MCQ – 90836

Correct Answer � C Explanation

Clonorchis sinensis, commonly known as the Chinese or oriental liver fluke, is a parasite that infects the liver of humans and can lead to a variety of hepatic conditions.

Biliary tract: This is the primary location where Clonorchis sinensis causes pathology. Adults of Clonorchis sinensis reside in the bile ducts, leading to biliary inflammation, cholangitis, and can contribute to cholelithiasis (gallstones). Over time, chronic infection can even increase the risk of cholangiocarcinoma (bile duct cancer).

Gallbladder: Clonorchis sinensis can lodge in the gallbladder and cause inflammation. However, it’s more commonly associated with the bile ducts rather than the gallbladder itself.

Urinary Bladder : Clonorchis sinensis does not typically involve the urinary system. Another parasite, Schistosoma haematobium, is more commonly associated with urinary bladder pathology.

Clonorchis sinensis or Chinese liver fluke causes clonorchiasis.

Clonorchis sinensis infection is endemic in south China, Japan, Korea, and Taiwan due to a long tradition of consuming raw freshwater fish or shellfish. Humans are infected by eating raw or undercooked fish containing encysted larvae (metacercariae).

The immature flukes after excystation in the duodenum enter the biliary ducts and differentiate into adults.

The hermaphroditic adults produce eggs that are excreted in the feces. Upon reaching freshwater the eggs are ingested by snails, which are the first intermediate hosts. The eggs hatch within the gut and differentiate first into larvae (rediae) and then into many free-swimming cercariae. Cercariae encyst to form metacercariae under the scales of certain freshwater fish (second intermediate host) which are then ingested by humans.

In humans, it infects the common bile duct and gallbladder. Liver imaging shows a dilated biliary tract. It is also associated with an increased risk of cholangiocarcinoma.