A man on return from a country complains of pain in abdomen, jaundice, with increased alkaline phosphatase and conjugated hyperbilirubinemia. U.S.G. shows blockage in the biliary tree. What could be the cause -

Ans. is 'b' i.e., Clonorchis sinensis Clonorchis sinensis is a trematode. It is also known as liver luke.Man is definitive host for Clonorchis and snail is the secondary host.Clonorchis sinensis is caused by ingestion of metacercaria in inadequately cooked freshwater fish.The organism's excyst in the duodenum.The larva travel through the ampulla of Vater and mature into adult worms in bile canaliculi.The adult worms release small operculated eggs which pass with bile into the intestines and are voided with stools.Most of the infections are asymptomatic because of the low worm burden.Chronic infection or repeated infection is associated with manifestations such as:CholangitisCholangiohepatitisBiliary obstruction (Biliary obstruction causes increase in alkaline phosphatase).Also know * Clonorchis sinensis infection is associated with cholangiocarcinoma