The study of viral infections that affect equine species assesses the relationship between viruses and horses. Infections can lead to a range of clinical symptoms and may impact the health and performance of horses. Common equine viruses include Equine Influenza Virus, Equine Herpesvirus, and West Nile Virus, among others. Understanding the mechanisms of viral transmission, pathogenesis, and host immune responses is essential for developing effective prevention and treatment strategies. This page compiles peer-reviewed research studies and scholarly articles that explore the epidemiology, molecular biology, and clinical management of viral infections in horses.
Del Piero F.Two 5-year-old grade male horses presented with epiphora, rhinorrhea, conjunctival and nasal mucosal hyperemia, and dorsal and thoracic macropapular rash. Skin biopsies were collected from the affected areas, and serial sections were evaluated following hematoxylin and eosin and immunoperoxidase histochemistry staining by using a murine monoclonal antibody of the immunoglobulin G2A isotype recognizing the 30-kDa membrane protein of equine arteritis virus (EAV). In both horses, lesions consisted of mild to moderate diffuse superficial dermal edema and vasculitis with mild perivascular lymphocyt...
McGuire TC, Leib SR, Lonning SM, Zhang W, Byrne KM, Mealey RH.Efficacious lentiviral vaccines designed to induce cytotoxic T lymphocytes (CTL) in outbred populations with a diverse repertoire of MHC class I molecules should contain or express multiple viral proteins. To determine the equine infectious anaemia virus (EIAV) proteins with epitopes most frequently recognized by CTL from seven horses infected for 0.5 to 7 years, retroviral vector-transduced target cells expressing viral proteins were used in CTL assays. Gag p15 was recognized by CTL from 100% of these infected horses. p26 was recognized by CTL from 86%, SU and the middle third of Pol protein ...
Mukaiya R, Kimura T, Ochiai K, Wada R, Umemura T.Equine herpesvirus-1 (EHV-1) infection was demonstrated in the lung tissue of seven aborted fetuses by immunohistochemical labelling and polymerase chain reaction. The placentas of the fetuses were also examined by non-isotopic in-situ hybridization for the EHV-1 glycoprotein B (gB) gene. Positive hybridization signals were observed in the cytoplasm of trophoblasts, especially in microcotyledons, of all seven placentas, and in villous epithelium of the allantochorion of six placentas. Despite the presence of EHV-1 RNA, EHV-1 antigens were not detected in placentas by immunohistochemical examin...
Wang LF, Yu M, Hansson E, Pritchard LI, Shiell B, Michalski WP, Eaton BT.An outbreak of acute respiratory disease in Hendra, a suburb of Brisbane, Australia, in September 1994 resulted in the deaths of 14 racing horses and a horse trainer. The causative agent was a new member of the family Paramyxoviridae. The virus was originally called Equine morbillivirus but was renamed Hendra virus (HeV) when molecular characterization highlighted differences between it and members of the genus Morbillivirus. Less than 5 years later, the closely related Nipah virus (NiV) emerged in Malaysia, spread rapidly through the pig population, and caused the deaths of over 100 people. W...
de la Rua-Domenech R, Reid SW, González-Zariquiey AE, Wood JL, Gettinby G.A Monte Carlo model that simulates the management life cycle of a horse population in training on a Thoroughbred flat racing yard (i.e. stable) was developed for computer implementation. Each horse was characterised by several state variables. Discrete events at the horse level were triggered stochastically to reflect uncertainty about some input assumptions and heterogeneity of the horse population in a particular yard. This mathematical model was subsequently used to mimic the spread of equine influenza (EI) within a typical yard following the introduction of one or several infectious horses...
Moncayo AC, Edman JD, Turell MJ.The effect of eastern equine encephalomyelitis (EEE) virus on the survivorship of Aedes albopictus (Skuse), Anopheles quadrimaculatus Say, and Coquillettidia perturbans (Walker) was determined experimentally. Female mosquitoes were allowed to feed on EEE viremic chicks, and survival rates were compared for infected and uninfected mosquitoes. Additionally, the survival of female Cq. perturbans and An. quadrimaculatus intrathoracically (i.t.) inoculated with EEE was compared with controls receiving diluent inoculations. Infection with EEE significantly reduced survival in Cq. perturbans compared...
