Fasciola hepatica (Sheep liver fluke)

Images:

Adult: 
http://www.k-state.edu/parasitology/625tutorials/Fasciola01.html
More adults: 
http://www.k-state.edu/parasitology/625tutorials/Hepatica.html
Eggs: 
http://www.k-state.edu/parasitology/625tutorials/Platys01.html
More eggs: 
http://www.k-state.edu/parasitology/625tutorials/Fasciola02.html

Life cycle:

Phylogeny:
Subclass Digenea, Order Echinostomata

Preferred definitive host:
Sheep and cattle, rarely among humans

Reservoir hosts:
Sheep, cattle, rabbits

Vector/intermediate hosts:
#1. Snails – Fossaria modicella or Stagnicola bulimoides; #2. Metacercariae encyst on vegetation.

Geographical location:
Cosmopolitan. Human cases documented in Central & South America, Africa, Asia and Europe

Organs affected:
Biliary ducts, liver.

Symptoms:
Necrosis of liver occurs because of migration through the liver. Anemia can result in heavy infections. Worms in bile ducts cause inflammation and edema, leading to fibrous tissue forming in walls of the ducts. Back pressure causes atrophy of liver parenchyma, thus leading to cirrhosis and jaundice. Ectopic infections occur in eye, brain, skin and lungs.

Treatment:
Rafoxanide, praziquantel