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.
Bannai H, Tsujimura K, Nemoto M, Ohta M, Yamanaka T, Kokado H, Matsumura T.Equine herpesvirus type 1 (EHV-1) infection is a major cause of pyrexias in winter among Japanese racehorses. In 2014-2015, the Japan Racing Association (JRA) changed the EHV-1 vaccine from an inactivated vaccine to a live vaccine (both produced by Nisseiken). To evaluate the effect of changing the vaccines, the capacities of these vaccines to induce virus-neutralizing (VN) antibodies were compared, and an epizootiological investigation of EHV-1 was performed at the JRA Ritto Training Center during epizootic periods from 2010-2011 to 2016-2017. Results: Three-year-old horses that received the ...
Kamel M, Pavulraj S, Osterrieder K, Azab W.Primary infection and pathogenesis of equine herpesvirus type 1 (EHV-1) require an intricate interaction of virus with the mucosal epithelium, mononuclear cells and the vascular endothelium. Studies on EHV-1 have been facilitated by the development of different models that recapitulate the tissue complexity. The available assays can be categorized into (i) models mimicking the epithelium-peripheral blood mononuclear cell (PBMC) interaction, which include mucosal (nasal and vaginal) explants and equine respiratory epithelial cells (EREC) cultures; and (ii) PBMC-endothelium mimicking models,...
Thorsteinsdóttir L, Jónsdóttir S, Stefánsdóttir SB, Andrésdóttir V, Wagner B, Marti E, Torsteinsdóttir S, Svansson V.Two types of gammaherpesviruses (γEHV) are known to infect horses, EHV-2 and EHV-5. Foals become infected early in life, probably via the upper respiratory tract, despite maternal antibodies. In this study, we analyzed samples from a herd of mares and their foals. The foals were followed from birth to 22 months of age and the dams during the first 6 months postpartum. Blood and nasal swab samples were taken regularly for evaluation of antibody responses, virus isolation and viral load by qPCR. EHV-2 was isolated on day 5, and EHV-5 on day 12, earlier than previously reported. γEHV specific a...
Ochi A, Sekiguchi M, Tsujimura K, Kinoshita T, Ueno T, Katayama Y.Equine multinodular pulmonary fibrosis (EMPF) is a recently described form of interstitial pneumonia associated with equine herpesvirus type 5 (EHV-5). This disease has been reported in North and South America, Europe and Oceania but not, to our knowledge, in horses in Japan. We diagnosed EMPF in two Thoroughbred horses in Japan on the basis of gross and histopathological findings. In both cases, significant gross lesions, restricted to the lungs, consisted of numerous firm and coalescing nodules widely distributed throughout the lung. The nodules were <3 cm in diameter and pale white to t...
Dall Agnol AM, Beuttemmuller EA, Pilz D, Leme RA, Saporiti V, Headley SA, Alfieri AF, Alfieri AA.Equid gammaherpesvirus 2 (EHV-2) and 5 (EHV-5) are members of the Herpesviridae family and have been reported in horse populations worldwide. This study aimed to evaluate the presence of herpesvirus DNA in the upper respiratory tract of horses. Twenty-six nasal swabs were collected from asymptomatic adult horses of two different horse farms (A, n = 18; B, n = 8), both located in Southern Brazil. The EHV-1, EHV-2, EHV-4, and EHV-5 DNA analyses were performed using nested PCR assays targeting the glycoprotein B gene. Four (15.3%) and 12 (46.1%) of the 26 nasal swab samples were positive ...
Azab W, Bedair S, Abdelgawad A, Eschke K, Farag GK, Abdel-Raheim A, Greenwood AD, Osterrieder N, Ali AAH.Equid herpesviruses (EHVs) threaten equine health and can cause significant economic losses to the equine industry worldwide. Different equid herpesviruses, EHV-1, EHV-2, EHV-4 and EHV5 are regularly detected among horse populations. In Egypt, monitoring is sporadic but EHV-1 or EHV-4 have been reported to circulate in the horse population. However, there is a lack of reports related to infection and health status of horses, likely due to the absence of regular diagnostic procedures. In the current study, the circulation of four infectious equid herpesviruses (EHV-1, EHV-2, EHV-4 and EHV-5) am...
