Genetic Characterization of Equine Herpesvirus 1 from Clinical Cases and Asymptomatic Horses in Serbia and Bosnia and Herzegovina

Equine herpesvirus 1 (EHV-1) causes considerable economic loss to the equine industry and is spread among susceptible animals during the cycles of latency and reactivation, causing rhinopneumonitis, abortion, and neurological disease. Nucleotide polymorphisms within ORF30 and ORF68 sequences of the viral genome are associated with strain neuropathogenicity and geographical origin. A total of 142 tissue and nasal swab samples from apparently healthy unvaccinated horses were examined to ascertain EHV-1 distribution, diversity, and clinical significance considering the results of virus isolation, sequence analysis, and anamnestic data. The ORF30 and ORF68 molecular study of these circulating strains and archival isolates from abortion storms aimed to contribute to the perception of strain pathogenicity and origin. EHV-1 was detected by PCR and virus isolation in 81 and 45.1% of the analyzed samples, respectively, and 82.1% of the representative samples were neuropathogenic strains. The ORF68-based grouping was restricted by the pronounced polymorphism of Balkan EHV-1 strains, and only two isolates were assigned to group 4. The cases of abortion were caused by neuropathogenic strains that also circulate within the horse population with no documented outbreaks of disease. It was evident that strain virulence is not solely accountable for the development of clinical symptoms in affected animals. Neural tissue is significant for virus latency and reactivation, considering the number of EHV-1 isolates from apparently healthy stressed horses. Special care must be taken when accommodating together immunologically naive and latently infected horses since asymptomatic carriers silently shed EHV-1.

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Molecular characterisation of the ORF68 region of equine herpesvirus-1 strains isolated from aborted fetuses in Hungary between 1977 and 2008

Acta Veterinaria Hungarica ◽

10.1556/avet.2012.015 ◽

2012 ◽

Vol 60 (1) ◽

pp. 175-187 ◽

Cited By ~ 9

Author(s):

Péter Malik ◽

Ádám Bálint ◽

Ádám Dán ◽

Vilmos Pálfi

Keyword(s):

Molecular Characterisation ◽

Equine Herpesvirus ◽

Nucleotide Polymorphisms ◽

Single Nucleotide ◽

Equine Herpesvirus 1 ◽

Special Attribute ◽

Grouping Method ◽

Herpesvirus 1 ◽

Set Up ◽

Made In

Equine herpesvirus-1 (EHV-1) can be classified into distinct groups by single nucleotide polymorphisms (SNPs) in their genomes. Only a few of these can be associated with a special attribute of the virus. Differences in the ORF30 region can determine the neuropathogenic potential, while by substitutions in the ORF68 region several strain groups can be made. In previous studies no connection was found between the neuropathogenic potential and the SNPs in ORF68, but the occurrence of members of distinct groups in different outbreaks can facilitate epidemiological investigations because the geographical distribution of a particular group is very often specific. The present study aimed at the molecular examination and grouping of 35 EHV-1 strains isolated from aborted equine fetuses in Hungary between 1977 and 2008. Genotyping was based on the comparison of nucleotide sequences of a polymorphic segment located in the ORF68 region, which had previously been found to be a useful tool for classification. After sequencing this region, the Hungarian EHV-1 isolates could be classified into seven groups. Only 23 of the 35 isolates belonged to the formerly described groups, while the SNPs of 12 isolates diverged, and four new groups could be set up. In addition, phylogenetic analysis was performed to compare the ORF68 sequences of the Hungarian strains with the sequences of isolates from Europe, America and Australia. The number of newly formed groups suggests that the further analysis of unknown EHV-1 isolates would involve the emergence of extended numbers of new groups, which can impair the usability of this grouping method.

