Equine Herpesvirus (EHV) is a contagious virus that affects horses, causing a range of clinical conditions. It primarily impacts the respiratory system but can also lead to neurological disorders, abortion in pregnant mares, and neonatal foal death. The virus is transmitted through direct contact with infected horses or through contaminated surfaces and equipment. There are several strains of EHV, with Equine Herpesvirus-1 (EHV-1) and Equine Herpesvirus-4 (EHV-4) being the most commonly studied due to their prevalence and impact on equine health. EHV-1 is associated with more severe outcomes, including equine herpesvirus myeloencephalopathy (EHM). This page aggregates peer-reviewed research studies and scholarly articles that explore the epidemiology, pathogenesis, clinical manifestations, and management strategies related to Equine Herpesvirus in horses.
McCann SH, Mumford JA, Binns MM.A search for variable restriction sites has been carried out for equine herpesvirus-1 (EHV-1) in an attempt to develop markers which can be used to group epidemiologically related viruses into groups, and to learn more about the dynamics of EHV-1 disease. Crude viral DNA extracts of EHV-1, prepared by Hirt extraction, were digested with AluI, HaeIII, or RsaI, and Southern blotted following electrophoresis. DNA fingerprints, produced by probing the Southern blots with the EHV-1 EcoR1-I fragment, separated 56 isolates into 16 groups. The variable sites within the EcoR1-I fragment were mapped app...
Blunden AS, Smith KC, Binns MM, Zhang L, Gower SM, Mumford JA.Equid herpesvirus 4 (EHV-4) infection was diagnosed as the cause of interstitial pneumonia in a 6-week-old conventionally reared Welsh pony foal, by cocultivation and immunolabelling with specific monoclonal antibodies, EHV-4 specific amplification of viral DNA, and immunohistological examination of infected tissues. The case was novel in that replication of the EHV-4 isolate in endothelial cells and in the synovial epithelium was a feature. Restriction digests of this isolate were compared with those of seven respiratory and one abortigenic EHV-4 isolate, and no differences in restriction pat...
McCartan CG, Russell MM, Wood JL, Mumford JA.An outbreak of equine herpesvirus-1 (EHV-1) occurred on a large stud farm with 133 mares, 54 foals and four stallions, and at least 85 mares, 22 foals and three stallions were infected. Clinical disease was observed in 16 mares, two stallions and 13 foals and the predominant clinical signs were scrotal oedema, ataxia and loss of libido in the stallions, ataxia and recumbency in the mares and uveitis and nasal discharge in the foals, although pneumonia and colic with intussusception were also recorded at autopsy. Neurological disease was more common in the mares nursing foals (12 of 38 infected...
Ficorilli N, Studdert MJ, Crabb BS.The nucleotide sequence of the glycoprotein G (gG) homologue of asinine herpesvirus 3 (AHV3), a respiratory alphaherpesvirus of donkeys, was determined. The AHV3 gG gene consists of 1233 base pairs (bp) and codes for a predicted protein of 411 amino acids. This is identical in size to the equine herpesvirus 1 (EHV1) gG gene and 6 amino acids longer than the equine herpesvirus 4 (EHV4) gG gene. The predicted amino acid sequence of AHV3 gG has characteristics of a class 1 membrane protein. The amino acid sequence of AHV3 gG shows 92% and 60% identity to EHV1 gG and EHV4 gG respectively. Two regi...
Crabb BS, MacPherson CM, Reubel GH, Browning GF, Studdert MJ, Drummer HE.We describe a type-specific ELISA, which distinguishes antibody to equine herpesvirus 4 (EHV4; equine rhinopneumonitis) and EHV1 (equine abortion virus) thereby identifying horses that have been infected with either or both of these antigenically related viruses. The antigens used are parts of the EHV4 and EHV1 glycoprotein G (gG) homologues expressed in E. coli as fusion proteins [Crabb and Studdert, 1993: J Virol 67: 6332-6338). The expressed proteins comprise corresponding regions of the gG molecules that are highly divergent and encompass strong, typespecific epitopes. Plasma samples from ...
Allen G, Yeargan M, Costa LR, Cross R.An experimental system that permits sensitive and reproducible detection of equine herpesvirus 1 (EHV-1)-specific cytotoxic T-lymphocyte (CTL) activity in the horse was developed. Peripheral blood mononuclear cells (PBMC) collected from immune horses were restimulated in vitro by culture with live EHV-1. Cytotoxic activity against virus-infected, pokeweed mitogen-stimulated lymphoblast targets was assessed in a 4-h 51Cr release assay. The optimal conditions for in vitro stimulation of equine memory CTLs and for preparation of EHV-1-infected target cells expressing viral antigens were systemati...
