title: Morphological observations of Echinochasmus japonicus cercariae and the in vitro maintenance of its life cycle from cercariae to adults.
abstract: The cercaria morphology of Echinochasmus japonicus was investigated using light and scanning electron microscopy. Cercariae, liberated from naturally infected snails (Parafossarulus manchouricus), had ovoid bodies and diminutive tails. The cercaria tegument was covered with minute spines. Four type II sensory papillae were observed on the dorsal side of the oral sucker, and type I papillae were distributed on the dorsal tegument surfaces. When cercariae were kept in the same bath as the freshwater fish, Pseudorasbora parva, which were free from trematode infections, parasites encysted only in the gills of fishes at day 4 postinfection (PI). The outermost metacercaria wall was fully formed in host tissues at day 7 PI. Adult worms were recovered from the intestines of rats, chicks, and ducks 28 days after experimental exposure to metacercariae. The head crown of the adult was armed with 24 collar spines, which were interrupted dorsal to the oral sucker, and the species was identified as E. japonicus.
authors.affiliation: Department of Parasitology and Tropical Medicine, Seoul National University College of Medicine and Institute of Endemic Diseases, Seoul National University Medical Research Center, Seoul 110-799, Korea.
authors.forename: Min-Ho
authors.initials: MH
authors.lastname: Choi
authors.forename: Sae Hoon
authors.initials: SH
authors.lastname: Kim
authors.forename: Jong-Hoon
authors.initials: JH
authors.lastname: Chung
authors.forename: Hye-Jin
authors.initials: HJ
authors.lastname: Jang
authors.forename: Joon-Ho
authors.initials: JH
authors.lastname: Eom
authors.forename: Byung-Suk
authors.initials: BS
authors.lastname: Chung
authors.forename: Woon-Mok
authors.initials: WM
authors.lastname: Sohn
authors.forename: Jong-Yil
authors.initials: JY
authors.lastname: Chai
authors.forename: Sung-Tae
authors.initials: ST
authors.lastname: Hong
mesh_terms: D000818:Animals; D002645:Chickens; D003530:Cyprinidae / Q000469:parasitology*; D004372:Ducks; D005393:Fish Diseases / Q000469:parasitology; D005618:Fresh Water / Q000469:parasitology; D005880:Gills / Q000469:parasitology; D006801:Humans; D008018:Life Cycle Stages / Q000502:physiology*; D008855:Microscopy, Electron, Scanning; D051381:Rats; D017207:Rats, Sprague-Dawley; D012908:Snails; D014200:Trematoda / Q000254:growth & development* / Q000648:ultrastructure*; D014201:Trematode Infections / Q000469:parasitology*