STUDY ON THE CERCARIA AND METACERCARIA OF PSEUDEXORCHIS MAJOR (HASEGAWA, 1935) YAMAGUTI, 1938, ESPECIALLY ON THE DEVELOPMENT OF ITS METACERCARIA, (HETEROPHYEIDAE, TREMATODA)
1956; National Institute of Infectious Diseases; Volume: 9; Issue: 1-2 Linguagem: Inglês
10.7883/yoken1952.9.1
ISSN1884-2828
Autores Tópico(s)Helminth infection and control
ResumoInitial report of this trematode was made by Hasegawa (1927) who found the metacercaria from the fins and scales of trout, Plecoglossus altivelis and also its adult worm from the intestine of a fish, Parasilurus asotus. Subsequently Takahashi (1929) reported its first intermediate snail host, Semisulcospira libertina, with a description of its cercaria and metacercaria. In 1935 Hasegawa again described the metacercaria and its adult worm under the name Exorchis major. Yamaguti (1938) set up a new genus Pseudexorchis for this species and separated from the Exorchis in two fundamental reasons; the extent of intestine and the position of genital organs.It is important to distinguish this cercaria from the others, especially from that of pathogenic famous Metagonimus parasitic in the same snail host, because of the strong resemblance of structures between them. As to the second intermediate host, as many as about twenty species of fresh water fishes has been reported by Okabe (1940), Date (1943), Miyoshi (1948), Takahashi (1953), etc. Therefore it seems also important to distinguish this metacercaria from that of pathogenic Metagonimus, Clonorchis, etc., as these cysts afire generally found in various fishes side by side with that of Pseudexorchis major.The author had opportunities of getting this cercaria from the snails at several areas in Japan, and also the metacercariae from the fins of experimentally infected gold fish, Carassius carassius. The following is a more detailed redescription of this cercaria, especially on its excretory system, sensory hairs and oral spines, and also the redescription of this metacercaria, especially on its development.
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