1. Department of Pathology, National Institute of Infectious Diseases, Tokyo, Japan
2. Department of Laboratory Animal Medicine, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
3. Section of Animal Models, Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
4. Laboratory of Viral Genomics, Pathogen Genomics Center, National Institute of Infectious Diseases, Tokyo, Japan
5. Department of Tissue Physiology, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
6. Department of Virology I, National Institute of Infectious Diseases, Tokyo, Japan
7. Department of Virology III, National Institute of Infectious Diseases, Tokyo, Japan
8. Influenza Virus Research Center, National Institute of Infectious Diseases, Tokyo, Japan