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

This research article explores the molecular characterisation of different strains of Equine Herpesvirus-1 (EHV-1) isolated from aborted foals in Hungary over a period of three decades, from 1977 to 2008, focusing specifically on differences in the ORF68 region of the EHV-1 genome.

Molecular Characterisation of EHV-1

• The research study is based on EHV-1, a virus known to cause substantial health issues and losses in the equine world.
• Different strains of EHV-1 have been classified based on single nucleotide polymorphisms (SNPs), slight variations in the DNA sequences of their genomes.
• Particular focus was given to variations in the ORF68 section of the EHV-1 genome – a region that has been previously found to be useful for classification purposes because it manifests significant variations in different EHV-1 strains.

Strain Classification and Analysis

• The researchers examined 35 EHV-1 strains which were all sourced from aborted equine fetuses in Hungary spanning 31 years.
• The strains were genetically typed based on a comparative analysis of the nucleotide sequences found in a polymorphic segment of the ORF68 region.
• The comparison process not only classified these strains into previously known groups but also identified variations in 12 of the studied samples, which were enough to form four new distinct groups of EHV-1 strains.

Geographic linkage and Phylogenetic Analysis

• The strains were compared to similar strains spread across different geographical regions that included Europe, America, and Australia.
• This comparative and phylogenetic analysis provided further insights into the relationship between different EHV-1 strains and their geographical distribution.

Significance and Limitations

• The researchers suggest that the emergence of new EHV-1 strain groups gives rise to a possibility that further analysis of unknown EHV-1 isolates might involve discovery of additional new groups.
• However, they also pointed out that an increase in the number of identified groups could negatively impact the efficacy of using this classification method, as it could lead to an overly complex grouping system that is harder to manage or effectively use for epidemiological investigations.