The equine arteritis virus isolate from the 2010 Argentinian outbreak.

The research involved identifying and analyzing a new strain of the equine arteritis virus (EAV) that was present during the 2010 outbreak in Argentina. The researchers concluded that monitoring infected stallions and their cryopreserved semen is essential to limit the spread and persistence of EAV in horse populations worldwide.

Methodology Used in the Research

In this research study, the authors used several scientific procedures and techniques:

• The authors obtained a semen sample from an infected stallion that was part of the 2010 EAV outbreak.
• The virus within the sample was identified using an immunofluorescence test which engaged a polyclonal antibody.
• A method known as reverse-transcription polymerase chain reaction (RT-PCR) was used to amplify a region of the GP5 gene within the virus. Specific primers, termed GL105F and GL673R, were used in this process.
• After the RT-PCR process, PCR products were purified and sequenced. Both strands of the virus were identified using a MegaBACE™1000 with inner primers CR2 and EAV32.
• To understand the genetic lineage and evolution of this virus strain, a phylogenetic dataset was built. This consisted of previously reported sequences from Argentinian strains, as well as selected sequences from GenBank, a worldwide genetic sequence repository.
• The evolutionary genetic framework (tree) was constructed using molecular evolutionary genetic analysis (MEGA) and further validated by bootstrap analyses.
• To predict possible N-glycosylation in GP5 sequences – a process critical for protein function and stability – the NetNGlyc server analysis online tool of the Technical University of Denmark was utilised.

Key Findings of the Study

The study provided some significant findings:

• The phylogenetic analysis revealed that the new strain (referred to as GLD-LP-ARG) is part of the EU-1 European group. However, this strain falls within a different branch, implying some evolutionary differences.
• The new strain was found to have very high nucleotide identities with two other strains: 99% with the Strain Al1, and 98.1% with the Belgian strain 08P178.
• The authors identified persistently infected stallions and their cryopreserved semen as a significant reservoir for EAV. This allows the EAV virus to continue spreading within global horse populations.
• The researchers recommended close monitoring of persistently infected stallions and their semen, suggesting RT-PCR or test mating methods comply with national regulations.