Figure 2.

Virulence of recombinant IBVs with reduced susceptibility to NAIs. In each group, ten BALB/c mice were infected by the intranasal route with 5 × 10⁶ PFUs of each recombinant B/Phuket/3073/2013 virus. Weight loss (A) and mortality (B) were monitored throughout the experiment. At day 3 p.i., 4 mice in each group were sacrificed and their lungs were harvested to determine lung viral titers (C). Statistical analyses of weight loss at day 4 (indicated in the legend) and lung titers were performed using one-way ANOVA, Dunnett’s multiple comparisons test between the WT group and each of the mutant groups. ns, not significant, *, p < 0.05 between WT and I222T, **, p < 0.01 between WT and R152K or N294S groups, ***, p < 0.001 between WT and H136N groups. For the WT group, due to a technical problem during infection, one mouse was excluded from our analysis.