Abstract:
African horse sickness virus (AHSV), a member of the Orbivirus genus in the family Reoviridae, is an
arthropod-transmitted pathogen that causes a devastating disease in horses with a mortality rate greater
than 90%. Fundamental research on AHSV and the development of safe, efficacious vaccines could benefit
greatly from an uncomplicated genetic modification method to generate recombinant AHSV. We demonstrate
that infectious AHSV can be recovered by transfection of permissive mammalian cells with transcripts
derived in vitro from purified AHSV core particles. These findings were expanded to establish a genetic
modification system for AHSV that is based on transfection of the cells with a mixture of purified core
transcripts and a synthetic T7 transcript. This approach was applied successfully to recover a directed
cross-serotype reassortant AHSV and to introduce a marker sequence into the viral genome. The ability to
manipulate the AHSV genome and engineer specific mutants will increase understanding of AHSV replication
and pathogenicity, as well as provide a tool for generating designer vaccine strains.