Reubel GH, Crabb BS, Studdert MJ.Nested polymerase chain reaction (PCR) assays were developed for the detection of equine herpesvirus 2 (EHV2) and equine herpesvirus 5 (EHV5) using the nucleotide sequences from the glycoprotein B (gB) gene of EHV2 and the thymidine kinase (TK) gene of EHV5. The simultaneous use of EHV2 specific and EHV5 specific primers in one nested amplification assay (multiplex PCR) enabled a rapid, specific and sensitive diagnosis for each virus. PCR was found to be 10(3) times more sensitive than virus isolation by cell culture for EHV2 and 10(6) for EHV5. In separate PCR assays, the routine detection li...
Dolby CA, Hannant D, Mumford JA.Five yearling ponies were vaccinated with inactivated Equid herpesvirus type 1 (EHV-1) in Freund's complete adjuvant as a double emulsion and revaccinated 6 weeks later with EHV-1 in Freund's incomplete adjuvant. These ponies and three age-matched controls were challenged intra-nasally after a further 6 weeks with homologous live virus and monitored clinically, biologically and serologically. After challenge, clinical signs were mild in both groups. No cell-associated viraemias were detected in vaccinated ponies. Vaccination induced high levels of complement-fixing (CF) and virus-neutralizing ...
Kydd JH, Smith KC, Hannant D, Livesay GJ, Mumford JA.Twelve adult ponies and 2 conventional foals were exposed intranasally to EHV-1, strain Ab4 (TCID50 10(-6.6) and samples of respiratory tract associated lymphoid tissues were recovered between 12 h and 13 days after infection. Infectious virus was detected in tissue homogenates using susceptible cell monolayers and expression of viral antigens was monitored using indirect immunoperoxidase histochemistry on paraffin sections. The results showed both infectious EHV-1 and viral antigens in respiratory tract associated lymph nodes 12 h after exposure. Infected leucocytes were identified morphologi...
Kydd JH, Smith KC, Hannant D, Livesay GJ, Mumford JA.Twelve adult ponies and 2 conventional foals were exposed to 10(6.6) TCID50 of Equid herpesvirus-1 (EHV-1), strain Ab4 and samples of respiratory tract tissues were recovered. Infectious virus in tissue homogenates was detected using susceptible cell monolayers and expression of viral antigens was monitored using indirect immunoperoxidase histochemistry of paraffin sections. The results illustrated the rapid dissemination of EHV-1 throughout the respiratory tract, with early replication in the lungs one day after exposure. Endothelial cell infection was prominent in all areas of the nasopharyn...
Gruys E, Beynen AC, Binkhorst GJ, van Dijk S, Koeman JP, Stolk P.The most important neurodegenerative diseases of the horse are reviewed. In addition to the literature, neurodegenerative diseases occurring in patients (horses, Mongolian Przewalski-horses, and two zebras) referred to the Utrecht Veterinary Faculty are mentioned. Neurodegenerative diseases described are: I. ataxia associated with: A/ static stenosis, B/ dynamic stenosis, C/ lesions at various locations in the central nervous system, D/ equine herpesvirus infections, E/ equine degenerative myelo-encephalopathy, or F/ cerebellar abiotrophy; II. equine motor neuron disease; III. grass sickness o...
Elliott GD.Gene 12 of equine herpesvirus 1 (EHV-1), the homolog of herpes simplex virus (HSV) VP16 (alpha TIF, Vmw65), was cloned into a eukaryotic expression vector by PCR and used in transactivation studies of both the EHV-1 and HSV-1 IE1 promoters. Results demonstrated that the product of gene 12 is a potent transactivator of immediate-early gene expression of both viruses, which requires sequences in the upstream HSV-1 promoter for activity. Mutational analysis of the gene 12 open reading frame indicated that removal of the C-terminal 7 amino acids, which contain a short region of homology with the e...
Slater JD, Borchers K, Thackray AM, Field HJ.Four specific pathogen-free ponies were infected intranasally with equine herpesvirus 1 (EHV-1) and two were similarly infected with an EHV-1 thymidine kinase deletion mutant. The primary infections were characterized by a transient fever accompanied by virus shedding into nasal mucus and viraemia. No virus was detected in clinical specimens after 15 days post-infection. Two months later a reactivation stimulus was administered to all six ponies and only the four that had been previously inoculated with wild-type EHV-1 shed virus into nasal mucus (for 10 days), proving the presence of a latent...
COllinson PN, O'Rielly JL, Ficorilli N, Studdert MJ.Ocular problems characterized by conjunctivitis, epiphora, and keratopathy were detected in 35 of 80 Thoroughbred weanling foals that also had respiratory disease. Ocular problems were determined to be caused by infection with equine herpesvirus type 2 (EHV-2) and were successfully treated with ophthalmic medication containing idoxuridine. Equine herpesvirus type 2 isolated from 3 of 5 foals from which samples were collected. The identity of the causative virus as EHV-2 was confirmed by use of electron microscopy, restriction endonuclease DNA fingerprinting, and Southern blot analysis.
Weiblen R, Rabuske M, Rebelatto MC, Nobre VM, Canabarro TF.We report an outbreak of abortion due to equine herpesvirus (EHV) in 5 mares between 9 and 11 months of gestation, from a herd of 22 Thoroughbred mares. Equine herpesvirus was isolated from extracts of the liver, spleen and thymus but not from the lungs of a 9-month fetus grown in Rabbit Kidney (RK13) cells. The virus was identified by electron microscopy, where virus particles could be seen in the nucleus of infected cells, and by the fluorescent antibody technique with polyclonal antibodies against the whole virus. Anamnesis, necropsy, histopathology, bacteriology, and virology data suggest ...
O'Keefe JS, Julian A, Moriarty K, Murray A, Wilks CR.A detection system incorporating the polymerase chain reaction was compared with the use of histopathology and virus isolation to determine the presence of equid herpesvirus type 1 or equid herpesvirus type 4 in equine tissues submitted to a diagnostic laboratory. When the polymerase chain reaction was performed, these tissues had been stored for up to 3 years. Thirty-eight tissues representing 14 cases had been stored embedded in paraffin wax. Analysis of these tissues using the PCR gave predictive values of 1.0 and 0.91 for a positive and negative result respectively, and sensitivity and spe...
Schmidt P, Meyer H, Hübert P, Hafner A, Andiel E, Grabner A, Dahme E.The detection of equine herpesvirus type 1 (EHV-1) in infected cell cultures, and in tissues taken at necropsy, by the in-situ hybridization technique is described. A 4.9 kb Bam HI fragment of EHV-1 vaccine strain RacH was used as a probe after labelling with [alpha-32P] thymidine 5'-triphosphate ([32P]TTP) or digoxigenin-deoxyuridine 5'-triphosphate (dUTP). Both probes specifically detected EHV-1 DNA in either cytospin or paraffin wax-embedded preparations of infected cells. The digoxigenin-labelled probe was further used to examine tissue sections of equine fetuses which had been aborted due...
Lawrence GL, Gilkerson J, Love DN, Sabine M, Whalley JM.Sets of primers were designed which enabled specific amplification of homologous regions of the glycoprotein C and gene 76 genetic loci of equine herpesviruses 1 and 4 (EHV-1 and EHV-4). The resultant virus-specific polymerase chain reaction (PCR) products arising from each loci could be discriminated easily on the basis of size on an agarose gel, allowing rapid differentiation of the two equine herpesviruses. Specificity of the amplifications were confirmed by Southern hybridization and restriction endonuclease digestion. The PCR test was applied to nasal swab samples from weanling foals and ...
Edington N, Welch HM, Griffiths L.Equid herpesviruses 1 or 4 (EHV-1 or -4) were isolated by cocultivation from 60% of 40 horses examined at slaughter. The lymph nodes draining the respiratory tract were the most common source of virus. EHV-1 or EHV-4 was never isolated from the trigeminal ganglia (SLG). The polymerase chain reaction (PCR) detected virus in 87.5% of bronchial lymph nodes and a similar level in the trigeminal ganglia that were examined. By both assays approximately one third of the positive animals harboured both viruses. Equid herpesvirus 2 (EHV-2) was isolated from all but one of the horses and from > 75% o...
Pilling A, Davison AJ, Telford EA, Meredith DM.Glycoprotein 45 is a major envelope glycoprotein of equine herpesvirus type 1. The gene encoding this protein is located between map units 0.615 and 0.636 on the virus genome and evidence has suggested that it is encoded by gene 52, one of four genes within this region. Using PCR we have amplified gene 52 and subsequently cloned it into a mammalian expression vector under the control of the human cytomegalovirus immediate early gene promoter. The gene was expressed in COS-7 cells and its product was detected by immunofluorescence and Western blotting. The results indicate that glycoprotein 45 ...
