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.
Mucha V, Hollý J, Varečková E, Kostolanský F.Avian influenza A viruses (IAVs) are able to overcome the interspecies barrier and adapt to the new non-avian host. The process of adaptation requires the adaptive changes of IAV genome resulting in amino acid substitutions. The aim of this work was the description of amino acid substitutions in avian influenza A viruses (IAVs) occurring during their adaptation to equine host. Today, viruses of the equine influenza H3N8 subtype, first isolated in 1963, represent a single genetic lineage of IAV causing a respiratory disease in horses. We compared the amino acid sequences of the conserve...
Ji S, Na L, Ren H, Wang Y, Wang X.Human myxovirus resistance protein 2 (huMxB) has been shown to be a determinant type I interferon (IFN)-induced host factor involved in the inhibition of human immunodeficiency virus type 1 (HIV-1) as well as many other primate lentiviruses. This blocking occurs after the reverse transcription of viral RNA and ahead of integration into the host DNA, which is closely connected to the ability of the protein to bind the viral capsid. To date, Mx2s derived from nonprimate animals have shown no capacity for HIV-1 suppression. In this study, we examined the restrictive effect of equine Mx2 (eqMx2) o...
Ramsay JD, Evanoff R, Mealey RH.Hepacivirus A (also known as nonprimate hepacivirus and equine hepacivirus) is a hepatotropic virus that can cause both transient and persistent infections in horses. The evolution of intrahost viral populations (quasispecies) has not been studied in detail for hepacivirus A, and its roles in immune evasion and persistence are unknown. To address these knowledge gaps, we first evaluated the envelope gene (E1 and E2) diversity of two different hepacivirus A strains (WSU and CU) in longitudinal blood samples from experimentally infected adult horses, juvenile horses (foals), and foals with sever...
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...
Schnabel CL, Wimer CL, Perkins G, Babasyan S, Freer H, Watts C, Rollins A, Osterrieder N, Wagner B.Equine herpesvirus type 1 (EHV-1) induces respiratory infection, abortion, and neurologic disease with significant impact. Virulence factors contributing to infection and immune evasion are of particular interest. A potential virulence factor of the neuropathogenic EHV-1 strain Ab4 is ORF2. This study on 24 Icelandic horses, 2 to 4 years of age, describes the infection with EHV-1 Ab4, or its deletion mutant devoid of ORF2 (Ab4ΔORF2) compared to non-infected controls (each group n = 8). The horses' clinical presentation, virus shedding, viremia, antibody and cellular immune responses were...
Soghigian J, Andreadis TG, Molaei G.Eastern Equine Encephalitis (EEE) (Togaviridae, Alphavirus) is a highly pathogenic mosquito-borne arbovirus that circulates in an enzootic cycle involving Culiseta melanura mosquitoes and wild Passeriformes birds in freshwater swamp habitats. Recently, the northeastern United States has experienced an intensification of virus activity with increased human involvement and northward expansion into new regions. In addition to its principal role in enzootic transmission of EEE virus among avian hosts, recent studies on the blood-feeding behavior of Cs. melanura throughout its geographic range sugg...
Meier K, Jaguva Vasudevan AA, Zhang Z, Bähr A, Kochs G, Häussinger D, Münk C.Human myxovirus resistance protein B (hMXB) is a restriction factor of HIV-1 that also inhibits a variety of retroviruses. However, hMXB is not antiviral against equine infectious anemia virus (EIAV). We show here that equine MX2 (eMX2) potently restricts EIAV in vitro. Additionally, eMX2 inhibits HIV-1 and other lentiviruses, including murine leukemia virus. Previously, it was reported that hMXB repression is reduced in hMXB Δ1-25, but not in GTP-binding mutant K131A and GTP-hydrolysis mutant T151A. In contrast to this phenomenon, our study indicates that eMX2 restriction is not diminished i...
García-Bocanegra I, Rivero A, Caballero-Gómez J, López-López P, Cano-Terriza D, Frías M, Jiménez-Ruiz S, Risalde MA, Gómez-Villamandos JC....Hepatitis E (HE) is an important emerging disease in European countries. To analyse the role of equids as potential reservoirs for HE virus (HEV), we determined the prevalence of HEV infection in 861 equines from 464 herds in Spain. HEV RNA in serum was detected in 0.4% (3/692) of horses, 1.2% (1/86) of donkeys and 3.6% (3/83) of mules. Phylogenetic analysis identified the zoonotic genotype 3 as being closely related to viral human and swine strains. In this first report on HEV in equids in Europe, we confirm the susceptibility of horses, donkeys and mules to HEV infection. The low prevalence ...
