Virology in horses encompasses the study of viruses that affect equine species, including their biology, transmission, and impact on horse health. This field investigates viral pathogens that can lead to a range of diseases, from respiratory infections to neurological disorders. Common viruses affecting horses include equine influenza virus, equine herpesvirus, and West Nile virus. Understanding these viruses involves examining their genetic makeup, modes of transmission, and interactions with the equine immune system. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, pathogenesis, and control measures of viral infections in horses.
Marsh GA, Wang LF.Henipavirus, including Hendra and Nipah viruses, is a group of emerging bat-borne paramyxoviruses which were responsible for severe disease outbreaks in humans, horses and pigs. The mortality rate of human infection varies between 50 and 100%, making them one of the most deadly viruses known to infect humans. Its use of highly conserved cell surface molecules (ephrin) as entry receptors and its highly effective replication and fusion strategies are believed to be important characteristics responsible for its high pathogenicity. Henipavirus also encodes multiple accessory proteins which play a ...
Burbelo PD, Dubovi EJ, Simmonds P, Medina JL, Henriquez JA, Mishra N, Wagner J, Tokarz R, Cullen JM, Iadarola MJ, Rice CM, Lipkin WI, Kapoor A.Genetic and biological characterization of new hepaciviruses infecting animals contributes to our understanding of the ultimate origins of hepatitis C virus (HCV) infection in humans and dramatically enhances our ability to study its pathogenesis using tractable animal models. Animal homologs of HCV include a recently discovered canine hepacivirus (CHV) and GB virus B (GBV-B), both viruses with largely undetermined natural host ranges. Here we used a versatile serology-based approach to determine the natural host of the only known nonprimate hepacivirus (NPHV), CHV, which is also the closest p...
Mori E, Borges AS, Delfiol DJ, Oliveira Filho JP, Gonçalves RC, Cagnini DQ, Lara MC, Cunha EM, Villalobos EM, Nassar AF, Castro AM, Brandao PE....This report describes the first detection of an equine herpesvirus 1 (EHV-1) neuropathogenic variant (G2254/D752) in Brazil from a case of fatal equine herpesvirus myeloencephalopathy (EHM) in a mare. The results of nucleotide sequencing of the EHV-1 ORF30 gene showed that two other Brazilian EHV-1 isolates from EHM cases are representatives of the non-neuropathogenic variant (A2254/N752), suggesting that other unidentified factors are probably also involved in the neuropathogenicity of EHV-1 in horses. These findings will contribute to the epidemiological knowledge of EHV-1 infection in Brazi...
Knox J, Cowan RU, Doyle JS, Ligtermoet MK, Archer JS, Burrow JN, Tong SY, Currie BJ, Mackenzie JS, Smith DW, Catton M, Moran RJ, Aboltins CA....Murray Valley encephalitis virus (MVEV) is a mosquito-borne virus that is found across Australia, Papua New Guinea and Irian Jaya. MVEV is endemic to northern Australia and causes occasional outbreaks across south-eastern Australia. 2011 saw a dramatic increase in MVEV activity in endemic regions and the re-emergence of MVEV in south-eastern Australia. This followed significant regional flooding and increased numbers of the main mosquito vector, Culex annulirostris, and was evident from the widespread seroconversion of sentinel chickens, fatalities among horses and several cases in humans, res...
Gryspeerdt AC, Vandekerckhove AP, Baghi HB, Van de Walle GR, Nauwynck HJ.Equine herpes virus (EHV)-1 replicates in the epithelial cells of the upper respiratory tract and reaches the lamina propria and bloodstream in infected mononuclear cells. This study evaluated expression of the late viral proteins gB, gC, gD and gM in respiratory epithelial and mononuclear cells using: (1) epithelial-like rabbit kidney cells and peripheral blood mononuclear cells infected with EHV-1 in vitro; (2) an equine ex vivo nasal explant system; and (3) nasal mucosa tissue of ponies infected in vivo. The viral proteins were expressed in all late-infected epithelial cells, whereas expres...
Pusterla N, Mapes S, David Wilson W.The objective of this study was to detect and characterize latent equine herpes virus (EHV)-1 and -4 from the submandibular (SMLN) and bronchial lymph (BLN) nodes, as well as from the trigeminal ganglia (TG) of 70 racing Thoroughbred horses submitted for necropsy following sustaining serious musculoskeletal injuries while racing. A combination of nucleic acid precipitation and pre-amplification steps was used to increase analytical sensitivity. Tissues were deemed positive for latent EHV-1 and/or -4 infection when found PCR positive for the corresponding glycoprotein B (gB) gene in the absence...
