Morphological observations of Echinochasmus japonicus cercariae and the in vitro maintenance of its life cycle from cercariae to adults.
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.
Choi
Min-Ho
MH
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.
Kim
Sae Hoon
SH
Chung
Jong-Hoon
JH
Jang
Hye-Jin
HJ
Eom
Joon-Ho
JH
Chung
Byung-Suk
BS
Sohn
Woon-Mok
WM
Chai
Jong-Yil
JY
Hong
Sung-Tae
ST
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*