1. Southeastern Cooperative Wildlife Disease Study, Department of Population Health, Wildlife Health Building, College of Veterinary Medicine, The University of Georgia, Athens, Georgia 30602, USA
2. Department of Health Administration, Biostatistics, and Epidemiology, College of Public Health, University of Georgia, Athens, Georgia 30602, USA
3. US Department of Agriculture, Agricultural Research Service, Southeast Poultry Research Laboratory, Athens, Georgia 30605, USA