Molenkamp R, Greve S, Spaan WJ, Snijder EJ.Equine arteritis virus (EAV), the prototype arterivirus, is an enveloped plus-strand RNA virus with a genome of approximately 13 kb. Based on similarities in genome organization and protein expression, the arteriviruses have recently been grouped together with the coronaviruses and toroviruses in the newly established order Nidovirales. Previously, we reported the construction of pEDI, a full-length cDNA copy of EAV DI-b, a natural defective interfering (DI) RNA of 5.6 kb (R. Molenkamp et al., J. Virol. 74:3156-3165, 2000). EDI RNA consists of three noncontiguous parts of the EAV genome fused ...
Dunowska M, Holloway SA, Wilks CR, Meers J.Seventeen New Zealand isolates of equine herpesvirus 5 (EHV-5) were compared to the Australian prototype strain. PCR primers were designed to amplify EHV-5 glycoprotein B (gB) gene, and Restriction Fragment Length Polymorphism (RFLP) was used to detect differences between cloned PCR products. EHV-5 isolates from different horses showed a high degree of heterogeneity. However, EHV-5 isolates from individual horses remained homogeneous when examined over a period of time or isolated from different sites. A single EHV-5 gB RFLP profile was detected in isolates from each individual horse but one. ...
Ruitenberg KM, Love DN, Gilkerson JR, Wellington JE, Whalley JM.We have shown previously that equine herpesvirus 1 (EHV-1) glycoprotein D (gD) DNA elicited protective immune responses against EHV-1 challenge in murine respiratory and abortion models of EHV-1 disease. In this study, 20 horses, all with pre-existing antibody to EHV-4 and two with pre-existing antibody to EHV-1, were inoculated intramuscularly with three doses each of 50, 200 or 500microg EHV-1 gD DNA or with 500microg vector DNA. In 8 of 15 horses, inoculation with EHV-1 gD DNA led to elevated gD-specific antibody and nine horses exhibited increased virus neutralising (VN) antibody titres co...
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....
Hultén C, Sandgren B, Skiöldebrand E, Klingeborn B, Marhaug G, Forsberg M.The acute phase protein serum amyloid A (SAA) has proven potentially useful as an inflammatory marker in the horse, but the knowledge of SAA responses in viral diseases is limited. The aim of this study was to evaluate SAA as a marker for acute equine influenza A2 (H3N8) virus infection. This is a highly contagious, serious condition that inflicts suffering on affected horses and predisposes them to secondary bacterial infections and impaired performance. Seventy horses, suffering from equine influenza, as verified by clinical signs and seroconversion, were sampled in the acute (the first 48 h...
Birch-Machin I, Ryder S, Taylor L, Iniguez P, Marault M, Ceglie L, Zientara S, Cruciere C, Cancellotti F, Koptopoulos G, Mumford J, Binns M....Three filamentous phage random peptide display libraries were used in biopanning experiments with purified IgG from the serum of a gnotobiotic foal infected with equine herpesvirus-1 (EHV-1) to enrich for epitopes binding to anti-EHV-1 antibodies. The sequences of the amino acids displayed were aligned with protein sequences of EHV-1, thereby identifying a number of potential antibody binding regions. Presumptive epitopes were identified within the proteins encoded by genes 7 (DNA helicase/primase complex protein), 11 (tegument protein), 16 (glycoprotein C), 41 (integral membrane protein), 70 ...
Christley RM, Rose RJ, Hodgson DR, Reid SW, Evans S, Bailey C, Hodgson JL.A questionnaire was administered to members of the Australian Equine Veterinary Association to investigate their attitudes and behaviours regarding the cause, diagnosis and treatment of lower-respiratory-tract disease in racehorses. The most-important perceived risk factors related to the level of exposure and resistance to infectious agents, whereas factors associated with racing and climatic factors were lower ranked. By far the most-commonly implicated primary cause of disease was respiratory viruses. However, specific diagnostic tests (such as viral serology or virus isolation) were rarely...
