fasciola is a liver fluke (a type of parasitic worm) that can infect the liver and bile duct of exposed people and animals
two species can infect people:
Fasciola hepatica: the main species that infects people.
AKA “the common liver fluke” and “the sheep liver fluke”
occurs on all continents except Antarctica, especially where there are sheep, cattle or goats, although human infections are rare in USA and Australia
Fasciola gigantica: a related species that primarily affects domestic and wild animals but can also infect people but only occurs in parts of Africa and Asia
most infections occur after eating raw watercress or freshwater plants contaminated by larvae, vegetables washed by contaminated water, or drinking contaminated water