Simplify the following text for a Grade 13 native English-speaking person.
Original: Fasciola hepatica , also known as the common liver fluke or sheep liver fluke , is a parasitic flatworm of the class Trematoda , phylum Platyhelminthes that infects liver of various mammals , including humans .
Simplified: Fasciola hepatica , also known as the common liver fluke or sheep liver fluke , is a parasitic flatworm of the class Trematoda , that infects liver of various mammals , including humans .