1. Departments of Virology and Bacteriology; The Kitasato Institute; Tokyo 108
2. Department of Pediatrics; Showa University Medical School; Tokyo 141
3. Section of Pediatrics; Okubo Municipal Hospital; Tokyo 160
4. Department of Pediatrics; Keio University School of Medicine; Tokyo 160
5. Department of Pediatrics; Juntendo University School of Medicine; Tokyo 113