Fukunaga Y, Wada R, Sugita S, Fujita Y, Nambo Y, Imagawa H, Kanemaru T, Kamada M, Komatsu N, Akashi H.Equine arteritis virus (EAV) was readily isolated in RK-13 cell monolayers by plaque assay from seminal plasma of experimental carrier stallions when they contained high titers of virus regardless of the presence of non-viral cytotoxicity in the seminal plasma. The cytotoxicity interfered with virus isolation from seminal plasma which contained virus at titers less than 10 PFU/ml. However, it was possible to detect the virus in seminal plasma pretreated with PEG (#6000). EAV was consistently identified by RT-PCR from crude seminal plasma which contained virus at titers of more than 10(2.7) PFU...
Carvalho R, Passos LM, Martins AS.In this study, a multiplex polymerase chain reaction (PCR) procedure was developed for differentiation of strains and field isolates of equine herpesvirus type 1 (EHV-1) and type 4 (EHV-4). Specific oli-gonucleotide primers were combined to amplify the thymidine kinase (TK) gene region of EHV-1 and EHV-4, which would yield fragments of different lengths for each virus in the same amplification reaction. The specificity of the largest PCR amplicon for EHV-4 was confirmed by restriction digestion with HindIII. The multiplex PCR proved to be a fast and sensitive method for typing EHV-1 and EHV-4 ...
Del Piero F.Equine viral arteritis (EVA) can cause prominent economic losses for the equine industry. The purpose of this review is to provide the pathologist some familiarity with the clinical history, lesions, pathogenesis, and diagnosis of EVA. EVA is caused by an arterivirus (equine arteritis virus, EAV), and the vascular system is the principal but not unique viral target. EVA has variable presentations, including interstitial pneumonia, panvasculitis with edema, thrombosis and hemorrhage, lymphoid necrosis, renal tubular necrosis, abortion, and inflammation of male accessory genital glands. EAV anti...
Del Piero F.Equine viral arteritis (EVA) can cause prominent economic losses for the equine industry. The purpose of this review is to provide the pathologist some familiarity with the clinical history, lesions, pathogenesis, and diagnosis of EVA. EVA is caused by an arterivirus (equine arteritis virus, EAV), and the vascular system is the principal but not unique viral target. EVA has variable presentations, including interstitial pneumonia, panvasculitis with edema, thrombosis and hemorrhage, lymphoid necrosis, renal tubular necrosis, abortion, and inflammation of male accessory genital glands. EAV anti...
Del Piero F.Equine viral arteritis (EVA) can cause prominent economic losses for the equine industry. The purpose of this review is to provide the pathologist some familiarity with the clinical history, lesions, pathogenesis, and diagnosis of EVA. EVA is caused by an arterivirus (equine arteritis virus, EAV), and the vascular system is the principal but not unique viral target. EVA has variable presentations, including interstitial pneumonia, panvasculitis with edema, thrombosis and hemorrhage, lymphoid necrosis, renal tubular necrosis, abortion, and inflammation of male accessory genital glands. EAV anti...
Del Piero F.Equine viral arteritis (EVA) can cause prominent economic losses for the equine industry. The purpose of this review is to provide the pathologist some familiarity with the clinical history, lesions, pathogenesis, and diagnosis of EVA. EVA is caused by an arterivirus (equine arteritis virus, EAV), and the vascular system is the principal but not unique viral target. EVA has variable presentations, including interstitial pneumonia, panvasculitis with edema, thrombosis and hemorrhage, lymphoid necrosis, renal tubular necrosis, abortion, and inflammation of male accessory genital glands. EAV anti...
Chesters PM, Hughes A, Edington N.Cell mediated responses to Equid herpesvirus 1 (EHV-1) are of short duration in vivo and require considerable expansion to be detected in vitro. Raised serum levels of active transforming growth factor B (TGF-B1) have been shown to depress proliferative T cell responses in experimental infections with EHV-1 in ponies. The present work indicates that latent transforming growth factor B (TGF-B1) is present in circulating platelets, lymph node, bronchial epithelium and alveolar macrophages. Activation of platelets in vitro by thrombin resulted in the release of latent TGF-B1 from platelets, with ...
