SREL Reprint #3045

Prevalence of Batrachochytrium dendrobatidis in American Bullfrog and Southern Leopard Frog Larvae from Wetlands on the Savannah River Site, South Carolina

John D. Peterson^1,2, Maranda B. Wood¹, William A. Hopkins^2,3, Jason M. Unrine², and
Mary T. Mendonça¹

¹Department of Biological Sciences, Auburn University, Auburn, Alabama 36849, USA
²Savannah River Ecology Laboratory, University of Georgia, Aiken, South Carolina 29802, USA
³Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, USA

Abstract: Batrachochytrium dendrobatidis, an aquatic fungus, has been linked to recent amphibian population declines. Few surveys have assessed B. dendrobatidis infections in areas where the disease is suggested to be less virulent and population declines have not been observed, such as southeastern North America. Although adult Rana catesbeiana and Rana sphenocephala from the Savannah River Site, South Carolina collected in 1979 and 1982 were identified as having B. dendrobatidis, it is unknown whether the fungus is currently present at the site or if susceptibility to infection varies among species or wetlands with different histories of environmental contamination. From 15 May through 15 August 2004, we collected R. catesbeiana and R. sphenocephala tadpoles from three wetlands with differing contamination histories on the Savannah River Site, South Carolina. We found B. dendrobatidis in only one of the wetlands we surveyed. Batrachochytrium dendrobatidis infection was identified in 64% of the R. catesbeiana tadpoles
sampled and histologically assessed (n=50) from a wetland contaminated with mercury, copper, and zinc. No R. sphenocephala tadpoles from this site (n=50) were infected. In combination with a recently published report, our data suggest that B. dendrobatidis has been present at the Savannah River Site for over 25 yr but has not caused any apparent population declines. This time period is similar to the known presence of 30 yr of B. dendrobatidis in northeastern North America. Our data suggest that R. sphenocephala larvae might be resistant to infection, even when occupying the same wetland as the infected R. catesbeiana. Our survey did not clarify the effects of environmental contamination on infection severity, but our study stresses the importance of additional field surveys to document how this pathogen is affecting amphibians globally.

Keywords: Amphibian decline, Batrachochytrium dendrobatidis, chytrid, Rana, tadpole, trace element

Peterson, J. D., M. B. Wood, W. A. Hopkins, J. M. Unrine, and M. T. Mendonça 2007. Prevalence of Batrachochytrium dendrobatidis in American Bullfrog and Southern Leopard Frog Larvae from Wetlands on the Savannah River Site, South Carolina. Journal of Wildlife Diseases 43(3):450-460.