Galba truncatula (O. F. M眉ller, 1774) or Mud Snail is the vector of fascioliasis in humans.It is the intermediate host for a number of parasitic flukes, including Fasciola hepatica. The snail is infected by the miracidium larva of Fasciola hepatica, various stages of the life cycle occur within the snail resulting in a metacercaria cyst which sticks to grass or water cress which is then ingested by large mammals such as cows, sheep and humans.The snail on the left is uninfected with Fasciola hepatica, the snail on the right with the white tip to its shell is infected with Fasciola hepatica, this is useful in determining the number of snails infected in a population.