title: Elucidation of the first definitively identified life cycle for a marine turtle blood fluke (Trematoda: Spirorchiidae) enables informed control.
abstract: Blood flukes of the family Spirorchiidae are significant pathogens of both free-ranging and captive marine turtles. Despite a significant proportion of marine turtle mortality being attributable to spirorchiid infections, details of their life cycles remain almost entirely unknown. Here we report on the molecular elucidation of the complete life cycle of a marine spirorchiid, identified as Amphiorchis sp., infecting vermetid gastropods and captive hatched neonate Caretta caretta in the Oceanogràfic Aquarium, in Valencia, Spain. Specimens of a vermetid gastropod, Thylaeodus cf. rugulosus (Monterosato, 1878), collected from the aquarium filtration system housing diseased C. caretta, were infected with sporocysts and cercariae consistent with the family Spirorchiidae. We generated rDNA sequence data [internal transcribed spacer 2 (ITS2) and partial 28S rDNA] from infections from the vermetid which were identical to sequences generated from eggs from the serosa of the intestine of neonate C. caretta, and an adult spirorchiid from the liver of a C. caretta from Florida, USA. Given the reliability of these markers in the delineation of trematode species, we consider all three stages to represent the same species and tentatively identify it as a species of Amphiorchis Price, 1934. The source of infection at the Oceanogràfic Foundation Rehabilitation Centre, Valencia, Spain, is inferred to be an adult C. caretta from the western Mediterranean being rehabilitated in the same facility. Phylogenetic analysis suggests that this Amphiorchis sp. is closely related to other spirorchiids of marine turtles (species of Carettacola Manter & Larson, 1950, Hapalotrema Looss, 1899 and Learedius Price, 1934). We discuss implications of the present findings for the control of spirorchiidiasis in captivity, for the better understanding of epidemiology in wild individuals, and the elucidation of further life cycles.
authors.affiliation: The University of Queensland, School of Biological Sciences, St Lucia, Queensland 4072, Australia. Electronic address: T.Cribb@uq.edu.au.
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Cribb
authors.affiliation: Fundación Oceanogràfic, Veterinary Services & Research Department, Avanqua Oceanogràfic-Ágora, C/ Eduardo Primo Yúfera 1B, 46013 Valencia, Spain.
authors.forename: Jose L
authors.initials: JL
authors.lastname: Crespo-Picazo
authors.affiliation: The University of Queensland, School of Biological Sciences, St Lucia, Queensland 4072, Australia.
authors.forename: Scott C
authors.initials: SC
authors.lastname: Cutmore
authors.affiliation: National Marine Fisheries Service, Office of Protected Resources and University of Florida, College of Veterinary Medicine, Gainesville, FL, USA.
authors.forename: Brian A
authors.initials: BA
authors.lastname: Stacy
authors.affiliation: The University of Queensland, Veterinary Marine Animal Research, Teaching and Investigation Unit, School of Veterinary Science, Gatton, Queensland 4343, Australia.
authors.forename: Phoebe A
authors.initials: PA
authors.lastname: Chapman
authors.affiliation: Fundación Oceanogràfic, Veterinary Services & Research Department, Avanqua Oceanogràfic-Ágora, C/ Eduardo Primo Yúfera 1B, 46013 Valencia, Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: García-Párraga
mesh_terms: D000818:Animals; D001483:Base Sequence; D018509:DNA, Helminth / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D007422:Intestines / Q000469:parasitology; D008018:Life Cycle Stages; D008099:Liver / Q000469:parasitology; D009792:Oceans and Seas; D010802:Phylogeny; D012339:RNA, Ribosomal, 28S / Q000235:genetics; D015203:Reproducibility of Results; D014200:Trematoda / Q000145:classification / Q000235:genetics / Q000254:growth & development*; D014201:Trematode Infections / Q000469:parasitology / Q000662:veterinary; D014426:Turtles / Q000097:blood* / Q000469:parasitology*
chemical_list: D018509:DNA, Helminth; D004275:DNA, Ribosomal; D012339:RNA, Ribosomal, 28S
keywords: Conservation; Life cycle; Sea turtles; Spirorchiidae; Transmission; Trematoda; Vermetidae