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The Identification of Equid Herpesvirus 1 in Paraffin-Embedded Tissues from Aborted Fetuses by Polymerase Chain Reaction and Immunohistochemistry

Journal of Veterinary Diagnostic Investigation ◽

10.1177/104063879300500206 ◽

1993 ◽

Vol 5 (2) ◽

pp. 174-183 ◽

Cited By ~ 13

Author(s):

Espen Rimstad ◽

Øystein Evensen

Keyword(s):

Polymerase Chain Reaction ◽

Retrospective Studies ◽

Virus Isolation ◽

Equine Herpesvirus ◽

Chain Reaction ◽

Perfect Agreement ◽

Equine Herpesvirus 1 ◽

Herpesvirus 1 ◽

Polymerase Chain

Paraffin-embedded organ samples from 28 aborted fetuses and three foals, partly archival and partly sampled in 1991, were examined by polymerase chain reaction (PCR) and immunohistochemistry for the presence of DNA and antigens, respectively, specific for equine herpesvirus 1 (EHV- 1). Virologic examination had been performed on 23 of the aborted fetuses. DNA fragments specific for EHV-1 were identified by PCR, and EHV-1 antigens were identified in situ by immunohistochemistry, with an agreement between the methods of 94% (kappa = 0.85). Compared with virus isolation, PCR agreement was 87% (kappa 0.69), and IH agreement was 82% (kappa = 0.47). These results showed that there was moderate to almost perfect agreement among the different methods and that PCR and immunohistochemistry are powerful tools for the identification of EHV-1 in paraffin-embedded tissues. The techniques give more rapid results than virus isolation and also detect inactivated virus, which are not identified by standard virus isolation. These techniques also make retrospective studies possible.

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Infectious causes of equine respiratory disease on Ontario standardbred racetracks

Journal of Clinical Microbiology ◽

10.1128/jcm.5.3.285-289.1977 ◽

1977 ◽

Vol 5 (3) ◽

pp. 285-289

Author(s):

J Sherman ◽

J Thorsen ◽

D A Barnum ◽

W R Mitchell ◽

D G Ingram

Keyword(s):

Respiratory Disease ◽

Influenza Viruses ◽

Late Winter ◽

Equine Herpesvirus ◽

Serum Samples ◽

Equine Herpesvirus 1 ◽

Nasal Swabs ◽

Upper Respiratory ◽

Herpesvirus 1 ◽

Apparently Healthy

Upper respiratory disease has been a serious problem in Standardbred horses on racetracks in Ontario, with outbreaks occurring once or twice annually in late winter and early spring seasons. To determine the causes of these epidemics, a 3-year investigation was carried out in which nasal swabs and serum samples were obtained at intervals from apparently healthy horses and from horses suffering from upper respiratory disease. The nasal swabs were used to isolate bacteria and viruses. The serum samples were examined for the presence and level of antibodies to equine influenza viruses and equine herpesvirus 1. None of the bacteria isolated were associated with the outbreaks of disease. Equine herpesvirus 2 was isolated 72 times from both diseased and apparently healthy horses. Equine herpesvirus 1 was isolated 10 times from horses with respiratory disease, both during and between epidemics. Influenza equine/1 virus was isolated seven times and influenza equine/2 was isolated once during severe outbreaks of upper respiratory disease. Serological evidence confirmed that influenza viruses were the causes of the major epidemics, with the equine/1 strain being involved most often.

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Seroprevalence and Rate of Infection of Equine Influenza Virus (H3N8 and H7N7) and Equine Herpesvirus (1 and 4) in the Horse Population in Israel

Journal of Equine Veterinary Science ◽

10.1016/j.jevs.2014.01.012 ◽

2014 ◽

Vol 34 (6) ◽

pp. 828-832 ◽

Cited By ~ 5

Author(s):

Karin Aharonson-Raz ◽

Irit Davidson ◽

Yael Porat ◽

Amira Altory ◽

Eyal Klement ◽

...