Brown LJ, Brown G, Kydd J, Stout TAE, Schulman ML.Equid herpesvirus type 1 is primarily a respiratory tract virus associated with poor athletic performance that can also cause late gestation abortion, neonatal foal death and encephalomyelopathy. Horizontal transmission is well described, whereas evidence of vertical transmission of equid herpesvirus type 1 associated with the birth of a healthy foal has not been demonstrated. This study sampled a population of Thoroughbred mares (n = 71), and their healthy neonatal foals and foetal membranes, to test for the presence of both equid herpesvirus types 1 and 4 using a quantitative polymerase chai...
Lee SK, Lee I.Equine herpesvirus (EHV) 2 and equine herpesvirus 5 (EHV-5) have been getting attention as potential causative pathogens of reproductive disorders in horses. Equine herpesviruses 2 and 5 are widespread among horses and have been detected in various samples including nasal swabs, blood, and ocular swabs. However, the detection of these pathogens in genital swabs has not been determined. The aims of this study were to determine the positive rate of EHV-2 and EHV-5 DNA in genital swabs taken from clinically normal mares and to define the genetic diversity of these EHV-2 and EHV-5 DNA sequences by...
Van Cleemput J, Poelaert KCK, Laval K, Van den Broeck W, Nauwynck HJ.The horse's respiratory tract daily encounters a plethora of respirable hazards including air pollutants, mycotoxins and airborne pathogens. To date, the precise effect of air pollution and mycotoxins on respiratory epithelial integrity and subsequent pathogen invasion in the horse has not been studied. Here, diesel exhaust particles (DEP) and three major mycotoxins (deoxynivalenol [DON], aflatoxin B1 [AFB1] and fumonisin B1 [FB1]) were applied to the apical surfaces of both ex vivo respiratory mucosal explants and in vitro primary equine respiratory epithelial cells (EREC) cultivated at the a...
Seo MG, Kwon OD, Kwak D.A 23-year-old male Thoroughbred horse at the Korean Military Academy appeared thin with visible rib bones and presented clinical signs of fever, anorexia, lethargy, and severe dehydration. To determine the presence of various febrile disease-causing agents, the 23 cohabiting horses at the academy, including this horse, were subjected to hematology, blood chemistry, and molecular analysis using whole blood samples collected during regular medical check-ups. On the basis of clinical history, physical examination, hematology, blood chemistry, and fecal examination, differential diagnosis using mo...
Poelaert KCK, Van Cleemput J, Laval K, Descamps S, Favoreel HW, Nauwynck HJ.Short-chain fatty acids (SCFA), such as sodium butyrate (SB), sodium propionate (SPr), and sodium acetate (SAc), are metabolic end-products of the fermentation of dietary fibers. They are linked with multiple beneficial effects on the general mammalian health, based on the sophisticated interplay with the host immune response. Equine herpesvirus 1 (EHV1) is a major pathogen, which primarily replicates in the respiratory epithelium, and disseminates through the body via a cell-associated viremia in leukocytes, even in the presence of neutralizing antibodies. Infected monocytic CD172a cells and ...
Perkins G, Babasyan S, Stout AE, Freer H, Rollins A, Wimer CL, Wagner B.Equid herpesvirus-1 (EHV-1) outbreaks continue despite widely used vaccination. We demonstrated previously that an ORF1/ORF71 gene deletion mutant of the EHV-1 strain Ab4 (Ab4ΔORF1/71) is less virulent than its parent Ab4 virus. Here, we describe the Ab4 challenge infection evaluating protection induced by the Ab4ΔORF1/71 vaccine candidate. Susceptible control horses developed respiratory disease, fever, nasal shedding, and viremia. Full protection after challenge infection was observed in 5/5 previously Ab4 infected horses and 3/5 Ab4ΔORF1/71 horses. Two Ab4ΔORF1/71 horses developed short...
Poelaert KCK, Van Cleemput J, Laval K, Favoreel HW, Couck L, Van den Broeck W, Azab W, Nauwynck HJ.Equine herpesvirus 1 (EHV1) replicates in the respiratory epithelium and disseminates through the body via a cell-associated viremia in leukocytes, despite the presence of neutralizing antibodies. "Hijacked" leukocytes, previously identified as monocytic cells and T lymphocytes, transmit EHV1 to endothelial cells of the endometrium or central nervous system, causing reproductive (abortigenic variants) or neurological (neurological variants) disorders. In the present study, we questioned the potential route of EHV1 infection of T lymphocytes and how EHV1 misuses T lymphocytes as a vehicle to re...
