Nasitrema attenuata (Digenia: Nasitrematidae) infection of long-beaked common dolphin (Delphius capensis) in the East Sea, Korea

The trematodes of Genus Nasitrema are the most common infection in the heads of small odontocetes. Five species of Nasitrema have been described in Asia. But those parasites has been not surveyed in the East Sea of Korean peninsula. There are no evidence of pathology associated with Nasitrema attenuate. To determine the infection ratio of N. attenuata in the dolphin, it was surveyed 9 long-beaked common dolphin, Delphinus capensis, caught incidentally from Samcheok to Pohang, East Sea, Korea. Five males and four females, estimated to be between 1 to 10 years old, were examined. The quantity of N. attenuata harvested by aspiration from pterygoid sinuses ranged from 10 to 100 with a 100% (9/9) infection with older dolphins exhibiting higher parasite counts. The body of trematoda was elongated with tegumental patches resembling the leaves of lilies and oral sucker located ventrally at the anterior terminal. Esophagus was absent and intestinal bifurcation arose immediately from the posterior of pharynx. The undulated intestinal caeca transversed the entire body and terminated at the posterior extremity of the worm. The genital pore opened anterior to the ventral sucker. This report confirms the prevalence and morphology of N. attenuata in the dolphins from the East Sea, Korea.