Fig. 6.

Trachea lesion scores.

At 5 days after challenge, the other five infected birds in each group were killed humanely using carbon dioxide over inhalation. Tissue samples were collected from the trachea and analyzed by H&E staining. Mucosal thickness (a), deciliation (b), goblet cells (c) and lymphocyte scores (d) for the trachea samples were evaluated blindly and scored from 1 to 5 based on severity. Kruskal–Wallis and Dunn–Bonferroni tests were employed to perform post hoc comparisons of trachea lesion scores using SPSS.