Zhao Y, Chang J, Zhang B, Tong P, Wang C, Ran D, Su Y.Equine herpesvirus 1 (EHV-1) induces serious respiratory infections, viral abortion, neurological signs, and neonatal mortality in horses. Despite the use of vaccines, EHV-1 infection also causes a high annual economic burden to the equine industry. The poor immunogenicity of and protection conferred by EHV-1 vaccines are the major factors responsible for the spread of EHV-1 infection. The present study examined the immunogenicity of a novel DNA vaccine co-expressing FliC, a flagellin protein, in Salmonella abortus equi and the gD protein of EHV-1. Mice and horses were immunized intramuscularl...
Van Cleemput J, Poelaert KCK, Laval K, Impens F, Van den Broeck W, Gevaert K, Nauwynck HJ.Pollens are well-known triggers of respiratory allergies and asthma. The pollen burden in today's ambient air is constantly increasing due to rising climate change and air pollution. How pollens interact with the respiratory mucosa remains largely unknown due to a lack of representative model systems. We here demonstrate how pollen proteases of Kentucky bluegrass, white birch and hazel selectively destroy integrity and anchorage of columnar respiratory epithelial cells, but not of basal cells, in both ex vivo respiratory mucosal explants and in vitro primary equine respiratory epithelial cells...
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...
Pusterla N, James K, Mapes S, Bain F.Due to the inconsistent development of enteric signs associated with ECoV infection in adult horses, many practitioners collect nasal secretions rather than feces for the molecular diagnostic work-up of such horses. ECoV infection should be considered in horses presenting with acute onset of fever, especially when nasal discharge is absent as one of the cardinal clinical sign. A total of 277 adult horses with acute onset of fever were enrolled in this study. Feces were tested for ECoV and nasal secretions for common respiratory pathogens (equine herpesvirus (EHV)-1, EHV-4, equine influenza vir...
Holz CL, Sledge DG, Kiupel M, Nelli RK, Goehring LS, Soboll Hussey G.Histopathological differences in horses infected with equine herpesvirus type 1 (EHV-1) of differing neuropathogenic potential [wild-type (Ab4), polymerase mutant (Ab4 N752), EHV-1/4 gD mutant (Ab4 gD4)] were evaluated to examine the impact of viral factors on clinical disease, tissue tropism and pathology. Three of 8 Ab4 infected horses developed Equine Herpesvirus Myeloencephalopathy (EHM) requiring euthanasia of 2 horses on day 9 post-infection. None of the other horses showed neurologic signs and all remaining animals were sacrificed 10 weeks post-infection. EHM horses had lymphohistiocyti...
Van Cleemput J, Poelaert KCK, Laval K, Nauwynck HJ.Equine herpesvirus type 5 (EHV5) is a ubiquitous, yet obscure pathogen in the horse population and is commonly associated with fatal equine multinodular pulmonary fibrosis (EMPF). To date, little is known about the precise pathogenesis of EHV5. Here, we evaluated the dynamics of EHV5 infection in representative ex vivo and in vitro equine models, using immunofluorescence staining and virus titration. EHV5 was unable to infect epithelial cells lining the mucosa of nasal and tracheal explants. Similarly, primary equine respiratory epithelial cells (EREC) were not susceptible to EHV5 following in...
Brosnahan MM, Al Abri MA, Brooks SA, Antczak DF, Osterrieder N.Equine herpesvirus type 1 (EHV-1)-induced myeloencephalopathy (EHM) is a neurologic disease of horses that represents one outcome of infection. The neurologic form of disease occurs in a subset of infected horses when virus-induced endothelial cell damage triggers vasculitis and subsequent ischemic insult to the central nervous system. EHM causes considerable animal suffering and economic loss for the horse industry. Virus polymorphisms have been previously associated with disease outcome but cannot fully explain why only some horses develop EHM. This study investigated the role of host geneti...
Serpa PBS, Brooks MB, Divers T, Ness S, Birschmann I, Papich MG, Stokol T.Horses with inflammatory and infectious disorders are often treated with injectable heparin anticoagulants to prevent thrombotic complications. In humans, a new class of direct oral acting anticoagulants (DOAC) appear as effective as heparin, while eliminating the need for daily injections. Our study in horses evaluated apixaban, a newly approved DOAC for human thromboprophylaxis targeting activated factor X (Xa). Our goals were to: (1) Determine pharmacokinetics and pharmacodynamics of apixaban after oral (PO) and intravenous (IV) administration in horses; (2) Detect any inhibitory effects of...
