Figure 2.

Virulence of wild-type and mutant highly pathogenic influenza A(H7N9) virus GD viruses in mice. Five mice per group were intranasally inoculated with 10², 10³, 10⁴, or 10⁵ PFU (each in 50 μL) of the indicated viruses. Body weight (A) and survival (B) were monitored daily for 14 days. A) The values represent the average body weight ± SD compared with the baseline weight from 5 mice. Two-way analysis of variance followed by a Dunnett test revealed that the body weight loss of mice infected with each mutant virus at any dose was significantly reduced compared with that of mice infected with GD wild-type virus (p<0.01). B) The 50% lethal doses for mice (in red) were calculated according to the Spearman-Karber method. Error bars indicate SD. GD, A/Guangdong/17SF003/2016; PA, polymerase acidic; PB, polymerase basic.