1. Department of Gastroenterology and Neurology, Graduate School of Medicine and Faculty of Medicine, Kagawa University, Japan
2. Department of Radiology, Graduate School of Medicine and Faculty of Medicine, Kagawa University, Japan
3. Department of Pathology, National Institute of Infectious Diseases, Japan
4. Department of Virology 1, National Institute of Infectious Diseases, Japan
5. Department of Neurosurgery, Graduate School of Medicine and Faculty of Medicine, Kagawa University, Japan