A parasitic worm, fluke.
A parasitic flatworm.
Parasitic flatworm, some of which cause disease in humans (e.g., schistosomiasis).
A type of parasitic flatworm that includes the fluke. Trematodes can live in four different animal hosts in the course of their life cycle. During the first stage, pond snails are hosts to trematode eggs, which hatch inside the snail into tiny swimming trematodes that migrate out of the snail and into the pond water. They locate a tadpole host and burrow in, converting into a tough cyst that remains in the tadpole throughout the tadpole’s life cycle. The tadpole undergoes metamorphosis to become a frog, and if there are many trematode cysts present, the frog may become deformed or grow extra legs. If the tadpole or frog is eaten by a garter snake, the snake then eats the trematodes and becomes a host for the parasite. In the snake, the trematode develops from a cyst into an adult that lays eggs. The eggs are eliminated from the snake’s intestines at the bottom of the pond, where aquatic snails feed. Trematode eggs on the plants and algae that the snails eat begin their life cycle again inside the snails. Trematodes enter the human body if people eat contaminated snails or drink contaminated water.
A parasitic flatworm belonging to the class Trematoda.