Lu G, Huang J, Li S.Theiler's disease-associated virus (TDAV) could be the aetiological agent of Theiler's disease. Horses experimentally inoculated with equine plasma containing TDAV develop acute and chronic infections with viraemia. Since its first identification in 2013, TDAV has not been detected in equines in the epidemiological studies that have been conducted. Until now, only one genome sequence of TDAV (HorseA1_serum) had been obtained. In this study, we sequenced the genome of four TDAV strains (A/China, F/China, H/USA and I/USA) in commercial equine sera used for cell culture propagation in China using...
Badenhorst M, Tegtmeyer B, Todt D, Guthrie A, Feige K, Campe A, Steinmann E, Cavalleri JMV.Since the discovery of equine hepacivirus (EqHV) in 2011, the virus has been detected in horse populations from more than twelve countries across five continents. EqHV seroprevalence has been reported to be as high as 61.8% and EqHV ribonucleic acid (RNA) prevalence to range between 0.9% and 34.1%. Molecular and serological indications of EqHV infection have never been reported in equids on the African continent. Therefore, investigation of EqHV prevalence in South African horses and subsequent viral genetic characterization contribute to a better understanding of the global epidemiology of th...
Baron AL, Schoeniger A, Becher P, Baechlein C.In recent years, hepatitis C virus (HCV)-related viruses were identified in several species, including dogs, horses, bats, and rodents. In addition, a novel virus of the genus has been discovered in bovine samples and was termed bovine hepacivirus (BovHepV). Prediction of the BovHepV internal ribosome entry site (IRES) structure revealed strong similarities to the HCV IRES structure comprising domains II, IIIabcde, pseudoknot IIIf, and IV with the initiation codon AUG. Unlike HCV, only one microRNA-122 (miR-122) binding site could be identified in the BovHepV 5' nontranslated region. In this ...
Stasiak K, Dunowska M, Rola J.Equid herpesviruses (EHVs) are widespread in equine populations worldwide. While the infection with equine α-herpesviruses (EHV-1 and EHV-4) has been linked to several clinical outcomes, the pathogenic potential for equine γ-herpesviruses (EHV-2 and EHV-5) is still unclear. The objective of the current study was to determine the prevalence of infection with EHVs among Polish horses, to investigate factors associated with EHV infections among horses sampled, and to determine genetic variability within Polish EHV-2 isolates. Virus-specific real-time PCR assays were used for detection of EHV-1,...
Burashev Y, Strochkov V, Sultankulova K, Orynbayev M, Sansyzbay A, Sandybayev N, Nurabayev S, Savitskaya I, Rock DL, Tulman ER.Here, we report the complete genome sequencing of strains A/equine/Kostanay/9/2012(H3N8) and A/equine/LKZ/9/2012(H3N8) of the equine influenza virus belonging to Florida sublineage, clade 2. The strains were isolated in 2012 in the northern and southern regions of Kazakhstan, respectively.
, and of the equine influenza group at the Animal Health Trust provide a timely reminder of risk of equine influenza and the importance of vaccination.
Tan Y, Lam TT, Heberlein-Larson LA, Smole SC, Auguste AJ, Hennigan S, Halpin RA, Fedorova N, Puri V, Stockwell TB, Shilts MH, Andreadis T....Eastern equine encephalitis virus (EEEV) has a high case-fatality rate in horses and humans, and Florida has been hypothesized to be the source of EEEV epidemics for the northeastern United States. To test this hypothesis, we sequenced complete genomes of 433 EEEV strains collected within the United States from 1934 to 2014. Phylogenetic analysis suggested EEEV evolves relatively slowly and that transmission is enzootic in Florida, characterized by higher genetic diversity and long-term local persistence. In contrast, EEEV strains in New York and Massachusetts were characterized by lower genet...