Wimer CL, Schnabel CL, Perkins G, Babasyan S, Freer H, Stout AE, Rollins A, Osterrieder N, Goodman LB, Glaser A, Wagner B.The equine herpesvirus type 1 (EHV-1) ORF1 and ORF71 genes have immune modulatory effects in vitro. Experimental infection of horses using virus mutants with multiple deletions including ORF1 and ORF71 showed promise as vaccine candidates against EHV-1. Here, the combined effects of ORF1 and ORF71 deletions from the neuropathogenic EHV-1 strain Ab4 on clinical disease and host immune response were further explored. Three groups of EHV-1 naïve horses were experimentally infected with the ORF1/71 gene deletion mutant (Ab4ΔORF1/71), the parent Ab4 strain, or remained uninfected. In comparison t...
Muscat KE, Padalino B, Hartley CA, Ficorilli N, Celi P, Knight P, Raidal S, Gilkerson JR, Muscatello G.The risk of respiratory disease in the transported horse can increase as a consequence of immunosuppression and stress associated primarily with opportunistic bacterial proliferation and viral reactivation. This study examines the ecology of equid herpesviruses (EHV) in these horses, exploring reactivation and changes in infection and shedding associated with transport, and any potential contributions to transport-related respiratory disease. Twelve horses were subjected to an 8-h road-transport event. Antibodies to EHV-1 and EHV-4 were detected by ELISA in serum collected prior to, immediatel...
Ghoniem SM, El Deeb AH, Aggour MG, Hussein HA.We developed a multiplex reverse-transcription real-time PCR (RT-rtPCR) assay for the simultaneous detection of the main equine respiratory viruses: equid alphaherpesviruses 1 and 4 (EHV-1, -4) and equine influenza virus (EIV; species Influenza A virus). The primers and probes amplified only the targeted viruses, and there were no inter-assay cross-amplifications or nonspecific interactions. The multiplex assay efficiencies were 92.5%, 97%, and 90% for EHV-1, EHV-4, and EIV, respectively. The R values of the monoplex and multiplex assays were ⩾0.990, and the slopes were -3.37 to -3.59. The p...
Ferreira CGT, Campos MG, Felix DM, Santos MR, Carvalho OV, Diaz MAN, Fietto JLR, Bressan GC, Silva-Júnior A, Almeida MR.Equid herpesvirus 1 (EHV-1) is a pathogen of high economic importance in equine breeding operations around the world. EHV-1 infection causes respiratory, neurologic and reproductive disease. The absence of an efficient therapy has caught the attention of the scientific community and the therapeutic activities of natural products with its antivirals effects might be effective for the disease's treatment. Herein it was evaluated the prophylactic and therapeutic potential of quercetin and ethanolic extracts of Bacharis dracunculifolia formulations compared to Penciclovir® in an in vivo EHV-1 inf...
Easton-Jones CA, Madigan JE, Barnum S, Maxwell LK, Taylor SD, Arnesen T, Pusterla N.Equine herpesvirus-5 is commonly isolated from the lungs of horses with EMPF, suggesting an etiological link. Valacyclovir is used empirically to treat EMPF; however, no data is available concerning its impact on EHV-5 viral kinetics. Objective: To determine the effect of oral administration of valacyclovir on EHV-5 viral load measured by qPCR in blood, nasal secretions (NS) and BALF in horses with EMPF. Methods: Six horses diagnosed with EMPF. Methods: A prospective clinical trial was performed. Horses received 10 days of PO administered valacyclovir (loading dose 30 mg/kg, maintenance dose 2...
Flanders JA, Wack RF, Pusterla N, Mapes SM, Collins D, Gamble KC.Infection by equine herpesvirus (EHV) strains (EHV-1, EHV-9) in ursid species, including polar bears ( Ursus maritimus), has been associated with neurological disease and death. A serosurvey of captive exotic equid and polar bear populations in US Association of Zoos and Aquaria institutions was performed to determine the prevalence of EHV strains using quantitative polymerase chain reaction (qPCR) and enzyme-linked immunosorbent assay (ELISA) tests. Equid species surveyed included zebra ( Equus spp.), Przewalski's wild horse ( Equus ferus przewalskii), Persian onager ( Equus hemionus), and So...
