1. Leading Program; Graduate School of Biomedical Sciences; Nagasaki University; Nagasaki Japan
2. Department of Bacteriology; Graduate School of Medicine; University of the Ryukyus; Nishihara Okinawa Japan
3. Vietnam Research Station; Institute of Tropical Medicine; Nagasaki University; Nagasaki Japan
4. Department of Virology; Institute of Tropical Medicine; Nagasaki University; Nagasaki Japan