlings , two-year-old and in-foal pony mares with appropriate controls were exposed to aerosols of a subtype 1 virus one to two months after two or three vaccinations; all became infected. No obvious differences in the febrile responses, clinical signs and subsequent abortions were found between vaccinated and control mares. All vaccinated yearlings and two-year-old ponies developed a febrile respiratory disease but this was less severe than that suffered by the controls and the amounts and duration of virus shedding were reduced.
Mumford JA, Bates J.Serological responses following two and three doses of an inactivated equid herpesvirus 1 ( EHV -1) vaccine containing a subtype 1 strain were examined in yearling ponies. Complement fixing antibody responses were significantly higher against the subtype 1 vaccine strain than against a subtype 2 virus. Complement fixing antibody responses declined rapidly after the second dose of vaccine and had returned to almost pre-vaccination levels eight weeks after the second dose of vaccine. Complement fixing antibody titres to the heterologous subtype 2 strain increased after each successive dose of va...
Yamagishi H, Ide S, Eiki T, Eiguchi Y, Nagamine T, Igarashi Y, Yoshioka I, Matumoto M.ESK cells, a stable cell line derived from a swine embryo kidney, were found to be a good medium for plaque formation of the Prague and Miami strains of equine influenza virus. Factors influencing the plaque formation were investigated and a plaque assay for these viruses was worked out. The method is not only simple enough for routine use, but also is as sensitive as the egg inoculation method. The method was readily adapted for a neutralization test.
Bean WJ.The RNAs coding for the nucleoproteins of a panel of influenza isolates from human and nonhuman hosts were compared by RNA-RNA hybridization to determine the extent of genetic diversity of this protein and to determine if related nucleoproteins (NP) are consistently found in viruses from certain hosts. Five nucleoprotein groups were defined. Group 1 contains nearly all of the avian influenza viruses, group 2 includes only certain viruses isolated from gulls, group 3 includes all recent equine influenza strains, group 4 contains only equine/Prague/1/56, and group 5 contains all human and swine ...
Coggins L.Presently available data continue to support the idea that once a horse is infected with equine infectious anemia virus it remains infected indefinitely. Infection may not always be demonstrated by inoculation of plasma, serum, or whole blood transfusions into susceptible recipients, but transfusions of fresh whole blood will be infective in at least 95% of the horses testing positive in the agar gel immunodiffusion test. For detection of infectivity in a small percentage of inapparent carriers, it appears necessary to inoculate washed leukocytes collected over a period of time.
Issel CJ, Foil LD.There are several factors involved in the mechanical transmission of equine infectious anemia (EIA) virus by insects. Large hematophagous insects, especially tabanids, which feed from extravascular sites (ie, pool feeding) appear to be the most efficient vectors. The biology of the host-seeking and blood-feeding behavior of the vectors are important variables that have been overlooked in the mechanical transmission of pathogens like EIA virus. The biology, population levels, and diversity of the vectors, in addition to the clinical status and proximity of EIA virus-infected horses maintained w...
Conner M, Kalica A, Kita J, Quick S, Schiff E, Joubert J, Gillespie J.Reoviruses have been isolated from a number of species including human, bovine, feline, canine and equine. In most species they seem to produce mild to inapparent disease. We have isolated a reovirus type 3 from a foal with diarrhea. The virus designated the Ralph strain has been propagated in both the MA-104 and A-72 cell lines. The strain produced cytoplasmic inclusion bodies in these cell cultures. Tissue-cultured virus fixed complement in the presence of reovirus antibodies, but failed to do so in the presence of rotavirus antiserum. By electron microscopy the viral particle measured +/- 6...
Staczek J, Wharton JH, Dauenhauer SA, O'Callaghan DJ.Semipermissive, primary hamster embryo (HE) cells were morphologically transformed in vitro by infection with UV-irradiated equine cytomegalovirus (equine herpesvirus type 2; ECMV). Cell lines (designated EC-1-3) were established independently from foci and were shown to exhibit growth and biological properties typically associated with transformed cells: altered morphology, loss of contact inhibition, increased saturation density, decreased generation time, immortality in culture, normal growth in low concentrations of serum, colony formation in soft agar, and resistance to ECMV superinfectio...
