FIG 5.

Pathogenicity of rVc_BR60, rYm_WI01, and their PA K338R mutants in ferrets. Ferrets were infected with Vc_BR60 backbone (WT and PA K338 mutant) and Ym_WI01 backbone (WT and PA K338 mutant) viruses. (A and B) Body weight (A) and temperature (B) changes were monitored for 7 days. (C and D) Viral titers in nasal wash samples (collected at 1, 3, and 5 dpi) (C) and in lungs (collected at 3 and 5 dpi) (D) were determined by plaque assay. PBS was used for mock infection. Mean values are indicated with a solid line. **, P < 0.01; ***, P < 0.001 (compared with the virus titers of rVc_BR60 and rYm_WI01, respectively).