Castro ER, Arbiza J.Infection with equid alphaherpesvirus 1 (EHV-1) causes respiratory disease, abortion and neurological disorders in horses. Molecular epidemiology studies have demonstrated that a single nucleotide polymorphism (A2254/G2254) in the genome region of open reading frame 30 which results in an amino acid variation (N752/D752) of the EHV-1 DNA polymerase, is significantly associated with the neuropathogenic potential of naturally occurring strains. In recent years, an increase in the number of cases of equine neurological disease caused by neuropathogenic variants of EHV-1 has been observed in numer...
Kim SK, Bowles DE, O'callaghan DJ.The equine herpesvirus 1 immediate-early (IE) phosphoprotein is essential for the activation of transcription from viral early and late promoters and trans-represses its own promoter. Transient-transfection assays showed that the IE protein trans-represses the gamma2 late gK promoter. Gel shift and DNase I footprinting assays demonstrated that the IE protein binds to the gK promoter sequences from -42 to -26 and from -13 to +12 that overlap the transcription initiation site (+1). These results indicated that the IE protein binds to the transcription initiation site of the gK promoter sequences...
Baxi MK, Efstathiou S, Lawrence G, Whalley JM, Slater JD, Field HJ.Neural tissues from specific pathogen-free ponies that had been experimentally infected with equine herpesvirus 1 (EHV-1) were analysed by in situ hybridization. Digoxigenin-labelled EHV-1 BamHI fragments spanning almost the entire EHV-1 genome were hybridized to RNA in tissue sections from latently infected trigeminal ganglia. The BamHI E fragment detected EHV-1 RNA antisense to gene 63 (HSV-1 homologue ICP0) in a small number of neurons. Sixteen other BamHI fragments gave negative results in 20 sections tested with each fragment. Latency associated transcripts (LATs) were localized to the ne...
Wagner B, Wimer C, Freer H, Osterrieder N, Erb HN.The recent increase in incidence, morbidity, and mortality of neurological disease induced by equine herpesvirus type 1 (EHV-1) has suggested a change of virulence of the virus. The exact mechanisms by which EHV-1 induces neurologic disease are not known. Environmental, viral, and host risk factors might contribute to neurological manifestation. Here, we investigated innate interferon-α (IFN-α), interleukin-10 (IL-10) and IL-4 responses after infection of equine peripheral blood mononuclear cells (PBMC) with EHV-1 using an available cytokine multiplex assay. Three viral strains representing ...
Browning GF, Studdert MJ.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...
Hasebe R, Sasaki M, Sawa H, Wada R, Umemura T, Kimura T.We investigated the mechanism by which equine herpesvirus-1 (EHV-1) enters primary cultured equine brain microvascular endothelial cells (EBMECs) and equine dermis (E. Derm) cells. EHV-1 colocalized with caveolin in EBMECs and the infection was greatly reduced by the expression of a dominant negative form of equine caveolin-1 (ecavY14F), suggesting that EHV-1 enters EBMECs via caveolar endocytosis. EHV-1 entry into E. Derm cells was significantly reduced by ATP depletion and treatments with lysosomotropic agents. Enveloped virions were detected from E. Derm cells by infectious virus recovery a...
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...
Friday PA, Scarratt WK, Elvinger F, Timoney PJ, Bonda A.An outbreak of neurologic disease associated with serologic evidence of equine herpesvirus type 1 (EHV-1) infection occurred in a herd of 46 riding school horses. Ataxia and paresis were observed in 14 geldings and 5 barren mares. Eight affected horses had distal limb edema, 1 horse had a head tilt, and 3 others had urinary incontinence. Other clinical signs included fever, depression, and inappetance in 30 horses. Seven horses with neurologic signs were treated with acyclovir. Serum neutralizing antibody titers against EHV-1 increased 4-fold between acute and convalescent samples or exceeded ...
Plummer G, Goodheart CR, Studdert MJ.Equine herpesviruses with a deoxyribonucleic acid density of 1.716 to 1.717 g/cm(3) were compared with one another by the plaque-reduction test and by the rate of development of cytopathic effect as indicated by plaque size in rabbit kidney cultures. Of the 19 isolates studied, the 9 which had already been tentatively labeled equine abortion viruses were serologically similar to one another; each of them grew more quickly than did any of the other 10 isolates although the mean plaque sizes formed a series of gradations with no clear hiatus which would permit the unequivocal delineation of the ...