Bonass WA, Hudson WA, Elton DM, Killington RA, Halliburton IW.Restriction enzyme digests of DNA from 22 unselected isolates of EHV-1 were analysed by hybridization with cloned DNA fragments covering the genome. In addition to a small amount of inter-strain variation, heterogeneity within strains was observed, caused by loss of specific restriction endonuclease sites in the DNA of a proportion of the virus particles of any one stock. Fifteen strains demonstrated the same intra-strain variation involving loss of the BamHI L-M site which was shown to lie within coding sequence for the large subunit of ribonucleotide reductase. This particular mutation may t...
Agius CT, Studdert MJ.This chapter describes the molecular and biological properties of equine herpesviruses (EHV)2 and EHV5. It highlights advances in the study of EHV2 and EHV5. The reclassification of EHV2 and EHV5 as gammaherpesviruses rather than betaherpesviruses has profound implications for future approaches to the study of the two equine herpesviruses. The chapter places emphasis on a comparison between the properties of EHV2 and EHV5 and those of other gammaherpesviruses, especially Epstein-Barr virus (EBV), which is the causative agent of infectious mononucleosis/glandular fever in humans. Studies of the...
Giles RC, Donahue JM, Hong CB, Tuttle PA, Petrites-Murphy MB, Poonacha KB, Roberts AW, Tramontin RR, Smith B, Swerczek TW.Pathology case records of 3,514 aborted fetuses, stillborn foals, or foals that died < 24 hours after birth and of 13 placentas from mares whose foals were weak or unthrifty at birth were reviewed to determine the cause of abortion, death, or illness. Fetoplacental infection caused by bacteria (n = 628), equine herpesvirus (143), fungi (61), or placentitis (351), in which an etiologic agent could not be defined, was the most common diagnosis. Complications of birth, including neonatal asphyxia, dystocia, or trauma, were the second most common cause of mortality and were diagnosed in 19% of the...
McCulloch J, Williamson SA, Powis SJ, Edington N.It has been suggested that EHV-1 infection may perturb immune responsiveness in the natural equine host. The mechanism underlying this phenomenon is not clear, but disturbances of circulating leucocyte populations could contribute. In order to objectively assess the nature of the haematological changes provoked by EHV-1 infection, two groups of conventionally-maintained Welsh mountain ponies were challenge-infected intra-nasally with the Ab4 isolate of EHV-1. These groups were controlled by similarly-sized groups of non-infected ponies. All data generated was subjected to rigorous statistical ...
Hoffman AM, Viel L, Prescott JF, Rosendal S, Thorsen J.Undifferentiated distal respiratory tract disease (nasal discharge, cough, pneumonia) in foals (1 to 8 months old) is a burdensome economic problem on breeding farms; yet, the infective agents associated with these episodes have not been well described. Possible causes of these episodes of illness were investigated by culturing specimens of proximal and distal airways of clinically diseased foals (n = 101), prior to any treatment, for aerobic and anaerobic bacteria and viruses (rhinoviruses, equine arteritis virus, equine herpesvirus subtype 1 [EHV-1], influenza virus, and adenovirus). Pairs o...
Thein P, Darai G, Janssen W, Bergle RD, Strube W, Floss G.From spring 1990 to summer 1991 we investigated 21 horses with clinical symptoms of EHV-infection by means of serological and virological methods including DNA-hybridization to identify the causative agents. The results indicated that, as already reported by us, EHV4 may also cause the paralytic form of the infection. The possibility of double infection with EHV4 and EHV1 cannot be excluded. In 3 out of 21 affected horses we could investigate brain tissue and/or spinal fluid by Dotblot hybridization with EHV1 and EHV4-DNA. The investigated samples of all three horses showed hybridization with ...
Art T, Lekeux P.This study was conducted in order to assess whether exercise- and training-induced cardio-respiratory adjustments are modified during the 10-day period which follows a booster vaccination with an oily adjuvanted inactivated vaccine against influenza and equine herpesvirus-1 (Equiffa). Nine healthy vaccinated thoroughbred horses were used. Six were revaccinated and three were kept as control. All the horses completed a standardised exercise test (SET) that was repeated 4 times, i.e. 10 (SET1) and 2 (SET2) days before revaccination, and 2 (SET3) and 10 (SET4) days after revaccination. During the...
Sledge DG, Miller DL, Styer EL, Hydrick HA, Baldwin CA.Granulomatous dermatitis in horses has been linked to many etiologies, including various parasites, fungi, and bacteria. Idiopathic forms of granulomatous inflammation-producing diseases, some of which are localized to the skin, also have been reported in horses. Herein we describe a case of recurrent equine granulomatous skin disease characterized by intranuclear viral inclusions within macrophages and giant cells. The histologic changes were primarily noted in the deep dermis and included multifocal to coalescing areas of necrosis marked by histiocytic cell infiltration and presence of giant...
