1. Department of Medicine, Shiga University of Medical Science, Otsu 520-2192, Japan
2. Tropical Infectious Diseases Research and Education Centre (TIDREC), Level 4, Block N & O, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
3. Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan