Paragonimus bangkokensis and P. harinasutai: Reappraisal of Phylogenetic Status

Abstract

Abstract

Paragonimus bangkokensis and P. harinasutai were first found in the same crab host in central Thailand, in 1967 and 1968, respectively. In addition to the repeated finding of both species in Thailand, they have also been found in China and Lao PDR. In Vietnam, only P. bangkokensis, but not P. harinasutai, was found recently in the northern provinces. These two species can be easily distinguished from each other by the morphological features of their metacercarial stage. Adult worms can also be easily distinguished from each other by the arrangement of the cuticular spines. However, recent phylogenetic analysis has revealed that the DNA sequences of the nuclear ribosomal second internal transcribed spacer region (ITS2) and the partial mitochondrial cytochrome oxidase subunit 1 (CO1) genes of P. bangkokensis and P. harinasutai are very similar. In addition, several Paragonimus spp–P. paishuihoensis, P. menglensis, and P. xiangshanensis in China–were found to be genetically similar to P. bangkokensis. The Thai isolate of P. paishuihoensis was also shown to be genetically similar to P. bangkokensis/P. harinasutai. Moreover, a possible monophyletic relationship of P. ohirai and its synonyms, P. sadoensis and P. iloktuenensis, with P. bangkokensis and P. harinasutai, has been reported repeatedly. In this review, the conflict and the congruence of morphological and molecular identifications of P. bangkokensis and P. harinasutai, and their phylogenetic status among the Paragonimus spp, are discussed.

Keywords : Paragonimus, P. bangkokensis, P. harinasutai, species complex