Study on the Eurytrema pancreaticum II. Life cycle

ABSTRACT

The life cycle of Eurytrema pancreaticum has been studied locally at Chejudo (Quelpart Island) in Korea, and found a land snail, Acusta despecta Gray served as the first intermediate host of the pancreatic fluke. The second intermediate host of the fluke also has been surveyed there, the tettigoniid grasshoppers, Conocephalus maculatus Le Guillon and C. gladiatius Redtenbacher. The land snail, Acusta despecta Gray, is acquired infection with the eggs of the fluke in the autum, then the miracidia grow in the liver of the land snails and become mother sporocysts through the winter. After one mother sporocyst has been divided into many spindle shaped daughter sporocysts during spring session, the fully matured daughter sporocysts penetrate into the membrane of mantle cavity in the land snail, and then, pass actively the membrane between June and July. The daughter sporocysts are eaten by the tettigoniid grasshoppers, C. maculatus and C. gladiatus, through the summer and autumn. Cercariae in the grasshoppers grow for about 20 days, and become matured metacercariae in the abdominal cavity. Finally, the matured metacercariae together with the grasshoppers are eaten by their final hosts; goat, rabbit, etc. The artificial infection with the metacercariae of the pancreatic fluke to rabbit as the final host in laboratory room was carried out successfully. The miracidia have been forced out by pressure from the eggs incubated at 20-25 C could live more than three hours swimming around the medium under the microscope.