Main » Infectious diseases » Snail-mediated Helminthiases » Liver fluke infections
Clonorchis sinensis is also known as the Chinese or oriental liver fluke. It is found in man and also in other fish-eating mammals in the areas shown (after Muller, 1975).(*Now referred to as Opisthorcis sinensis)
Distribution map of the liver fluke infections.
Photo 1. Ctenopharyngodon idellus, a common host for cercariae of Clonorchis sinensis. Fishponds are frequently contaminated by eggs in human faeces. Unlike F. buski the miracidia of Clonorchis sinensis hatch in the snail host after it has eaten the eggs (see 307). Several genera of snails serve as intermediate hosts (eg Bithynia spp. 426) for the development of sporocysts, rediae, and cercariae.
Photo 2. Cercaria of Clonorchis sinensis. The cercariae leave the snail and encyst under the scales of various species of freshwater cyprinoid fish. (x40)
Photo 3. Metacercaria in fish. Man is infested by eating raw or incompletely cooked fish, a common delicacy among many Chinese. Metacercariae are thus ingested and excyst in the duodenum. (x 100)
Photo 4. Clonorchis sinensis in cat liver. The young worms migrate up the common bile duct to the liver. They are seen here as whitish spots.
Photo 5. Adult Clonorchis sinensis. At maturity they may reach two cm in length.
Photo 6. Section of Clonorchis sinensis in bile duct. Direct mechanical damage and possibly toxic effects of the adult worms lead to fibrotic changes in the bile ducts. (x 15)
Photo 7. Cholangiocarcinoma of the liver. Severe chronic infection with Clonorchis sinensis may lead to marked pericholangitic fibrosis, and finally multifocal cholangio- cellular carcinoma of the liver. In this case métastasés were widely distributed throughout the body. (x60)
Photo 8. Bithynia funiculata. The life cycle is similar to that of Clonorchis sinensis. Snails of the genus Bithynia serve as intermediate hosts of Opisthorchis felineus and Opisthorchis viverrini (see also 419). (x3)
Opisthorhis felineus and Opisthorchis viverrini.
The distribution is shown in Distribution map Opisthorchis felineus is common in domestic cats, dogs, and some other animals in Eastern and Southeastern Europe, and parts of the USSR. It is largely replaced by Opisthorchis viverrini in the Far East. This occurs mainly in Northeast Thailand where it infects up to 90% of the population in some villages. Cats as well as man serve as reservoirs of infection.
Photo 9. Lophocercous cercariae of Opisthorchis viverini (with keeled tails). The cercariae encyst in small fish and man is infected by eating the metacercariae in these. (x 90)
Photo 10. Metacercaria in fish. Uncooked fish are the usual source of infection. (x 200)
Photo 11. Cyprinus carpio, host metacercariae of Opisthorchis felineus. This edible freshwater fish is commonly infected in Taiwan.
The adult flukes of Opisthorchis which are similar to those of C. sinensis live in the bile ducts and produce similar pathological changes. They can be distinguished by the structural details as seen in the figure.
Photo 12. Adult of Opisthorchis felineus.(x 4.5)
Photo 13. Adult of Opisthorchis viverrini.
Photo 14. Adult of Clonorchis sinensis.
Photo 15. Cholangiogram of patient with opisthorciasis.
Photo 16. Adult D. dentriticum from Egypt. This is a rare infection of man but very common in sheep and other herbivora. The adult trematode grows up to 1.5 cm long and lives in the biliary tract. The eggs are similar to those of the Clonorchis group. (x 6)
See also Fasciola hepatica and Fasciola gigantica
» Schistosoma mansoni
» Schistosoma haematobium
» Schistosoma japonicum
» Schistosomes Found Uncommonly in Man
» The intestinal flukes
» Liver fluke infections
» Fasciola hepatica and Fasciola gigantica
» Paragonimus westermani