DNA barcoding of sea turtle leeches (Ozobranchus spp.) in Florida coastal waters

Abstract

<p>Fibropapillomatosis (FP) is a neoplastic disease originally identified only on green sea turtles (Chelonia mydas). The disease is likely to be terminal if tumors are developed internally, but external tumors on the eyes, mouth, and flippers can also lead to fatal impairment of vision and difficulty feeding and swimming. The involvement of an environmental cofactor appears possible since many FP outbreaks occur at sites of poor water quality in Florida, Hawaii, Brazil, and other similar places around the world, but outbreaks have also been recorded at less contaminated sites. Studies have shown an association between FP and the fibropapilloma-associated turtle herpesvirus (FPTHV), but not all turtles with FPTHV develop FP. Thus, the etiological agent of FP is still unknown. Recently, high viral loads of FPTHV were detected in marine turtle leeches (Ozobranchus spp.) from a green sea turtle but the study failed to identify the species of marine leech. Leeches, known to be indicators of environmental stress factors, may transmit or activate FPTHV but are impossible to identify at all life stages using current standard taxonomic practices. In this study, character-based DNA barcoding using mitochondrial cytochrome c oxidase I (COI) gene as a molecular marker was employed successfully to identify both species of Ozobranchus spp. (Ozobranchus branchiatus and Ozobranchus margoi) at all stages of development from eight different sites in Florida (Daytona Beach to Key West). This is the first study to document the O. branchiatus leech on a loggerhead (Caretta caretta) and the first to identify multiple leech species infestation on one turtle (C. mydas). Genetic sequences for O. branchiatus and O. margoi were submitted to the National Center for Biotechnology Information GenBank with O. branchiatus added as a new species to the database. The spread of FP to other species of turtles combined with the discovery of a new turtle host for the O. branchiatus leech suggests the vector organism involvement behind FP maybe species specific. </p><p>This poster was presented at the Wright State University Campus-Wide Celebration of Research, Scholarship and Creative Activities on April 8, 2011 and at the Dayton Chapter American Chemical Society/ Ohio Valley Section of the Society for Applied Spectroscopy on March 1, 2011.</p>