1. Immunology and Pathogenesis Branch, National Center for Immunization and Respiratory Diseases, Atlanta, GA, USA;
2. Influenza Division, Centers for Disease Control and Prevention, Atlanta, GA, USA;
3. Battelle Memorial Institute, Atlanta, GA, USA;
4. Department of Comparative Pathobiology, Purdue University, West Lafayette, IN, USA;
5. Oak Ridge Institute for Science and Education (ORISE), CDC Fellowship Program, Oak Ridge, TN, USA;
6. Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA, USA