1. Laboratory of Hematology and Virology, Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, Yaoundé, Cameroon
2. Division of Infectious Diseases, Department of Medicine, Case Western Reserve University, 2109 Adelbert Rd., Cleveland, Ohio 44195
3. Department of Viral Infection and International Health, School of Medicine, Kanazawa University, Kanazawa, Japan