Turan N, Yildirim F, Altan E, Sennazli G, Gurel A, Diallo I, Yilmaz H.The aim of the present study was to investigate abortion storms that occurred in the Marmara region of Turkey in 2008-2009 using a real-time PCR. Two aborted foetuses were necropsied and histo-pathological findings reported herein. Ten lungs, 3 brains and one nasal swab from 10 aborted foetuses, 6 nasal swabs and 3 vaginal swabs from aborting mares were included in this study. EHV-1 was isolated from the lung, liver and brain of 1 aborted foetus. EHV-1 DNA was detected in the lungs, livers and spleens of 2 necropsied foetuses and in 3 lungs from 10 foetuses submitted for diagnosis. A brain fro...
Pennick KE, McKnight CA, Patterson JS, Latimer KS, Maes RK, Wise AG, Kiupel M.Immunohistochemistry (IHC) and in situ hybridization (ISH) can be used either to detect or to differentiate between Eastern equine encephalitis virus (EEEV) and West Nile virus (WNV) within formalin-fixed, paraffin-embedded (FFPE) brain tissue of horses. To compare the diagnostic sensitivity and specificity of ISH and IHC, FFPE brain tissue from 20 EEEV-positive horses and 16 WNV-positive horses were tested with both EEEV and WNV oligoprobes and EEEV- and WNV-specific antibodies. Reverse transcription polymerase chain reaction (RT-PCR) for detection of EEEV and WNV was used as the gold standar...
Burgess BA, Tokateloff N, Manning S, Lohmann K, Lunn DP, Hussey SB, Morley PS.There is little information on the duration of nasal shedding of EHV-1 from horses with naturally occurring equine herpesvirus myeloencephalopathy (EHM). Objective: To evaluate the duration of nasal shedding of EHV-1 in horses affected by EHM. Methods: One hundred and four horses naturally exposed to EHV-1, 20 of which had clinical signs of EHM. Methods: All horses on affected premises were monitored. Those horses developing EHM were sampled in a longitudinal outbreak investigation. Nasal swabs were collected daily from 16 of 20 horses affected by EHM. A qPCR was performed on 98 of 246 nasal s...
Kulikov E, Kropinski AM, Golomidova A, Lingohr E, Govorun V, Serebryakova M, Prokhorov N, Letarova M, Manykin A, Strotskaya A, Letarov A.Lytic coliphage vB_EcoP_G7C and several other highly related isolates were obtained repeatedly from the samples of horse feces held in the same stable thus representing a component of the normal indigenous intestinal communities in this population of animals. The genome of G7C consists of 71,759 bp with terminal repeats of about 1160 bp, yielding approximately 73 kbp packed DNA size. Seventy-eight potential open reading frames, most of them unique to N4-like viruses, were identified and annotated. The overall layout of functional gene groups was close to that of the original N4 phage, with som...
Sykora S, Samek L, Schönthaler K, Palm F, Borzacchiello G, Aurich C, Brandt S.Squamous cell carcinomas (SCC) are malignant tumours arising from keratinocytes. In horses, there is increasing evidence for Equus caballus papillomavirus type 2 (EcPV-2) being causally involved in SCC development. However, only little is known regarding intralesional transcription of the virus, and sparse information on the incidence of EcPV-2 infection in healthy equids is available so far. Using RT-PCR, total mRNA from 8 EcPV-2 DNA-positive and 1 EcPV-2 negative SCC/SCC precursor lesions was screened for the presence of EcPV-2 E6 and E1 transcripts. Using PCR, we tested 193 sample specimens...
Bogaert L, Willemsen A, Vanderstraeten E, Bracho MA, De Baere C, Bravo IG, Martens A.Squamous cell carcinoma (SCC) represents the most common genital malignant tumor in horses. Similar to humans, papillomaviruses (PVs) have been proposed as etiological agents and recently Equine papillomavirus type 2 (EcPV2) has been identified in a subset of genital SCCs. The goals of this study were (1) to determine the prevalence of EcPV2 DNA in tissue samples from equine genital SCCs, penile intraepithelial neoplasia (PIN) and penile papillomas, using EcPV2-specific PCR, (2) to examine the prevalence of latent EcPV2 infection in healthy genital mucosa and (3) to determine genetic variabili...
van Eeden C, Williams JH, Gerdes TG, van Wilpe E, Viljoen A, Swanepoel R, Venter M.To determine which agents cause neurologic disease in horses, we conducted reverse transcription PCR on isolates from of a horse with encephalitis and 111 other horses with acute disease. Shuni virus was found in 7 horses, 5 of which had neurologic signs. Testing for lesser known viruses should be considered for horses with unexplained illness.
Pérez Ruiz M, Gámez SS, Clavero MA.West Nile virus (WNV) is an arbovirus usually transmitted by mosquitoes. The main reservoirs are birds, although the virus may infect several vertebrate species, such as horses and humans. Up to 80% of human infections are asymptomatic. The most frequent clinical presentation is febrile illness, and neuroinvasive disease can occur in less than 1% of cases. Spain is considered a high-risk area for the emergence of WNV due to its climate and the passage of migratory birds from Africa (where the virus is endemic). These birds nest surrounding wetlands where populations of possible vectors for the...
