Fig. 4.

Histopathological changes in the trachea, lungs, kidneys, and bursa of SPF chickens infected with the recombinant rH120, rIBYZ, and rH120-S1/YZ strains at 1-day-of-age. Black arrows in the trachea indicate cilia and necrosis loss. Black arrows in the lungs indicate congestion and hemorrhage. Trachea samples were collected at 3, 5 dpi (A–D); lung and bursa samples were collected at 7, 10 dpi (E–H; M–P); and kidney samples were collected at 5, 7 dpi (I–L). Black arrows in kidneys indicate tubular dilation, congestion, and inflammation. Scale bar = 100 μm or 200 μm.