Development of a HiBiT-tagged reporter Akabane virus and its application in antiviral drug screening.

Akabane virus (AKAV), an arthropod-borne pathogen causing severe reproductive failure in ruminants, poses a major threat to livestock industry. Given the lack of vaccines and antiviral drugs against AKAV, the development of rapid antiviral screening tools is urgently needed. To establish a quantifiable platform for AKAV research, we constructed a reporter virus (rAKAV-L-HiBiT) by inserting the 11-amino-acid HiBiT subunit of NanoLuc luciferase into the C-terminus of the L protein. The recombinant virus was characterized for growth kinetics, genetic stability, and luciferase activity. rAKAV-L-HiBiT exhibited a similar replication profile to wild-type AKAV and maintained stable luciferase activity over 10 passages in vitro. Crucially, luciferase activity of rAKAV-L-HiBiT showed a strong positive correlation with viral loads (r > 0.99), validating its utility as a convenient and rapid platform for AKAV quantification. Subsequently, we applied this platform to neutralization and antiviral compound screening assays and Remdesivir was identified as a potent inhibitor of AKAV. Taken together, our study presents rAKAV-L-HiBiT as a reliable tool for rapid antiviral drug discovery and neutralization testing.