David E. Swayne, DVM, MSc, PhD, DACVP, DACPV, is Laboratory Director at the Southeast Poultry Research Laboratory within the U.S. Department of Agriculture's Agricultural Research Service, in Athens, Georgia. He is also the editor of Diseases of Poultry, 13th edition (Wiley, 2013) and Avian Influenza (Wiley, 2008).