Pretorius A, Van Kleef M, Van Wyngaardt W, Heath J.African horsesickness (AHS) is an infectious but noncontagious viral disease affecting all species of Equidae. The recall immune response of AHSV naïve horses immunised with an attenuated African horsesickness virus serotype 4 (AHSV4) was characterised using immune assays including ELISPOT, real-time PCR (qPCR) and flow cytometry. The recall immune response detected in PBMC isolated from three inoculated horses showed an upregulation of circulating B lymphocytes that correlated with elevated IL-4 mRNA expression indicative of humoral immunity, but reduced frequency of CD4⁺ cells. In additio...
Foord AJ, Middleton D, Heine HG.Hendra virus (HeV) is a zoonotic paramyxovirus endemic in Australian Pteropus bats (fruit bats or flying foxes). Although bats appear to be unaffected by the virus, HeV can spread from fruit bats to horses, causing severe disease. Human infection results from close contact with the blood, body fluids and tissues of infected horses. HeV is a biosecurity level 4 (BSL-4) pathogen, with a high case-fatality rate in humans and horses. Current assays for HeV detection require complex instrumentation and are generally time consuming. The aim of this study was to develop a Loop-Mediated Isothermal Amp...
Fuentealba NA, Sguazza GH, Eöry ML, Valera AR, Pecoraro MR, Galosi CM.Equid herpesvirus 1 (EHV-1) infection has a significant economic impact on equine production, causing abortion, respiratory disease, neonatal death and neurological disorders. The identification of specific EHV-1 genes related to virulence and pathogenicity has been the aim of several research groups. The purpose of the present study was to analyze different genomic regions of Argentinean EHV-1 strains and to determine their possible relationship with virulence or clinical signs. Twenty-five EHV-1 Argentinean isolates recovered from different clinical cases between 1979 and 2007 and two refere...
Ma G, Feineis S, Osterrieder N, Van de Walle GR.Major histocompatibility complex class I (MHC-I) molecules play an important role in host immunity to infection by presenting antigenic peptides to cytotoxic T lymphocytes (CTLs), which recognize and destroy virus-infected cells. Members of the Herpesviridae have developed multiple mechanisms to avoid CTL recognition by virtue of downregulation of MHC-I on the cell surface. We report here on an immunomodulatory protein involved in this process, pUL56, which is encoded by ORF1 of equine herpesvirus type 1 (EHV-1), an alphaherpesvirus. We show that EHV-1 pUL56 is a phosphorylated early protein w...
Vairo S, Vandekerckhove A, Steukers L, Glorieux S, Van den Broeck W, Nauwynck H.Equine viral arteritis (EVA) is an infectious disease with variable clinical outcome. Outbreaks, causing important economic losses, are becoming more frequent. Currently, there is a shortage of pathogenesis studies performed with European strains. In the present study, eight seronegative ponies were experimentally inoculated with the Belgian strain of equine arteritis virus (EAV) 08P178 (EU-1 clade) and monitored daily for clinical signs of EVA. Nasopharyngeal swabs, ocular swabs, bronchoalveolar cells and blood were collected for virological and serological testing. Two ponies were euthanized...
Capomaccio S, Willand ZA, Cook SJ, Issel CJ, Santos EM, Reis JK, Cook RF.The genetically distinct wild horse herds inhabiting Shackleford Banks, North Carolina are probably the direct descendents of Spanish stock abandoned after failed attempts to settle mid-Atlantic coastal regions of North America in the Sixteenth Century. In a 1996 island survey, 41% of the gathered horses were discovered seropositive for Equine Infectious Anemia Virus (EIAV) with additional cases identified in 1997 and 1998. As a result of their unique genetic heritage, EIAV seropositive individuals identified in the two latter surveys were transferred to a quarantine facility on the mainland. ...
Mattar S, Komar N, Young G, Alvarez J, Gonzalez M.We prospectively sampled flavivirus-naïve horses in northern Colombia to detect West Nile virus (WNV) and St. Louis encephalitis virus (SLEV) seroconversion events, which would indicate the current circulation of these viruses. Overall, 331 (34.1%) of the 971 horses screened were positive for past infection with flaviviruses upon initial sampling in July 2006. During the 12-month study from July 2006-June 2007, 33 WNV seroconversions and 14 SLEV seroconversions were detected, most of which occurred in the department of Bolivar. The seroconversion rates of horses in Bolivar for the period of M...
Yeh JY, Lee JH, Park JY, Seo HJ, Moon JS, Cho IS, Kim HP, Yang YJ, Ahn KM, Kyung SG, Choi IS, Lee JB.The detection of West Nile virus (WNV) in areas endemic for Japanese encephalitis virus (JEV) is complicated by the extensive serological cross-reactivity between the two viruses. A testing algorithm was developed and employed for the detection of anti-WNV antibody in areas endemic for JEV. Using this differentiation algorithm, a serological survey of poultry (2004 through 2009) and horses (2007 through 2009) was performed. Among 2681 poultry sera, 125 samples were interpreted as being positive for antibodies against JEV, and 14 were suspected to be positive for antibodies against undetermined...
Miszczak F, Legrand L, Balasuriya UB, Ferry-Abitbol B, Zhang J, Hans A, Fortier G, Pronost S, Vabret A.During the summer of 2007, an outbreak of equine viral arteritis (EVA) occurred in Normandy (France). After investigation, a link was suggested between an EAV carrier stallion (A) and the index premise of the outbreak. The full-length nucleotide sequence analysis of a study reference strain (F27) isolated from the lung of a foal revealed a 12,710 nucleotides EAV genome with unique molecular hallmarks in the 5'UTR leader sequence and the ORF1a sequence encoding the non-structural protein 2. The evolution of the viral population in the persistently infected Stallion A was then studied by cloning...
Yao S, Qi J, Liu J, Chen R, Pan X, Li X, Gao F, Xia C.In order to clarify the structure and the peptide-presentation characteristics of the equine major histocompatibility complex (MHC) class I molecule, a complex of equine MHC class I molecule (ELA-A1 haplotype, 7-6 allele) with mouse β(2)-microglobulin and the cytotoxic T lymphocyte (CTL) epitope Env-RW12 (RVEDVTNTAEYW) derived from equine infectious anaemia virus (EIAV) envelope protein (residues 195-206) was refolded and crystallized. The crystal, which belonged to space group P2(1), diffracted to 2.3 Å resolution and had unit-cell parameters a = 82.5, b = 71.4, c = 99.8 Å, β = 102.9°. T...
Aleman M, Pickles KJ, Simonek G, Madigan JE.Trigeminal neuralgia or neuropathic pain has been regarded as a putative cause of idiopathic headshaking in horses. Equine herpesvirus-1 (EHV-1) infection and resultant postherpetic pain have been suggested as a possible cause of such neuropathic pain. Objective: To determine the presence of EHV-1 in the trigeminal ganglia of horses with idiopathic headshaking. Methods: Nineteen horses: control (n = 11, 9 geldings, 2 mares, median age 11 years) and headshaking (n = 8, all geldings, median age 11.5 years) horses were sourced from the equine research herd and caseload at the Veterinary Medical T...
Matthijnssens J, Miño S, Papp H, Potgieter C, Novo L, Heylen E, Zeller M, Garaicoechea L, Badaracco A, Lengyel G, Kisfali P, Cullinane A, Collins PJ....In this study, the complete genome sequences of seven equine group A rotavirus (RVA) strains (RVA/Horse-tc/GBR/L338/1991/G13P[18], RVA/Horse-wt/IRL/03V04954/2003/G3P[12] and RVA/Horse-wt/IRL/04V2024/2004/G14P[12] from Europe; RVA/Horse-wt/ARG/E30/1993/G3P[12], RVA/Horse-wt/ARG/E403/2006/G14P[12] and RVA/Horse-wt/ARG/E4040/2008/G14P[12] from Argentina; and RVA/Horse-wt/ZAF/EqRV-SA1/2006/G14P[12] from South Africa) were determined. Multiple novel genotypes were identified and genotype numbers were assigned by the Rotavirus Classification Working Group: R9 (VP1), C9 (VP2), N9 (NSP2), T12 (NSP3), ...
Oura CA, Batten CA, Ivens PA, Balcha M, Alhassan A, Gizaw D, Elharrak M, Jallow DB, Sahle M, Maan N, Mertens PC, Maan S.Prior to the recent outbreak of equine encephalosis in Israel in 2009, equine encephalosis virus (EEV) had only been isolated from equids in South Africa. In this study we show the first evidence for the circulation of EEV beyond South Africa in Ethiopia, Ghana and The Gambia, indicating that EEV is likely to be freely circulating and endemic in East and West Africa. Sequence analysis revealed that the EEV isolate circulating in The Gambia was closely related to an EEV isolate that was isolated from a horse from Israel during the EEV outbreak in 2009, indicating that the two viruses have a com...
Glorieux S, Vandekerckhove AP, Goris N, Yang XY, Steukers L, Van de Walle GR, Croubels S, Neyts J, Nauwynck HJ.Equine herpesvirus 1 (EHV1) is a ubiquitous equine alphaherpesvirus that causes respiratory disease, neurological symptoms and abortions. Current vaccines are not fully protective and effective therapeutics are lacking. A-5021 [(1'S,2'R)-9-[[1',2'-bis(hydroxymethyl)cycloprop-1'-yl]methyl]guanine], previously shown to possess potent anti-herpetic activity against most human herpesviruses, was evaluated for its potential to inhibit EHV1 replication. In equine embryonic lung (EEL) cells, infected with either a non-neurovirulent (97P70) or a neurovirulent (03P37) EHV1 isolate, A-5021 proved to be ...
