}} The Clonorchis sinensis is a human liver fluke in the class Trematoda, Phylum Platyhelminthes. This parasite lives in the liver of humans, and is found mainly in the common bile duct and gall bladder, feeding on bile. These animals, which are believed to be the third most prevalent worm parasite in the world, are endemic to Japan, China, Taiwan, Vietnam, Korea, and Southeast Asia, currently infecting an estimated 30,000,000 humans. Look up Fluke in Wiktionary, the free dictionary. ... Subclasses Aspidogastrea Digenea The Trematoda is a class within the phylum Platyhelminthes, which contains two groups of parasitic worms. ... Classes Monogenea Trematoda Cestoda Turbellaria The flatworms (Platyhelminthes, Greek platy: flat; helminth: worm) are a phylum of relatively simple soft-bodied invertebrate animals. ... A parasite is an organism that spends a significant portion of its life in or on the living tissue of a host organism and which causes harm to the host without immediately killing it. ... The liver is an organ present in vertebrates and some other animals. ... A bile duct is any of a number of long tube-like structures that carry bile. ... The gallbladder (or cholecyst) is a pear-shaped organ that stores bile (or gall) until the body needs it for digestion. ... Bile (or gall) is a bitter, yellow or green alkaline fluid secreted by hepatocytes from the liver of most vertebrates. ... This article is about the Korean peninsula and civilization. ... Location of Southeast Asia Southeast Asia is a subregion of Asia. ...

Life cycle

The egg of a Clonorchis sinensis (commonly: human liver fluke, which contains the miracidium that develops into the adult form, floats in freshwater until it is eaten by a snail.

Once inside of the snail body, the miracidium hatches from the egg, and parasitically grows inside of the snail. The miracidium develops into a sporocyst, which in turn house the asexual reproduction of redia, the next stage. The redia themselves house the asexual reproduction of free-swimming cercaria. This system of asexual reproduction allows for an exponential multiplication of cercaria individuals from one miracidium. This aids the Clonorchis in reproduction, because it enables the miracidium to captilatize on one chance occasion of passively being eaten by a snail before the egg dies.

Once the redia mature, having grown inside the snail body until this point, they actively bore out of the snail body into the freshwater environment. There, instead of waiting to be consumed by a host (as is the case in their egg stage), they seek out a fish. Boring their way into the fish's body, they again become parasites of their new hosts.

Once inside of the fish muscle, the cercaria create a protective metacercarial cyst with which to encapsulate their bodies. This protective cyst proves useful when the fish muscle is consumed by a human. The acid-resistant cyst enables the metacercaria to avoid being digested by the human gastric acids, and allows the metacercaria to reach the small intestine unharmed. Reaching the small intestines, the metacercaria navigate toward the human liver, which becomes its final habitat. Clonorchis feed on human bile created by the liver. In the human liver, the mature Clonorchis reaches its stage of sexual reproduction. The hemaphroditic adults produce eggs every 1–30 seconds, resulting in the rapid multiplication of inhabitants in the liver.

Effects on human health

Dwelling in the bile ducts, Clonorchis induces an inflammatory reaction, epithelial hyperplasia and sometimes even adenocarcinoma of the bile ducts (cholangiocarcinoma), the incidence of which is high in fluke-infested areas. One adverse effect of Clonorchis is the possibility for the adult metacercaria to consume all bile created in the liver, which would inhibit the host human from digesting, especially fats. Another possibility is obstruction of the bile duct by the parasite or its eggs, leading to biliary obstruction and cholangitis (specifically oriental cholangitis). Hyperplasia (or hypergenesis) is a general term for an increase in the number of the cells of an organ or tissue causing it to increase in size. ... Adenocarcinoma is a form of carcinoma that originates in glandular tissue. ... // [edit] Introduction Cholangiocarcinoma is an adenocarcinoma of the biliary duct system. ... A bile duct is any of a number of long tube-like structures that carry bile. ... Cholangitis is one of a number of problems associated with the bile duct. ...

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