Viral growth in the upper and lower respiratory tract of pigs.
Three-week-old piglets were inoculated intranasally with 1.4 × 106 PFU of WT, Y17H, or R106K viruses in PBS. (A) Mean (± SD) virus titers in the nasal cavity of pigs (n = 5). Nasal swabs were collected and titrated by TCID50. Two-way ANOVA with Bonferroni multiple comparisons was performed, and significant differences between the WT and Y17H groups at time points (*) and at the peak of infection (#) are shown as follows:*,#P < 0.05, ***P < 0.001, ****P < 0.0001. There was no significant difference between the WT and R106K groups. (B, C, D) Mean (± SD) virus titers in the lower respiratory tract of pigs (n = 3). Animals were euthanized on day 3 after inoculation. Tracheobronchoalveolar lavage (TBAL) fluid (B) and tissues (C, D) were collected and titrated by TCID50. Comparisons between groups were performed using Student t-tests; *P < 0.05.
