Disease. echinostomiasis

Geographic distribution. Korea, Japan, Taiwan, and Java

Infection rate. Sporadically occurring cases in man are documented in some Asian countries.

Life cycle. Several fresh water snails, i.e., Hippeutis cantori, Segmentina hemispaerula and Austropeplea ollula, have been known as the first intermediate hosts. Several freshwater snail species, i.e., H. cantori, Radix auricularia coreana, Physa acuta, Cipangopaludina chinensis malleata, S. hemisperula, A. ollula, and Corbicula fluminea were also reported as the second molluscan intermediate hosts. Other second intermediate hosts include a loach, Misgurnus anguillicaudatus, and tadpole of Rana nicromaculata. Rats and dogs are found to be the natural definitive hosts. Humans can be infected by eating raw snails and loaches.

Morphology. The adult worms are 10.8-12.6 mm in length and 2.6-3.2 mm in width. Head crown with 37-38 collar spines and abnormal location or disappearance of one or two testes are characteristic. The eggs are oval-shaped and measure 99-116 x 65-76 ㎛.

Pathology and clinical symptoms. Gastrointestinal symptoms like nausea, vomiting, abdominal pain, and diarrhea can be observed.

Diagnosis. Detection of eggs in feces.

Prevention. Avoid eating raw snails and loaches.

Comments. Differential diagnosis from Fasciola hepatica and F. buski is necessary.

Egg of Echinostoma cinetorchis.

E. cinetorchis larvae in the experimental snail, Hippeutis cantori.

The 2nd generation redia of E. cinetorchis isolated from an experimental snail, Hippeutis cantori.

Metacercaria of E. cinetorchis isolated from an experimental snail, Hippeutis cantori.

An adult fluke of Echinostoma cinetorchis in the feces of an infected person. See that the anterior testis has been displaced a little from its original position. x 10.

An adult fluke of Echinostoma cinetorchis recovered from an experimentally infected rat. Note that the 2 testes disappeared in this specimen. x 10.

E. cinetorchis with two testes recovered from a rat, which was experimentally infected with metacercariae. Semichon's acetocarmine stained.

E. cinetorchis with one testis recovered from a rat, which was experimentally infected with metacercariae. Semichon's acetocarmine stained.

E. cinetorchis with one dislocated-testis recovered from a rat, which was experimentally infected with metacercariae. Semichon's acetocarmine stained.

E. cinetorchis recovered from an experimentally infected rat. Testis is not seen. Semichon's acetocarmine stained.

Cipangopaludina chinensis malleata : second imtermediate host of Echinostoma cinetorchis

Hippeutis cantori : first and second intermediate host of Echinostoma cinetorchis

Radix auricularia coreana : second intermediate host of Echinostoma cinetorchis