Mayr A, Thein P.At the moment, horse praxis is confronted by two disease complexes which are difficult to fight against as well in prophylaxis as in therapy, but which get an increasing importance. First they concern virus infections of the foals and second primary virus-caused respiratory diseases. Foals get infected during the embryonal/fetal development, in the perinatal or postnatal period. Normally the infection is caused by latent infected, clinical healthy mares, or in the postnatal period by ubiquitous, normally opportunistic socalled problem-viruses, i.e. equine herpes-viruses 1 and 2, rota-, corona-...
Gosztonyi G, Ludwig H.The brains of eight horses that had suffered from natural Borna disease were examined with virologic, immunohistological, and electron-microscopic methods. All brains harbored infectious virus as shown by inoculation of experimental animals. Regional assessment of the infectivity exhibited the highest titers in the hippocampus and piriform cortex and the lowest in the cerebellum. Conventional histology yielded pathologic alterations very similar to those of the classical description of the disease. Immunohistology demonstrated the highest amounts of Borna disease virus-specific antigen in the ...
Evans KS, Carpenter SL, Sevoian M.The enzyme-linked immunosorbent assay (ELISA) antigen-positive and agar-gel immunodiffusion test (AGID)-negative horses do not have infective equine infectious anemia (EIA) virus. The ELISA testing of horse leukocyte culture (HLC) supernatants did detect EIA virus in a HLC that was infected with the Wyoming strain of EIA virus and in HLC derived from horses in febrile, acute, or subacute stages of EIA infection. In supernatants of HLC derived from chronic and inapparent carrier horses, EIA virus was not detected with ELISA. Direct fluorescent antibody tests detected EIA virus in HLC infected w...
Nishimura M, Nakajima H.Using purified equine infectious anemia (EIA) virus labeled with 3H-glucosamine or 14C-protein hydrolysate, structural proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. As a result, 2 glycoproteins and 10 proteins with molecular weights (mol wt) ranging from 12,000 to 115,000 daltons were demonstrated. Of 12 structural proteins, 3 proteins, namely a glycoprotein with mol wt of 76,000 (gp76) and 2 proteins with mol wt of 25,000 (p25) and 12,000 (p12), respectively, had distinct antigenic activity from one another in immunodiffusion. Development of antibodies a...
Tewari SC, Prasad S.The gel diffusion test was applied direct to field samples from cases of equine abortion, foal mortality and equine paralysis due to equine herpesvirus type 1 (EHV-1). Following polyethylene glycol concentra tion of viral antigen, one line was formed against EHV-1 antiserum after 24 hours incubation at 25°C. Tests carried out simultaneously on 41 field samples showed a high correlation between diagnosis based on this test and virus isolation in primary lamb kidney cell culture. Advantages of gel diffusion over isolation of virus in cell culture were its rapidity and simplicity. The precipit...
Rogers GN, Pritchett TJ, Lane JL, Paulson JC.Human and animal (avian and equine) influenza A virus isolates of the H3 serotype exhibit marked differences in their ability to bind specific sialyloligosaccharide sequences that serve as cell surface receptor determinants (G. Rogers and J. Paulson, 1983, Virology 127, 361-373). Whereas human isolates of this subtype strongly agglutinate enzymatically modified human erythrocytes containing the terminal SA alpha 2,6Gal sequence, avian and equine isolates preferentially agglutinate erythrocytes bearing the SA alpha 2, 3Gal sequence. As shown in this report, a glycoprotein found in horse serum, ...
