1. Infectious Disease Research Division; Hyogo Prefectural Institute of Public Health and Environmental Sciences; Kobe Hyogo 652-0032 Japan
2. Kobe Steel Hospital; Kakogawa Hyogo 675-0115 Japan
3. Awaji Hospital; Sumoto Hyogo 656-0013 Japan
4. Infectious Disease Surveillance Center; National Institute of Infectious Diseases; Shinjuku-ku Tokyo 162-8640 Japan
5. National Institute of Infectious Diseases; Musashi-murayama Tokyo 208-0011 Japan
6. Department of Microbiology; National Institute of Public Health; Minato-ku Tokyo 108-8638 Japan