1. Division of Infectious Diseases, Department of Internal Medicine, Asahi General Hospital, I 1326, Asahi City, Chiba 289-2511, Japan
2. Residency Program, Asahi General Hospital, I 1326, Asahi City, Chiba 289-2511, Japan
3. Division of Respiratory Internal Medicine, Department of Internal Medicine, Asahi General Hospital, I 1326, Asahi City, Chiba 289-2511, Japan
4. Department of Emergency Medicine, Asahi General Hospital, I 1326, Asahi City, Chiba 289-2511, Japan