Fig 2.
Virus replication in respiratory organs of ferrets. Ferrets were intranasally infected with 106 PFU/500 μl of virus. Three animals from each group were euthanized on days 3 and 6 postinfection for virus titration. Red and blue horizontal bars show the mean titers for Norway3487 and Norway3568 viruses, respectively. No statistically significant differences between virus titers in respiratory tissues of ferrets infected with Norway3487 virus and those infected with Norway3568 virus were found at day 3 postinfection. The titers of Norway3487 virus in trachea and lungs were significantly higher than those of Norway3568 virus at day 6 postinfection (P < 0.01 in trachea; P < 0.05 in lungs).