Molecular characterisation of equid alphaherpesvirus 1 strains isolated from aborted fetuses in Poland

Natalia Anna Jackulak,Anna Karolina Matczuk,Barbara Anna Bażanów,Małgorzata Skarbek

doi:10.1186/s12985-018-1093-5

Natalia Anna Jackulak, Anna Karolina Matczuk + Show 2 more

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https://doi.org/10.1186/s12985-018-1093-5

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Abstract

BackgroundEquid alphaherpesvirus 1 (EHV-1) is one of the main infectious causative agents of abortion in mares and can also be associated with stillbirth, neonatal foal death, rhinopneumonitis in young horses and a neurological disorder called equine herpesvirus myeloencephalopathy (EHM). The neuropathogenicity of the virus was shown to be significantly higher in EHV-1 strains that carry a single nucleotide point (SNP) mutation in the ORF30, which encodes a catalytic subunit of viral DNA polymerase (ORF30 D752). Another gene, ORF68 is frequently used for phylogenetic analysis of EHV-1.Methods27 EHV-1 strains isolated from aborted equine fetuses in Poland, collected between 1993 and 2017, were subjected to PCR targeting the open reading frames (ORFs) 30 and 68 of the EHV-1 genome. PCR products obtained were sequenced and SNPs were analyzed and compared to sequences available in GenBank.ResultsNone of the analyzed sequences belonged to the ORF30 D752neuropathogenic genotype: all EHV-1 belonged to the non-neuropathogenic variant N752. On the basis of ORF68 sequences, the majority of EHV-1 sequences (76.9%) cannot be assigned to any of the known groups; only six sequences (23.1%) clustered within groups II and IV.ConclusionsEHV-1 strains obtained from abortion cases belong to the non-neuropathogenic genotype. Many EHV-1 ORF68 sequences have similar SNPs to those already described in Poland, but a clear geographical distribution was not observed. A single particular ORF68 sequence type was observed in strains isolated from 2001 onwards.

Highlights

Equid alphaherpesvirus 1 (EHV-1) is one of the main infectious causative agents of abortion in mares and can be associated with stillbirth, neonatal foal death, rhinopneumonitis in young horses and a neurological disorder called equine herpesvirus myeloencephalopathy (EHM)
The mechanism of EHM development is not well understood, the potential to cause neuropathogenicity is significantly higher in EHV-1 strains that carry a single nucleotide point (SNP) mutation in the ORF30, which encodes a catalytic subunit of viral DNA polymerase [12]
Guanidine was not observed in ORF30, meaning that all 27 strains isolated from aborted equine fetuses in Poland between 1993 and 2017 belonged to the non-neuropathogenic variant (N752) of EHV-1

Summary

Introduction

Equid alphaherpesvirus 1 (EHV-1) is one of the main infectious causative agents of abortion in mares and can be associated with stillbirth, neonatal foal death, rhinopneumonitis in young horses and a neurological disorder called equine herpesvirus myeloencephalopathy (EHM). The neuropathogenicity of the virus was shown to be significantly higher in EHV-1 strains that carry a single nucleotide point (SNP) mutation in the ORF30, which encodes a catalytic subunit of viral DNA polymerase (ORF30 D752). The mechanism of EHM development is not well understood, the potential to cause neuropathogenicity is significantly higher in EHV-1 strains that carry a single nucleotide point (SNP) mutation in the ORF30, which encodes a catalytic subunit of viral DNA polymerase [12]. The A to G mutation in nucleotide (nt) position 2254 of the virus genome causes substitution of asparagine (N) by aspartic acid (D) at amino acid position 752

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