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Korean J Parasitol > Volume 7(3):1969 > Article

Original Article
Korean J Parasitol. 1969 Dec;7(3):178-200. English.
Published online Mar 20, 1994.  http://dx.doi.org/10.3347/kjp.1969.7.3.178
Copyright © 1969 by The Korean Society for Parasitology
Study on the Eurytrema pancreaticum II. Life cycle
Du Hwan Jang, D.V.M., M.S.
Department of Veterinary Medicine, College of Agricueture, Seoul National University, Korea.
Abstract

The life cycle of Eurytrema pancreaticum has been studied locally at Chejudo (Quelpart Island) in Korea, and found a land snail, Acusta despecta Gray served as the first intermediate host of the pancreatic fluke. The second intermediate host of the fluke also has been surveyed there, the tettigoniid grasshoppers, Conocephalus maculatus Le Guillon and C. gladiatius Redtenbacher.

The land snail, Acusta despecta Gray, is acquired infection with the eggs of the fluke in the autum, then the miracidia grow in the liver of the land snails and become mother sporocysts through the winter. After one mother sporocyst has been divided into many spindle shaped daughter sporocysts during spring session, the fully matured daughter sporocysts penetrate into the membrane of mantle cavity in the land snail, and then, pass actively the membrane between June and July.

The daughter sporocysts are eaten by the tettigoniid grasshoppers, C. maculatus and C. gladiatus, through the summer and autumn.

Cercariae in the grasshoppers grow for about 20 days, and become matured metacercariae in the abdominal cavity. Finally, the matured metacercariae together with the grasshoppers are eaten by their final hosts; goat, rabbit, etc.

The artificial infection with the metacercariae of the pancreatic fluke to rabbit as the final host in laboratory room was carried out successfully.

The miracidia have been forced out by pressure from the eggs incubated at 20°-25℃ could live more than three hours swimming around the medium under the microscope.

Figures


Fig. 1
Chejudo (Quelpart Island) and enzootic area of Eurytremiasis


Fig. 2
Statistics of Livestock in Chejudo


Fig. 3
Average precipitation in each month in Chejudo


Fig. 4
Division of germ balls in a egg of pancreatic fluke


Fig. 5
Escaping mechanism of Eurytrema pancreaticum


Fig. 6
Miracidium of Eurytrema pancreaticum


Fig. 7
Miracidia of the pancreatic fluke


Fig. 8
Mother sporocyst detected from the liver of the land snail, Acusta despecta Gray


Fig. 9
Daughter sporocyst formation in the mother sporocyst


Fig. 10
Development of the daughter sporocyst in a mother sporocyst


Fig. 11
Daughter sporocyst of Eurytrema pancreaticum


Fig. 12
Escape of daughter sporocyst through the mantle of the land snail


Fig. 13
Cercaria of Eurytrema pancreaticum


Fig. 14
Cercariae in the cercarial sac which is inside the daughter sporocyst


Fig. 16
Metacercaria, 3 days old


Fig. 17
Metacercaria, 4 days old


Fig. 18
Metacercaria, 5 days old


Fig. 19
Metacercaria, 7 days old


Fig. 20
Metacercaria, 9 days old


Fig. 21
Elasticity of metacercarial capsule


Fig. 22
Metacercaria, 13 days old


Fig. 23
Metacercaria, 22 days old


Fig. 24
Naturally infected metacercaria (dead)


Fig. 25
Naturally infected metacercaria (live)


Fig. 26
The land snail, Acusta despecta Gray


Fig. 27
Genital organ of Acusta despecta Gray.

1. Vagina 2. Dart sac 3. Mucus gland 4. Penis



Fig. 27
The tettigoniid grasshopper, C. maculatus


Fig. 28
Characteristics of Comocephalus maculatus Le Guillon

1. Sound organ 2. Fastigium 3. Ovipositor (♀) 4. Cercus(♂)



Fig. 29
The tettigoniid grasshopper, C. gladiatuds


Fig. 30
Characteristics of Comocephalus maculatus Redtenbacher

1. Sound organ 2. Fastigium 3. Ovipositor (♀) 4. Cercus(♂)



Fig. 31
Life cycle of Eurytrema pancreaticum


Fig. 32
Terraria for the snails


Fig. 33
Collected snails in terraria


Fig. 34
Terraria for the grasshoppers

Tables


Table 1
Monthly collected snails and dissected number


Table 2
Infectious status with sporocyst in the land snails


Table 3
Measurment of Daughter sporocyst


Table 4
Measurment formation of one sporocyst detected from three parts of the land snail


Table 5
Measurment of cercaria (unit: µ)


Table 6
Growth of Metacercarial cysts of the pancreatic fluke in the tettigoniid grasshoppers (unit: µ)


Table 7
Growth and infections ability of Metacercariae of Eurytrema pancreaticum (unit: µ)


Table 8
Investigation of metacercaria in naturally infected tettugoniid grasshopper


Table 9
Life History of the land snail, Acusta despecta in Chejudo


Table 10
Collection of Conocephalus spp. for the artificial infection with the sporocyst and for field survey of infections status


Table 11
Life history of Conocephalus maculatus

References
1. Basch PF. Completion of the life cycle of Eurytrema pancreaticum (Trematoda: dicrocoeliidae). J Parasitol 1965;51(3):350–355.
  
2. Basch PF. Am J Vet Res 1969;27:234–240.
3. Skvortsov AA, et al. Trudy Kazak Nauchno-Issled Inst 1940;3:329–335.
4. Tang CC. Studies on the life history of Eurytrema pancreaticum Janson, 1889. J Parasitol 1950;36(6:1):559–573.
  
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