Opisthorchiasis is a parasitic disease caused by certain species of genus Opisthorchis (specifically, Opisthorchis viverrini and Opisthorchis felineus). Chronic infection may lead to cholangiocarcinoma, a cancer of the bile ducts. Medical care and loss of wages caused by Opisthorchis viverrini in Laos and in Thailand costs about $120 million annually. In Asia, infection by Opisthorchis viverrini and  other liver flukes affects the poorest people. Along with other foodborne trematode infections such as clonorchiasis, fascioliasis and paragonimiasis, opisthorchiasis is listed among the World Health Organizations list of neglected tropical diseases. Signs and symptoms
Symptoms of opisthorchiasis are indistinguishable from clonorchiasis. About 80% of infected people have no symptoms, though they can have eosinophilia. Asymptomatic infection can occur when there are less than 1000 eggs in one gram of feces. Infection is considered heavy when there are 10,000-30,000 eggs in one gram of feces. Symptoms of heavier infections may include diarrhea, epigastric and right upper quadrant pain, lack of appetite, fatigue, yellowing of the eyes and skin and mild fever.These parasites are long-lived and cause heavy chronic infections that may lead to accumulation of fluid in the legs (edema) and in the peritoneal cavity (ascites), enlarged non-functional gallbladder and also ascending cholangitis, which can lead to periductal fibrosis, cholecystitis and cholelithiasis, obstructive jaundice, hepatomegaly and/or portal hypertension. Chronic opisthorchiasis and cholangiocarcinoma
Both experimental and epidemiological evidence strongly implicates Opisthorchis viverrini infections in the etiology of a malignant cancer of the bile ducts (cholangiocarcinoma) in humans which has a very poor prognosis.
Research
Using CRISP gene editing technology in animal models, researchers have been able to eliminate the genes responsible for symptoms of opisthorchiasis, which may lead to further research toward novel treatment and control of this disease and its sequelae. References


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