1 The Research Center for Global Viral Diseases, National Center for Global Health and Medicine Research Institute, Tokyo, Japan.
2 Division of Virology, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan.
3 The Research Center for Global Viral Diseases, National Center for Global Health and Medicine Research Institute, Tokyo, Japan. yoshihiro.kawaoka@wisc.edu.
4 Division of Virology, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan. yoshihiro.kawaoka@wisc.edu.
5 Department of Special Pathogens, International Research Center for Infectious Diseases, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan. yoshihiro.kawaoka@wisc.edu.
6 Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA. yoshihiro.kawaoka@wisc.edu.