title: Mass mortality associated with a frog virus 3-like Ranavirus infection in farmed tadpoles Rana catesbeiana from Brazil.
abstract: Ranaviruses (Iridoviridae) are increasingly associated with mortality events in amphibians, fish, and reptiles. They have been recently associated with mass mortality events in Brazilian farmed tadpoles of the American bullfrog Rana catesbeiana Shaw, 1802. The objectives of the present study were to further characterize the virus isolated from sick R. catesbeiana tadpoles and confirm the etiology in these outbreaks. Sick tadpoles were collected in 3 farms located in Goiás State, Brazil, from 2003 to 2005 and processed for virus isolation and characterization, microbiology, histopathology, and parasitology. The phylogenetic relationships of Rana catesbeiana ranavirus (RCV-BR) with other genus members was investigated by PCR with primers specific for the major capsid protein gene (MCP) and the RNA polymerase DNA-dependent gene (Pol II). Sequence analysis and multiple alignments for MCP products showed >99% amino acid identity with other ranaviruses, while Pol II products showed 100% identity. Further diagnostics of the pathology including histology and transmission electron microscopy confirmed the viral etiology of these mass deaths. As far as we know, this is the first report of a ranaviral infection affecting aquatic organisms in Brazil. Additionally, our results suggest that American bullfrogs may have served as a vector of transmission of this virus, which highlights the potential threat of amphibian translocation in the world distribution of pathogens.
authors.affiliation: Instituto de Investigaciones Pesqueras, Facultad de Veterinaria, Universidad de la República, Montevideo, Uruguay. rolo@pes.fvet.edu.uy
authors.forename: Rolando
authors.initials: R
authors.lastname: Mazzoni
authors.forename: Albenones José
authors.initials: AJ
authors.lastname: de Mesquita
authors.forename: Luiz Fernando F
authors.initials: LF
authors.lastname: Fleury
authors.forename: Wilia Marta Elsner Diederichsen
authors.initials: WM
authors.lastname: de Brito
authors.forename: Iolanda A
authors.initials: IA
authors.lastname: Nunes
authors.forename: Jacques
authors.initials: J
authors.lastname: Robert
authors.forename: Heidi
authors.initials: H
authors.lastname: Morales
authors.forename: Alexandre Siqueira Guedes
authors.initials: AS
authors.lastname: Coelho
authors.forename: Denise Leão
authors.initials: DL
authors.lastname: Barthasson
authors.forename: Leonardo
authors.initials: L
authors.lastname: Galli
authors.forename: Marcia H B
authors.initials: MH
authors.lastname: Catroxo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017756:Aquaculture; D001938:Brazil / Q000453:epidemiology; D004266:DNA Virus Infections / Q000453:epidemiology / Q000662:veterinary* / Q000821:virology; D007814:Larva; D008969:Molecular Sequence Data; D011892:Rana catesbeiana; D017995:Ranavirus / Q000145:classification*; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D014764:Viral Proteins