Vissani MA, Zabal O, Tordoya MS, Parreño V, Thiry E, Barrandeguy M.Equid alphaherpesvirus 3 (EHV3) is the etiological agent of equine coital exanthema (ECE), which is a venereal, highly contagious disease, characterized by the formation of papules, vesicles, pustules and ulcers on the external genitalia of mares and stallions. EHV3 remains in a latent state after a successful infection and there are latently infected animals in which the virus is reactivated and generally re-excreted subclinically. There are no available vaccines for this condition and prevention is based on the clinical examination of mares prior to mating, which allows to segregate those sh...
Wilson ME, Holz CL, Kopec AK, Dau JJ, Luyendyk JP, Soboll Hussey G.Equine herpesvirus type 1 (EHV-1) is the cause of respiratory disease, abortion storms, and outbreaks of herpesvirus myeloencephalopathy (EHM). Infection of the spinal cord is characterised by multifocal regions of virally infected vascular endothelium, associated with vasculitis, thrombosis and haemorrhage that result in ischaemia and organ dysfunction. However, the mechanism of thrombosis in affected horses is unknown. Objective: To evaluate tissue factor (TF) procoagulant activity and thrombin-antithrombin complex (TAT) levels in horses following infection with EHV-1. Methods: In vitro and ...
Cursino AE, Vilela APP, Franco-Luiz APM, de Oliveira JG, Nogueira MF, Júnior JPA, de Aguiar DM, Kroon EG.Equine infectious anemia (EIA) has a worldwide distribution, and is widespread in Brazil. The Brazilian Pantanal presents with high prevalence comprising equine performance and indirectly the livestock industry, since the horses are used for cattle management. Although EIA is routinely diagnosed by the agar gel immunodiffusion test (AGID), this serological assay has some limitations, so PCR-based detection methods have the potential to overcome these limitations and act as complementary tests to those currently used. Considering the limited number of equine infectious anemia virus (EIAV) seque...
van Rijn PA, Maris-Veldhuis MA, Boonstra J, van Gennip RGP.African Horse Sickness Virus (AHSV) (Orbivirus genus, Reoviridae family) causes high mortality in naïve domestic horses with enormous economic and socio-emotional impact. There are nine AHSV serotypes showing limited cross neutralization. AHSV is transmitted by competent species of Culicoides biting midges. AHS is a serious threat beyond the African continent as endemic Culicoides species in moderate climates transmit the closely related prototype bluetongue virus. There is a desperate need for safe and efficacious vaccines, while DIVA (Differentiating Infected from Vaccinated) vaccines would...
Downs J, Vaziri M, Jenkins A, Unnasch T.Eastern Equine Encephalitis Virus (EEEV) is the most pathogenic arbovirus endemic to the United States. EEEV primarily infects birds but can be fatal to humans, horses, and some other mammals. Although EEEV transmission occurs in the Northeastern, Southeastern, and Midwestern United States, the largest number of horse and human cases have been reported in Florida, the only state where transmission occurs year round. Currently, a GIS-based risk index (RI) model is used to map EEE transmission risk to horses in Florida. This study validates that RI model using a 5-yr dataset of horse cases in Fl...
Urie NJ, Lombard JE, Marshall KL, Digianantonio R, Pelzel-McCluskey AM, McCluskey BJ, Traub-Dargatz JL, Kopral CA, Swenson SL, Schiltz JJ.Vesicular stomatitis (VS) is caused by a contagious rhabdovirus that affects horses, cattle, and swine. Clinical signs of vesicular stomatitis virus (VSV) infection in pigs and cattle are indistinguishable from foot-and-mouth disease (FMD), a foreign animal disease and reportable disease in the United States (Rodriguez et al., 2000). A VS epidemic occurred in the Rocky Mountain region in 2014-15. A study was conducted in Colorado to evaluate horse- and management-level factors associated with VS. For a horse to be considered a clinical VS horse, there were two requirements. First, clinical VS ...
Forni D, Cagliani R, Pontremoli C, Pozzoli U, Vertemara J, De Gioia L, Clerici M, Sironi M.Hepatitis C virus (HCV) belongs to the genus and is genetically heterogeneous, with seven major genotypes further divided into several recognized subtypes. HCV origin was previously dated in a range between ∼200 and 1000 years ago. Hepaciviruses have been identified in several domestic and wild mammals, the largest viral diversity being observed in bats and rodents. The closest relatives of HCV were found in horses/donkeys (equine hepaciviruses, EHV). However, the origin of HCV as a human pathogen is still an unsolved puzzle. Using a selection-informed evolutionary model, we show that the c...
