C. sinensis metacercariae were obtained from naturally-infected fish, Pseudorasbora parva, caught in Jin-Ju, South Korea, using previously published methods . We administered 500 metacercariae orally twice to each New Zealand white rabbit (Orient Bio Inc., Seongnam, Korea), and adult worms were collected from the bile ducts of the infected rabbits at 2 months post-infection. Then, the worms were prepared for immunohistochemistry.