Introduction

Clonorchiasis, due to Clonorchis sinensis and opisthorchiasis, due to Opisthorchis, occur in Southeast Asia and Eastern Europe

-Clonorchiasis and opisthorchiasis are clinically indistinguishable. 

-Humans are infected by eating raw, pickled, frozen, dried, salted, and smoked fish containing the encysted larvae (metacercariae)

-After excystation in the duodenum, immature flukes invade the biliary ducts and differentiate into adults 

Symptoms & Signs 

Most infections are asymptomatic

Fever, chills, abdominal pain, urticaria, eosinophilia, hepatomegaly, cholecystitis, cholangitis, pancreatitis, liver abscess, jaundice 

-Chronic infection is associated with increased risk of cholangiocarcinoma 

Diagnosis 

Definitive diagnosis is made by finding the typical brownish, small, operculated eggs in the stool 

-The eggs of Opisthorchis are indistinguishable from those of Clonorchis

– Imaging studies: Biliary tract dilatations with filling defects due to flukes 

Treatment 

The drug of choice is praziquantel

Other effective agent: Albendazole 

Fascioliasis is an infectious disease caused by Fasciola hepatica, the sheep liver fluke

-it is prevalent in sheep-raising areas 

-it results from ingestion of encysted metacercariae on aquatic vegetables or water plants such as watercress 

Symptoms & Signs 

Fever, malaise, abdominal pain, weight loss, urticaria, marked eosinophilia, leukocytosis, tender hepatomegaly, cholangitis 

CT and other imaging studies show hypodense migratory lesions of the liver. 

Diagnosis 

Definitive diagnosis: Identification of characteristic eggs in stool, duodenal or biliary aspirates 

CT/imaging studies: hypodense nodules in the liver; tracts or tunnels (representing the migration of larvae)  

Treatment 

The treatment of choice is triclabendazole

Other effective agents: Bithionol, emetine, dehydroemetine, nitazoxanide 

-it does not respond well to praziquantel