Infection by and Molecular Features of (Digenea: Schistosomatoidea) in Green Sea Turtles () on the Ogasawara Islands, Japan.

Price, 1934 , is a blood fluke found in sea turtles, and the adult fluke parasitizes the cardiovascular system of the host. In this study we surveyed 46 green sea turtles, , on the Ogasawara Islands, Japan, and blood flukes were detected in the heart and blood vessels of 26 turtles. The flukes were identified as based on a detailed morphological description. In addition, molecular identification and characterization of the parasite were performed. The nucleotide sequences of nuclear internal transcribed spacer 2 () regions were almost identical to those of reported previously, but not to those of spp., which is the closest related genus. The nucleotide sequences of the ribosomal DNA region formed a single clade with those of the reference in the phylogenetic tree, but not with those of spp. Therefore, the nucleotide sequences of and are robust markers for distinguishing from other species. The nucleotide sequences of the mitochondrial cytochrome oxidase subunit 1 () region were analyzed to evaluate the genetic variations in . The haplotypes revealed the extremely high genetic diversity of the species as well as the host turtles on the Ogasawara Islands. The haplotype frequency in the mitochondrial DNA of the green sea turtles on the Ogasawara Islands is known to be significantly different from those in other Pacific rookeries. Although the number of analyzed flukes is small in this study, no haplotype was close to that in other areas; on the basis of the data, we hypothesized that differentiated along with the host turtles on the Ogasawara Islands.