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.
CASALS J.A study by hemagglutination-inhibition test showed that 19 strains of eastern equine encephalitis virus grouped themselves in two main types, which have been designated North American and South American. The former consists of ten strains from the eastern half of the United States, from Massachusetts to Florida; Jamaica, the Dominican Republic, and, subject to confirmation, Thailand. The South American type comprises nine strains from Panama, Trinidad, British Guiana, Brazil, and Argentina. The strains were isolated from different natural hosts over a period of 30 years.
Marois P, Pavilanis V, Boudreault A, Di Franco E.The clinical diagnosis of equine influenza was first based on the spectacular contagiousness of the disease, the general clinical resemblances to human influenza and the almost complete absence of complications usually observed in infectious viral arteritis, viral rhinopneumonitis or in other respiratory infections of the horses. The specific viral etiology of the epizootic was ascertained through the isolation of a type A influenza virus and further substantiated by evaluation of the immunological response of the sick horses, as demonstrated by complement fixation and hemagglutination-inhibit...
RANDALL CC, WALKER BM.Randall, Charles C. (University of Mississippi School of Medicine, Jackson) and Barbara M. Walker. Degradation of deoxyribonucleic acid and alteration of nucleic acid metabolism in suspension cultures of L-M cells infected with equine abortion virus. J. Bacteriol. 86:138-146. 1963.-Metabolic alterations in log-phase suspension cultures infected with equine abortion virus (EAV) were determined in L-M cells simultaneously labeled or prelabeled with H(3)- or C(14)-thymidine. Although infection produced an early stimulation of the uptake of labeled thymidine (TdR) into the acid-soluble fraction of...
Yeşilbağ K, Herzog S, Kennerman E, Tuncer P, Schmid S, Kaya G, Thiel HJ.Distribution of Borna disease virus (BDV) infection outside endemic areas has been studied in several countries. We examined serum samples for anti-BDV antibodies in purebred racing horses and other domestic animals in Turkey. In total serum samples of 437 animals including 282 horses, 50 sheep, 25 goats, 50 cattle, and 30 cats were tested by indirect immunofluorescence assay (IFA). Anti-BDV antibodies were detected in 4.9% of horses, 12% of sheep, 4% of goats, 14% of cattle and 6.6% of cats. No statistical difference was observed between seroprevalence in Arabic and English purebred horses fr...
Sellon DC, Russell KE, Monroe VL, Walker KM.Seven ponies were infected with the virulent wild-type Wyoming strain of equine infectious anaemia virus (EIAV). Infection status was monitored by serum reverse transcriptase activity, rectal temperature, and complete blood count. Preinfection serum and serum obtained during the initial febrile episode following infection were assayed for interleukin 6 (IL-6) activity. Postinfection IL-6 activity was significantly increased as compared to preinfection values. The magnitude of increase in IL-6 was positively correlated with reverse transcriptase activity (an indirect measure of viraemia) but wa...
Boudreault A, Boulay G, Marois P, Pavilanis V.Live human and equine influenza virus strains modified by serial passage on allantois-on-shell system (AOS) in the presence of normal horse serum were administered orally or intranasally to volunteers or horses. Mostly mild clinical short-lasting reactions, replication in nasal mucosae, transmission to placebo recipients and significant local or circulating antibody rises were observed following administration to volunteers of strains modified by five or less serial passages on AOS in the presence of normal horse serum (NHS). Milder clinical reactions, no replication, no viral transmission and...
Zaleska M, Anusz K, Winnicka A, Kita J.Twelve horses, all of them 10 years old, were vaccinated intramuscularly on 0 and 28 days of the experiment with inactivated vaccine containing only antigens of A-equi-2/Miami/63. Another three unvaccinated horses, each at the age of 10 years, were the negative control group. One, ten-year-old horse was vaccinated with commercial inactivated vaccine containing both antigens of A-equi-2/Miami/63 as well as A-equi-1/Praha/56 as positive control. Three horses were challenged intranasally with homotypic strain of Miami/63, while six other were challenged with heterotypic strains--three with Suffol...
Voss JL, Pickett BW.Haemospermia caused infertility in the stallion and frequently results from a urethritis in the area of the ejaculatory ducts. Urethroscopic examination, urethrography, bacterial and viral cultures, biopsy, surgery of the urethra and histocytological examination should be used for diagnosis and it is essential that the exact cause and location of the haemorrhage be known before treatment is initiated. Optimal treatment includes sexual rest and appropriate antibiotics used systemically in conjunction with local medication of the urethra. Cauterization of the urethra with silver nitrate solution...