Capomaccio S, Cappelli K, Cook RF, Nardi F, Gifford R, Marenzoni ML, Passamonti F.Equine infectious anaemia virus (EIAV) is classified within the Retroviridae and, like other lentivirus, has the propensity for considerable antigenic variation. An extensive phylogenetic analysis in Bayesian fashion, with significant amounts of new EIAV gag sequence information, revealed a strong geographic compartmentalization clearly related to the phylogeographic history of modern horses, pointing out that New World EIAV strains form a distinct group with a potentially common origin. This evidence suggests that a single founder event may have occurred during the reintroduction of horses to...
Sun X, Yao H, Zhang C, Lu C.Equine herpesvirus type 1 (EHV-1) is a major cause of respiratory and reproductive diseases in horses worldwide. The genome of EHV-1 strain 438/77 (isolated from an aborted equine fetus) was cloned as a bacterial artificial chromosome (BAC) in E. coli without any gene deletions. The mini-F plasmid sequence was inserted in the middle of ORF19 and 20 via homologous recombination following co-transfection of viral DNA and plasmid pE19_20/HA into RK13 cells. Circular viral DNA was extracted from RK13 cells infected with purified recombinant virus expressing green fluorescent protein (GFP) and elec...
Patel JR, Bateman H, Williams J, Didlick S.A German abortion isolate of EHV-1 (strain M8) was grown in equine dermal (ED) cells at a low multiplicity of infection in presence of 5-bromo-2-deoxy uridine. The resulting stock was dialysed, titrated and cloned by terminal dilution in ED cells grown in 96-well microtitration plates. Of 192 clones each originating from a single focus, clone 147 (C147) was found to be restricted for growth at and above temperatures of 38.5 degrees C. It was also restricted for growth at 37 degrees C in rabbit kidney (RK-13) cells which are widely used for the isolation and titration of EHV-1; hence clone 147 ...
Zevenhoven-Dobbe JC, Greve S, van Tol H, Spaan WJM, Snijder EJ.Equine arteritis virus (EAV) contains seven structural proteins that are all required to produce infectious progeny. Alphavirus-based expression vectors have been generated for each of these proteins to explore the possibilities for their constitutive expression in cell lines. This approach was successful for minor glycoproteins GP(2b), GP(3) and GP(4) and for the E protein. Subsequently, it was demonstrated that cell lines expressing these proteins could rescue EAV mutants that were disabled in the expression of the corresponding gene, resulting in the production of virus particles carrying t...
Kim SK, Kim S, Dai G, Zhang Y, Ahn BC, O'Callaghan DJ.The equine herpesvirus 1 (EHV-1) negative regulatory IR2 protein (IR2P), an early 1,165-amino acid (aa) truncated form of the 1487-aa immediate-early protein (IEP), lacks the trans-activation domain essential for IEP activation functions but retains domains for binding DNA, TFIIB, and TBP and the nuclear localization signal. IR2P mutants of the N-terminal region which lack either DNA-binding activity or TFIIB-binding activity were unable to down-regulate EHV-1 promoters. In EHV-1-infected cells expressing full-length IR2P, transcription and protein expression of viral regulatory IE, early EICP...
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 ...
Ntafis V, Fragkiadaki E, Xylouri E, Omirou A, Lavazza A, Martella V.Severe outbreaks of diarrhoeic syndrome occurred in young foals at the same stud farm during two consecutive breeding periods namely spring 2006 and 2007. Rotavirus-like particles were detected by electron microscopy in the faeces of the affected foals and group A rotavirus infection was confirmed by Reverse-Transcription (RT)-PCR with selected sets of rotavirus-specific primers. Sequence analysis of the genes encoding the outer capsid rotavirus proteins VP7 and VP4 enabled classification of the viruses as G3AP[12] and revealed that the viruses were highly similar to recently reported equine r...
Kooijman LJ, Mapes SM, Pusterla N.Equine coronavirus (EqCoV) infection has been documented in most reports through quantitative qPCR analysis of feces and viral genome sequencing. Although qPCR is used to detect antigen during the acute disease phase, there is no equine-specific antibody test available to study EqCoV seroprevalence in various horse populations. We developed an enzyme-linked immunosorbent assay (ELISA) targeting antibodies to the spike (S) protein of EqCoV and validated its use, using acute and convalescent sera from 83 adult horses involved in 6 outbreaks. The EqCoV S protein-based ELISA was able to reliably d...