Bażanów B, Frącka A, Jackulak N, Romuk E, Gębarowski T, Owczarek A, Stygar D.Equine rhinitis A virus (ERAV) is considered to be an important pathogen in horses, but relatively few studies are available. Objective: The purpose of this study was to verify ERAV seroprevalence in selected horses in Poland, in addition to correlation between ERAV and age and sex of analysed animals and the antioxidant status. Methods: The material collected from clinically healthy horses was tested using the VNT (353 serum samples) and virus isolation method (44 nasal swabs). 27 serum samples with antibody titers between 0 and ≥1 : 2048 were chosen for further analysis. The study was ...
Yadav PD, Albariño CG, Nyayanit DA, Guerrero L, Jenks MH, Sarkale P, Nichol ST, Mourya DT.A virus isolated from a sick horse from India in 2008 was confirmed by next-generation sequencing analysis to be equine encephalosis virus (EEV). EEV in India is concerning because several species of Culicoides midge, which play a major role in EEV natural maintenance and transmission, are present in this country.
Fortuna PRJ, Bielefeldt-Ohmann H, Ovchinnikov DA, Wolvetang EJ, Whitworth DJ.Horses are susceptible to a number of neurotropic viruses, including West Nile virus (WNV), which is a pathogen of global significance in both horses and humans. However, there are no in vitro models with which to study infectious neuropathic diseases in the horse. In an effort to redress this, we have generated neurons from equine induced pluripotent stem cells (equiPSCs) that express a range of cortical neuron-specific markers, in addition to the membrane-bound ligand ephrin B3, which plays an important role in axon guidance as well as functioning as the receptor through which henipaviruses,...
Chapman GE, Baylis M, Archer D, Daly JM.Equine populations worldwide are at increasing risk of infection by viruses transmitted by biting arthropods, including mosquitoes, biting midges (Culicoides), sandflies and ticks. These include the flaviviruses (Japanese encephalitis, West Nile and Murray Valley encephalitis), alphaviruses (eastern, western and Venezuelan encephalitis) and the orbiviruses (African horse sickness and equine encephalosis). This review provides an overview of the challenges faced in the surveillance, prevention and control of the major equine arboviruses, particularly in the context of these viruses emerging in ...
Carossino M, Dini P, Kalbfleisch TS, Loynachan AT, Canisso IF, Shuck KM, Timoney PJ, Cook RF, Balasuriya UBR.Equine arteritis virus (EAV) can establish long-term persistent infection in the reproductive tract of stallions and is shed in the semen. Previous studies showed that long-term persistence is associated with a specific allele of the CXCL16 gene (CXCL16S) and that persistent infection is maintained despite the presence of a local inflammatory and humoral and mucosal antibody responses. In this study, we demonstrated that equine seminal exosomes (SEs) are enriched in a small subset of microRNAs (miRNAs). Most importantly, we demonstrated that long-term EAV persistence is associated with the dow...
Moeller RB, Crossley B, Pipkin A, Li Y, Balasuriya UBR.A 2-y-old female Grant's zebra ( Equus quagga [ burchellii] boehmi) was presented with a clinical history of depression, anorexia, and weakness of 1-wk duration. Postmortem examination identified ulcers on the tongue and palate; a large abscess adjacent to the larynx; left lung consolidation; mild swelling, darkening, and congestion of the liver with accentuation of the lobular pattern; and edema and congestion of the distal small and large intestines. Histologic examination identified necrotizing bronchopneumonia, necrotizing hepatitis, nephritis, and enterocolitis. Eosinophilic intranuclear ...
Uehlinger FD, Wilkins W, Godson DL, Drebot MA.Cache Valley virus, an orthobunyavirus, is an important cause of ovine neonatal malformations. Information on the seroprevalence of this virus in Saskatchewan livestock populations is lacking. The objectives of this study were to determine the seroprevalence of Cache Valley virus and closely related viruses in sheep, cattle, goats, horses, and mule deer in Saskatchewan by performing a plaque-reduction neutralization test using Cache Valley virus. In total, sera from 130 sheep from 50 flocks were tested. Seroprevalence in sheep was 64.6% (84/130) and 94.0% (47/50) of flocks had 1 or more seropo...
Ahlers LRH, Goodman AG.Vector-borne diseases, including arboviruses, pose a serious threat to public health worldwide. Arboviruses of the flavivirus genus, such as Zika virus (ZIKV), dengue virus, yellow fever virus (YFV), and West Nile virus (WNV), are transmitted to humans from insect vectors and can cause serious disease. In 2017, over 2,000 reported cases of WNV virus infection occurred in the United States, with two-thirds of cases classified as neuroinvasive. WNV transmission cycles through two different animal populations: birds and mosquitoes. Mammals, particularly humans and horses, can become infected thro...
Kleiboeker SB, Schommer SK, Johnson PJ, Ehlers B, Turnquist SE, Boucher M, Kreeger JM.Over a period of 6 years, antemortem and postmortem examinations were performed on a number of donkeys suffering from respiratory disease. For many cases, initial diagnostic efforts failed to identify an etiology consistent with the pathologic findings. However, retrospective examination of these cases using consensus primer polymerase chain reaction, designed to recognize herpesviruses from all 3 subfamilies of the Herpesviridae, amplified a fragment of the highly conserved herpesvirus DNA polymerase gene from a number of these animals. Two novel herpesviruses, herein designated asinine herpe...
Howe L, Leroux C, Issel CJ, Montelaro RC.Equine infectious anemia virus (EIAV) infection of horses is characterized by well-defined waves of viremia associated with the sequential evolution of distinct viral populations displaying extensive envelope gp90 variation; however, a correlation of in vivo envelope evolution with in vitro serum neutralization phenotype remains undefined. Therefore, the goal of the present study was to utilize a previously defined panel of natural variant EIAV envelope isolates from sequential febrile episodes to characterize the effects of envelope variation during persistent infection on viral neutralizatio...
Matsuo E, Celma CC, Roy P.African horse sickness virus (AHSV), a member of the orbivirus genus of the family Reoviridae, is an insect-vectored pathogen of horses of concern to the equine industry. Studies on AHSV replication and pathogenesis have been hampered by the lack of reverse genetics allowing targeted mutation of viral genomes. We demonstrate that AHSV single-stranded RNA synthesized in vitro (core transcripts) is infectious and that there are distinct primary and secondary stages of the replication cycle. Transfection with a mixture of core transcripts from two different serotypes or a mixture of core transcri...
Carossino M, Dini P, Kalbfleisch TS, Loynachan AT, Canisso IF, Cook RF, Timoney PJ, Balasuriya UBR.Equine arteritis virus (EAV) has the unique ability to establish long-term persistent infection in the reproductive tract of stallions and be sexually transmitted. Previous studies showed that long-term persistent infection is associated with a specific allele of the CXCL16 gene (CXCL16S) and that persistence is maintained despite the presence of local inflammatory and humoral and mucosal antibody responses. Here, we performed transcriptomic analysis of the ampullae, the primary site of EAV persistence in long-term EAV carrier stallions, to understand the molecular signatures of viral persiste...
Lu G, Sun L, Xu T, He D, Wang Z, Ou S, Jia K, Yuan L, Li S.Since 2012, three viruses, known as equine hepacivirus (EqHV), equine pegivirus (EPgV) and Theiler's disease-associated virus (TDAV), have been discovered in equines. Given that these viruses are the newest members of the Flaviviridae family, genomic information concerning circulating EqHV, EPgV and TDAV strains around the world is limited. To date, no genetic surveillance studies have been performed on these three viruses in the equine population of China. Here, a total of 177 serum samples were collected from equines across China between 2014 and 2015. Using PCR, we detected viral RNA in the...
Sykora S, Jindra C, Hofer M, Steinborn R, Brandt S.In horses, squamous cell carcinomas (SCC) commonly affect the external genitals. There is growing evidence that equine papillomavirus type 2 (EcPV2) infection promotes disease development. To assess the possible association of EcPV2 with equine SCCs of the head (HSCC), 15 HSCC DNA samples were screened by E6/E7, E2, and LCR PCR and amplicons were analysed for sequence variations. The physical form of EcPV2 in HSCC, genital lesions, and smegma from horses with SCC was then addressed using EcPV2 immunocapture PCR (IC/PCR) for detection of virion, and E6 vs. E2 qPCR to investigate possible integr...
Kemeny L, Pearson JE.An agent which possessed the properties of herpesviruses was isolated from the leukocytes of 71 out of 80 (88.7%) apparently normal Iowa horses. It was ether- and heat-sensitive, DNA type, and produced type-A intranuclear inclusion bodies in cell cultures. Electron micrographs revealed a virion of typical herpesvirus structure. Leukocyte isolate virus could be differentiated from equine rhinopneumonitis virus (ERV) by serum neutralization, by growth differences in rabbit kidney cells, and by fluorescent antibody staining. Specific neutralizing antibody against this agent was found in a pooled ...
Pronost S, Legrand L, Pitel PH, Wegge B, Lissens J, Freymuth F, Richard E, Fortier G.Equid herpesvirus 1 (EHV-1)-associated myeloencephalopathy (EHM) is a disease affecting the central nervous system of horses. Despite the constantly increasing interest about this syndrome, epidemiological data are limited especially when related to the description of large outbreaks. The aim of this article is to describe clinical, virological and molecular data obtained throughout a severe outbreak of EHM, with emphasis on laboratory diagnostic methods. The epidemic disease concerned a riding school in France where 7/66 horses aged 12-22 years developed signs of neurological disease in July ...
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...
Chambers TM, Holland RE, Tudor LR, Townsend HG, Cook A, Bogdan J, Lunn DP, Hussey S, Whitaker-Dowling P, Youngner JS, Sebring RW, Penner SJ....Flu Avert IN vaccine is a new, live attenuated virus vaccine for equine influenza. We tested this vaccine in vivo to ascertain 1) its safety and stability when subjected to serial horse to horse passage, 2) whether it spread spontaneously from horse to horse and 3) its ability to protect against heterologous equine influenza challenge viruses of epidemiological relevance. For the stability study, the vaccine was administered to 5 ponies. Nasal swabs were collected and pooled fluids administered directly to 4 successive groups of naïve ponies by intranasal inoculation. Viruses isolated from th...
Meredith DM, Stocks JM, Whittaker GR, Halliburton IW, Snowden BW, Killington RA.Equine herpesvirus types 1 and 4 (EHV-1 and EHV-4) labelled with [14C]glucosamine were purified from infected cell culture medium and profiles of their structural proteins were obtained that enabled identification of the major glycoproteins. Nine glycosylated polypeptides were identified for each virus. Preparations of the purified viruses each contained a glycoprotein which was linked by disulphide bonds, as determined by diagonal gel electrophoresis under reducing/non-reducing conditions. High Mr forms of this glycoprotein were detected for EHV-1 when the sample was not heated. The EHV-1 pro...
Hall RA, Khromykh AA.West Nile virus (WNV) is a mosquito-borne flavivirus that is emerging as a global pathogen. In the last decade, virulent strains of the virus have been associated with significant outbreaks of human and animal disease in Europe, the Middle East and North America. Efforts to develop human and veterinary vaccines have taken both traditional and novel approaches. A formalin-inactivated whole virus vaccine has been approved for use in horses. DNA vaccines coding for the structural WNV proteins have also been assessed for veterinary use and have been found to be protective in mice, horses and birds...
Rutkowska DA, Mokoena NB, Tsekoa TL, Dibakwane VS, O'Kennedy MM.African horse sickness (AHS) is a severe arthropod-borne viral disease of equids, with a mortality rate of up to 95% in susceptible naïve horses. Due to safety concerns with the current live, attenuated AHS vaccine, alternate safe and effective vaccination strategies such as virus-like particles (VLPs) are being investigated. Transient plant-based expression systems are a rapid and highly scalable means of producing such African horse sickness virus (AHSV) VLPs for vaccine purposes. Results: In this study, we demonstrated that transient co-expression of the four AHSV capsid proteins in agroin...
