African horsesickness virus serotyping and identification of multiple co-infecting serotypes with a single genome segment 2 RT-PCR amplification and reverse line blot hybridization.

This study presents a quick and efficient procedure for identifying the specific serotype of African horsesickness virus (AHSV), a task vital for selecting the appropriate vaccine during an outbreak. This one-day method can scan for multiple serotypes at once and even detect the virus directly from infected horse tissues.

Introduction

• The African horsesickness virus (AHSV) is a contagious and sometimes lethal disease that affects horses. Its control relies heavily on the identification of the AHSV serotype, as different types require different vaccines.
• Traditionally, the serotyping methods have been laborious and lengthy. This study introduces a one-day serotyping procedure that can identify multiple serotypes in a single assay.

Methodology

• This novel process involves amplifying the same region of genome segment 2 of all nine AHSV serotypes in a single RT-PCR reaction.
• The researchers designed a universal primer set that could amplify a particular section of the AHSV genome from all nine serotypes. They then created serotype-specific probes using dsRNA from infected tissue cultures or organ samples.
• These probes were then used to detect the presence of specific serotypes by hybridizing with immobilized AHSV genome cDNA in a checkerboard reverse line blot format.

Results

• This method proved successful in accurately identifying all nine reference AHSV serotypes and several vaccine and field strains isolated over decades.
• The entire process can complete within a day, dramatically reducing the time needed for serotyping.
• The sensitivity of the method is such that it can obtain enough information from just 1pg dsRNA to identify the AHSV serotype in the lung and spleen tissue samples taken from infected horses directly.

Conclusion

• This study presents a reliable, rapid, and efficient serotyping procedure that can aid in the timely control of AHS outbreaks.
• By quickly identifying the specific serotype or types present in an outbreak, this method can facilitate the selection of the appropriate vaccine, crucial for preventing the disease’s spread in both endemic and non-endemic regions.