Trematoda is a class within the phylum Platyhelminthes, which contains two groups of parasitic worms, commonly referred to as flukes.
- Aspidogastrea are parasites of freshwater and marine molluscs and vertebrates (cartilaginous and bony fishes and turtles), but do not infect humans.
- Digenea infect all classes of vertebrates, including humans.
Flukes can be classified into two groups, on the basis of the system which they infect. Tissue flukes, are species which infect the bile ducts, lungs, or other biological tissues. This group includes the lung fluke, Paragonimus westermani, and the liver flukes, Clonorchis sinensis and Fasciola hepatica. The other group are known as blood flukes, and inhabit the blood in some stages of their life cycle. Blood flukes include various species of the genus Schistosoma (see Category:Schistosoma).
See also Category:Liver flukes