1. Department of Medical Microbiology, Central South University, Changsha, China
2. China-Africa Research Center of Infectious Diseases, School of Basic Medical Sciences, Central South University, Changsha, China
3. Department of Occupational and Environmental Health, Xiangya School of Public Health, Central South University, Changsha, P. R. China
4. Department of Neurosurgery, Xiangya Hospital of Central South University, Changsha, China
5. Department of Epidemiology and Health Statistics, Xiangya School of public health central South University, Changsha, P. R. China