FIG 6.
Incorporation of U12137C, C18114G, A19047U and A20139Fin nsp 10, 14, 15 and 16, respectively, within rVV M41-R generated a rIBV, M41-K, that exhibits a pathogenic phenotype in vivo. Groups of 12 8-day-old SPF RIR chicks were inoculated with 105 PFU of rIBV M41-K or M41-CK via the intranasal and intraocular route. Mock-infected birds were inoculated with serum-free BES medium. Birds were observed for clinical signs from 3 to 7 dpi. (A) The average number of snicks per bird per minute and (B) the percentage of birds exhibiting rales per group were calculated. (C) Ciliary activities were measured from the tracheas harvested from three randomly selected birds per group on 4 and 6 dpi. Average percentages for each group are displayed with error bars representing SEM. Statistical differences were analyzed using a two-way ANOVA with Tukey analysis for multiple comparisons and are indicated by **** (P < 0.0001).