Pathogenicity of clade 1.1 H5N1 viruses in ferrets.

a H5N1 virus infection was compared to a seasonal H3N2 virus infection. All ferrets were inoculated with 106 PFU of virus.
b The percentage mean maximum weight loss (n = 3) observed during the first 10 days post-inoculation (p.i.)
c Peak mean log10 PFU/ml nasal wash titer (day p.i. in parentheses).
d Number of animals euthanized before the end of the 14 day experimental period because of reaching a clinical end point.
e Tissue homogenates from 3 ferrets (day 3 p.i.) were titrated, and the results are expressed as the mean log10 PFU/g ± standard deviation.
nd = not detected.
Pathogenicity of clade 1.1 H5N1 viruses in ferrets.