Sabine M, Feilen C, Herbert L, Jones RF, Lomas SW, Love DN, Wild J.Until 1977 no case of abortion caused by equine herpesvirus 1 (EHV1) had been recorded in Australia although the virus, called equine rhinopneumonitis virus, had been known to have been present at least since 1962. Outbreaks of EHV1 abortion occurred in New South Wales in 1977 and in 1981. Sporadic cases of EHV1 abortion had been confirmed in some parts of Australia each year since 1975. It was concluded that an abortigenic subtype of EHV1 had been introduced to Australia in 1977 and that the previously endemic respiratory subtype occasionally caused abortion. Virus isolation in a variety of c...
Collins P.In vitro sensitivity data suggest that acyclovir should be effective against clinical manifestations of herpes simplex virus types 1 and 2, varicella-zoster virus and possibly Epstein-Barr virus. The clinical potential against herpes simplex virus types 1 and 2 is further supported by results in animal models. Human cytomegalovirus and the veterinary herpes viruses, with the possible exception of equine herpes virus type 1, may be insufficiently sensitive to be amenable to treatment.
Emmons RW, Woodie JD, Laub RL, Oshiro LS.Main Drain virus, which is thought to be transmitted normally among rabbits and various rodents by its natural vector, Culicoides variipennis, was isolated repeatedly from brain tissue of a sick horse from Sacramento County, California, and was implicated as the causative agent. Signs of illness were incoordination and ataxia, stiff neck, head pressing, inability to swallow, fever, and tachycardia.
Prutton JSW, Barnum S, Pusterla N.Equine coronavirus (ECoV) is considered an emerging enteric virus with reported morbidity rates ranging from 10 to 83% and fatality rates ranging from 7 to 27% in adult horses; a vaccine for ECoV is currently not available. This study investigated the safety, humoral response and viral shedding in horses inoculated with a commercially available modified-live bovine coronavirus (BCoV) vaccine. Twelve healthy adult horses were vaccinated twice, 3 weeks apart, either orally, intranasally or intrarectally. Two healthy unvaccinated horses served as sentinel controls. Following each vaccine adminis...
Siedek EM, Whelan M, Edington N, Hamblin A.Equine herpesvirus type 1 (EHV-1) causes respiratory disease, abortion and myeloencephalopathy in horses. As with other herpesviruses, cell-mediated immunity is considered important for both recovery and protection. Although virus-specific T-cell proliferation and cytotoxicity can be detected following in vivo infection, little is known about the role of antigen presenting cells such as dendritic cells (DCs) in these processes. Peripheral blood DCs were shown to express the viral glycoprotein gB perinuclearly following exposure to EHV-1 in vitro, demonstrating EHV-1 replication within them. Co...
Minato E, Aoshima K, Kobayashi A, Ohnishi N, Sasaki N, Kimura T.Equine herpesvirus 1 (EHV-1) uses equine major histocompatibility complex class I (MHC class I) as an entry receptor. Exogenous expression of equine MHC class I genes in murine cell lines confers susceptibility to EHV-1 infection. To examine the in vivo role of equine MHC class I as an entry receptor for EHV-1, we generated transgenic (Tg) mice expressing equine MHC class I under the control of the CAG promoter. Equine MHC class I protein was expressed in the liver, spleen, lung, and brain of Tg mice, which was confirmed by Western blot. However, equine MHC class I antigen was only detected in...
Grewar JD, Sergeant ES, Weyer CT, van Helden LS, Parker BJ, Anthony T, Thompson PN.An African horse sickness (AHS) outbreak occurred in South Africa's AHS controlled area in autumn 2016. A freedom from disease survey was performed to establish the likelihood of ongoing circulation of the associated virus during the same period the following year. A single-stage surveillance strategy was employed with a population-level design prevalence of 1% to establish a survey population sensitivity of 95% (probability that one or more positive horses would be detected if AHS was present at a prevalence greater than or equal to the design prevalence). In March 2017, a total of 262 random...
Anderson C, Baha H, Boghdeh N, Barrera M, Alem F, Narayanan A.Zoonotic pathogens that are vector-transmitted have and continue to contribute to several emerging infections globally. In recent years, spillover events of such zoonotic pathogens have increased in frequency as a result of direct contact with livestock, wildlife, and urbanization, forcing animals from their natural habitats. Equines serve as reservoir hosts for vector-transmitted zoonotic viruses that are also capable of infecting humans and causing disease. From a One Health perspective, equine viruses, therefore, pose major concerns for periodic outbreaks globally. Several equine viruses ha...