Keyword(s):

Influenza Virus ◽

Equine Herpesvirus ◽

Equine Influenza Virus ◽

Horse Population ◽

Equine Herpesvirus 1 ◽

Equine Influenza ◽

Herpesvirus 1

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Detection of equine herpesvirus 1 DNA in a single embryo and in horse semen by polymerase chain reaction

Arquivo Brasileiro de Medicina Veterinária e Zootecnia ◽

10.1590/s0102-09352000000400002 ◽

2000 ◽

Vol 52 (4) ◽

pp. 302-306 ◽

Cited By ~ 4

Author(s):

R. Carvalho ◽

L.M.F. Passos ◽

A.M. Oliveira ◽

M. Henry ◽

A.S. Martins

Keyword(s):

Polymerase Chain Reaction ◽

Infectious Virus ◽

Virus Isolation ◽

Equine Herpesvirus ◽

Peripheral Blood Leukocytes ◽

Chain Reaction ◽

Blood Leukocytes ◽

Equine Herpesvirus 1 ◽

Herpesvirus 1 ◽

Polymerase Chain

The genome of one equine embryo and three equine semen specimens collected from a Brazilian farm were tested by polymerase chain reaction (PCR) for the presence of EHV-1 and EHV-4-specific timidine kinase (TK) sequences. The PCR detected specific EHV-1 TK gene sequences in all samples tested. The peripheral blood leukocytes (PBL) of the embryo donor mare also was amplified by EHV-1 TK primers. Infectious virus was not recovered from any specimens. The animals did not show any clinical signal of EHV-1 or EHV-4 infections. EHV-4 was not detected in the studied specimens. The results indicate that PCR was more sensitive than virus isolation in cell culture for detecting EHV-1 in semen of carrier horses.

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Antemortem detection of latent infection with neuropathogenic strains of equine herpesvirus-1 in horses

Journal of the American Veterinary Medical Association ◽

10.2460/javma.229.4.561 ◽

2006 ◽

Vol 229 (4) ◽

pp. 561-561 ◽

Cited By ~ 1

Author(s):

George P. Allen

Keyword(s):

Latent Infection ◽

Equine Herpesvirus ◽

Equine Herpesvirus 1 ◽

Herpesvirus 1

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The highly O-glycosylated glycoprotein gp2 of equine herpesvirus 1 is encoded by gene 71.

Journal of Virology ◽

10.1128/jvi.70.11.8195-8198.1996 ◽

1996 ◽

Vol 70 (11) ◽

pp. 8195-8198 ◽

Cited By ~ 8

Author(s):

J E Wellington ◽

G P Allen ◽

A A Gooley ◽

D N Love ◽

N H Packer ◽

...

Keyword(s):

Equine Herpesvirus ◽

Equine Herpesvirus 1 ◽

Herpesvirus 1

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Evaluation of the Variability of the ORF34, ORF68, and MLST Genes in EHV-1 from South Korea

Pathogens ◽

10.3390/pathogens10040425 ◽

2021 ◽

Vol 10 (4) ◽

pp. 425

Author(s):

Hyung-Woo Kang ◽

Eun-Yong Lee ◽

Kyoung-Ki Lee ◽

Mi-Kyeong Ko ◽

Ji-Young Park ◽

...

Keyword(s):

Nucleotide Sequence ◽

South Korea ◽

Molecular Level ◽

Economic Losses ◽

Equine Herpesvirus ◽

Equine Herpesvirus 1 ◽

Mlst Analysis ◽

Herpesvirus 1 ◽

First Time ◽

Group 1

Equine herpesvirus-1 (EHV-1) is an important pathogen in horses. It affects horses worldwide and causes substantial economic losses. In this study, for the first time, we characterized EHV-1 isolates from South Korea at the molecular level. We then aimed to determine the genetic divergences of these isolates by comparing them to sequences in databases. In total, 338 horse samples were collected, and 12 EHV-1 were isolated. We performed ORF30, ORF33, ORF68, and ORF34 genetic analysis and carried out multi-locus sequence typing (MLST) of 12 isolated EHV-1. All isolated viruses were confirmed as non-neuropathogenic type, showing N752 of ORF30 and highly conserved ORF33 (99.7–100%). Isolates were unclassified using ORF68 analysis because of a 118 bp deletion in nucleotide sequence 701–818. Seven EHV-1 isolates (16Q4, 19R166-1, 19R166-6, 19/10/15-2, 19/10/15-4, 19/10/18-2, 19/10/22-1) belonged to group 1, clade 10, based on ORF34 and MLST analysis. The remaining 5 EHV-1 isolates (15Q25-1, 15D59, 16Q5, 16Q40, 18D99) belonged to group 7, clade 6, based on ORF34 and MLST analysis.

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