1. Department of Emergency Medicine, Shimane Prefectural Central Hospital, Izumo, Japan
2. Department of Infectious Diseases, Shimane Prefectural Central Hospital, Izumo, Japan
3. Clinical Education and Research Center, Shimane Prefectural Central Hospital, Izumo, Japan
4. Department of Community Medicine, Shimane Prefectural Central Hospital, Izumo, Japan
5. Department of General Medicine, Shimane Prefectural Central Hospital, Izumo, Japan
6. Department of Clinical Epidemiology, Hyogo College of Medicine, Nishinomiya, Japan