Equine infectious anemia (EIA) is a viral disease, caused by the Equine Infectious Anemia virus (EIAV) belonging to the Retroviridae family, genus Lentivirus. Horses (or equids) infected with EIAV are lifelong carriers and they remain contagious for other horses even in the absence of clinical signs. So far, EIAV infection has been reported among horses in North and South America, France, Germany, Italy, Hungary and Romania, with no publication regarding the presence of EIAV in horses in Serbia. To determine the circulation of EIAV among, approximately, the 5000 horses of the Vojvodina region,...
Furrer E, Bilzer T, Stitz L, Planz O.Experimental Borna disease virus (BDV) infection of rats and natural infection of horses and sheep leads to severe central nervous system disease based on immunopathological pathways. The virus replicates slowly, and the cellular immune response results in immunopathology. CD8(+) T cells exert effector cell functions, and their activity results in the destruction of virus-infected cells. Previously, Oldach and colleagues (D. Oldach, M. C. Zink, J. M. Pyper, S. Herzog, R. Rott, O. Narayan, and J. E. Clements, Virology 206:426-434, 1995) have reported protection against Borna disease after inocu...
Daly JM, Sindle T, Tearle J, Barquero N, Newton JR, Corning S.Surveillance of equine influenza viruses has suggested that strains included in currently licensed vaccines are a poor match for those predominantly circulating in the field. Objective: To assess the ability of Duvaxyn IE-T Plus to provide cross protection against the newly evolved South Africa/4/03 (H3N8) strain of equine influenza virus. Methods: The vaccine efficacy was evaluated by challenge infection with influenza strain A/eq/South Africa/4/03 (H3N8) 2 weeks after a primary course of 2 vaccinations with Duvaxyn IE-T Plus given at a 4-week interval. The outcome of challenge in vaccinated ...
Yaniv A, Dahlberg J, Gazit A, Sherman L, Chiu IM, Tronick SR, Aaronson SA.Molecular clones of the integrated form of the genome of equine infectious anemia virus (EIAV), the etiologic agent of a naturally occurring, worldwide disease of horses, were obtained. The restriction map of a full-length genome was determined. Additional evidence for the close evolutionary relationship between EIAV and a prototype lentivirus (caprine arthritis encephalitis virus) was acquired by Southern blotting and immunological analyses. An interspecies radioimmunoassay was developed in which EIAV and ovine and caprine lentiviruses could be detected equally well. These studies make availa...
Kainzbauer C, Rushton J, Tober R, Scase T, Nell B, Sykora S, Brandt S.In January 2010, 18 months after excision of an ocular squamous cell carcinoma (SCC), a Connemara mare presented with anorexia and periorbital/parotideal lesions. Post mortem examination revealed these lesions as forming one entity, with 2 additional growths in the retropharyngeal region and the left jugular groove, respectively. The lesions were confirmed histopathologically as SCCs. Using PCR, peripheral blood mononuclear cells (PBMCs) from 2008 and 2010, tumour tissue, intact skin and vulval mucosa were screened for Equus caballus papillomavirus type 2 (EcPV-2) and bovine papillomavirus typ...
Damiani AM, Scicluna MT, Ciabatti I, Cardeti G, Sala M, Vulcano G, Cordioli P, Martella V, Amaddeo D, Autorino GL.During local respiratory disease outbreaks, occurring in 2003 and 2004 in horse training stables within race-tracks in Rome, and on a stud horse farm in Bari in 2005, four strains of equine influenza (EI) virus were isolated. All outbreaks occurred in flu-vaccinated horses. Here, we are reporting the results of the genetic characterization of these isolates, together with that of another EI virus strain isolated in 1999 from a dead foal presenting pulmonary lesions. Alignment and phylogenetic analyses were carried out using the haemagglutinin amino acid sequences. The Rome and Bari isolates we...
Johansen CA, Williams SH, Melville LF, Nicholson J, Hall RA, Bielefeldt-Ohmann H, Prow NA, Chidlow GR, Wong S, Sinha R, Williams DT, Lipkin WI....In northern Western Australia in 2011 and 2012, surveillance detected a novel arbovirus in mosquitoes. Genetic and phenotypic analyses confirmed that the new flavivirus, named Fitzroy River virus, is related to Sepik virus and Wesselsbron virus, in the yellow fever virus group. Most (81%) isolates came from Aedes normanensis mosquitoes, providing circumstantial evidence of the probable vector. In cell culture, Fitzroy River virus replicated in mosquito (C6/36), mammalian (Vero, PSEK, and BSR), and avian (DF-1) cells. It also infected intraperitoneally inoculated weanling mice and caused mild c...
Zheng YH, Sentsui H, Kono Y, Ikuta K.An attenuated equine infectious anemia virus (EIAV), named V26, was previously obtained after 50 passages of the Japanese virulent strain V70 in primary macrophage culture. To clarify the differences between both viruses, their full-length sequences were determined. There were higher mutations in S2 (6.15% amino acid difference) and LTR (10.7% nucleotide difference). The presumed initiation codon of the S2 gene was absent from the sequence of V26. There was a large insertion within the long-terminal repeat (LTR) U3 hypervariable region of V26. In addition, there were minor mutations in gag (1....
Burrows R, Denyer M, Goodridge D, Hamilton F.Experimental ponies developed signs of disease four days after the intranasal instillation of A/England 1/79 equine influenza virus and virus was recovered from the nasopharynx from the second to the ninth day. No significant antigenic difference was found between the virus and the prototype A/Miami 1/63 virus, using post infection ferret and chicken sera and post vaccination pony sera. No antigenic differences were found between four viruses isolated between January and July 1979, although some differences were found in their ability to detect haemagglutination inhibiting antibody in convales...
Radcliffe PA, Sion CJ, Wilkes FJ, Custard EJ, Beard GL, Kingsman SM, Mitrophanous KA.Effective gene therapy for haemophilia A necessitates a vector system that is not subject to a pre-existing immune response, has adequate coding capacity, gives long-term expression and preferably can target non-dividing cells. Vector systems based on lentiviruses such as equine infectious anaemia virus (EIAV) fulfil these criteria for the delivery of factor VIII (FVIII). We have found that B domain-deleted (BDD) FVIII protein inhibits functional viral particle production when co-expressed with the EIAV vector system. Although particle numbers (as measured by reverse transcriptase activity) ar...
Tözsér J, Friedman D, Weber IT, Bláha I, Oroszlan S.The proteinase of the equine infectious anemia virus (EIAV), a lentivirus closely related to human immunodeficiency virus (HIV), was purified from concentrated virus. The specificity of the enzyme was characterized using oligopeptides representing naturally occurring cleavage sites in the Gag and Gag-Pol polyproteins. The length of the substrate binding pocket was found to be 1-2 residues longer than that of HIV proteinases. Although the EIAV and HIV proteinases cleaved most of the peptides at the same bond, some were hydrolyzed by only the EIAV enzyme. Oligopeptides representing cleavage site...
Shakya AK, O'Callaghan DJ, Kim SK.Equine herpesvirus 1 (EHV-1) is a major pathogen affecting equines worldwide. The virus causes respiratory disease, abortion, and, in some cases, neurological disease. EHV-1 Kentucky A (KyA) is attenuated in the mouse and equine, whereas wild-type pathogenic strain RacL11 induces severe inflammatory infiltration of the lung, causing infected mice to succumb. The complete DNA sequencing of the KyA genome revealed that genes UL17 (ORF17), US6 (ORF73; gI), US7 (ORF74; gE), and US8 (ORF75; 10 K) are deleted as compared to the RacL11 and Ab4 genomes. In-frame deletions in the US1 (ORF68), US4 (OR...
Turell MJ.Experimental studies were undertaken to evaluate the vector competence of selected mosquito species [Aedes taeniorhynchus (Wiedemann), Culex declarator Dyar and Knab, and Mansonia titillans (Walker)] from northwestern Venezuela for the epizootic (IC) strain of Venezuelan equine encephalitis (VEE) virus that was responsible for the 1995 outbreak of VEE in this area. Ae. taeniorhynchus was highly susceptible to infection (94% of 35), and 89% had a disseminated infection. Virus-exposed Ae. taeniorhynchus that refed on susceptible hamsters readily transmitted virus, confirming that this species wa...
Gray WL, Yalamanchili R, Raengsakulrach B, Baumann RP, Staczek J, O'Callaghan DJ.Equine herpesvirus type 1 (EHV-1) preparations enriched in defective interfering particles (DIPs) have previously been demonstrated to mediate the coestablishment of persistent infection and oncogenic transformation in primary hamster embryo fibroblasts. In this study, it was demonstrated that infection of a rabbit kidney (RK) cell line with EHV-1 DIP-enriched preparations also results in the establishment of persistent infection. Viral transcription was characterized in RK cells infected with DIP-enriched stocks and compared to viral transcription in RK cells infected with standard (STD) EHV-...
Egberink H, Horzinek MC.Feline immunodeficiency virus (FIV) has morphological, physical and biochemical characteristics similar to human immunodeficiency virus (HIV), the cause of AIDS in man. However, it is antigenically and genetically distinct from HIV; an antigenic relatedness with equine infectious anaemia virus has been demonstrated. FIV has been molecularly cloned and sequenced. Diagnostic tests are commercially available and attempts at preparing inactivated, subunit and molecularly engineered vaccines are being made in different laboratories. During FIV infection a transient primary illness can be recognized...
