Fig. 4From: Comparative features of infections of two Massachusetts (Mass) infectious bronchitis virus (IBV) variants isolated from Western Canadian layer flocksHistological changes in trachea and lungs induced by Western Canadian Mass-type IBV isolates. The representative images of trachea and lungs (a) and average lesion scores of trachea (b) and lung (c) for each group of chickens (IBV 15AB-01, IBV 15SK-02 and uninfected control) at 4 dpi are depicted. a = cilia, b = tracheal cartilage, c = tracheal lumen, d = tracheal mucosa, e = parabronchial lumen and f = inter-parabronchial septum. The error bars represent the ±SEM. Statistical significance: *p < 0.05, **p < 0.01, ***p < 0.001Back to article page