1. Disease Control and Prevention Center, National Center for Global Health and Medicine , 1-21-1, Toyama, Shinjuku-ku, Tokyo 162-8655, Japan
2. Department of Microbiology and Immunology, Aichi Medical University School of Medicine , Nagakute, Aichi 480-1195, Japan
3. Department of Tropical Medicine and Malaria, Research Institute, National Center for Global Health and Medicine , 1-21-1 Toyama, Shinjuku-ku, Tokyo 162-8655, Japan