FIG 3.
M41-R displays an attenuated phenotype in vivo. Groups of 12 8-day-old SPF RIR chicks were inoculated with 105 PFU of Beau-R, rIBV M41-R-6, rIBV M41-R-12, 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. Only birds infected with M41-CK displayed these two clinical signs. (C) Ciliary activities were measured from tracheas harvested from three randomly selected birds per group at 4, 6, and 7 dpi. The 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. Statistical differences are indicated by * (P < 0.05). There were no statistical differences between the mock, the apathogenic control group Beau-R, M41-R-6, and M41-R-12 groups.