Aetiologic study on an influenza-like epidemic in horses in China.

This study explores an epidemic caused by the equine 2 influenza virus (H3N8) in China that affected approximately 30,000 horses, resulting in hundreds of deaths. The research discovered that the virus strains involved were antigenically different from the prototype strain which indicates that the virus had undergone antigenic drift.

Study Background

• The research was conducted in response to an epidemic outbreak in horses in China caused by the equine influenza virus.
• About 30,000 horses were infected during this epidemic, with hundreds reported dead; the estimated morbidity and mortality rates were approximately 81% and 2%, respectively.

Resaearch Methodology and Findings

• Researchers conducted an aetiologic study, which is a study of the causes or origins of a disease.
• The viral protein and RNA electrophoresis patterns, methods used to study the virus’s properties and behavior revealed significant findings.
• The researchers found out that the new strains of the virus isolated during this outbreak were antigenically different from the prototype strain named influenza A/eq/Miami/1/63(H3N8).

Implications of the Research

• The discrepancy found between the previous prototype strain and the new isolates suggest that the virus has undergone antigenic drift, which is a mechanism that viruses use to alter their properties and potentially become more deadly or resistant to current treatments or vaccines.
• This research implies that the representative strain of the equine 2 subtype of influenza A virus, which is commonly used for producing reference reagents, vaccines, and for serological diagnosis, may no longer be accurate due to the observed antigenic drift.
• Thus, there may be a need to adjust the representative strain to account for these changes to ensure the efficacy of future vaccines and serological diagnostics.