Morphological and molecular characterization of Explanatum explanatum from cattle and buffaloes in Myanmar.

A robust molecular marker is needed for discrimination of amphistome species, because identification based on morphology alone requires specialized knowledge and techniques. In this study, we performed morphological and molecular characterization of Explanatum explanatum, a species that causes severe liver damage in definitive host species. Fifty-five adult amphistomes were collected from cattle and water buffaloes in Myanmar. Eighteen of the amphistomes, arbitrarily chosen, were morphologically identified as E. explanatum using sagittal sections. All of the 55 amphistome isolates had identical second internal transcribed spacer (ITS2) of ribosomal DNA sequences; these sequences differed at 7 nucleotide sites from those of the closest species, Paramphistomum leydeni. Our data indicate that the ITS2 sequence could be a useful molecular marker for epidemiological studies on E. explanatum.