Mahmoud HY, Andoh K, Hattori S, Terada Y, Noguchi K, Shimoda H, Maeda K.In this study, we attempted to express twelve glycoproteins of equine herpesvirus-1 (EHV-1) in 293T cells and to characterize these using monoclonal antibodies (MAbs) and horse sera against EHV-1. Expression of glycoprotein B (gB), gC, gD, gG, gI and gp2 was recognized by immunoblot analysis using horse sera, but that of gE, gH, gK, gL, gM and gN was not. Four MAbs recognized gB, four recognized gC and one recognized gp2. Two MAbs against gB cross-reacted with EHV-4. Interestingly, coexpression of gE and gI and gM and gN enhanced their antigenicity. Furthermore, immunoblot analysis of gp2 show...
Barbosa JD, Lins AMC, Bomjardim HDA, Silveira NDSES, Barbosa CC, Beuttemmuller EA, Brito MF, Salvarani FM.An investigative and epidemiological study was carried out for equine herpesvirus type 1 (HVE-1) in 10 outbreaks of neurological disease from different farms in the state of Pará, Brazil. 25 horses were studied: six male and 19 females, aged between one and 13 years. A necropsy of six horses was performed, and the others recovered either with or without treatment (T1-vitamin B1 + dexamentasone; T2-vitamin B1 + flunixim meglumine). Animals that received treatment recovered after eight days. The main clinical signs observed were motor incoordination, progressive paresis, thoracic and/or pelvic ...
Awan AR, Baxi M, Field HJ.The most important consequence of equine herpesvirus-1 (EHV-1) infection is abortion. The object of the present study was to characteristic further a murine EHV-1 abortion model and to make comparisons with the natural host with particular reference to the stage of gestation during which the infection occurs. BALB/c mice at different stages of pregnancy were infected intranasally with EHV-1 (strain AB4); they suffered respiratory distress, weight loss, and other constitutional signs of infection. When the virus was inoculated in the late second or early third week of gestation dead or dying fe...
Frippiat T, Dams L, Wielick C, Delguste C, Ludwig-Begall LF, Art T, Thiry E.Viruses can be involved in respiratory disorders in horses, with limited therapeutic options. Citrate-complexed silver nanoparticles (C-AgNP) have shown bactericidal properties after in vitro nebulization. The aim of the present study was to assess the virucidal activity of C-AgNP after in vitro instillation or nebulization on equine herpesvirus-1 (EHV-1) and murine norovirus (MNV), the latter used as surrogate for small non-enveloped viruses. Both viruses were instilled or nebulized with C-AgNP of increasing concentrations, and titres were determined via TCID50 method. We demonstrated efficie...
Kang HW, Lee EY, Lee KK, Ko MK, Park JY, Kim YH, Lee K, Choi EJ, Kim J, So B, Park CK, Jeoung HY.Equine herpesvirus-1 (EHV-1) is an important pathogen in horses. It affects horses worldwide and causes substantial economic losses. In this study, for the first time, we characterized EHV-1 isolates from South Korea at the molecular level. We then aimed to determine the genetic divergences of these isolates by comparing them to sequences in databases. In total, 338 horse samples were collected, and 12 EHV-1 were isolated. We performed ORF30, ORF33, ORF68, and ORF34 genetic analysis and carried out multi-locus sequence typing (MLST) of 12 isolated EHV-1. All isolated viruses were confirmed as ...
Kimura T, Hasebe R, Mukaiya R, Ochiai K, Wada R, Umemura T.Intrauterine infection with equine herpesvirus-1 (EHV-1) has been considered to be the consequence of transplacental transmission of the virus following maternal cell-associated viraemia. In this study the state of EHV-1 gene expression in the placenta of seven naturally aborted equine fetuses was examined. Neither lesions nor viral antigens were detected in the placenta of the fetuses. The amount of infectious virus in the placentas was considerably lower than that in the fetal lungs, which showed pneumonia and typical herpesvirus inclusions. Quantitative dot blot hybridization with probes sp...
Bouchey D, Evermann J, Jacob RJ.Examination of six field isolates of equine herpesvirus 3, the causative agent of equine coital exanthema, indicates that all were temperature sensitive (ts) at the body temperature, 39 degrees C, of their host (Equine asinus and callabus) when grown in cell culture. The isolates were characterized by fingerprint analysis with the restriction endonucleases XbaI, EcoRI, BamHI and Hind III to establish possible epidemiologic relatedness. Three of the six isolates may be considered related. Variation in the mobility of the BamHI-A and Hind III-K fragments indicates that a small plaque isolate may...
