Emergence of novel equine arteritis virus (EAV) variants during persistent infection in the stallion: origin of the 2007 French EAV outbreak was linked to an EAV strain present in the semen of a persistently infected carrier stallion.

The study investigates the connection between a persistent infection in a carrier stallion and the outbreak of equine viral arteritis (EVA) in France in 2007. The researchers discovered that the strain of EAV in the stallion evolved over several years, producing new variants that were genetically similar to the strain responsible for the outbreak.

Research Purpose and Methodology

• The primary purpose of this research was to investigate the possible origin of the equine arteritis virus (EAV) outbreak that occurred in Normandy, France in 2007. To do this, the researchers conducted a detailed analysis of the EAV genome.
• The researchers utilized nucleotide sequence analysis of a reference strain (F27) isolated from the lung of a foal. Molecular hallmarks in specific regions of the EAV genome were identified.
• Furthermore, the team studied the evolution of the viral population in Semen samples of Stallion A, taken between the years 2000 and 2007. These samples allowed the researchers to trace the development and changes in the EAV genome over a substantial period.

Key Findings

• Through their analysis, the researchers found that the EAV genome was comprised of 12,710 nucleotides and had unique molecular hallmarks in the 5’UTR leader sequence and the ORF1a sequence encoding non-structural protein 2.
• One of the significant findings by the researchers was the evolution of the viral population in a persistently infected Stallion (referred to as Stallion A). The clones taken from this stallion showed yearly emergence of new variants of EAV, which were genetically similar to the F27 strain.
• Together, these findings confirmed the likely implication of Stallion A in the origin of the 2007 outbreak.

Implications of the Research

• The results of this study shed light on the dynamics of EAV within persistently infected hosts, adding to our understanding of how the virus evokes and spreads in equine populations.
• Moreover, these findings provide valuable insights into our understanding of how EAV transmission occurs, potentially informing better strategies to prevent and control future EAV outbreaks.
• This type of genomic research can inform the development of more effective diagnostic tools and treatments for EAV, an infectious disease that can have severe economic and health impacts on equine industries worldwide.