Clonorchis sinensis, also called liver fluke, parasitizes in human or mammalian bile ducts. Eggs mixed with the bile enter the digestive tract and are discharged with feces. Then they are swallowed by the first intermediate host---freshwater snail and they hatch miracidium in the snails’ digestive tract. The miracidiums develop through three stages: sporocyst, ray larvae and cercariae.
What are the symptoms of infection?
No clinical symptoms or few obvious symptoms appear during mild infection. Patients with severe infections present allergic reactions and gastrointestinal discomfort, including fever, stomach pain, bloating and loss of appetite. But most patients’ acute symptoms are not apparent. Most clinical cases are chronic phase and symptoms often appear gradually over several years. The most common sign is hepatomegaly in the left lobe. Patients with serious infection can also experience dizziness, weight loss, anemia and edema. Clonorchis in the late stages may cause liver cirrhosis, ascites, and even death. Children and adolescents infected with clonorchiasis have heavier clinical manifestations and a higher mortality rate. Young patients can also experience gastrointestinal symptoms, malnutrition, anemia, hypoalbuminemia, edema, hepatomegaly as well as developmental disorders.
How to test for clonorchis?
It can be tested from three aspects:
First, etiology check. Clonorchis suck eggs are found in feces, which is the only apparent evidence of Clonorchis. In general the eggs can be found after one month of infection. These are the common methods :
(1) Smear method, direct smear method is simple but detection rate is not high as the stool is little and the eggs are too small. According to a large-scale survey of intestinal parasites, quantitative transparent method is regarded as the one of most effective methods which can be used in both qualitative and quantitative examination.
(2) Egg collection, detection rate of this method is higher than smear method. Egg collection contains floating eggs and precipitation of egg collection.
(3) Duodenal bile drainage inspection. Centrifugal precipitation by bile drainage can also find eggs.
Second, immuno-diagnosis. With the development of marker technology including enzyme, isotope, biotin and colloidal gold as well as new methods, sensitivity and specificity of serum antibody and antigen have been improved greatly. So, the diagnosis rate has been increased substantially. The general methods conclude IHA,IFAT and ELISA. Immune methods are used widely in clinics now.
Third, image diagnosis. This is also a common method for Clonorchis diagnosis.
How is clonorchis sinensis transmitted?
Eating raw or undercooked fish and shrimp containing metacercariae are the main causes of transmission. So it is necessary to avoid taking metacercariae . It is suggested that eating cooked freshwater fish and using separate utensils for raw food from that for cooked food can help to mitigate against infection. The most widely used drugs for clonorchiasis
are albendazole and praziquantel. If you feel something wrong, do not hesitate to go to hospital for test.
About author: Venus Timberlake from Creative Diagnostics