Liu Q, Yu YY, Wang HY.Increasing evidence suggests that DNA methylation has key roles in the replication of retroviruses, including lentiviruses, and pathogenesis of diseases. However, the precise characteristics of CpG islands are not known for many retroviruses. In this study, we compared the distribution of CpG islands among strains of equine infectious anemia virus (EIAV), a lentivirus in the family Retroviridae and a model for HIV research. We identified CpG islands in 32 full-length EIAV genomic sequences obtained from the GenBank database using MethPrimer. Only one CpG island, from 100 to 120 bp, was identi...
Yu YY, Xu MS, Liang H, Wang HY, Yu CQ, Liu Q.Despite over 40 years of research on the human immunodeficiency virus type 1 (HIV-1) vaccine, we still lack a considerable progress. Equine infectious anemia virus (EIAV) is a lentivirus in the Retroviridae family, akin to HIV-1 in genome structure and antigenicity. EIA is an important infectious disease in equids, characterized by anemia, persistent infection, and repeated fevers. The EIAV attenuated vaccine in China is the only lentiviral vaccine used on a large scale. Elucidating the mechanism of waning and induction of protective immunity from this attenuated vaccine strain will provide a ...
Pelegrino JL, Vázquez S, Morier L, Castillo A, Guzmán MG, Kourí G.We present the results attained in the identification of Eastern equine encephalomyelitis virus isolations in Vero and XL-2 cell systems, using a double-antibody ELISA technique and the indirect immunofluorescence method. The results attained through these two techniques coincided by 100% with identification through neutralization. With the former, the virus was detected within 6-8 hours after inoculation. Better results were attained with XL-2 cells.
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...
Sergeant ES, Cowled BD, Bingham P.This observational study was undertaken in order to evaluate the diagnostic specificity of the blocking enzyme-linked immunosorbent assay (bELISA) for serum antibodies to influenza A virus nucleoprotein during the equine influenza (EI) outbreak response in New South Wales, Australia, in 2007. Using data collected during the outbreak response, bELISA testing data were collated for assumed uninfected horses from areas where EI infection was never recorded. Diagnostic specificity of the bELISA used during the EI response was high, but varied significantly between some regions, although the reason...
Zientara S, Sailleau C.The authors briefly review the clinical forms of equine rhinopneumonitis and indicate changes in the nomenclature of equine herpesviral infections. The value of restriction profiles for epidemiological studies is described, taking as an example the strains of virus isolated in France. A technique is given for preparing molecular probes, as well as the application of these probes in direct diagnosis from biological specimens.
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...
Miszczak F, Pronost S, Vabret A.Equine arteritis virus (EAV) is the causative agent of equine viral arteritis, a disease observed only in equids. EAV is the prototype of the family Arteriviridæ within the order Nidovirales. EAV is an enveloped, positive-sense, single-stranded RNA virus with a considerable variation in the genome as observed in other RNA viruses. During natural infections, EAV may cause abortion and persistent subclinical infections in stallions which can shed the virus in the semen for years, or even lifetime. Chronically infected stallions represent the natural reservoir of the virus. They ensure the persi...
Dai CM, Zhang XY, Zhang RR, Shao YM, Shen RX.To develop a novel vaccine candidate of Equine infectious anemia virus(EIAV). Methods: env genes of EIAV Chinese donkey leukocyte attenuated strain (EIAV DLV) and its parental virus strain (EIAV LN) were expressed using the BAC-To-BAC system, and Env proteins were confirmed by SDS-PAGE and Western blot. BALB/c mice were immunized with recombinant vaccinia viruses containing env genes of EIAV alone or boosted with Env proteins expressed by recombinant baculovirus. Both protective humoral and cellular immune responses were detected. Results: Recombinant baculovirus could express complete Env pro...
Starick E.A reverse transcription-polymerase chain reaction (RT-PCR) assay using four different primer pairs for the detection of equine arteritis virus (EAV) RNA in semen and tissue samples was evaluated. A fragment encoding the leader sequence of the EAV genome was most successfully amplified. The specificity and sensitivity of RT-PCR was assessed by virus isolation in cell culture, restriction analysis, dot blot hybridisation and nested PCR. To this end, 23 semen samples from seropositive stallions and 11 tissue samples from 4 aborted foals were tested. Compared to the virus isolation test in cell cu...
Bannai H, Nemoto M, Tsujimura K, Yamanaka T, Kokado H, Kondo T.In order to establish an efficient system for serological diagnosis of equine viral arteritis in Japan, we compared enzyme-linked immunosorbent assays (ELISAs) provided by two manufacturers (Nisseiken Co., Ltd., Tokyo, Japan, and VMRD Inc., Pullman, WA, U.S.A.) by testing a series of horse sera. The results revealed that 159 of 160 virus-neutralizing (VN) antibody-positive serum samples were positive in both the Nisseiken-ELISA and VMRD-ELISA. Of the VN-negative sera (n=157), 134 and 154 samples were negative in the Nisseiken-ELISA and VMRD-ELISA, respectively. Sensitivity was 99.4% for both t...
Reubel GH, Studdert MJ.We report the first nucleotide sequence data on equine adenovirus 2 (EAdV2) which corroborate on the molecular level that EAdV2 is distinct from equine adenovirus 1 (EAdV1). Based on sequence homology with Eadv1 the hexon gene of Eadv2 was identified. HindIII restriction fragments containing the hexon and eight other viral genes were cloned into the plasmid pUC19 and the nucleotide sequence of the hexon and the 23K proteinase genes completely determined. Amino acid (aa) comparison of sequence fragments with published adenovirus (AdV) proteins identified the genes for the E1B/19K, IVa2, DNA pol...
Klug E, Sieme H.The equine virus arteritis (EVA) consistently epidemically varying throughout the different breeds of the horse breeding countries is up to now only of lower significance by means of the typical clinical manifestation as well as an abortion causing factor. The susceptibility of the sexual mature stallions against the equine arteritis virus (EAV) causes different infection response which may lead to some restrictions in their use in natural breeding especially in the artificial insemination. In a certain not precisely predictable part of the stallion population EAV infection will cause a transi...
Song JW, Na KS, Tae SH, Kim YK.During the last two decades, Borna disease virus (BDV) has received much attention as a possible zoonotic agent, particularly as a cause of psychiatric disease. Although several studies have shown that BDV is present in Asia, BDV has not been detected in Korea. This study was designed to further investigate the presence of BDV infection in Korea. Methods: Blood samples were taken from 39 race horses and 48 jockeys. Antibody to BDV was detected by indirect immunofluorescence antibody test and RNA of BDV by real time reverse transcriptase PCR (rRT-PCR). Results: No evidence of BDV was detected i...
Liang CZ, Cao RB, Wei JC, Zhu LH, Chen PY.According to the antigenic analysis of equine arteritis virus (EAV) GL protein, one pair of primers were designed, with which the gene fragment coding the high antigenic domain of EAV GL protein was amplified from the EAV genome. The cloned gene was digested with BamH I and Xho I and then inserted into pET-32a and resulted pET-GL1. The pET-GL1 was transformed into the host cell BL21(DE3) and the expression was optimized including cultivation temperature and concentration of IPTG. The aim protein was highly expressed and the obtained recombinant protein manifested well reactiongenicity as was c...
Chung CJ, Grimm AL, Wilson CL, Balasuriya UB, Chung G, Timoney PJ, Bandaranayaka-Mudiyanselage CB, Lee SS, McGuire TC.In an effort to improve a competitive blocking enzyme-linked immunosorbent assay (cELISA) for antibody detection to Equine arteritis virus (EAV), antigen purified by anion-exchange membrane chromatography capsule (AEC) was evaluated. Virus purification by the AEC method was rapid and easily scalable. A comparison was made between virus purified by the AEC method with that obtained by differential centrifugation based on the following: 1) the relative purity and quality of EAV glycoprotein 5 (GP5) containing the epitope defined by monoclonal antibody 17B7, and 2) the relative sensitivity of a c...
Mumford EL, McCluskey BJ, Traub-Dargatz JL, Schmitt BJ, Salman MD.To determine potential risk factors for vesicular stomatitis (VS) in Colorado livestock in 1995 and evaluate VS virus (VSV) exposure of Colorado livestock in 1996. Methods: Retrospective case-control study of VS risk factors and seroprevalence evaluation. Methods: Premises included 52 that had VS-positive animals and 33 that did not have VS-positive animals during the 1995 epidemic, and 8 in the vicinity of premises that had VS-positive animals during the 1995 epidemic. Methods: Layout and management data for premises were collected during site visits in 1996. Signalment and management data we...
Black WD, Hartley CA, Ficorilli NP, Studdert MJ.Equine rhinitis B virus (ERBV), genus Erbovirus, is most closely related to the Cardiovirus genus in the family Picornaviridae. The structural proteins (VP1-4) of erboviruses are not well described, but are predicted by sequence to be 35, 29, 26 and 7 kDa. Methods for the purification of cardioviruses (polyethylene glycol, trypsin treatment) were used to characterise the structural proteins of ERBV1. Only one of the virus proteins detected was an expected molecular mass, and this 26 kDa protein was identified as VP3 by N-terminal amino acid sequencing. N-terminal sequencing of the 56 and a 29 ...
