Experiment on Artificial Infection of Chickens with Liver Flukes

Fifteen chickens, Nos. 1 to 15, were infected with 300 to 500 metacercariae. Then young flukes were found in the liver parenchyma in Nos. 1, 2, and 15. They were 7.0×2.7mm in size (No.1), with oral and ventral suckers and enteron clearly visible.Liver changes were recognized in 4 birds and divided into two types, acute (Nos. 1, 3, and 15) and chronic (No.2).a. Acute type: Macroscopically, this type showed surface lesions cream or gray in color, some of which were nodes 3 to 5mm in diameter and others streaks about 10mm long and 3 to 5 mm wide. The parenchyma exhibited homorrhagic inflammation, focal necrosis, and cloudy swelling. The bile ducts remained normal in size. Histologically, these lesions were necrotic tracts caused by the migration of young flukes. The space left in the wake of the flukes was filled with cell debris, lymphocytes, eosinophils, and erythrocytes, or involved in hemolysis. Hepatic cells near by were atrophic with pyknotic nuclei. Infiltration of lymphocytes, plasmacytes, and eosinophils was observed in some lobules and around blood vessels near the necrotic tracts.b. Chronic type: Macroscopically, this type was characterized by atrophy and cirrhosis. Yellowishwhite nodes were seen on the posterior surface.Dilated bile ducts had thick walls, containing yellowish-brown masses of coagulated bile. The parenchyma showed focal necrosis and cloudy swelling.Histologically, necrotic foci and bile ducts completely surrounded by connective tissue were scattered in the parenchyma.Infiltration of lymphocytes and eosinophils appeared in some lcbules and around bile ducts. Fibroblasts, mostly arranged concentrically, were seen in the periphery of the lesion.Argyrophil fibers increased around necrotic foci and bile ducts.