1. 1Department of Microbiology, Yamagata Prefectural Institute of Public Health, Yamagata, 990-0031, Japan
2. 2Department of Neurology, Yamagata Prefectural Central Hospital, Yamagata, 990-2292, Japan
3. 3Department of Pediatrics, Yamagata City Hospital, Saiseikan, Yamagata, 990-8533, Japan
4. 4Yamanobe Pediatric Clinic, Yamagata, Yamanobe, 990-0301, Japan
5. 5Katsushima Pediatric Clinic, Yamagata, 990-2461, Japan