1. United States Department of Agriculture Agricultural Research Service U.S. National Poultry Research Center Southeastern Poultry Research Laboratory Athens GA USA
2. United States Department of Agriculture Agricultural Research Service National Animal Disease Center Ames IA USA
3. Department of Veterinary Diagnostic and Production Animal Medicine College of Veterinary Medicine Iowa State University Ames IA USA
4. Department of Diagnostic Medicine/Pathobiology College of Veterinary Medicine Kansas State University Manhattan KS USA