title: Detection of pathogenic Batrachochytrium dendrobatidis using water filtration, animal and bait testing.
abstract: The pathogen Batrachochytrium dendrobatidis (Bd) can be challenging to detect at endangered amphibian reintroduction sites. Pre-release Bd detection can be confounded by imperfect animal sampling and the absence of animals. In Study 1, we used historical Bd-positive sites, to concurrently evaluate water filtrates and mouth bar (tadpoles) or skin swab (caudates) samples for Bd using molecular beacon realtime PCR. In Study 2, during a natural outbreak, we used PCR to detect Bd from zoospore-attracting keratin baits (three avian, three snake species). In Study 1, no captured animals (n=116) exhibited clinical signs, although 10.6% were positive, representing three of seven species sampled. In contrast, 5.4% of water filters (n=56) were Bd-positive. In Study 2, after short incubation times, a single duck down feather tested Bd-positive. In conclusion, Bd was detected in asymptomatic amphibians and water filtrate at two sites, and from water only, at two other sites. With continued refinement, semi-quantitative Bd water filtrate screening could better define zoospore-specific disease risk, allowing better characterization of the free-living phase of the organism's life cycle. Finally, these results suggest wild aquatic birds (e.g., waterfowl) should be systematically explored as a means of Bd spread. Since large numbers of aquatic birds migrate, even low Bd transfer rates could be a significant means for disease dissemination.
authors.affiliation: Department of Medicine, West Virginia University, Morgantown, West Virginia.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Wimsatt
authors.forename: Sanford H
authors.initials: SH
authors.lastname: Feldman
authors.forename: Meghan
authors.initials: M
authors.lastname: Heffron
authors.forename: Meagan
authors.initials: M
authors.lastname: Hammond
authors.forename: Margaret P Roth
authors.initials: MP
authors.lastname: Ruehling
authors.forename: Kristine L
authors.initials: KL
authors.lastname: Grayson
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Mitchell
mesh_terms: D000818:Animals; D001001:Anura / Q000382:microbiology*; D008411:Chytridiomycota / Q000302:isolation & purification* / Q000472:pathogenicity; D017931:DNA Primers / Q000235:genetics; D004372:Ducks / Q000382:microbiology; D005241:Feathers / Q000382:microbiology; D005618:Fresh Water / Q000382:microbiology*; D007814:Larva / Q000382:microbiology; D009657:North Carolina; D060888:Real-Time Polymerase Chain Reaction; D012911:Snakes / Q000382:microbiology; D014768:Virginia
chemical_list: D017931:DNA Primers
keywords: Batrachochytrium dendrobatidis; amphibians; chytridiomycosis; keratin; molecular beacon realtime PCR; water testing