<i>Echinostoma hortense</i> metacercariae naturally encysted in <i>Odontobutis obscura interrupta</i> (a freshwater fish) and experimental infection to rats

, Ahn, Yung Kyum; , Ryang, Yong Suk; , Chung, Pyung Rim; , Lee, Keun Tae

doi:1985.23.2.230

Korean J Parasito > Volume 23(2):1985 > Article

Original Article


Korean J Parasitol. 1985 Dec;23(2):230-235. English. Published online Mar 20, 1994. http://dx.doi.org/10.3347/kjp.1985.23.2.230
Copyright © 1985 by The Korean Society for Parasitology


Echinostoma hortense metacercariae naturally encysted in Odontobutis obscura interrupta (a freshwater fish) and experimental infection to rats
Yung Kyum Ahn,Yong Suk Ryang,^*Pyung Rim Chung and Keun Tae Lee
^*Department of Parasitology and Department of Public Health and Adiministration, Wonju Medical College, Yonsei University, Korea.
Department of Parasitology, Medical College, Yonsei University, Korea.


Abstract
The metacercariae of an echinostomatid fluke were detected from a freshwater fish, Odontobutis obscura interrupta caught from the Seom river system, Wonseong-gun, Kangwon-do, and experimenally infected into rats to obtain the adult worms for the species identification. A total of 32 metacercariae was detected from 10 fishes (27.8 percent) out of 36 O. obscura interrupta caught from the river. The average size of metacercariae was 153.4 × 149.0 µm. Also, it was uniquely specific that thickened membrane was formed around the metacercarial cyst wall. The rats orally infected with those metacercariae were sacrificed 20 days after infection to get the adult worms. The mean length and width of the adult worms were 0.75 cm and 0.13 cm, respectively. The number of collar spines on circumoral disk was 26 to 28, and the end group spines at lateral sides of the oral sucker were 4 on each side. The echinostomatid flukes observed in this study were all identified as Echinostoma hortense according to the morphologies of the cirrus sac, ovary, vitellaria and testes of the adult worms and the shape of eggs. On the other hand, O. obscura interrupta is one of the fresh-water fish that are preferably eaten raw by the rural inhabitants. Although no human case of E. hortense infection by eating O. obscura interrupta has been experienced yet, the possibility is strongly suggested in this study.

Figures

Figs. 1-5
Fig. 1.Odontobutis obscura interrupta; A. dosal view, B. lateral view.

Fig. 2. Metacercariae encysted in intestinal muscle. Thick cyst walls are surrounded by adherent membrane produced by the tissues (Scale: 0.1mm).

Fig. 3. Magnification of Fig. 4, showing collar spines in circumoral disk.

Fig. 4. Adult of Echinostoma hortense detected from the experimentally infected 20 days old rats (OS, oral sucker; CR, cirrus sac; VS, ventral sucker; U, uterus; O. ovary; MG, Mehlis gland; T. testes; VT, vitellaria), stained by carmine (Scale: 1mm).

Fig. 5. Eggs of E. hortense in feces from the infected rat (Scale: 0.05mm).

Tables


	Table 1 Metacercariae of Echinostoma hortense detected from Odontobutis obscura interrupta (fresh-water fish) caught along the Seomgang-river in Wonseong-gun, Kangwon-do


	Table 2 Measurements (in µm) of adult Echinostoma hortense recovered from experimentally infected rats

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