1. Virology, Surveillance, and Diagnosis Branch Influenza Division National Center for Immunization and Respiratory DiseaseCenters for Disease Control and Prevention (CDC) Atlanta GA USA
2. Exotic and Emerging Avian Viral Diseases Research Unit Agricultural Research Service U.S. National Poultry Research CenterU.S. Department of Agriculture Athens GA USA
3. Department of Infectious Diseases St Jude Children's Research Hospital Memphis TN USA
4. Division of Virology National Institute for Biological Standards and Control Potters Bar UK