[Objective] This study aimed to investigate the histopathological changes of hens with colibacillosis.[Method] Epidemiological investigation,clinical symptoms observation,pathological autopsy,laboratory diagnosis and paraffin-embedded tissue section were performed to diagnose the laying hens from a farm in Changli County,affected by a disease similar to pericarditis and perihepatitis in clinical symptoms.[Result] The pathogen isolated from those hens was E.coli.The histopathological changes of the diseased hens included myocardial cell degeneration and inflammatory cell infiltration in heart,fibrotic perihepatitis,necrotic hepatitis in liver,decreased lymphoid cells and inflammatory cell infiltration in spleen,lung congestion,lung room full of erythrocytes,hyaline degeneration in glomerular capillary and small intestinal epithelial cell shedding.[Conclusion] This study will provide scientific basis for the diagnosis and control of colibacillosis in poultry.
