国家传染病科技重大专项课题(2008ZX10002011,2012ZX10004503)%科技部国际合作与交流专项(2011DFA31030)%华中科技大学研究生创新创业基金(No. HF-11-30-2013)This work was supported by grants from the National Major Science and Technology Special Project for Infectious Diseases of China(2008ZX10002011,2012ZX10004503)%International Science & Technology Cooperation Program of China(2011DFA31030)%Gradu-ates'Innovation Fund of HUST(HF-11-30-2013)