Clonorchis sinensis (chinese or oriental liver fluke infection)


Diagnostic Form:

The eggs are the diagnostic form and are small. They measure approximately 27-35 µm by 12-19 µm. Yellow-brown in color, they tend to have a thick outer shell with a seated operculum. There is a characteristic small knob at the abopercular end. The eggs will contain a miracidium when passed into the Feces.

shell operculum knob interior clonorchis sinensis operculum abopercular abopercular operculum

clonorchis sinensis egg illustration


Geographic Prevalence:

Endemic to Southeast Asia, Japan, Taiwan, China, southern Korea, and northern Vietnam.


Disease It Causes And The Clinical Symptoms:

Dwelling in the bile ducts, Clonorchis induces an inflammatory reaction, epithelial hyperplasia and sometimes even cholangiocarcinoma.

Ingestion of bile by the parasite can disrupt the digestion of fats in the host. The parasite can also obstruct the bile duct leading to cholangitis.


Location In The Host:

The parasite is located in the human liver and bile duct.


Primary Vector:

1st intermediate dost is the snail. 2nd intermediate host is the fish. The definitive host are humans. Humans consuming infected raw, slightly salted or frozen fish are at risk for acquiring the parasite.


Life Cycle:





Test Recommended For Detection/Diagnosis:

Microscopic identification of eggs in formalin preserved concentrated stool is recommended for the detection/diagnosis. Three specimens submitted over a one week period are recommended.