Fig. 2

A liver from breeder chicken (38 weeks old) naturally infected with REV; showing massive primitive reticular cell proliferation (RC) around central vein (CV) (H&E, scale bar: 200 μm) B liver from breeder chicken (27 weeks old) naturally infected with REV; showing diffuse lymphoblastic cell infiltration (LC) with severely congested blood vessels (BV) (H&E, scale bar: 200 μm). C Spleen from breeder chicken (23 weeks old) naturally infected with REV; showing massive primitive reticular cell proliferation (RC) with thickening of the splenic capsule (SC) (H&E, scale bar: 200 μm). D Spleen from breeder chicken (35 weeks old) naturally infected with REV; showing diffuse lymphoblastic cell infiltration, the cells were hyperchromatic and pleomorphic (arrows) (H&E, scale bar: 50 μm). E Bursa from breeder chicken (61 weeks old) naturally infected with REV; showing diffuse lymphoblastic cell infiltration (LC) with severely degenerated mucosa (M (H&E, scale bar: 200 μm) F Bursa from breeder chicken (61 weeks old) naturally infected with REV; showing congestion of stroma blood vessels (BV) and lymphoblastic cell infiltration (LC) (H&E, scale bar: 50 μm)