Kaaden OR, Truyen U.There is a continuous change in viral epidemics with respect to clinical symptoms, their duration or disappearance and the emergence of new diseases. This can be observed both in human and animal diseases. This evolution of virus diseases is mainly related to three factors: etiological agent, host and environment. As far as genetic alterations of the virus are concerned, two major mechanisms are involved: 1) mutations such as recombination and reassortment; 2) selection for resistance or susceptibility. The epidemiology of newly emerged virus diseases in man and animals, such as AIDS and hemor...
Archambault D, St-Laurent G.Equine arteritis virus (EAV) is the etiological agent of equine viral arteritis, a contagious viral disease of equids. EAV is the prototype virus of the arteriviruses, a group of small enveloped viruses with positive single-stranded RNA genomes. Because apoptosis or programmed cell death is believed to play an important role in the biogenesis of several cytopathogenic viruses, we examined whether EAV was able to induce cell apoptosis in vitro. To do this, Vero cells were infected with EAV at a multiplicity of infection of 0.1 tissue culture infectious dose (TCID50) per cell, and analyzed at va...
MacLachlan NJ, Conley AJ, Kennedy PC.A number of viruses have the capacity to cross the placenta and infect the fetus to cause, among other potential outcomes, developmental defects (teratogenesis), fetal death and abortion. Bluetongue virus (BTV) infection of fetal ruminants provides an excellent model for the study of virus-induced teratogenesis. This model has shown that only viruses modified by passage in cell culture, such as modified live virus vaccine strains, readily cross the ruminant placenta, and that the timing of fetal infection determines the outcome. Thus, cerebral malformations only occur after fetal infection at ...
Hammond SA, Li F, McKeon BM, Cook SJ, Issel CJ, Montelaro RC.Persistent infection of equids by equine infectious anemia virus (EIAV) is typically characterized by a progression during the first year postinfection from chronic disease with recurring disease cycles to a long-term asymptomatic infection that is maintained indefinitely. The goal of the current study was to perform a comprehensive longitudinal analysis of the course of virus infection and development of host immunity in experimentally infected horses as they progressed from chronic disease to long-term inapparent carriage. We previously described the evolution of EIAV genomic quasispecies (C...
Schumacher J, Edwards JF, Cohen ND.A review of reported cases of inflammatory bowel diseases (IBDs) of horses for which no etiology was identified included cases of granulomatous enteritis (GE), multisystemic eosinophilic epitheliotropic disease (MEED), lymphocytic-plasmacytic enterocolitis (LPE), and idiopathic eosinophilic enterocolitis (EC). The terms EC and MEED were both used to describe a disease in horses characterized by infiltration of intestine and extraintestinal tissues with eosinophils. We use EC to describe IBD characterized by only intestinal infiltration by eosinophils. Horses with GE, MEED, or LPE are usually e...
Smith KC, Whitwell KE, Mumford JA, Hannant D, Blunden AS, Tearle JP.The V592 strain of equid herpesvirus-1 (EHV-1), which was originally isolated from a fetus during an abortion epizootic, has proved to be of low virulence in infection studies. Five Welsh Mountain pony mares and one foal were challenged intranasally or by aerosol with this isolate, and monitored clinically and virologically. All six animals shed virus in nasopharyngeal mucus, and viraemia was recorded from day 7 post-infection (PI). Pathological investigations revealed mild rhinitis and bronchiolitis in the mares, with viral antigen expression in degenerating epithelial cells of the nasal muco...
Yates P, Mumford JA.To investigate the level of cross-protection induced by equine influenza H3N8 vaccines derived from different lineages, two studies have been carried out with ponies vaccinated with 'American-like' and 'European-like' vaccines and experimentally challenged with a European-like strain. The results demonstrated that equine influenza vaccines clearly protect against challenge with homologous virus if serum antibody titres are sufficiently high. On the other hand, protection is incomplete even when animals vaccinated with heterologous strains have comparative antibody levels. Nevertheless, the pro...
Afshar A, Shakarchi NH, Dulac GC.Two competitive (C) enzyme-linked immunosorbent assays (ELISAs) were developed for the detection of antibodies to vesicular stomatitis virus (VSV) in animal sera. The assays are based upon the availability of polyclonal antibodies (PAbs) from mouse ascitic fluids prepared against the New Jersey (NJ) and the Indiana (IN) VSV serotypes. The assays were performed by the immobilization of VSV-NJ and VSV-IN antigens on a solid phase (microtiter plate). Appropriately diluted test serum mixed with an equal volume of serotype-specific PAb was allowed to incubate in the presence of the relevant VSV ant...
