1. Laboratory of Infectious Diseases, Kitasato Institute for Life Sciences & Graduate School of Infection Control Sciences, Kitasato University, Minato-ku, Tokyo, Japan
2. Research and Education Center for Prevention of Global Infectious Diseases of Animals, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, Japan
3. Department of Medical Technology, Kansai University of Health Sciences, Kumatori, Osaka, Japan
4. Department of Microbiology, Tokyo Medical University, Shinjuku-ku, Tokyo, Japan