Metacercariae of Echinostoma cinetorchis encysted in the fresh water snail, Hippeutis(Helicorbis) cantori, and their development in rats and mice
Soon Hyung Lee,Joon Ky Lee,Woon Mok Sohn,*Sung Tae Hong,Sung Jong Hong,** and Jong Yil Chai
Department of Parasitology and Institute of Endemic Diseases, College of Medicine, Seoul National University, Seoul 110-460, Korea.
*Department of Parasitology, Inje Medical College, Busan 614-112, Korea.
**Department of Parasitology, College of Medicine, Gyong-Sang National University, Chinju 660-280, Korea.
The fresh water snail, Hippeutis(Helicorbis) cantori, caught from the rice paddies in Namyangju-gun, Gyeonggi-do, was found to be a new second intermediate host of E. cinetorchis in Korea. The metacercariae were found from 89(76.7 %) out of 116 snails examined and the average metacercarial burden was 4.7 per infected snails. Some developmental characteristics of E. cinetorchis were observed after experimental infection of the metacercariae to rats and mice.
Fig. 1 Hippeutis (Helicorbis) cantori, a kind of fresh water snail, found to be a new second intermediate host of E. cinetorchis (scale: 1mm).
2. Two metacercariae encysted in the soft tissue of H. cantori.
3. A metacercaria isolated from H. cantori, showing end group spines(ES).
4. An excysted metacercaria showing oral sucker(OS), pharynx(P) and ventral sucker(VS).
Fig. 5 Growth curves in the ratio of posterior body(posterior to ventral sucker) to whole body length by the age of worms in rats and mice. (EMC : excysted metacercariae)
Figs. 6-11 Developmental stages of E. cinetorchis recovered from albino rats.
6. A 2-day old worm.
7. A 3-day old worm.
8. A 5-day old worm showing an ovary, testis and uterine tubule.
9. A 7-day old worm showing cirrus pouch(CP), uterus(U), ovary(O) and a testis (T).
10. A 10-day old worm showing more convoluted uterine tubule(U), vitellaria(V) and Mehlis' gland(MG).
11. A 12-day old worm showing many eggs in uterus.
Figs. 12-17 Developmental stages of E. cinetorchis recovered from albino rats.
12. A 14-day old worm.
13. A 20-day old worm showing an abnormally located testis(T).
14. A 50-day old worm.
15. A 88-day old worm showing no testis.
16. A 88-day old worm showing one testis.
17. A 88-day old worm showing two testes.
Table 1 Infection status of E. cinetorchis metacercariae in H. cantori, which were collected from Namyangju-gun, Gyeonggi-do in October, 1985
Table 2 Measurements of E. cinetorchis metacercariae* obtained from H. cantori
Table 3 Recovery rate of E. cinetorchis from experimentally infected rats and mice
Table 4 Measurements of E. cinetorchis recovered from experimentally infected rats and mice
Table 5 Newly appeared organs of E. cinetorchis according to the age of infection
Table 6 Number of testes by the age of E. cinetorchis
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