Bażanów B, Pawęska JT, Pogorzelska A, Florek M, Frącka A, Gębarowski T, Chwirot W, Stygar D.Huculs () are an old breed of primitive mountain horses, originating from the Carpathian Mountains. To the best of our knowledge, data concerning the epidemiology of viral infections observed within this breed are sparse. The objective of this study was to estimate the serological status of a semi-isolated, unvaccinated Hucul herd, with respect to both common equine viral infections and horse-infecting arboviruses, the presence of which was previously reported in Poland. Twenty horses of the Hucul breed, living in a remote area in Poland, were studied in 2018 from March to May. Using nasal sec...
Tewari D, Gibson JS, Slater JD, O'Neill T, Hannant D, Allen GP, Field HJ.EHV-1 was inoculated into specific pathogen-free (SPF) foals in order to study uncomplicated primary responses. Infection resulted in a strong serological response recognizing EHV-1-specific antigens; this contrasts with a previous publication where a weak response was recorded in SPF animals. Antibodies to EHV-1 were readily detected by four techniques (virus neutralization, complement fixation, Western blots and immune precipitation), yet there was comparatively little cross-reaction to EHV-4 target antigen. Re-inoculation with the same virus strain stimulated antibodies to EHV-1 but no addi...
Iniguez P, Zientara S, Marault M, Machin IB, Hannant D, Cruciere C.A random hexapeptide fusion-phage library was screened to isolate phages that bind to antibodies present in horse sera positive for equine arteritis virus (EAV). Analysis of the peptide sequences displayed by isolated phages identified seven groups. 25% of the isolated phages used as antigens in an ELISA test were specifically recognised by a pool of sera which was positive for EAV in virus neutralisation test (VN). Five of these, when used as antigen in ELISA, detected greater than 50% of sera (n = 30) containing antibodies to EAV as detected by VN. When these five phages were pooled together...
Ward MP.Using reports of clinical West Nile virus (WNV) encephalomyelitis in Texas equids during 2002, the distribution of disease was analyzed using cluster statistics and spatial modeling to develop hypotheses of disease spread during the first year of its detection. Significant (P < 0.05) clusters of cases reported early during the outbreak were identified in east, northcentral, and north Texas, and significant (P < 0.05) clusters late during the outbreak were detected in central, south, and west Texas. Two counties on the south Texas coast first reported disease significantly (P < 0.05) e...
Madden CR, Shih DS.Sequential passage of the tissue culture-adapted prototype strain of EIAV in fetal donkey dermal (FDD) cell cultures generated a virus stock which exhibits cytopathic effects in FDD cell cultures. In this study, the effects of the long terminal repeat (LTR) region on virus replication and cytopathogenicity were examined. The FDD-adapted virus LTR was found to contain a number of base pair mutations and a large insertion within the U3 region in comparison with the previously characterized LTR, lambda12. Transient gene expression studies showed that basal promoter activity, in FDD cell cultures,...
Golke A, Cymerys J, Słońska A, Dzieciatkowski T, Chmielewska A, Tucholska A, Bańbura MW.Real-time cell electronic sensing (RT-CES) based on impedance measurements is an emerging technology for analyzing the status of cells in vitro. It allows label-free, real time monitoring of the biological status of cells. The present study was designed to assess dynamic data on the cell processes during equine herpesvirus type 1 (EHV-1) infection of ED (equine dermal) cells and primary murine neuronal cell culture. We have demonstrated that the xCELLigence system with dynamic monitoring can be used as a rapid diagnostic tool both to analyze cellular behavior and to investigate the effect of v...
Harry P, de Haro L, Asfar P, David JM.To assess early clinical and biological prognosis factors in viper envenomings, and assess efficacy of Viperfav immunotherapy. Viperfav contains purified F(ab')2 fragments of equine antibodies. Methods: A retrospective case review study of viper envenomings collected by two poison centers in France, treated or not treated by Viperfav, was conducted. Two hundred seven cases of viper bites including 119 moderate or severe envenomings (Grade II and III, recorded in adults and children and collected from 1992 to 1997 were included. Before treatment, clinical gradation and early biological severity...
