Liver fluke laying eggs. Close up of an adult liver fluke (Fasciola hepatica) laying eggs. The liver fluke is a hermaphrodite parasitic trematode (flatworm). It infects the livers of various mammals, including humans, causing a disease known as fascioliasis. Immature flukes emerge from cysts ingested with infected vegetation. They migrate into the bile ducts via the duodenum and liver, where they feed on blood and tissue. They mature and lay eggs which contaminate water via the host's faeces. The eggs hatch in water and infect certain freshwater pond snails from which larvae later emerge. The larvae form cysts on nearby vegetation, thus continuing the fluke's life cycle. Footage filmed at Ridgeway Research, Gloucestershire, United Kingdom.