Rees WA, Harkins JD, Woods WE, Blouin RA, Lu M, Fenger C, Holland RE, Chambers TM, Tobin T.Amantadine is an antiviral agent effective against influenza A viruses. We investigated 1) the antiviral efficacy, 2) analytical detection, 3) bioavailability and disposition, 4) pharmacokinetic modelling and 5) adverse reactions of amantadine in the horse. In vitro, amantadine and its derivative rimantadine suppressed the replication of recent isolates of equine-2 influenza virus with effective doses (EDs) of less than 30 ng/ml. Rimantadine was more effective than amantadine against most viral isolates; we suggest a minimum plasma concentration of 300 ng/ml of amantadine for therapeutic effic...
Han X, Zou J, Wang X, Guo W, Huo G, Shen R, Xiang W.The Chinese EIAV vaccine is an attenuated live-virus vaccine obtained by serial passage of a virulent horse isolate (EIAV(L)) in donkeys (EIAV(D)), and subsequently in donkey cells in vitro. In this study, we compare the env gene of the original horse virulent virus (EIAV(L)) with attenuated strains serially passaged in donkey MDM (EIAV(DLV)), and donkey dermal cells (EIAV(FDDV)). Genetic comparisons among parental and attenuated strains found that vaccine strains contained amino acid substitutions/deletions in gp90 that resulted in a loss of three potential N-linked glycosylation sites, desig...
McGuire TC.Isolated equine immunoglobulin (Ig)G(T) antibodies to equine infectious anemia virus P26 antigen did not precipitate with antigen when the ratio of antibody to antigen was high. However, at lower ratios of antibody to antigen precipitation occurred. In addition, complement-fixation by IgG and P26 antigen was inhibited by high concentrations of IgG(T). The unusual reaction pattern noted with IgG(T) antibodies was still detectable by the immunodiffusion test for equine infectious anemia virus. In situations of nonprecipitability by IgG(T), the adjacent positive control line was inhibited, and th...
Liu IK, Pascoe DR, Chang LW, Zee YC.Serum antibody concentrations against influenza A-equi-1 virus and A-equi-2 virus were measured in a group of 18 foals from birth to 4 months of age. More than 50% of the foals were seronegative to A-equi-1 virus infection by 4 weeks of age, with titers of less than or equal to 1:16. For A-equi-2 virus, more than 50% of the foals were seronegative by 2 weeks of age, with titers of less than or equal to 1:8. Passively derived antibodies against influenza A-equi-1 virus and A-equi-2 virus in foals obtained from recently vaccinated mares and from mares not vaccinated within 6 months before foalin...
Paweska JT.Clinical, virological and serological responses were investigated in five pregnant donkey mares after experimental exposure to the South African asinine-94 strain of equine arteritis virus (EAV), and the duration of maternal immunity to EAV was studied in their foals. In four intranasally inoculated mares, fever with maximum rectal temperatures of 39.1-40.7 degrees C was recorded 2-11 d after challenge. All the inoculated mares developed mild depression, and a serous ocular and nasal discharge; in three mares mild conjuctivitis was observed. The virus was recovered from the nasopharynx and fro...
Mason DK, Watkins KL, McNie JT, Luk CM.In late November 1988 large numbers of thoroughbred horses in training in Hong Kong developed a transient pyrexia with, in some cases, the clinical signs of viral respiratory disease. Serial blood samples for haematological examination were taken from 10 of the horses which were stabled in six different blocks. They had developed a high temperature within three days of each other and subsequently seroconverted to equine herpes virus 1 (EHV1). The absolute monocyte count was more than 0.5 x 10(9)/litre in all 10 within the first five days, and nine of them had a high neutrophil/lymphocyte ratio...
De Paolis L, De Ciucis CG, Peletto S, Cappelli K, Mecocci S, Nervo T, Guardone L, Crescio MI, Pietrucci D, Fruscione F, Gabbianelli F, Turco S....Papillomavirus (PV) infections may be related to anogenital lesions and cancer development in humans and several other animal species. To date, 11 different PVs have been reported in horses. Among them, a newly described PV named Papillomavirus Type9 (EcPV9) was thus far only reported in the semen of a stallion with penile lesions in Australia. This study reports for the first time the presence of EcPV9 in asymptomatic Italian horses. From July 2020 to January 2022, genital brush samples were collected from 209 horses with no apparent signs of neoplastic disease and no PV-associated lesions, ...
Reemers S, van Bommel S, Cao Q, Sutton D, van de Zande S.Equine influenza virus (EIV) is a major cause of respiratory disease in horses. Vaccination is an effective tool for infection control. Although various EIV vaccines are widely available, major outbreaks occurred in Europe in 2018 involving a new EIV H3N8 FC1 strain. In France, it was reported that both unvaccinated and vaccinated horses were affected despite >80% vaccination coverage and most horses being vaccinated with a vaccine expressing FC1 antigen. This study assessed whether vaccine type, next to antigenic difference between vaccine and field strain, plays a role. Horses were vaccin...
Kyvsgaard NC, Høier R, Brück I, Nansen P.Ionizing irradiation and binary ethylenimine treatment have previously been shown to be effective for in-vitro inactivation of virus in biological material. In the present study the 2 methods were tested for possible effects on measurable concentrations of reproductive hormones in equine plasma (luteinizing hormone (LH), folliclestimulating hormone (FSH), progesterone (P4), and oestradiol-17 beta (E2)). The inactivation methods were electron beam irradiation with a dose from 11 to 44 kGy or treatment with binary ethylenimine (BEI) in concentrations of 1 and 5 mmol/L. Generally, there was a clo...
Archambault D, Laganière G, St-Laurent G.The genetic variation in equine arteritis virus (EAV) nonstructural (NS) protein-encoding open reading frames (ORF) 3 and 4 genes was investigated. Nucleotide and deduced amino acid sequences from seven different EAV isolates (one European, one American and five Canadian isolates) and the Arvac vaccine strain were compared with those of the Bucyrus reference strain. ORF 3 nucleotide and amino acid sequence identities amongst these isolates (including the Arvac vaccine strain) and the Bucyrus reference strain ranged from 85.6 to 98.8%, and 85.3 to 98.2%, respectively, whereas ORF 4 nucleotide a...
Della-Porta AJ.There has been concern that the present nomenclature system for the members of the Reoviridae family, and particularly the Orbivirus genus, does not represent the actual relationships exhibited between the members. In order to follow the conventions established by the International Committee for the Taxonomy of Viruses (ICTV), it is tentatively proposed that the present Reoviridae genera be upgraded in status to the following sub-families: reovirinae, orbivirinae, Fijivirinae, cypovirinae, rotavirinae, coltivirinae and phytoreovirinae. Below the sub-family level, divisions of genus (equivalent...
Jacob RJ, Price R, Allen GP.Equine herpesvirus type 3 (EHV-3) DNA, isolated from purified virions of the large-plaque strain, was digested with the restriction endonucleases XbaI, Bg/II, EcoRI, and HindIII. Several lines of evidence indicated that the DNA extracted from purified virions was composed of long (L) and short (S) components and was present as two isomeric forms, P and IS. The evidence included: (i) after electrophoresis on agarose gels, the summed molecular weights of the digestion products exceeded that expected from intact, unit size DNA; (ii) quantitative measurements of radioactivity (molar ratios) indica...
El-Hage C, Hartley C, Savage C, Watson J, Gilkerson J, Paillot R.During Australia's first and only outbreak of equine influenza (EI), which was restricted to two northeastern states, horses were strategically vaccinated with a recombinant canarypox-vectored vaccine (rCP-EIV; ProteqFlu™, Merial P/L). The vaccine encoded for haemagglutinin (HA) belonging to two equine influenza viruses (EIVs), including an American and Eurasian lineage subtype that predated the EIV responsible for the outbreak (A/equine/Sydney/07). Racehorses in Victoria (a southern state that remained free of EI) were vaccinated prophylactically. Although the vaccine encoded for (HA) belon...
Kong XG, Pang H, Sugiura T, Sentsui H, Onodera T, Matsumoto Y, Akashi H.Equine infectious anemia virus (EIAV) core proteins were obtained from a baculovirus expression system. Recombinant baculoviruses (rBVs) highly expressed the Gag precursor and p26 antigens in an rBV-infected Sf21 cell culture supernatant. Enzyme-linked immunosorbent assay (ELISA) and agar gel immunodiffusion (AGID) were conducted using the expressed proteins to detect antibodies from experimentally infected horses. The expressed antigens showed low background levels, high specificity and sensitivity in ELISA and AGID. The results of the serological tests using the expressed antigens were ident...
Hu Z, Zhu C, Chang H, Guo W, Liu D, Xiang W, Wang X.The objective of this study was to develop a novel EvaGreen (EG) based real-time PCR technique for the simultaneous detection of Equine herpesvirus 1 (EHV-1) and Equine herpesvirus 4 (EHV-4) genomes from equine nasal swabs. Viral genomes were identified based on their specific melting temperatures (T m), which are 88.0 and 84.4 °C for EHV-1 and EHV-4, respectively. The detection limitation of this method was 50 copies/μl or 0.15 pg/μl for EHV-1 and 5 copies/μl or 2.5 fg/μl for EHV-4. This assay was 50-1,000 times more sensitive than the SYBR Green (SG)-based assay using the same primer...
Murakami K, Sentsui H, Shibahara T, Yokoyama T.Three horses were experimentally infected with equine infectious anemia virus (EIAV). All horses were febrile after inoculation with EIAV and then developed chronic symptoms with intermittent fever. The febrile period was characterized by a rise in body temperature with reduced PBL and erythrocyte counts. Flow cytometric analysis showed that the reduced number of lymphocytes was due to significant decreases in CD4+ and CD8+ T cells in the absence of any change in B cell number. At the end of the febrile period the body temperature began to recover and numbers of CD4+ and CD8+ T cells showed a ...
Del Piero F, Wilkins PA, Timoney PJ, Kadushin J, Vogelbacker H, Lee JW, Berkowitz SJ, La Perle KM.A case of fatal nonneurological equine herpesvirus 1 (EHV-1) infection in a yearling filly is described. Gross lesions included extensive pulmonary edema, prominent laryngeal lymphoid follicles, and congestion and edema of the dorsal third ventricle choroid plexus. Histologically, there was vasculitis, hemorrhage, and edema in the lungs and dorsal third ventricle choroid plexus as well as mild intestinal crypt necrosis with occasional intranuclear inclusion bodies. The perivascular and vascular inflammatory infiltrates were comprised mainly of T lymphocytes and macrophages. EHV-1 antigen was i...
Tong P, Ren M, Xu X, Song X, Zhang L, Kuang L, Xie J.Multiple novel circular replication-associated protein (Rep)-encoding single stranded (CRESS) DNA viruses have been extensively identified in the feces of humans and animals. Here, we first detected CRESS DNA virus (named Horse-CRESS DNA-like virus, HCLV) in two fecal samples from 10 imported thoroughbred (TB) horses in the customs quarantine station in North Xinjiang province, China. Additionally, we found that this virus was not detected in local breeds (LBs) (0/41) and was found only in imported TB horses (2/73). We obtained the whole-genome sequences of four viruses (HCLV ALSK-3-4, ALSK-13...
Horsington J, Hartley CA, Gilkerson JR.Respiratory infections are a major burden in the performance horse industry. Equine rhinitis B virus (ERBV) has been isolated from horses displaying clinical respiratory disease, and ERBV-neutralizing antibodies have been detected in 50-80% of horses in reported surveys. Current ERBV isolation and detection methods may underestimate the number of ERBV-positive animals and do not identify multiple serotype infections. The aim of the current study was to develop a serotyping ERBV antibody-detection enzyme-linked immunosorbent assay (ELISA) and examine the seroprevalence of ERBV in a group of Aus...
Giles C, Vanniasinkam T, Barton M, Mahony TJ.Equine adenovirus 2 (EAdV-2) is one of two serotypes of adenoviruses known to infect equines. Initial studies did not associate EAdV-2 infections with any specific clinical syndromes, although more recent evidence suggests that EAdV-2 may be associated with clinical and subclinical gastrointestinal infections of foals and adults respectively. In contrast, Equine adenovirus 1 is well recognised as a pathogen associated with upper respiratory tract infections of horses. In this study the complete genome sequence of EAdV-2 is reported. As expected, genes common to the adenoviruses were identified...
Liu C, Cook SJ, Craigo JK, Cook FR, Issel CJ, Montelaro RC, Horohov DW.Unlike other lentiviruses, EIAV replication can be controlled in most infected horses leading to an inapparent carrier state free of overt clinical signs which lasts for many years. While the resolution of the initial infection is correlated with the appearance of virus specific cellular immune responses, the precise immune mechanisms responsible for control of the infection are not yet identified. Since the virus undergoes rapid mutation following infection, the immune response must also adapt to meet this challenge. We hypothesize that this adaptation involves peptide-specific recognition sh...
Olitsky PK, Long PH.The virus of vesicular stomatitis is not readily killed by formalin. This chemical is one of a group which coagulates the proteins of the medium in which the virus is usually contained. It has already been found(7) that other reagents of the protein-coagulating group are not actively virucidal) and the effect of formalin in this instance is therefore characteristic of the group. The so called formalinized vaccines which give rise to immunity can be shown to have done so because of the presence of living virus. A single injection of such so called "vaccine," or of other material containing livi...
Plowright W.An account is presented of the development and use of herpesvirus vaccines in domestic animals, with particular reference to those viruses causing cytolytic rather than oncogenic infections. The chief infections covered are Aujeszky's disease (AD or pseudorabies), infectious bovine rhinotracheitis (IBR) and equine rhinopneumonitis (equine abortion; EHV-1). Others mentioned are feline viral rhinotracheitis and malignant catarrhal fever of cattle. Both live-modified and inactivated vaccines are widely used or under development for ADV, IBR and EHV-1. Live vaccines are generally regarded as succe...
Qi T, Hu Y, Hu Z, Zhao S, Cullinane A, Lyons P, Gildea S, Wang X.Quantitation of virions is one of the important indexes in virological studies. To establish a sensitive and rapid quantitative detection method for equine arteritis virus (EAV), an antigen-capture enzyme-linked immunosorbent assay (AC-ELISA) was developed by using two EAV nucleoprotein monoclonal antibodies (mAbs), 2B9 and 2B3, prepared in this study. After condition optimization, mAb 2B9 was used as the capture antibody, and HRP-labeled 2B3 was chosen as the detecting antibody. The AC-ELISA had a good standard curve when viral particles of the Bucyrus EAV strain were used as a reference stan...
Moore BD, Balasuriya UB, Nurton JP, McCollum WH, Timoney PJ, Guthrie AJ, MacLachlan NJ.To compare growth characteristics of strains of equine arteritis virus (EAV) of differing virulence to horses in rabbit kidney (RK)-13 cells and equine endothelial cells (EECs) cultured from the pulmonary artery of a foal. Methods: 13 strains of EAV, including 11 field isolates of differing virulence to horses; the highly virulent, horse-adapted Bucyrus strain; and the modified-live virus (MLV) vaccine derived from it. Methods: The growth characteristics of the 13 strains were compared in EECs and RK-13 cells. Viral nucleoprotein expression, cytopathogenicity, and plaque size were compared to ...