Szeredi L, Aupperle H, Steiger K.Formalin-fixed, paraffin wax-embedded fetal membranes from 76 cases of equine abortion were examined immunohistochemically for equine herpesvirus (EHV)-1 antigen. Of the 76 cases, 11 had been proved EHV-1-positive by diagnostic methods applied to the aborted fetuses (viral isolation in tissue culture, or immunohistochemical examination, or both). Of the 11 fetal membranes from the virus-positive animals, five gave positive results on immunohistochemical examination, and three on in-situ hybridization; the positive signals were detected in trophoblastic cells and occasionally in monocytes and e...
Furr M.Diagnosis of neuro-inflammatory conditions in the horse can be challenging. Current methods include evaluation of cerebrospinal fluid (CSF) for inflammation and determination of specific antibody status. The antibody index (AI) and Goldman-Witmer coefficient (C-value) can be used to aid in the interpretation. Objective: The null hypothesis to be tested was that the Al and C-values do not change in horses with neuroinflammation. Methods: Twelve horses of various ages (3-17 years) and breeds (Thoroughbred, Thoroughbred cross, draft, and Arabian) were included in the study. Methods: The study was...
Singh BK, Ahuja S, Gulati BR.A single-dilution, sensitive and specific monoclonal antibody-based blocking enzyme-linked immunosorbent assay (B-ELISA) was developed as an alternative to the cumbersome virus neutralization test (VNT) for detection of equine herpesvirus-1 (EHV-1) antibodies. Neutralizing monoclonal antibodies (1H6 and 9C6) raised against EHV-1 (Hisar-90-7 strain) and sera from 70 horses (30 known negative and 40 known positive for EHV-1 antibodies by VNT) were used for standardization of the B-ELISA. Using a single serum dilution of 1:250 in B-ELISA, 100% specificity was obtained with both monoclonal antibod...
Sherman J, Mitchell WR, Martin SW, Thorsen J, Ingram DG.The outbreaks of upper respiratory tract infections in horses at Standardbred racetracks were investigated over a three year period. The most serious epidemics of respiratory disease occurred in the winter and spring seasons. Both influenza viruses and equine herpesvirus 1 were shown to be present in the horse population. The herpesvirus was associated with respiratory disease particularly in the winter but the equine influenza viruses apparently were responsible for the major epidemics of respiratory disease at these tracks. Younger horses, two or three years of age, were particularly suscept...
Ellis JA, Bogdan JR, Kanara EW, Morley PS, Haines DM.The ability of monovalent and bivalent equine herpesvirus (EHV) vaccines to stimulate cellular and antibody responses to EHV-1 and EHV-4 was compared in healthy horses. Comparison of data from lymphocyte blastogenesis tests in which live viruses were used as antigens and that were conducted prior to vaccination and after 2 vaccinations revealed that horses given modified-live EHV-1 had significant increases in proliferative responses to EHV-1 (P = 0.03) and EHV-4 (P = 0.04). Responses to EHV-1 and EHV-4 in horses given the inactivated-virus bivalent vaccine were less; however, significant diff...
Vengust M, Baird JD, van Dreumel T, Ackerley C, Bienzle D.A case of a 1-month-old Thoroughbred foal with dysphagia, salivation, pyrexia, oral mucosal pustules, and esophageal ulceration is reported. Swabs from the ulcerated lesions yielded Equid herpesvirus 2 (EHV-2) in virus isolation assays, and histopathology of a biopsy from the esophageal lesion identified nuclear inclusions suggestive of herpesviruses. Immunohistochemical staining with antibodies specific for EHV-2 was positive for epithelial cells in the vicinity of the ulcer but not in more distant mucosa. Electron microscopic evaluation of the biopsy showed herpesviral particles in epithelia...
Crabb BS, Studdert MJ.A series of truncated equine herpesvirus 1 (EHV1) glycoprotein C (gC) molecules was examined for use as serodiagnostic antigens for EHV1 and EHV4. Small regions of EHV1 glycoprotein C, an immunodominant EHV1 glycoprotein, were expressed in Escherichia coli as glutathione S-transferase (GST) fusion proteins using the bacterial expression vector pGEX-2T. Sera obtained from horses, including sera from specific-pathogen-free (SPF) foals, following exposure to either EHV1, EHV4 or both viruses were used. Several of the fusion proteins were shown to encompass EHV1 specific epitopes while others enco...
