1 Department of Clinical Training Management Center, Hamamatsu Medical Center, 328 Tomitsuka-cho, Naka-ku, Hamamatsu, 432-8580 Japan.
2 Department of Infectious Disease, Hamamatsu Medical Center, 328 Tomitsuka-cho, Naka-ku, Hamamatsu, 432-8580 Japan.
3 Department of Community Health and Preventive Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu 431-3192, Japan.
4 Department of Mechanical Engineering, Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, 441-8580 Japan.