title: Novel, panzootic and hybrid genotypes of amphibian chytridiomycosis associated with the bullfrog trade.
abstract: Global amphibian declines are linked with the presence of specific, highly virulent genotypes of the emerging fungal disease chytridiomycosis caused by Batrachochytrium dendrobatidis (Bd) known as the global panzootic lineage (Bd-GPL). The global trade in amphibians for human consumption is suspected to have facilitated emergence of the disease, but evidence to support this is largely lacking. Here, we investigated the role the Lithobates catesbeianus (North American bullfrog) trade in spreading Bd genotypes by comparing strains associated with L. catesbeianus to a global panel using 36 sequenced loci from multiple chromosomal regions. Most bullfrogs were infected with Bd-GPL genotypes, but we also detected novel, highly divergent Bd genotypes (Bd-Brazil) from a live bullfrog in a US market and from native Brazilian anurans in the Atlantic Forest where bullfrogs are widely farmed. Sexual reproduction was also detected for the first time in Bd in the form of a hybrid genotype between the Bd-GPL and Bd-Brazil lineages in the Atlantic Forest. Despite the demonstration that ribosomal RNA types in Bd fail to undergo concerted evolution (over 20 sequence types may be found in a single strain), the Bd-GPL and Bd-Brazil lineages form largely separate clusters of related internal transcribed spacer (ITS) RNA sequences. Using ITS sequences, we then demonstrate the presence of Bd-Brazil in Japan, primarily on invasive L. catesbeianus. The finding that Bd is capable of sexual reproduction between panzootic and endemic genotypes emphasizes the risk of international wildlife trade as a source of additional Bd epizootics owing to hybridization.
authors.affiliation: EcoHealth Alliance, New York, NY 10001, USA. schloegel@ecohealthalliance.org
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Schloegel
authors.forename: Luís Felipe
authors.initials: LF
authors.lastname: Toledo
authors.forename: Joyce E
authors.initials: JE
authors.lastname: Longcore
authors.forename: Sasha E
authors.initials: SE
authors.lastname: Greenspan
authors.forename: Conrado Augusto
authors.initials: CA
authors.lastname: Vieira
authors.forename: Maria
authors.initials: M
authors.lastname: Lee
authors.forename: Serena
authors.initials: S
authors.lastname: Zhao
authors.forename: Catherine
authors.initials: C
authors.lastname: Wangen
authors.forename: Claudia Maris
authors.initials: CM
authors.lastname: Ferreira
authors.forename: Márcio
authors.initials: M
authors.lastname: Hipolito
authors.forename: Angela J
authors.initials: AJ
authors.lastname: Davies
authors.forename: Christina A
authors.initials: CA
authors.lastname: Cuomo
authors.forename: Peter
authors.initials: P
authors.lastname: Daszak
authors.forename: Timothy Y
authors.initials: TY
authors.lastname: James
mesh_terms: D000818:Animals; D001938:Brazil; D002678:Chimera / Q000235:genetics*; D008411:Chytridiomycota / Q000235:genetics*; D004271:DNA, Fungal / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D014644:Genetic Variation; D005838:Genotype; D007564:Japan; D008969:Molecular Sequence Data; D009181:Mycoses / Q000382:microbiology / Q000662:veterinary; D011892:Rana catesbeiana / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D014481:United States
chemical_list: D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer