Fig 4.

Viral shedding and macroscopic pneumonia are unaltered by PB1-F2 expression in swine. Groups of pigs (n = 10) were infected with 10⁵ TCID₅₀ of PB1-F2 recombinant viruses, and nasal swabs were collected from 1 to 3 dpi for measuring virus shedding. At 1 and 3 dpi, five animals from each group were euthanized, and the lungs were scored for gross pneumonia. (A) Viral shedding in nasal secretions of pigs. Viral titers in nasal swabs were determined by TCID₅₀ on MDCK cells. Values are shown as the mean and range and expressed as log₁₀TCID₅₀/ml. (B) Percentage of macroscopic lung lesions. Values are shown as the mean ± the standard error of the mean. The differences are not statistically significant (two-way ANOVA).