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 the livers of various mammals, including humans. The disease caused by the fluke is called fascioliasis (also known as fasciolosis). One of the largest flukes in the world, F. hepatica reaches 30 mm in length and 13 mm in width.
It is large enough that the above photo of a prepared slide was not taken with a microscope, but scanned on a flat bed scanner!
F. hepatica is distributed worldwide, and causes great economic losses in sheep and cattle. It has been known as an important parasite of sheep and cattle for hundreds of years.
The photomicrograph below shows eggs found in the black masses on the left of the main photo near the fluke’s head.