Subsequently, it was demonstrated that delNSs SFTSV virulence could be restored by removing the type II IFN (IFNɣ) response, suggesting that IFNɣ is critical for controlling delNSs SFTSV infection, and that NSs can inhibit the action of the IFNɣ pathway or downstream IFNɣ-stimulated genes to confer virulence, hinting at another unexplored role for SFTSV NSs in viral pathogenesis that requires future investigation. This evidence concerns the gene IFNA1 and infection.