Evidence of Diversity, Site, and Host Specificity of Sea Turtle Blood Flukes (Digenea: Schistosomatoidea: Spirorchiidae): A Molecular Prospecting Study

Brian A Stacy, Phoebe A Chapman, Allen M Foley, Ellis C Greiner, Lawrence H Herbst, Alan B Bolten, Paul A Klein, Charles A Manire, Elliott R Jacobson

Neospirorchis (Digenea: "Spirorchiidae") are blood flukes of sea turtles. Trematodes tentatively identified as Neospirorchis sp. infect various sites within sea turtles inhabiting waters of the southeastern United States, but efforts to obtain specimens adequate for morphologic study has proven difficult. Two genetic targets, the internal transcribed spacer region of the ribosomal RNA gene and the partial mitochrondrial cytochrome c oxidase subunit I gene, were used to investigate potential diversity among parasite specimens collected from stranded sea turtles. Sequence data were obtained from 215 trematode and egg specimens collected from 92 individual free-ranging cheloniid sea turtles comprising 4 host species. Molecular analysis yielded over 20 different genotypes. We were able to assign 1 genotype to 1 of the 2 recognized species, Neospirorchis pricei Manter and Larson, 1950. In many examples, genotypes exhibited host and site specificity. Our findings indicate considerable diversity of parasites resembling Neospirorchis with evidence of a number of uncharacterized blood flukes that require additional study.