1. Department of Zoology, University of Cambridge, Cambridge, UK.
2. Department of Virology, Erasmus Medical Centre, Rotterdam, Netherlands.
3. Universitat Pompeu Fabra, Barcelona, Spain.
4. World Health Organization (WHO) Collaborating Centre for Reference and Research on Influenza, Melbourne, Australia.
5. WHO Collaborating Center for Influenza, Centers for Disease Control and Prevention, Atlanta, GA, USA.