Bannai H, Tsujimura K, Kondo T, Nemoto M, Yamanaka T, Sugiura T, Maeda K, Matsumura T.An immunoglobulin G (IgG) subclass response against equine herpesvirus type 1 (EHV-1) infection was investigated in horses that were naïve to EHV-1/4 and those that had previously been exposed to EHV-4. The IgG subclass response was determined by an ELISA using EHV-1-specific recombinant gG protein as an antigen. In most horses naïve to EHV-1/4, IgGa, IgGb, and IgG(T) were induced after experimental infection with EHV-1. In contrast, a subclass response dominated by IgGa and IgGb, with no apparent increase in IgG(T), was observed after EHV-1 infection in horses previously infected with EHV-4...
Hallauer C.1. Equine infectious anemia (EIA) is an immunologically-medicated disease. Immune complexes formed in blood and tissues are responsible for most symptoms and lesions (anemia, splenomegaly, lymphadenopathy, glomerulonephritis, etc.). In addition, a state of cellular hypersensitivity of the delayed type is involved in the pathogenesis. 2. Periodical attacks of pyrexia and clinical illness in the presence of immunity are caused by antigenically-modified variants of virus. By means of immunosuppressive treatments similar relapses of fever associated with the appearance of new virus variants can be...
León B, González G, Nicoli A, Rojas A, Pizio AD, Ramirez-Carvajal L, Jimenez C.Venezuelan Equine Encephalitis virus (VEEV) is an arboviral pathogen in tropical America that causes lethal encephalitis in horses and humans. VEEV is classified into six subtypes (I to VI). Subtype I viruses are divided into epizootic (IAB and IC) and endemic strains (ID and IE) that can produce outbreaks or sporadic diseases, respectively. The objective of this study was to reconstruct the phylogeny and the molecular clock of sequences of VEEV subtype I complex and identify mutations within sequences belonging to epizootic or enzootic subtypes focusing on a sequence isolated from a mare in C...
Mashin VV, Sergeev AN, Martynova NN, Oganov MD, Sergeev AA, Kataeva VV, Zagidullin NV.Equine blood plasma/serum and intermediates must be monitored for the presence of live viruses pathogenic in humans during production of equine immunoglobulins. Information concerning low-cost and simple methods for the detection of live horse viruses pathogenic and non-pathogenic to humans was gained using data of modern domestic and foreign literature. These methods are based on cultivation of these viruses on sensitive biosystems. The presented information can be used to set up blood plasma/serum control of horses at different stages of immunoglobulin production, i.e., when taking blood fro...
Ma Y.Equine rotavirus (ERV) strain L338 (G13P[18]) has a unique G and P genotype. However, the evolutionary relationship of L338 with other ERVs is still unknown. Here whole genome analysis of the L338 ERV strain was independently performed. Its genotype constellations were determined as G13-P[18]-I6-R9-C9-M6-A6-N9-T12-E14-H11, confirming previous genotype assignments. The L338 strain only shared the P[18] and I6 genotypes with other ERVs. The nucleotide sequences of the other 9 RNA segments were different from those of cogent genes of all other group A rotavirus (RVA) strains including ERVs and fo...
Schultheiss PC, Collins JK, Carman J.An indirect immunoperoxidase (IP) procedure using the avidin-biotin-peroxidase complex detection technique was developed to detect viral equine herpesvirus-1 (EHV-1) antigen in formalin-fixed paraffin-embedded tissues from aborted equine fetuses. The procedure was applied to liver, lung, and other tissues from 20 cases of confirmed or suspected EHV-1-induced abortions. Specific staining was observed in tissue sections from EHV-1-infected fetuses. Positive IP staining was present in tissues of 7 cases that were also positive by fluorescent antibody (FA) and virus isolation (VI) and that had typ...
Kalemkerian PB, Metz GE, Peral-Garcia P, Echeverria MG, Giovambattista G, Díaz S.Polymorphisms at Major Histocompatibility Complex (MHC) genes have been associated with resistance/susceptibility to infectious diseases in domestic animals. The aim of this investigation was to evaluate whether polymorphisms of the DRA gene the Equine Lymphocyte Antigen is associated with susceptibility to Equine Arteritis Virus (EAV) infection in horses in Argentina. The equine DRA gene was screened for polymorphisms using Pyrosequencing® Technology which allowed the detection of three ELA-DRA exon 2 alleles. Neither allele frequencies nor genotypic differentiation exhibited any statistical...
