Figure 5.

Analysis of the in vivo virulence of NSs mutant viruses. Six-week-old BALB/c mice were intraperitoneally inoculated with 5 PFU of rWT, rT1, rT3, rT4 or r△NSs-eGFP, or inoculated with PBS as a control. The mice in each group (n = 10) were observed for 7 days on a daily basis after infection. The mice survival rates (A) and body weights (B) were evaluated. Error bars represent standard deviation. Comparison of survival curves between mutants and rWT was analyzed by Log-rank (Mantel–Cox) testing. *** p < 0.001, ** p < 0.01. The p values were calculated based on comparison with the rWT. (C) Liver and spleen samples were harvested from infected mice 5 days post infection. RNA was extracted from tissue homogenates using TRIzol Reagent. RNA viral load in liver and spleen were determined by quantitative RT-PCR.