Clonorchis sinensis
Common name. Oriental liver fluke, Chinese liver fluke
Disease. Clonorchiasis
Geographic distribution. China, Korea, Russia, Taiwan, Hong Kong, and Vietnam
Infection rate. The total number of persons infected worldwide is estimated more than 20 million.
Life cycle. The adult worms live in the bile ducts of the final hosts. The eggs pass out with the feces and hatch to miracidia when ingested by suitable freshwater snails (first intermediate hosts). Stages of sporocyst, redia, and cercaria undergo in snails, i.e., Parafossarulus manchouricus. Mature cercariae hatch into the water and infect freshwater fish of Family Cyprinidae (second intermediate hosts) to make encysted metacercariae in the muscle. The final hosts get infected by ingesting raw or undercooked fish. The important final hosts are humans, dogs, cats, pigs, and rodents.
Morphology. Adult worms are flat, slender leaf-shaped between 10 and 25 mm in length, and two branched testes are located in posterior one third. The yellow to light brown eggs measure about 30 by 15 §. The operculum has prominent shoulder rim, and on the opposite side, comma shaped terminal knob locates.
Pathology and clinical symptoms. The mechanical irritation and toxic metabolites of the parasite cause inflammatory responses in biliary epithelium. Obstruction of biliary tract, pyogenic cholangitis, pancreatitis, cholecystitis, cholelithiasis, liver cirrhosis, and cholangiocarcinoma may be induced as the result of heavy and chronic infection.
Diagnosis. Detection of eggs in feces makes definite diagnosis. ELISA and radiologic techniques (mainly sonography) can provide indirect evidences of clonorchiasis.
Prevention. Avoiding ingestion of raw fresh-water fish.
Comments. Differential diagnosis from heterophyid eggs is necessary. Sung-Tae Hong
Egg of Clonrochis sinensis. Operculum, shoulder rim and surface wrinkling are distinctive. Length of 28-30 micrometer, width 14-18 micrometer. Sung-Tae Hong
Clonorchis sinensisegg. Tai Soon Yong
Egg of Clonorchis sinensis. 29 um x 15 um. Sung-Jong Hong
Egg of Clonorchis sinensis. 30 um x 16 um. Sung-Jong Hong
Egg of Clonorchis sinensis. 29 um x 16 um. Sung-Jong Hong
An amorphous egg of Clonorchis sinensis longer than the typical ones. 33 um x 16 um. Sung-Jong Hong
An amorphous egg of Clonorchis sinensis widerer than the typical ones. 27 um x 18 um. Sung-Jong Hong
The egg of Clonorchis sinensis from human.Woon-Mok Sohn
The egg of C. sinensis from a cat.Woon-Mok Sohn
Egg of C. sinensis from human. Woon-Mok Sohn
Metacercariae of Clonorchis sinensis collected from digested fish. The cyst wall is elliptical 0.16-0.20 mm long. Dark granules are in the bladder. Sung-Tae Hong
A metacercaria of Clonorchis sinensis. The larva in the cyst wall is actively moving. Note two suckers and a excretory bladder filled with dark granules. x150. Sung-Tae Hong
Cercaria of Clonorchis sinensis. The cercaria is liberated from its first intermediate host, a fresh water snail. Tai Soon Yong
Metacercaria of Clonorchis sinensis collected from Pseudorasbora parva. x400. Sung-Jong Hong
Metacercaria of Clonorchis sinensis isolated from P. parva. Woon-Mok Sohn
Metacercaria of Clonorchis sinensis isolated from Pungtungia herzi. Woon-Mok Sohn
Clonorchis sinensis adult worms (about 2900) recovered from a heavy infected case during surgery of gall bladder. Sung-Tae Hong
A destroyed Clonorchis sinensis by praziquantel treatment. Only anterior part and the body margin remained. Sung-Tae Hong
Fresh adult worms of Clonorchis sinensis recovered from experimentally infected rabbits. Worms in the right side are 4 weeks old and those in the left are 12 weeks old. The worm is grossly red but the intestinal ceca and distal uterus are dark. Sung-Tae Hong
Adult Clonorchis sinensis, acetocarmine stained. Its uterus is full of eggs, ovary and two tandem branched testes are seen well. Sung-Tae Hong
Clonorchis sinensis : from liver of rabbit, Acetocarmine stain, X40 Yong Suk Ryang
Clonorchis sinensis collected from a patient. Sung-Jong Hong
