1. Center for Water and the Environment, Natural Resources Research Institute, University of Minnesota—Duluth, 5013 Miller Trunk Hwy, Duluth, Minnesota 55811-1442, USA
2. Departments of Veterinary Biosciences and Veterinary Pathobiology, University of Illinois at Urbana–Champaign, 2001 South Lincoln Ave., Urbana, Illinois 61802, USA
3. U.S. Geological Survey, National Wildlife Health Center, 6006 Schroeder Rd., Madison, Wisconsin 53711, USA