1. Department of Viral Infection and International Health, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan and Kenya Medical Research Institute, Nairobi, Kenya
2. Kenya Medical Research Institute, Nairobi, Kenya
3. Department of Viral Infection and International Health, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
4. Shiga University of Medical Science, Otsu, Japan
5. Kyoto Prefectural University of Medicine, Kyoto, Japan