Taube R, Fujinaga K, Irwin D, Wimmer J, Geyer M, Peterlin BM.Transcriptional transactivators (Tat) from human immunodeficiency and equine infectious anemia viruses (HIV and EIAV) interact with their transactivation response elements (TAR) to increase the rates of viral transcription. Whereas the human cyclin T1 is required for the binding of Tat to TAR from HIV, it is unknown how Tat from EIAV interacts with its TAR. Furthermore, Tat from EIAV functions in equine and canine cells but not in human cells. In this study, we present sequences of cyclins T1 from horse and dog and demonstrate that their N-terminal 300 residues rescue the transactivation of Ta...
Defang GN, Khetawat D, Broder CC, Quinnan GV.The emergence of Hendra Virus (HeV) and Nipah Virus (NiV) which can cause fatal infections in both animals and humans has triggered a search for an effective vaccine. Here, we have explored the potential for generating an effective humoral immune response to these zoonotic pathogens using an alphavirus-based vaccine platform. Groups of mice were immunized with Venezuelan equine encephalitis virus replicon particles (VRPs) encoding the attachment or fusion glycoproteins of either HeV or NiV. We demonstrate the induction of highly potent cross-reactive neutralizing antibodies to both viruses usi...
Parera M, Martrus G, Franco S, Clotet B, Martinez MA.Canine hepacivirus (CHV) was recently identified in domestic dogs and horses. The finding that CHV is genetically the virus most closely related to hepatitis C virus (HCV) has raised the question of whether HCV might have evolved as the result of close contact between dogs and/or horses and humans. The aim of this study was to investigate whether the NS3/4A serine protease of CHV specifically cleaves human mitochondrial antiviral signaling protein (MAVS) and Toll-IL-1 receptor domain-containing adaptor inducing interferon-beta (TRIF). The proteolytic activity of CHV NS3/4A was evaluated using ...
Vereecke N, Carnet F, Pronost S, Vanschandevijl K, Theuns S, Nauwynck H.Five equine herpesvirus 1 (EHV-1) genome sequences with links to an EHV-1 outbreak with neurological disorders after a horse gathering in Valencia, Spain, in February 2021, were determined. All strains showed the closest relationships to strains from Belgium and the United Kingdom, indicating a common source of infection.
Knight CG, Munday JS, Peters J, Dunowska M.Forty cases of equine penile disease were screened with polymerase chain reaction for the presence of papillomaviral DNA. Cases consisted of 20 squamous cell carcinomas (average age of horse, 23.9 years) and 20 non-squamous cell carcinoma diseases (average age of horse, 13.3 years). All horses but one originated from the Northeastern United States. Breeds were not recorded. As based on MY09/MY11 consensus primers, DNA sequences from equine papillomavirus type 2 were amplified from 9 of 20 horses (45%) with penile squamous cell carcinoma and only 1 of 20 horses (5%) with non-squamous cell carci...
Johnson DJ, Ostlund EN, Pedersen DD, Schmitt BJ.A traditional single-stage reverse transcription-polymerase chain reaction (RT-PCR) procedure is effective in determining West Nile (WN) virus in avian tissue and infected cell cultures. However, the procedure lacks the sensitivity to detect WN virus in equine tissue. We describe an RT-nested PCR (RT-nPCR) procedure that identifies the North American strain of WN virus directly in equine and avian tissues.
Yang H, Xiao Y, Meng F, Sun F, Chen M, Cheng Z, Chen Y, Liu S, Chen H.Equine influenza virus is a major respiratory pathogen in horses. Although both horses and donkeys belong to the genus Equus, donkey infection with influenza viruses is rare. In March 2017, an influenza outbreak occurred in donkeys in Shandong province, China. The causative virus, A/donkey/Shandong/1/2017(H3N8), was isolated from a dead donkey. Genetic analysis indicated that the virus originated from influenza A (H3N8) clade 2 of the Florida sub-lineage that has been circulating in Asian equine populations. Comparison of the deduced amino acid sequence of the HA gene of this causative virus w...
St-Laurent G, Morin G, Archambault D.A reverse transcription (RT)-PCR assay was developed for the detection of equine arteritis virus (EAV) in cell culture supernatant and in horse semen. Four different sets of oligonucleotide primers complementary to sequences located in the 3' end of the polymerase gene (open reading frame [ORF] 1b) and to sequences representing the entire ORFs 3, 4, and 7, which encode for nonstructural (ORFs 3 and 4) or viral nucleocapsid (ORF 7) proteins, were compared for their abilities to amplify the targeted EAV sequences by the RT-PCR procedure. The sensitivities of the RT-PCR for amplification of EAV s...
