title: Frog virus 3 prevalence in tadpole populations inhabiting cattle-access and non-access wetlands in Tennessee, USA.
abstract: Ranaviruses have been associated with most of the reported larval anuran die-offs in the United States. It is hypothesized that anthropogenically induced stress may increase pathogen prevalence in amphibian populations by compromising immunity. Cattle use of wetlands may stress resident tadpole populations by reducing water quality. We isolated a Ranavirus from green frog Rana clamitans (n = 80) and American bullfrog R. catesbeiana (n = 104) tadpoles collected at 5 cattle-access and 3 non-access wetlands on the Cumberland Plateau, Tennessee, USA. Sequencing confirmed Frog virus 3 (FV3); therefore, we compared its prevalence between tadpole populations inhabiting cattle-access and non-access wetlands, and among 3 seasons (winter, summer, and autumn) in 2005. We found FV3 in both tadpole species and cattle land-use types; however, prevalence of FV3 was greater in green frog tadpoles residing in cattle-access wetlands compared to those in non-access wetlands. No difference in FV3 prevalence was detected between cattle land uses for American bullfrog tadpoles. A seasonal trend in FV3 prevalence also existed, with prevalence greater in autumn and winter than in summer for both species. In addition, we found that FV3 prevalence decreased significantly as Gosner stage increased in American bullfrog tadpoles. No trend was detected between FV3 prevalence and developmental stage for green frog tadpoles. Our results suggest that cattle use of wetlands may increase prevalence of FV3 in Rana tadpoles, although this effect may depend on species, season, and tadpole developmental stage.
authors.affiliation: Center for Wildlife Health, Department of Forestry, Wildlife and Fisheries, University of Tennessee, 274 Ellington Plant Sciences Building, Knoxville, Tennessee 37996-4563, USA. mgray11@utk.edu
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Gray
authors.forename: Debra L
authors.initials: DL
authors.lastname: Miller
authors.forename: A Chandler
authors.initials: AC
authors.lastname: Schmutzer
authors.forename: Charles A
authors.initials: CA
authors.lastname: Baldwin
mesh_terms: D000818:Animals; D001483:Base Sequence; D036022:Capsid Proteins / Q000235:genetics; D002417:Cattle; D017931:DNA Primers / Q000737:chemistry; D004266:DNA Virus Infections / Q000453:epidemiology / Q000662:veterinary*; D007814:Larva / Q000821:virology; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction / Q000662:veterinary; D015995:Prevalence; D011892:Rana catesbeiana / Q000821:virology; D017995:Ranavirus / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D011898:Ranidae / Q000821:virology*; D012621:Seasons; D013714:Tennessee / Q000453:epidemiology; D053833:Wetlands
chemical_list: D036022:Capsid Proteins; D017931:DNA Primers