The Chinese liver fluke, Clonorchis sinensis attaches to the wall of the bile duct in the liver and consumes the tissue cells there.
Symptoms of clonorchiasis (Chinese liver fluke infection)
Many people in East and Southeast Asia harbour Chinese liver flukes, usually acquired by eating raw fish, and don’t know it: light infections are common, and may cause no symptoms. Some infections, however, involve thousands of worms.
Most symptoms of clonorchiasis are the result of long term (chronic) infection; however, symptoms of acute clonorchiasis have been reported (Ip et al), When present, these symptoms may include:
- fever
- malaise (a general feeling of being unwell)
- rash
- discomfort in the area of the liver (on the right, high up under the edge of the ribs)
Over the long term, the presence of C. sinensis flukes in the bile ducts causes inflammation and obstruction of the flow of bile. Chronic symptoms reflect these processes:
- thickening of bile duct walls
- blockage of bile ducts, possibly leading to jaundice
- damage to liver tissue and function due to perforation of bile duct walls
- acute inflammation of the pancreas
- acute inflammation of the common bile duct
- gall stones, which form around eggs produced by the worms
Does Clonorchis sinensis cause liver cancer?
An association between high rates of infection with Chinese liver fluke and high incidence of liver cancer has long been noted. These worms feed on tissue cells in the bile ducts and may excrete a substance that induces cells to multiply, a process that could lead to the uncontrolled multiplication of cells seen in cancer. This has been studied in Opistorchis viverrini, a similar fluke of Southeast Asia.
Diagnosis and treatment of clonorchiasis
Most cases of Chinese liver fluke infection are diagnosed by recovery of the characteristic eggs in stool samples; however, this method is subject to false negative results because eggs may be too rare for detection. Other methods that have been used include blood tests for antibodies to the parasite, and skin tests to detect an immune reaction. Scans of the liver and examination of bile can also be used.
Clonorchiasis can be treated with anti-parasitic drugs.
Disclaimer: The information contained in this article is for educational purposes only and should not be used for diagnosis or to guide treatment without the opinion of a health professional. Any reader who is concerned about his or her health should contact a doctor for advice.
Sources
Ip, Margaret, Nancy Leung, Augustine F. Cheng. “Acute Clonorchiasis.” Scandinavian Journal of Infectious Diseases 27:6 1995
Kim, Ho Gak, Jimin Han, Myung-Hawn Kim et al. “Prevalence of Clonorchiasis in Patients With Gastrointestinal Disease: A Korean Nationwide Multicenter Survey.” World Journal of Gastroenterology 15:1 2009
Roberts, Larry S., and John Janovy Jr. Foundations of Parasitology 6th ed. Boston: McGraw Hill, 2000
Rosemary Drisdelle - Rosemary Drisdelle has been published many times as a nonfiction writer and several times as a poet. Her first book, Parasites: Tales of ...
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