Ata EB, Zaghawa A, Ghazy AA, Elsify A, Abdelrahman K, Kasem S, Nayel M.Equine herpesvirus-1 (EHV-1) is an important pathogen, which infects horses worldwide with high morbidity but low mortality rates. The respiratory disorders and abortions are the most common indicators. Ab4p (an abortigenic and paralytic virus) is one of the most important and virulent strains. The development and functional characterization of the open reading frame-68 (ORF68) negative EHV-1 Ab4p mutants and an assessment of their roles in the infection at the cellular level were the main targets of the current study. Escherichia coli DH10β containing the Ab4p bacterial artificial chromosome...
Cano A, Galosi CM, Martin Ocampos GP, Ramirez GC, Vera VJ, Villamil LC, Chaparro JG.This paper describes the isolation and characterisation of equine herpesvirus 1 (EHV-1) in Colombia. The virus was isolated from a nasal swab and an aborted foetus of a pregnant mare imported from Argentina, with clinical signs of rhinopneumonitis. The new strain was characterised through culture and morphological, serological and immunocytochemical studies. Polymerase chain reaction and DNA restriction maps revealed an EHV-1 1P genome. This is the first report on the isolation and characterisation of EHV-1 in Colombia.
Slater J, Hannant D.The identification of some of the adaptive immune responses to infection with equine viruses has been the first step toward rational immunoprophylactic design. Sufficient knowledge of infection-induced immunity and informed estimates of the requirements for long-term immunity for EIV have now been obtained. Thus, the future for inactivated EIV vaccines is promising now that new adjuvants have been applied to induce cellular immunity and safe methods have been designed to stimulate virus-neutralizing (VN) antibody at mucosal surfaces. Adenoviruses induce circulating VN antibody, the presence of...
Dolby CA, Hannant D, Mumford JA.Five yearling ponies were vaccinated with inactivated Equid herpesvirus type 1 (EHV-1) in Freund's complete adjuvant as a double emulsion and revaccinated 6 weeks later with EHV-1 in Freund's incomplete adjuvant. These ponies and three age-matched controls were challenged intra-nasally after a further 6 weeks with homologous live virus and monitored clinically, biologically and serologically. After challenge, clinical signs were mild in both groups. No cell-associated viraemias were detected in vaccinated ponies. Vaccination induced high levels of complement-fixing (CF) and virus-neutralizing ...
Damiani AM, Matsumura T, Yokoyama N, Maeda K, Miyazawa T, Kai C, Mikami T.The nucleotide sequences of the glycoprotein I (gI) and E (gE) genes of equine herpesvirus type 4 (EHV-4) strain TH20 were determined. The predicted region encoding the EHV-4 gI gene is 1,263 nucleotides, corresponding to a polypeptide of 420 amino acids in length. The predicted region encoding the EHV-4 gE gene is 1,647 nucleotides, corresponding to a polypeptide of 548 amino acids in length. The EHV-4 gI and gE genes show 74% and 85% identity at the amino acid level with those of equine herpesvirus type 1 (EHV-1), respectively. Furthermore, we have found an open reading frame homologous to t...
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...
Osińska E, Golke A, Słońska A, Cymerys J, Bańbura MW, Dzieciatkowski T.Equid herpesvirus type 2 (EHV-2) together with equid herpesvirus type 5 are members of Gammaherpesvirinae subfamily, genus Rhadinovirus. EHV-2 is one of major agents causing diseases of horses common worldwide. A possible role of EHV-2 in reactivating latent equid herpesvirus type-1 has been suggested, because reactivation of latent EHV-1 was always accompanied by EHV-2 replication. Variety techniques, including cell culture, PCR and its modifications, have been used to diagnose EHV-2 infections. The aim of this study was to develop, optimize and determine specificity of real-time PCR (qPCR) f...
Hardt M, Teifke JP, Weiss E.Formalin-fixed and Paraplast-embedded tissue samples of 42 aborted equine fetuses were examined by polymerase chain reaction for the presence of equine herpesvirus DNA. The used set of primers was located in the glycoprotein 13 open reading frame and allowed the amplification of both EHV 1 und EHV 4. By cleaving pattern analysis after Hinf I digestion EHV 1 could be distinguished from EHV 4. In 9 of the cases investigated EHV 1-DNA was detected. This finding is in absolute context with the results of the virological investigations.