Tewari D, Kim H, Feria W, Russo B, Acland H.West Nile virus (WNV) RNA was quantified in WNV infected crows and horses with the help of a real-time reverse transcriptase-PCR assay. A 5' nuclease assay, based on NS5 gene detection with a fluorescent probe was used for quantifying WNV RNA using formalin fixed paraffin embedded tissue specimens. Quantitative detection of WNV RNA showed the presence of a higher amount of the viral RNA in crow tissues compared to equine tissues and these results correlated well with the detection of WNV antigen by immunostaining. In crows, the highest amount of virus was seen in the intestine and in horses in...
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 ...
Abraham M, Bauquier J.The peripartum period is critical in equine medicine for maintaining healthy mares, and ensuring the delivery of healthy neonatal foals. The field of perinatal mortality in horses is continuously evolving, with several advances being recently made in causes of perinatal fetal and foal loss. This review details the main causes of perinatal loss in horses, through late pregnancy, parturition and the neonatal period. Recent advances in identification of infectious organisms and indicators of survival in neonatal foals will be discussed. Continued advances in reproductive and neonatal medicine wil...
Faur YC, Weisburd MH, Wilson ME.NYC medium supplemented with cow blood (NYC-C) and sheep blood (NYC-S) were tested for the growth of N. gonorrhoeae and urogenital mycoplasma in comparison with standard NYC medium which contains horse blood. In situations where horse blood is not available, cow blood could be substituted in NYC standard medium, whereas the use of sheep blood was found unsuitable.
McGuire TC, Fraser DG, Mealey RH.Cytotoxic T lymphocytes (CTL) are associated with virus control in horses infected with equine infectious anemia virus (EIAV). Early in infection, control of the initial viremia coincides with the appearance of CTL and occurs before the appearance of neutralizing antibody. In carrier horses, treatment with immunosuppressive drugs results in viremia before a change in serum neutralizing antibody occurs. Clearance of initial viremia caused by other lentiviruses, including human immunodeficiency virus-1 and simian immunodeficiency virus, is also associated with CTL and not neutralizing antibody. ...
Pauvolid-Corrêa A, Komar N.Current methods for detecting Flavivirus antibodies are enzyme-linked immunosorbent assays (ELISAs) and neutralization tests, both of which require laboratories and trained staff. We evaluated the VectorTest™ West Nile Virus Antigen Assay in an inhibition platform (VecTest-inhibition assay [VIA]) as a simpler screening method for detecting antibodies for a variety of flaviviruses among a population of equines from Brazil. We found that the VIA is a field-deployable rapid method with 100% sensitivity and 64% specificity compared with blocking ELISA for the detection of group-specific Flavivir...
Fraser DG, Oaks JL, Brown WC, McGuire TC.Equine infectious anaemia virus (EIAV) is a horse lentivirus causing lifelong, persistent infection. During acute infection, CD8(+) cytotoxic T lymphocytes (CTL) are probably involved in terminating plasma viraemia. However, only a few EIAV CTL epitopes, restricted to fewer horse major histocompatibility complex (MHC) class I alleles, are known. As interferon-gamma (IFN-gamma)-secreting CD4(+), T helper 1 (Th1) lymphocytes promote CTL activity and help maintain memory CTL, identifying broadly recognized EIAV Th1 epitopes would contribute significantly to vaccine strategies seeking to promote s...
Zientara S, Sailleau C, Moulay S, Wade-Evans A, Cruciere C.The development of a coupled reverse transcriptase-polymerase chain reaction assay (RT-PCR) is described for the detection of African horse sickness virus (AHSV) double-stranded RNA. Genome segments 7 and 10 were chosen as target templates for primers selected for use in the RT-PCR. Using these AHSV-specific primers all 9 serotypes were detectable. The sensitivity and specificity of the RT-PCR results were compared to those obtained by competition ELISA.
