FIG 4.

Effects of mutations in PA at positions 343 and 347 on virulence of QT1728 virus in mice. (A to H) Three mice per group were inoculated intranasally with the indicated dose of viruses and monitored for survival (A to D) and weight changes (E to H) for 14 days. The body weight loss data shown in panel A are identical to those in Fig. 2A; they are presented again for a better comparison of wild-type and mutant viruses; likewise, the body weight loss data presented in panel E are identical to those in Fig. 2C.