Surface fine topography and PCR-based determination of metacercaria of Paragonimus sp. from edible crabs in Arunachal Pradesh, Northeast India

Abstract

In several mountainous regions of Northeastern India, foci of Paragonimus infection reportedly involving species that are known to prevail in China have been identified. The present study was undertaken to demonstrate the surface fine topography and sequence analysis of the ribosomal deoxyribonucleic acid (rDNA; second internal transcribed spacer, ITS2) of the metacercarial stages of the lung fluke collected from a mountain stream of the area (Miao, Changlang District in Arunachal Pradesh). The encysted metacercariae were oval in shape and had a smooth surface. The newly excysted metacercaria had a ventral sucker larger than the oral; the body surface was covered with numerous single-pointed and thorn-like tegumentary spines, of which those on the anterior part of the body were bigger in size and showed a gradual reduction in length and number towards the posterior end; dome-shaped papillae in variable numbers were seen around the rim of the oral sucker and were sparsely distributed all over the body surface. The polymerase chain reaction-amplified rDNA ITS2 sequences of the metacercariae were aligned with known sequences for the various species of Paragonimus, and the expectation value was found to be most significant with P. westermani, revealing an absolute match. The surface topography including the number and distribution of papillae and spination patterns and the ITS2 sequences of the metacercariae strongly suggest that the Paragonimus species, prevalent in the region of India, is in fact P. westermani.

Molecular Characterization of the North American Lung Fluke Paragonimus kellicotti in Missouri and its Development in Mongolian Gerbils

“…22,23 Prior studies have used molecular diagnostics to speciate Paragonimus metacerariae in snails. [24][25][26] However, relatively few studies have attempted to detect Paragonimus DNA in the definitive host. [27][28][29] Our PCR studies confirmed the presence of P. kellicotti DNA in clinical specimens from two Missouri cases.…”

North American Paragonimiasis (Caused by Paragonimus kellicotti ) in the Context of Global Paragonimiasis

“…In this study, they determined that the species present in this area was P. westermani. Once the species designation was fully established using molecular methods (i.e., once any doubt regarding species designation was removed), then the researchers were able to more fully characterize the microscopic morphology of this stage of this species (178). This is an example of how molecular methods may actually strengthen, rather than replace, traditional morphology-based parasitologic methods.…”

A review on the molecular characterization of digenean parasites using molecular markers with special reference to ITS region

“…With the help of these studies, 3 new genera (Caulanus gen. nov., Latuterus gen. nov., (Miller & Cribb, 2007) and Allobilharzia gen. nov. (Kolářová et al, 2006) and 49 new species have been established. Molecular studies of ITS rDNA region verifi ed as promising genetic marker having broad range of application for phylogenetic analyses at generic and species level (Blair et al, 1999;Iwagami et al, 2000;Huang et al, 2004;Tandon et al, 2007;). According to Vilas et al (2005) and Al-Kandari et al (2011) ITS-1 is more variable than ITS-2 due to variable nucleotide repeats (Warberg et al, 2005 in microphallid species) and accretion of substitutions at higher rate (Morgan & Blair, 1995;van Herwerden et al, 1999;Tkach et al, 2000).…”