Clonorchis sinensis collected from a naturally infected cat. Semichon's acetocarmine stained. Woon-Mok Sohn
C. sinensis collected from a naturally infected cat. Semichon's acetocarmine stained. Woon-Mok Sohn
An Israeli carp, Cyprinus carpio nudus, one of favourate freshwater fish for eating raw. Sung-Tae Hong
Pseudorasbora parva, the most suitable freshwater fish host of Clonorchis sinensis. Sung-Tae Hong
A man caught freshwater fish in an endemic village of clonorchiasis, China. Sung-Tae Hong
Favourite freshwater fish in the endemic village of clonorchiasis in China. Sung-Tae Hong
A woman preparing sliced raw freshwater fish. Sung-Jong Hong
Topmouth gudgeons, Pseudorasbora parva, one of the second intermediat hosts of Clonorchis sinensis. Sung-Jong Hong
Cyprinus carpio, carp. Woon-Mok Sohn
Carassius auratus, Crucian carp. Woon-Mok Sohn
Pseudorasbora parva, top mouth minnow. Woon-Mok Sohn
Hemibarbus longirostris, long nose barbel. Woon-Mok Sohn
Pseudogobio esocinus, goby minnow. Woon-Mok Sohn
Pungtungia herzi, black striped gudgeon. Woon-Mok Sohn
Coreoleuciscus splendidus. Woon-Mok Sohn
Microphysogobis yaluensis. Woon-Mok Sohn
Zacco platypus, pale chub. Woon-Mok Sohn
Zacco temminckii, dark chub. Woon-Mok Sohn
Hemibarbus labeo, steel barbel. Woon-Mok Sohn
Sarcocheilichthys nigripinnis morii, Korean oily shinner. Woon-Mok Sohn
Sarcocheilichthys variegatus wakiyae, Korean oily shinner. Woon-Mok Sohn
Acanthorhodeus assumussi, deep body bitterling. Woon-Mok Sohn
Acanthorhodeus gracilis, Korean spined bitterling. Woon-Mok Sohn
Culter brevicauda. Woon-Mok Sohn
Hemiculter eigenmanni. Woon-Mok Sohn
Hypomesus olidus, pond smelt. Woon-Mok Sohn
Squalidus japonicus coreanus, short barbel gudgeon. Woon-Mok Sohn
Hemiculter leucisculus. Woon-Mok Sohn
A cook is cutting fish in the kitchen to prepare raw sliced fish (sushi) in a restaurant, China. Sung-Tae Hong
Many restaurants serve raw freshwater fish at the endemic area of clonorchiasis in Korea. Sung-Tae Hong
View of a branch of the Nakdong-gang, one of endemic area of Clonorchis sinensis. Sung-Tae Hong
Cutting a freshwater fish to prepare a dish of raw fish (sushi). Eating raw fish is common and favourite habit in Korea. Sung-Tae Hong
Boys are fishing with a net in a stream at an endemic area of clonorchiasis, China. Sung-Tae Hong
An intrahepatic bile duct of a rabbit infected with Clonorchis sinensis. The bile duct showes severe papillary and glandular hyperplasia of the mucosa, dilatation, and periductal fibrosis and inflammation. HE stained, x60. Sung-Tae Hong
Cirrhotic liver of a rabbit with chronic infection of Clonrochis sinensis. Liver margin discolored yellow and became fibrotic. Several worms (dark spots at the yellow part) are seen. Sung-Tae Hong
The intrahepatic bile duct of an experimentally infected rabbit with Clonorchis sinensis, one year after treatment. Note the persistent duct wall thickening but resolved inflammation, mucosal hyperplasia and lumen dilatation. Sung-Tae Hong
Metaplasia of mucin-secreting cells (red) in the bile duct mucosa of a rabbit infected with Clonorchis sinensis. PAS stained, x300. Sung-Tae Hong
Metaplasia of acid mucin-secreting cells (blue) in the bile duct mucosa of the Clonorchis sinensis infected rabbit. Alcian blue stained, x150. Sung-Tae Hong
A patient with heavy clonorchiasis (EPG 26,000) at an endemic village in China. Sung-Tae Hong
Pathologic section of the liver of chronic clonorchiasis patient. Note hyperplasia of biliary epithelium and periductal fibrosis. Sung-Jong Hong
In liver section of chronic clonorchiasis patient, pronounced are the hyperplasia of biliary epithelium and periductal fibrosis. Sung-Jong Hong
Clonorchis sinensis provoked thickening of biliary epithelium, in which a blood vessel was generated. H & E stained. Sung-Jong Hong
Liver of a healthy rat. Woon-Mok Sohn
Liver of a rat infected with C. sinensis. Woon-Mok Sohn
Liver of a guinea pig infected with C. sinensis. Woon-Mok Sohn
Ultrasound scanning of the liver can easily make diagnosis of clonorchiasis. Diffuse dilatation of the intrahepatic bile duct and ductal wall thickening are major findings. Sung-Tae Hong