Molecular characterization and histopathological studies on Fasciola gigantica in Mithun (Bos frontalis)

Abstract

Mitochondrial DNA sequence of the sub-unit 1 of cytochrome c oxidase (Cox1) and ribosomal DNA sequence of the first internal transcribed spacer (ITS-1) of Fasciola collected from mithun and cattle from Arunachal Pradesh, India were characterized at molecular level in order to identify the species of parasite. Based on sequence and phylogenetic analysis, the identity of the parasite was confirmed as Fasciola gigantica in mithun as well as from cattle. In order to know histopathological alteration in Fasciola infection, a histopathological study was performed on eight liver specimens, out of 110 animals studied during the period from 2010-2016. Histopathological examination of F.gigantica infected liver showed extensive fibrous connective tissue proliferation with necrosis of hepatocytes and infiltration of polymorphonuclear cell. There was evidence of migratory tracts of parasites with losing of normal lobular hepatic architecture. Bile duct proliferation was followed by congestion of portal vein with perivascular cuffing with surrounding degeneration of hepatocytes. The hepatocytes showed pyknosis with hyperplasia of bile duct.