Doubli-Bounoua N, Richard EA, Léon A, Pitel PH, Pronost S, Fortier G.The potential involvement of viruses in inflammatory airway disease (IAD) was previously investigated through either serology or PCR from nasopharyngeal swabs (NS). The aims of this study were to determine the prevalence and incidence of viral genome detection by qPCR in the equine airways, and their association with respiratory clinical signs. Both NS and tracheal washes (TW) were collected monthly on 52 Standardbred racehorses at training, over 27 consecutive months (581 samples). Equid herpesviruses (EHV)-1, -4, -2 and -5, equine rhinitis virus-A and -B (ERBV), equine adenovirus-1 and -2, e...
Ataseven VS, Bilge-Dagalp S, Oguzoglu TC, Karapinar Z, Güzel M, Tan MT.The equid herpesvirus 2 (EHV-2) and 5 (EHV-5), identified agents of respiratory infections and keratoconjunctivitis cases in some equids, comprise a high degree of antigenic heterogeneity. Prevalence and genetic characterization of EHV-2 and EHV-5 strains from Turkey were investigated in this study. A total of 73 nasal swabs and 54 blood specimens were sampled from horses with respiratory tract diseases characterized by mucopurulent nasal discharge and occasional coughing. Overall, EHV-2- and EHV-5-specific DNA amplicons were obtained from 19.2% (14/73) and 21.9% (16/73) of horses tested by mu...
Sasaki M, Hasebe R, Makino Y, Suzuki T, Fukushi H, Okamoto M, Matsuda K, Taniyama H, Sawa H, Kimura T.The endotheliotropism of equine herpesvirus-1 (EHV-1) leads to encephalomyelitis secondary to vasculitis and thrombosis in the infected horse central nervous system (CNS). To identify the host factors involved in EHV-1 infection of CNS endothelial cells, we performed functional cloning using an equine brain microvascular endothelial cell cDNA library. Exogenous expression of equine major histocompatibility complex (MHC) class I heavy chain genes conferred susceptibility to EHV-1 infection in mouse NIH3T3 cells, which are not naturally susceptible to EHV-1 infection. Equine MHC class I molecule...
Pusterla N, Hussey SB, Mapes S, Johnson C, Collier JR, Hill J, Lunn DP, Wilson WD.Recrudescence of latent equine herpesvirus 1 (EHV-1) with subsequent viral shedding via nasal secretions is a potential source of infection for susceptible horses and has been implicated in outbreaks occurring in closed populations. Objective: To describe the viral kinetics of reactivated EHV-1 in blood and nasal secretions from latently infected horses after administration of corticosteroids, and to study the infectious nature of reactivated EHV-1 to sentinel horses. Methods: Eight healthy horses. Methods: Four horses infected 4 months previously with EHV-1 received dexamethasone on 5 consecu...
Bürki F, Rossmanith W, Nowotny N, Pallan C, Möstl K, Lussy H.Eighteen horses, vaccinated on a number of occasions over a period of 12 to 20 months with either a live equine herpesvirus-1 (EHV-1) or an inactivated EHV-1 vaccine, were challenged by the intranasal instillation of the subtype 1 virus isolated from the 1983 outbreak of abortion and paralytic disease at the Lipizzan Stud, Piber, Austria. The prechallenge serum titres of all vaccinated horses were remarkably low, although most horses had received their last vaccine dose only 3 weeks before test-infection. Higher titres were obtained with the inactivated product than with the live virus vaccine...
Garré B, van der Meulen K, Nugent J, Neyts J, Croubels S, De Backer P, Nauwynck H.Equine herpesvirus 1 (EHV-1) is an important equine pathogen that causes respiratory disease, abortion, neonatal death and paralysis. Although vaccines are available, they are not fully protective and outbreaks of disease may occur in vaccinated herds. Therefore, there is an urgent need for effective antiviral treatment. For three abortigenic (94P247, 97P70 and 99P96) and three neuropathogenic isolates (97P82, 99P136 and 03P37), the effect of acyclovir, ganciclovir, cidofovir, adefovir, 9-(2-phosphonylmethoxyethyl)-2,6-diaminopurine (PMEDAP) and foscarnet on plaque number was studied. Addition...
van der Meulen KM, Nauwynck HJ, Pensaert MB.Equine herpesvirus-1 (EHV-1) may cause abortion in vaccination- and infection-immune horses. EHV-1-infected peripheral blood mononuclear cells (PBMCs) play an important role in virus immune evasion. The mechanisms by which infected PBMCs can avoid destruction by EHV-1-specific antibody and equine complement were examined. The majority of EHV-1-infected PBMCs (68.6 %) lacked surface expression of viral antigens and these cells were not susceptible to complement-mediated lysis. In infected PBMCs with surface expression of viral antigens, 63 % showed focal surface expression, whereas 37 % showed ...
