That's the disease caused by me, the Chinese liver fluke. I'm a parasite
. You can read about me in my profile, but just to reiterate, clonorchiasis is a chronic infection caused by Clonorchis sinensis
(that's me!), or the liver fluke, a parasitic worm 10 to 25 mm long that lives in the bile ducts of the liver in humans and other mammals. Clonorchiasis is a common disease in China, Vietnam, Korea, and Japan and is acquired by eating freshwater fish containing the fluke larvae.
Fluke infections are diseases of the digestive tract and other organ systems caused by several different species of parasitic flatworms (Trematodes) that have complex life cycles involving hosts other than human beings. Trematode comes from a Greek word that means "having holes" and describes the external suckers that the adult flukes use to draw nutrients from their hosts. Fluke infections are contracted by eating uncooked fish, plants, or animals from fluke-infected waters. The symptoms vary according to the type of fluke infection.
In humans, fluke infections can be classified according to those diseases caused by liver flukes and those caused by lung flukes. Diseases caused by liver flukes include fascioliasis, opisthorchiasis, and clonorchiasis. Cases of liver fluke infection have been reported in Europe and the United States, as well as the Middle East, China, Japan, and Africa. Diseases caused by lung flukes include paragonimiasis. Paragonimiasis is a common infection in the Far East, Southeast Asia, Africa, Central and South America, Indonesia, and the Pacific Islands.
It is estimated that between 40 million and 100 million people worldwide suffer from either liver or lung fluke infections.
In their adult stage, liver and lung flukes are symmetrical in shape and look somewhat like long, plump leaves or blades of grass. They enter through the mouth and can infect any person at any age.
The symptoms of fluke infection differ somewhat according to the type of fluke involved. All forms of liver and lung fluke infection, however, have the following characteristics:
• Most persons who becomeinfected do not develop symptoms (asymptomatic)
• The early symptoms of an acute fluke infection are not unique to these diseases alone (nonspecific symptoms)
• Infection does not confer immunity against re-infection by the same species or infection by other species of flukes.
This blog was created as a project for a class at Stanford University: Human Biology 103, Parasites and Pestilence. Its goal is to provide basic information about the parasite and the disease in these early posts, and to continue updating as news and research about clonorchiasis continue to be produced. Some navigational aids:
• Graphic credits, links and references are posted under "Comments" for each section. Any images used will be taken down immediately if their owners email a request.
• The "favorite books" section of the profile also includes helpful sources that were used in creating this blog.
• The "Archives" section for May 2004 will contain all of the basic information, so please navigate from there if you are new to the site.
• Please email me with questions or comments! We would welcome your feedback.