A case of severe infection of metacercariae from the liver of garfish Xenentodon cancila (Beloniformes: Belonidae): morphological and molecular evidence

Abstract

Using only the morphological traits to describe trematode parasites are a poor indicator of their identification and validation. The current work uses molecular data to describe diplostomoid metacercariae supplemented with morphology found in freshwater garfish, Xenentodon cancila Ham., 1822 collected from River Ganga, of district Bijnour, Meerut region (Uttar Pradesh), India. The metacercariae were identified as Posthodiplostomum pandei (= Neascus pandei) collected from liver shows a high mass of cysts embedded and surrounded by partially damaged liver tissue. Partial DNA sequences of the 18S, internal transcribed spacers (ITS1-5.8S-ITS2) and 28S of nuclear ribosomal DNA were generated and compared with available sequences on the Genbank database. In the phylogenetic analysis of partial sequences from 18S, ITS cluster (ITS1-5.8S-ITS2) and 28S rDNA, P. pandei from India fell within the superfamily Diplostomoidea with other members of Posthodiplostomum also confirms its distinct status and was found close to other Indian species. In Indian region, along with morphology, many species described under Neascus-type metacercariae are awaiting for their validation to be supplemented with molecular data. Furthermore, the validity of few species of genus Posthodiplostomum is also discussed to synonymized with P. pandei in the present study.