Azab W, Bedair S, Abdelgawad A, Eschke K, Farag GK, Abdel-Raheim A, Greenwood AD, Osterrieder N, Ali AAH.Equid herpesviruses (EHVs) threaten equine health and can cause significant economic losses to the equine industry worldwide. Different equid herpesviruses, EHV-1, EHV-2, EHV-4 and EHV5 are regularly detected among horse populations. In Egypt, monitoring is sporadic but EHV-1 or EHV-4 have been reported to circulate in the horse population. However, there is a lack of reports related to infection and health status of horses, likely due to the absence of regular diagnostic procedures. In the current study, the circulation of four infectious equid herpesviruses (EHV-1, EHV-2, EHV-4 and EHV-5) am...
Jang HK, Albrecht RA, Buczynski KA, Kim SK, Derbigny WA, O'Callaghan DJ.The sole immediate-early (IE) gene of equine herpesvirus 1 encodes a 1,487-amino-acid (aa) regulatory phosphoprotein that independently activates expression of early viral genes. Coimmunoprecipitation assays demonstrated that the IE protein physically interacts with the general transcription factor TFIIB. Using a variety of protein-binding assays that employed a panel of IE truncation and deletion mutants expressed as in vitro-synthesized or glutathione S-transferase fusion proteins, we mapped a TFIIB-binding domain to aa 407 to 757 of the IE protein. IE mutants carrying internal deletions of ...
Fortier G, van Erck E, Fortier C, Richard E, Pottier D, Pronost S, Miszczak F, Thiry E, Lekeux P.The objectives of this study were to estimate the prevalence and the potential role of equine herpesviruses (EHVs) detection in both bronchoalveolar lavage (BAL) and tracheal wash (TW). The population included a control group (CTL; 37 TW and 25 BAL) and a pathological group (PAT; 259 TW and 387 BAL), including horses either suffering from respiratory diseases including syndrome of tracheal inflammation, inflammatory airway disease, recurrent airway obstruction, or submitted to respiratory investigation because of exercise intolerance or poor performance. Each respiratory liquid was submitted t...
Back H, Ullman K, Treiberg Berndtsson L, Riihimäki M, Penell J, Ståhl K, Valarcher JF, Pringle J.The equine gamma herpesviruses 2 and 5 (EHV-2 and -5) have frequently been observed in the equine population and until recently presumed low to nonpathogenic. However, recent reports linking presence of equine gamma herpesviruses with clinical signs of mild to severe lung disease, suggest that the role of these viruses in respiratory disease and poor performance syndrome is still unclear. Moreover, baseline data regarding the temporal pattern of shedding of EHV-2 and EHV-5 within stables and within individual actively racing horses have been lacking. In a prospective longitudinal study, we fol...
Vissani MA, Becerra ML, Olguín Perglione C, Tordoya MS, Miño S, Barrandeguy M.Infection with Equid Herpesvirus type 1 (EHV-1) leads to respiratory disease, abortion, and neurological disorders in horses. Molecular epidemiology studies have demonstrated that a single nucleotide polymorphism (A(2254)/G(2254)) in the genome region of the open reading frame 30 (ORF30), which results in an amino acid variation (N(752)/D(752)) of the EHV-1 DNA polymerase, is significantly associated with the neuropathogenic potential of naturally occurring strains. In order to estimate the prevalence of the EHV-1 neuropathogenic genotype in our country, we analyzed the ORF30 genome region of ...
Smith KC.Abortion or neonatal disease may follow infection with several alpha, beta and gamma-herpesviruses. The alpha-herpesvirus, equid herpesvirus-1 (EHV-1), causes single or epizootic abortions or neonatal deaths in equids, and the closely related virus EHV-4 causes sporadic equine abortions. In cattle, the alpha-herpesviruses, bovine herpesvirus-1 (infectious bovine rhinotracheitis virus) and bovine herpesvirus-5 (bovine encephalitis virus), and a gamma-herpesvirus, bovine herpesvirus-4, have all been implicated as causes of abortion. In pigs, suid herpesvirus-1 (SHV-1: pseudorabies virus), an alp...
Ambagala APN, Gopinath RS, Srikumaran S.Equine herpesvirus-1 (EHV-1) downregulates surface expression of major histocompatibility complex (MHC) class I molecules on infected cells. The objective of this study was to investigate whether EHV-1 interferes with peptide translocation by the transporter associated with antigen processing (TAP) and to identify the proteins responsible. Using an in vitro transport assay, we showed that EHV-1 inhibited transport of peptides by TAP as early as 2 h post-infection (p.i). Complete shutdown of peptide transport was observed by 8 h p.i. Furthermore, pulse-chase experiments revealed that maturation...
van Der Meulen KM, Nauwynck HJ, Bí¶®rt W, Pensaert MB.In the present study, the outcome of an inoculation of equine peripheral blood mononuclear cells (PBMC) with equine herpesvirus type 1 (EHV-1) was studied in vitro. Cytoplasmic and plasma membrane expression of viral antigens, intra- and extracellular virus titres, and plaque formation in co-culture were determined. EHV-1 replicated in monocytes, although in a highly restricted way. Viral antigens were found at maximum levels (8.7% of the monocytes) at 12 h post-infection. The infection was productive in 0.16% of the monocytes. The virus yield was 10(0.7) TCID(50) per productive cell. In a pop...
Pusterla N, Leutenegger CM, Wilson WD, Watson JL, Ferraro GL, Madigan JE.Based on the hypothesis that the viral load of cells infected with EHV-4 will likely change during the course of disease, TaqMan PCR was used to investigate and characterize the kinetics of EHV-4 viral DNA load (glycoprotein B gene) and transcriptional activity (glycoprotein B and latency-associated transcripts) in peripheral blood leukocytes (PBLs) and nasopharyngeal secretions (NSs) collected from 11 foals during a field outbreak of respiratory disease. The EHV-4 DNA load in PBLs was low and of short duration after onset of clinical signs. In contrast, the EHV-4 load in NSs remained high for...
Pusterla N, James K, Barnum S, Bain F, Barnett DC, Chappell D, Gaughan E, Craig B, Schneider C, Vaala W.A voluntary biosurveillance program was established in 2008 in order to determine the shedding frequency and prevalence factors for common respiratory pathogens associated with acute onset of fever and/or respiratory signs in equids from the USA. Over a period of 13 years, a total of 10,296 equids were enrolled in the program and nasal secretions were analyzed for the qPCR detection of equine influenza virus (EIV), equine herpesvirus-1 (EHV-1), EHV-4, equine rhinitis A and B virus (ERVs), and subspecies (). Single infections with respiratory pathogens were detected in 21.1% of the submission...
Léon A, Fortier G, Fortier C, Freymuth F, Tapprest J, Leclercq R, Pronost S.The major role of EHV-1 in equine abortion is widely reported in the literature but the contribution of EHV-2, EHV-3, EHV-4 or EHV-5 remains less well documented. The objective of this study is to evaluate the contribution of these five different EHVs to equine abortion in a variety of biological tissues using a consensus polymerase chain reaction (PCR). The test was validated for specificity and sensitivity in horses before screening specimens from 407 foetuses, stillbirths and premature foals collected over a 2.5-year interval. Positive results obtained with this assay were compared to other...
Pagamjav O, Sakata T, Matsumura T, Yamaguchi T, Fukushi H.Equine herpesvirus 1 (EHV-1) is a pathogen causing rhinopneumonia in young horses, abortion in mares, and myeloencephalitis in adult horses. Two types, EHV-1 P and EHV-1 B, have recently been dominant among 16 electropherotypes. EHV-1 P and EHV-1 B viruses were compared by long and accurate polymerase chain reaction (LA-PCR) and restriction fragment length polymorphism (RFLP) analysis. Differences in restriction sites were found to be focused in ORF64, which encodes the infected cell protein 4 (ICP4), and downstream of the ICP4 gene. The 3 ' -end and downstream of ICP4 gene of EHV-1 B were fou...
Kim SK, Buczynski KA, Caughman GB, O'Callaghan DJ.The equine herpesvirus 1 (EHV-1) immediate-early (IE) phosphoprotein is essential for the activation of transcription from viral early and late promoters and regulates transcription from its own promoter. The IE protein of 1487 amino acids contains a serine-rich tract (SRT) between residues 181 and 220. Deletion of the SRT decreased transactivation activity of the IE protein. Previous results from investigation of the ICP4 protein, the IE homolog of herpes simplex virus 1 (HSV-1), revealed that a domain containing a serine-rich tract interacts with EAP (Epstein-Barr virus-encoded small nuclear...
