Recovery of Infectious Oz Virus From Cloned cDNA

This study established a reverse genetics system for Oz virus (OZV), a recently identified tick-borne orthomyxovirus associated with a fatal human case in Japan. The authors constructed six plasmids encoding the full-length viral genome segments along with four helper plasmids expressing essential polymerase proteins (NP, PA, PB1, and PB2), and co-transfected them into BHK/T7-9 cells to recover infectious virus. They successfully generated recombinant OZV (rOZV), which induced cytopathic effects in cocultured cells and produced high viral titers comparable to wild-type virus. Growth kinetics analysis in Vero cells showed that rOZV replicated similarly to the wild-type strain, confirming the functional integrity of the rescued virus. The study also demonstrated that all genome segments and polymerase components are required for virus recovery, and that the chosen cell system significantly improves efficiency. Overall, this work provides a robust platform for studying OZV replication, pathogenicity, and for future development of antiviral strategies.
(TMR)