Takanori Funaki1, Isao Miyairi2. 1. Division of Infectious Diseases, Department of Medical Specialties, National Center for Child Health and Development, Tokyo, Japan. 2. Division of Infectious Diseases, Department of Medical Specialties, National Center for Child Health and Development, Tokyo, Japan; Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center, Memphis, TN, USA. Electronic address: miyairi-i@ncchd.go.jp.