Ciupe SM, Schwartz EJ.We develop a mathematical model for the interaction between two competing equine infectious anemia virus strains and neutralizing antibodies. We predict that elimination of one or both virus strains depends on the initial antibody levels, the strength of antibody mediated neutralization, and the persistence of antibody over time. We further show that the ability of a subdominant, neutralization resistant virus to dominate the infection transiently or permanently is dependent on the antibody-mediated neutralization effect. Finally, we determine conditions for persistence of both virus strains. ...
Dunowska M, Meers J, Johnson RD, Wilks CR.Representational difference analysis (RDA) was used to compare gene expression in equine mononuclear cells either infected with equine herpesvirus-2 (EHV-2) or adsorbed with inactivated EHV-2. Seven clones identified in non-infected cells after three rounds of selective subtraction and enrichment for differentially expressed genes contained sequences homologous to equine monocyte chemoattractant protein 1 (MCP-1). This suggested that EHV-2 may down-regulate MCP-1 transcription in infected cells. These findings correlate well with similar findings described for human cytomegalovirus and support...
Zhang X, Wang Y, Liang H, Wei L, Xiang W, Shen R, Shao Y.The equine infectious anemia virus (EIAV) donkey-leukocyte attenuated vaccine (DLV) has been used to protect against equine infectious anaemia (EIA) disease for several decades in China. The attenuated mechanism and immunological protective mechanisms remain to be elucidated. To identify responses that correlate with the protection against disease, we immunized horses with DLV, followed by challenge with an EIAV wild-type strain LN. All vaccinated horses were asymptomatic and had a low level of virus replication (<10 copies ml-1). The expression level of cytokines including gamma interferon...
Kleiboeker SB, Loiacono CM, Rottinghaus A, Pue HL, Johnson GC.The North American West Nile virus (WNV) epizootic, which began in 1999, has caused significant morbidity and mortality in horses. Because experimental infection has failed to consistently produce encephalitis in inoculated horses, investigation of naturally occurring cases was used to optimize strategies for diagnosis of this disease. Although WNV RNA could be detected by reverse transcriptase-polymerase chain reaction (RT-PCR) performed on whole blood collected from both clinically affected horses and unaffected herdmates, the diagnostic sensitivity of this approach was low compared with IgM...
Lee E, Kim EJ, Shin YK, Song JY.The avian influenza A virus causes respiratory infections in animal species. It can undergo genomic recombination with newly obtained genetic material through an interspecies transmission. However, the process is an unpredictable event, making it difficult to predict the emergence of a new pandemic virus and distinguish its origin, especially when the virus is the result of multiple infections. Therefore, identifying a novel influenza is entirely dependent on sequencing its whole genome. Occasionally, however, it can be time-consuming, costly, and labor-intensive when sequencing many influenza...
Information on equine infectious anaemia (EIA) in mules, including those with an equivocal reaction in agar gel immunodiffusion test (AGIDT), is scarce. For this, a study was conducted to evaluate the clinical, viral loads and pathological findings of two groups of naturally infected asymptomatic mules, respectively with a negative/equivocal and positive AGIDT reactivity, which were subjected to pharmacological immune suppression (IS). A non-infected control was included in the study that remained negative during the observation period. Throughout the whole study, even repeated episodes of rec...
Cursino AE, Lima MT, Nogueira MF, de Aguiar DM, Franco Luiz APM, Alves PA, Araujo Junior JP, Kroon EG.The aetiological agent of equine infectious anaemia (EIA) is the retrovirus equine infectious anemia virus (EIAV) that infects all members of the Equidae family. The EIA is widely disseminated in the Brazilian territory with a high seroprevalence in the Brazilian Pantanal and is mainly diagnosed using agar gel immunodiffusion (AGID). There are few complete EIAV genome sequences available in GenBank, which had an impact on molecular detection studies. In this study, we conducted molecular detection and sequencing of EIAV proviral DNA from Brazilian horses. We analysed the genomic region from ex...
Okada A, Suganuma S, Badr Y, Omatsu T, Mizutani T, Ohya K, Fukushi H.VP22 is a major tegument protein of equine herpesvirus type 1 (EHV-1). In the present study, we examined functions of VP22 in EHV-1 replication by viral protein expression analyses in cells infected with the VP22-deficient virus. The expressions of several viral proteins in the cells infected with the VP22-deficient virus were lower than those in the cells infected with the parent virus. One of the weakly expressed proteins was identified as ICP4, which is a major regulatory protein encoded by an immediate early gene of EHV-1. A real-time PCR analysis showed that the mRNA expression of ICP4 wa...
