Liver fluke. Macro photograph showing the dorsal (upper, left) and ventral (underside, right) views of an adult liver fluke (Fasciola hepatica). Liver flukes are parasitic tremotode flatworms that live in the bile duct of various mammals. The ventral view shows the oral and ventral suckers (round, top) which the fluke uses to attach itself to its host. The branching brown pattern is the diverticulum (gut) engorged with blood and the white dots are eggs.