1. Neurovirology Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
2. Virus Research Center, Clinical Research Division, Sendai Medical Center, Sendai, Japan
3. Department of Microbiology, Yamagata Prefectural Institute of Public Health, Yamagata, Japan
4. Department of Viral Infection and International Health, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan