FIG 7.

EndoU-deficient mutants profoundly attenuated avian coronavirus infection in vivo. (A to D) Survival rates (A), tracheal ciliostasis scores (B), viral loads in different tissues (C), and kidney lesions (D) of chickens inoculated with rSD-WT, rSD-H238A, and rSD-Y334A strains. The average ciliostasis score was calculated according to the following criteria: 0, cilia in the complete tracheal section showed movement; 1, cilia in 75% to 100% of the tracheal section showed movement; 2, cilia in 50% to 75% of the trachea showed movement; 3, cilia in 25% to 50% of the tracheal section showed movement; and 4, cilia in <25% of the tracheal section showed movement or no movement. The average ciliostasis score was calculated for each group. Statistical significance was considered the following: significant at P < 0.05 (*), highly significant at P < 0.01 (**), and extremely significant at P < 0.001 (***).