Velloso Alvarez A, Jose-Cunilleras E, Dorrego-Rodriguez A, Santiago-Llorente I, de la Cuesta-Torrado M, Troya-Portillo L, Rivera B, Vitale V....Real-time PCR is the diagnostic technique of choice for the diagnosis and control of equine herpesvirus-1 (EHV-1) in an outbreak setting. The presence of EHV-1 in nasal swabs (NS), whole blood, brain and spinal cord samples has been extensively described; however, there are no reports on the excretion of EHV-1 in urine, its DNA detection patterns, and the role of urine in viral spread during an outbreak. Objective: To determine the presence of EHV-1 DNA in urine during natural infection and to compare the DNA detection patterns of EHV-1 in urine, buffy coat (BC) and NS. Methods: Descriptive st...
Schneider C, James K, Craig BW, Chappell DE, Vaala W, van Harreveld PD, Wright CA, Barnum S, Pusterla N.Equine rhinitis B virus is a lesser-known equine respiratory pathogen that is being detected with increasing frequency via a voluntary upper respiratory biosurveillance program in the United States. This program received 8684 nasal swab submissions during the years 2012-2023. The nasal swabs were submitted for qPCR testing for six common upper respiratory pathogens: Streptococcus equi subspecies equi (S. equi), equine influenza virus (EIV), equine herpesvirus type 1 (EHV-1), equine herpesvirus type 4 (EHV-4), equine rhinitis A virus (ERAV), and equine rhinitis B virus (ERBV). The overall ERBV ...
Holmes CM, Babasyan S, Eady N, Schnabel CL, Wagner B.Equine herpesvirus type 1 (EHV-1) is one of the most prevalent respiratory pathogens in horses with a high impact on animal health worldwide. Entry of the virus into epithelial cells of the upper respiratory tract and rapid local viral replication is followed by infection of local lymphoid tissues leading to cell-associated viremia and disease progression. Pre-existing mucosal immunity has previously been shown to reduce viral shedding and prevent viremia, consequently limiting severe disease manifestations. Here, nasopharyngeal transcriptomic profiling was used to identify differentially expr...
Li S, Li L, Sun Y, Khan MZ, Yu Y, Ruan L, Chen L, Zhao J, Jia J, Li Y, Wang C, Wang T.Equid herpesvirus type 8 (EqHV-8) is known to cause respiratory disease and miscarriage in horses and donkeys, which is a major problem for the equine farming industry. However, there are currently limited vaccines or drugs available to effectively treat EqHV-8 infection. Therefore, it is crucial to develop new antiviral approaches to prevent potential pandemics caused by EqHV-8. This study evaluates the antiviral and antioxidant effects of cepharanthine against EqHV-8 by employing both in vitro assays and in vivo mouse models to assess its therapeutic efficacy. To assess the effectiveness of ...
van Maanen K, van den Wollenberg L, de Haan T, Frippiat T.Monitoring infectious diseases is essential for safeguarding equine health and ensuring the sustainability of the horse industry. In 2019, the Royal Veterinary Association of the Netherlands (KNMvD) and Royal GD (GD Animal Health) launched SEIN (Surveillance of Equine Infectious diseases in the Netherlands), a voluntary surveillance system for laboratory-confirmed outbreaks of equid alphaherpesvirus 1 (EHV-1), equid alphaherpesvirus 4 (EHV-4), equine influenza virus (EIV), and subsp. . This retrospective study analyzed 364 confirmed outbreaks reported through SEIN between June 2019 and April ...
Wagner B, Schnabel CL, Rollins A.Equine herpesvirus type-1 (EHV-1) enters through the upper respiratory tract (URT) and causes respiratory disease, abortions, and myeloencephalopathy in equids. Pre-existing immunity at the viral entry site, especially mucosal IgG4/7 antibodies, has recently been shown to correlate with protection from disease and incomplete viral replication at the URT. Here, we tested whether intramuscular (i.m.) vaccination with a commercial inactivated EHV-1/4 vaccine can induce mucosal antibodies (mucAbs) at the URT. Methods: Adult horses with complete EHV-1 vaccination and/or exposure histories were vacc...
El Brini Z, Cullinane A, Garvey M, Fassi Fihri O, Fellahi S, Amraoui F, Loutfi C, Sebbar G, Paillot R, Piro M.This study aimed to investigate the molecular prevalence and genetic characterization of EHV-1 and EHV-4 in equid populations in Morocco. A total of 154 equids (114 horses, 9 donkeys, and 31 mules) were sampled, with nasal swabs and tissue samples subjected to multiplex real-time PCR for the detection of EHV-1 and EHV-4. Additionally, an isolate from the tissue of an aborted horse fetus was included in the analysis. A subset of EHV-positive samples underwent virus isolation followed by whole-genome sequencing. PCR assays revealed that 42 samples (27%) tested positive for EHV-4, while only 3 sa...
