Fig. 2.

Histopathological changes in trachea of experimentally infected broilers. Trachea sections were stained by H&E and evaluated for lesions by light microscopy. Lesions comprised loss of cilia and goblet cells (black arrows), vacuoles containing single dead cells (white arrows) which often show high level of viral protein expression in immunohistochemical staining (not shown), inflammatory cell infiltration (arrow heads) and epithelial desquamation and heterophil presence after exocytosis (asterisk). Inset picture IBV D388, 2 day p.i.: trachea of other than primarily-depicted animal with most prominent epithelial desquamation and heterophil presence (main picture presents average trachea on this time point regarding inflammatory cell infiltration into the tissue better).