Experimental life history of Echinostoma cinetorchis
S H Lee,J Y Chai,S T Hong and W M Sohn*
Department of Parasitology and Institute of Endemic Diseases, College of Medicine, Seoul National University, Seoul 110-460, Korea.
The life history of Echinostoma cinetorchis was completed in the laboratory using Hippeutis cantori as the first and second intermediate host. The incubation for maturation of eggs and hatching of miracidia took 24 days at 28℃. On the 66th day after miracidial challenge, 16 snails were crushed and examined for the presence of E. cinetorchis larvae. The metacercariae were detected in all of the snails, and from three of them were found the rediae and cercariae. The morphological characteristics of the larvae and the experimentally obtained adults were compatible with that of E. cinetorchis.
Figs. 1-4 The larvae and snail intermediate host of E. cinetorchis.
Fig. 1. An embryonated egg developed in the 28℃ incubator during 24 days.
Fig. 2. Miracidium hatched from an embryonated egg, showing eye spots and numerous cilia.
Fig. 3.Hippeutis (Helicorbis) cantori, a fresh water snail, identified to be a new intermediate host of E. cinetorchis.
Fig. 4. Rediae(R), cercariae (arrow heads) and metacercariae (round-shape) detected from an experimental snail in the 66th day after miracidial challenge.
Figs. 5-8 The larvae and adults of E. cinetorchis.
Fig. 5. The second generation redia obtained from an experimental snail.
Fig. 6. Cercaria detected from an experimental snail.
Fig. 7. Metacercaria isolated from an experimental snail.
Fig. 8. Two adult worms recovered from an experimental rat in 17th day after infection.
Table 1 Detection of E. cinetorchis larvae from the experimentally infected snails
Table 2 Measurements of the second generation rediae of E. cinetorchis obtained from the experimental snails
Table 3 Measurements of E. cinetorchis cercariae obtained from the experimentally infected snails
Table 4 Measurements of adult E. cinetorchis* from experimentally infected rats in 17 days after infection
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