(A) A549 cells were pre-treated with the UGCG inhibitor D,L-threo-PDMP for 24 hours before infection with rVSV-SFTSV. Drug was kept in the media throughout the infection. Ten hours post-infection cells were harvested, immunostained for VSV M, and analyzed by flow cytometry. Mean ± S.E.M. for 3 independent experiments. (B) A549 cells were pre-treated with the UGCG inhibitor N-butyldeoxynojirimycin-HCl (NB-DNJ) for 24, 48, or 72 hours before infection with rVSV-SFTSV. Drug was kept in the media throughout the infection. Ten hours post-infection, cells were harvested, immunostained for VSV M, and analyzed by flow cytometry. Mean ± S.E.M. for 3 independent experiments. (C,D) A549 cells were pre-treated with NB-DNJ (C) or N-(n-Butyl) deoxygalactonojirimycin (NB-DGJ) (D) for 48 hours before infection with rVSV-SFTSV, VSV, SV40, or RVFV. Drug was kept in the media throughout infection. Ten hours (rVSV-SFTSV, VSV, RVFV) or 24 hours (SV40) post-infection, cells were harvested, immunostained for viral antigen, and analyzed by flow cytometry. Mean ± S.E.M. for 3 independent experiments. **** p<0.0001 using Student’s t-test with Bonferroni correction.