Gregory CR, Latimer KS, Niagro FD, Campagnoli RP, Steffens WL, Ritchie BW.Eastern equine encephalomyelitis (F.EE) virus was detected in infected formalin-fixed horse and emu tissues and in infected chicken embryo fibroblasts. Results of in situ hybridization using a digoxigenin-labeled 40-base DNA probe complementary to a conserved region of the EEE virus RNA compared favorably with results of both virus isolation and serum neutralization tests. This technique may be useful for diagnosis of EEE virus infection in various animal species, especially when fresh tissues are not available for analysis, and also will provide a means for studying the involvement of alphavi...
Hornyák A, Bakonyi T, Tekes G, Szeredi L, Rusvai M.The authors determined partial nucleic sequences of the variable regions of open-reading frame (ORF5) from 151 nucleotide to 668 nucleotide and deduced amino acid sequences of 518 nucleotide respectively of 20 equine arteritis virus (EAV) isolates. About 19 Hungarian and one Austrian EAV strains were subjected to sequence analysis, the further data of 20 EAV strains: six North American and 14 European were obtained from the GenBank. Comparative sequence analysis of the Hungarian EAV strains indicated that among the three variable regions the first has been affected mostly by point mutations. G...
Alshahrani SH, Alameri AA, Kahar F, Alexis Ramírez-Coronel A, Fadhel Obaid R, Alsaikhan F, Zabibah RS, Qasim QA, Altalbawy FMA, Fakri Mustafa Y....Recently in vivo and in vitro studies have provided evidence establishing the significance of microRNAs (miRNAs) in both physiological and pathological conditions. In this regard, the role of miRNA-128 (miR-128) in health and diseases has been found, and its critical regulatory role in the context of some viral diseases has been recently identified. For instance, it has been found that miR-128 can serve as an antiviral mediator and significantly limit the replication and dissemination of human immunodeficiency virus type 1 (HIV-1). Besides, it has been noted that poliovirus receptor-related 4 ...
Zheng YH, Sentsui H, Sugita M, Nakaya T, Kishi M, Hagiwara K, Inoshima Y, Ishihara C, Kono Y, Lu JL, Ikuta K.An attenuated equine infectious anemia virus (EIAV), V26, was previously prepared by 50 passages of the Japanese virulent strain V70 in primary horse macrophage culture. The horses inoculated with this V26 virus were shown to raise neutralizing antibodies against V70 without any viremia. Here, we investigated the in vitro and in vivo replication ability of V26. Comparison of the long-terminal repeat (LTR) sequences between V26 and V70 revealed a large insertion within the LTR U3 hypervariable region of V26. V26 with the mutation in the LTR showed much higher promoter activity in vitro than V70...
Saman E, Breugelmans K, Heyndrickx L, Merregaert J.The genome of equine infectious anemia virus (EIAV) contains several small open reading frames (ORFs), the importance of which in the development of the virus is not clear. We investigated the possibility that the largest of these ORFs (ORF S3) is expressed during the course of the viral infection. The ORF S3 information was expressed in Escherichia coli, and the antigen was used to raise monospecific antiserum. A 20-kDa protein expressed in cells producing EIAV was identified as the gene product of ORF S3. Furthermore, sera from EIAV-infected animals specifically recognized this protein, indi...
Turki I, Hammami A, Kharmachi H, Mousli M.Human and equine rabies immunoglobulins are currently available for passive immunization against rabies. However, these are hampered by the limited supply and some drawbacks. Advances in antibody engineering have led to overcome issues of clinical applications and to improve the protective efficacy. In the present study, we report the generation of a trivalent single-chain Fv (scFv50AD1-Fd), that recognizes the rabies virus glycoprotein, genetically fused to the trimerization domain of the bacteriophage T4 fibritin, termed 'foldon' (Fd). scFv50AD1-Fd was expressed as soluble recombinant protei...
