Recovery of infectious Oz virus from cloned cDNA

Oz virus (OZV) is a tick-borne, six-segmented, negative-strand RNA virus in the genus Thogotovirus, family Orthomyxoviridae. A fatal human infection was reported in Japan in 2023. In this study, we established a reverse genetics system to generate infectious recombinant OZV. Six plasmids encoding the full-length OZV genome segments under a murine RNA polymerase I promoter, together with four plasmids expressing viral proteins essential for polymerase activity, were co-transfected into murine cells. This approach enabled efficient recovery of infectious OZV. The recovered recombinant virus exhibited replication kinetics comparable to wild-type OZV. This system provides a platform for molecular studies of OZV.