Clonorchiasis (Clonorchis Infection)

Clonorchiasis, or Clonorchis Infection, is an infectious disease caused by the Clonorchis sinensis. Also known as the Chinese Liver Fluke or the Oriental Liver Fluke, Clonorchis sinensis is a trematode.

The life cycle of the Clonorchis sinensis begins as eggs that are expelled through the stool. The embryonated eggs are consumed by a snail which serves as an intermediate host. There are over a hundred different species of snails that are suitable hosts for the Clonorchis sinensis. The eggs then release miracidia, which develop into sporocysts, then rediae, then finally cercariae.

The cercariae are expelled from the snail and can survive in fresh water for a short time. They then enter fish to encyst as metacercariae. Humans become infected when consumption of the fish takes place, which is why people should take caution when consuming undercooked, raw, salted, smoked, or pickled fish. Inside the human body, the metacercariae excyst inside the duodenum. They then travel through the biliary tract via the ampulla of Vater. It takes one month for them to mature fully. The adult form of the flukes can be 25mm by 5mm in size and inhabit the biliary ducts. Carnivorous animals also make good alternative hosts.

Clonorchiasis is especially common to parts of Asia such as China, Vietnam, Korea and Taiwan. There have been reports of the infectious disease in the Untied States, however, cases are rare and are usually found in immigrant populations or have been determined to be caused by consumption of imported or undercooked foods, particularly fresh water fish with metacercariae in it.

Symptoms of Clonorchiasis are usually caused by an obstruction or inflammation of the biliary ducts. The early stage of Clonorchiasis, known as the acute stage, manifests as nausea, eosinophilia, diarrhea, and abdominal pain. Untreated, the infection progresses and can develop into pancreatitis, cholangitis, cholangiocarcinoma, or cholelithiasis. The end result of Clonorchiasis can be fatal without prompt treatment.

Diagnosis of Clonorchiasis requires microscopy and morphologic comparison with various intestinal parasites. Stool samples may be required by your doctor to check for eggs. Your doctor may also look for eggs in the duodenal aspirate. Doctors have recovered adult forms of the Clonorchis sinensis during surgery. Treatment for Clonorchiasis requires the prescription medication Albendazole. Praziquantel is another viable option.