1. Kumagai Pediatric Clinic; Sapporo Japan
2. Department of Pediatrics; Fujita Health University School of Medicine; Toyoake Japan
3. Department of Virology; Graduate School of Medicine, Toyama University; Toyama Japan
4. Department of Virology; Okayama University Graduate School of Medicine and Dentistry; Okayama Japan
5. Laboratory of Viral Infection; Kitasato Institute for Life Sciences; Tokyo Japan