Southgate CD, Green MR.Lentivirus Tat proteins comprise a novel class of RNA-binding transcriptional activators that are essential for viral replication. In this study, we performed a series of protein fusion experiments to delineate the minimal protein domains and promoter elements required for Tat action. We show that a 15-amino-acid region of equine infectious anemia virus (EIAV) Tat protein, when fused to the GAL4 or LexA DNA binding domain, can activate transcription in appropriate promoter contexts. In the natural human immunodeficiency virus type 1 long terminal repeat, activation by Tat is dependent on multi...
van der Kuyl AC.Information on endogenous retroviruses fixed in the horse (Equus caballus) genome is scarce. The recent availability of a draft sequence of the horse genome enables the detection of such integrated viruses by similarity search. Using translated nucleotide fragments from gamma-, beta-, and delta-retroviral genera for initial searches, a full-length beta-retrovirus genome was retrieved from a horse chromosome 5 contig. The provirus, tentatively named EqERV-beta1 (for the first equine endogenous beta-retrovirus), was 10434 nucleotide (nt) in length with the usual retroviral genome structure of 5'...
Jin S, Issel CJ, Montelaro RC.We recently reported a highly protective attenuated live virus vaccine for equine infectious anemia virus (EIAV) based on a proviral construct (EIAVUKDeltaS2) with a genetically engineered mutation in the viral S2 gene that eliminates expression of this accessory protein. While the EIAVUKDeltaS2 vaccine provides protection from detectable infection by experimental challenge with highly virulent virus, the potential for commercial application of this vaccine is complicated by the fact that horses inoculated with the EIAVUKDeltaS2 vaccine strain become seropositive in various reference diagnosti...
Jiang CG, Gao X, Ma J, Lin YZ, Wang XF, Zhao LP, Hua YP, Liu D, Zhou JH.Preliminary studies revealed that the gene of the gp45 transmembrane protein (TM) of the attenuated equine infectious anemia virus (EIAV) vaccine strain EIAV(FDDV13) had a high frequency of a premature stop codon at position 261W, which generated a 154-residue truncation at the C-terminus. EIAV(FDDV-TM36), a recombinant virus with the TM truncated at the intracytoplasmic (CT) domain due to the presence of a stop codon, was constructed based on EIAV(FDDV)3-8, which is a proviral derivative of the vaccine. EIAV(FDDV-TM36) had a significantly reduced replication capability compared to EIAV(FDDV)3...
Stadejek T, Mittelholzer Ch, Oleksiewicz MB, Paweska J, Belák S.Equine arteritis virus (EAV) was detected by RT-nested PCR in semen samples from a naturally infected South African donkey. Sequence analysis of the amplified ORF5 fragment revealed only 60 to 70% nucleotide identity to a panel of EAV reference sequences. The unique donkey EAV sequence was also found to be stable during passage in horses. The sequence data reported in this study indicate that the South African donkey variant might represent a new genotype of EAV. The distinct genetic properties of the South African asinine strain of EAV suggest a divergent evolution of this arterivirus in vari...
Allen GP, O'Callaghan DJ, Randall CC.Infection of cells with equine herpesvirus type 1 (EHV-1) or type 3 (EHV-3) resulted in the induction of a DNA polymerase activity distinguishable from host cell DNA polymerases by its high salt requirement for maximal activity. By column chromatography on DEAE-cellulose, DNA-cellulose, phosphocellulose, and hydroxyapatite, the EHV-1-induced polymerase was purified 500-fold with 1–2% recovery of total activity from the nuclei of infected hamster livers. The final enzyme preparation was homogeneous as judged by electrophoresis in sodium dodecyl sulfate-polyacrylamide gels. Calculations based ...
Cantón GJ, Navarro MA, Asin J, Chu P, Henderson EE, Mete A, Uzal FA.Reproductive failure represents an important cause of economic loss for the equine industry. We reviewed the cases of equine abortion and stillbirth submitted to the California Animal Health and Food Safety Laboratory System, University of California-Davis from 1990 to 2022. A total of 1,774 cases were reviewed. A confirmed cause of abortion was determined in 29.2% of the cases. Abortion or stillbirth was attributed to infectious agents in 18.7% of the cases, with Streptococcus spp., equine herpesvirus 1, and Leptospira spp. being the most prevalent. Noninfectious causes of abortion were estab...
Schochetman G, Fine D, Arthur L, Gilden R, Heberling R.A new retravirus (SMRV) isolated from a squirrel monkey, Saimiri sciureus, has an Mg2+-dependen reverse transcriptase and a buoyant density of 1.17 g/cm3 in sucrose and 1.21 g/cm3 in cesium chloride, similar to the mouse mammary tumor virus and the Mason-Pfizer monkey virus. The polypeptide patter of SMRV as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was distinct from the reported polypeptide patterns of known retraviruses. Four major polypeptides of molecular weights 40,000, 20,000, 14,000 and 8,000 were resolved in virus propagated in human, mink, and canine cell...
