Larva develop into adults that reside in the liver tissue and bile ducts. Clonorchis senensis is commonly known as the Chinese liver fluke, and infection by this fluke is common in Southeast Asia. Larva in infected water burrow through the skin of a host to gain entry to the host circulatory system. They then emerge in the GI tract, where they find their way up the bile ducts where they prefer to live. The male and female adult worms live in the bile ducts in a state of continuous copulation, producing eggs that traverse the bile ducts to pass with the feces to contaminate water for the infectious cycle to repeat with another unwary host.
Anemia is common with heavy infection.
The worm infects a host by either ingestion of the worm eggs, or by the larva of the worm entering the skin of the host and then traveling by way of the blood to the vessels surrounding the gastrointestinal tract, from which the larva exit to colonize the intestine. Eggs passed from an infected mammal can hatch into larva that reside on moist grass- waiting for the skin of an unwary animal to pass by, so that the cycle can repeat. The larvae colonize the lymphatic vessels and grow into adult worms in the lymphatics, usually in the groin and extremity regions of the lymphatic system. An infected host sheds eggs. Blood loss, anemia, hunger.