Fasciola spp.

This large fluke is distributed worldwide and infects the bile duct of ruminants including cattle and sheep. The fluke often causes hepatitis and cholangitis in ruminants, resulting in financial losses to livestock industries. In humans, it causes fever and abdominal pain, similar to symptoms of gall-stones.

The Japanese species had been believed to be Fasciola hepatica. However, some flukes morphologically similar to Fasciola gigantica (native to African and Asian regions) have been discovered and some flukes with morphological characteristics intermediate between the two species have also been found in Japan. Thus, the identity of the Japanese species has not yet determined.