Paropisthorchis caninus Stephens, 1912: Synopsis of identity and pathological findings due to spontaneous infection in the liver of a street dog in Assam, India.

The present study describes a small liver fluke recovered at post-mortem and the pathological alteration produced by the parasite in the liver of a street dog from Assam, India. The spatulate parasite measured 3-4 mm in length and 1.0-1.25 mm in width with spiny body surface and showed a grossly visible peduncle projecting from the ventral surface at the anterior portion. The eggs of the parasite contained well developed miracidia. The parasite was identified as Paropisthorchis caninus. Identity of the parasite is discussed in the light of available literature and found to be morphologically different from other reported species of dog Opisthorchis. Pathological lesions observed in the liver included degeneration of hepatic parenchyma, hyperplasia of bile duct epithelium, fibrous tissue proliferation and formation of pseudo lobule which were the characteristics of chronic proliferative inflammation.