Imagawa H, Tanaka T, Sekiguchi K, Fukunaga Y, Anzai T, Minamoto N, Kamada M.Electropherotypes (ET), serotypes, and subgroups of equine rotaviruses isolated from foals in Japan were determined. The ETs of 136 isolates from 1981 through to 1991 were divided into six groups: ET-A-ET-F. The ET-A, -B, -C, -D, -E, and -F were present in 3, 1, 121, 9, 1, and 1 strains, respectively. Representative viruses of ET-A, -B, -C, and -D were identified as serotype G3. Viruses of ET-E and -F were identified as serotypes G 10 and G 5, respectively. The four representative viruses of serotype G 3 did not belong to either subgroup I or II. The two viruses of serotypes G 5 and G 10 belon...
Nakamura Y, Kishi M, Nakaya T, Asahi S, Tanaka H, Sentsui H, Ikeda K, Ikuta K.Borna disease (BD) is a progressive poliomeningoencephalomyelitis which occurs naturally in horses and sheep. Here, peripheral blood mononuclear cells (PBMC) derived from 57 healthy horses in Japan were examined by a nested reverse transcription-polymerase chain reaction to determine the prevalence of BD virus (BDV) infection. Seventeen (29.8%) of the samples were positive by this examination and the specificity of the amplified product was confirmed by hybridization with authentic oligomer probes. About 60% of the BDV RNA-positive individuals also showed seropositivity by Western blotting. Th...
Mealey RH, Fraser DG, Oaks JL, Cantor GH, McGuire TC.Acute infection with equine infectious anemia virus (EIAV), a lentivirus of horses, results in a persistent high-level viremia in Arabian foals affected with severe combined immunodeficiency (SCID). This observation argues against the idea that the transient nature of acute lentiviral viremia is solely a function of viral population dynamics. To extend these studies, EIAV-specific immune reconstitution was attempted prior to EIAV challenge in two SCID foals, using adoptively transferred virus-stimulated lymphocytes derived from persistently EIAV-infected half sibling donors. Following transfer...
Baccam P, Thompson RJ, Li Y, Sparks WO, Belshan M, Dorman KS, Wannemuehler Y, Oaks JL, Cornette JL, Carpenter S.Lentiviruses exist in vivo as a population of related, nonidentical genotypes, commonly referred to as quasispecies. The quasispecies structure is characteristic of complex adaptive systems and contributes to the high rate of evolution in lentiviruses that confounds efforts to develop effective vaccines and antiviral therapies. Here, we describe analyses of genetic data from longitudinal studies of genetic variation in a lentivirus regulatory protein, Rev, over the course of disease in ponies experimentally infected with equine infectious anemia virus. As observed with other lentivirus data, t...
Beck C, Leparc-Goffart I, Desoutter D, Debergé E, Bichet H, Lowenski S, Dumarest M, Gonzalez G, Migné C, Vanhomwegen J, Zientara S, Durand B....New Caledonia and French Polynesia are areas in which arboviruses circulate extensively. A large serological survey among horses from New Caledonia and French Polynesia was carried out to investigate the seroprevalence of flaviviruses in the horse population. Here, 293 equine sera samples were screened for flaviviruses using a competitive enzyme-linked immunosorbent assay (cELISA). The positive sera were then confirmed using a flavivirus-specific microsphere immunoassay (MIA) and seroneutralization tests. This serosurvey showed that 16.6% (27/163) and 30.8% (40/130) of horses were positive for...
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...
Zheng YH, Nakaya T, Sentsui H, Kameoka M, Kishi M, Hagiwara K, Takahashi H, Kono Y, Ikuta K.We have studied a horse which exhibited typical clinical signs of disease when experimentally infected with a non-adapted virulent strain of equine infectious anaemia virus (EIAV), designated V70. Five viruses (F1V, F2V, F3V, F4V and F5V) were recovered during periodic febrile episodes. Cross-neutralization tests revealed that all of these variants and the parental V70 were antigenically distinct. Sequencing of their full-length env gp90 genes and gp45 5' sequences revealed novel mutations at a limited number of nucleotide positions, consisting of insertions and duplications in the gp90 princi...
