1. State Key Lab for Infectious Diseases Prevention and Control, National Institute for Communicable Diseases Prevention and Control, China Centers for Disease Control and Prevention, Beijing 102206
2. PLA Institute of Disease Control and Prevention, Beijing 100071
3. Anhui Center for Disease Control and Prevention, Hefei, Anhui 230061
4. Department of Pathology, University of Texas Medical Branch, Galveston, Texas 77555-0609
5. Chinese Centers for Disease Control and Prevention, Beijing 100050
6. Fuyang City Center for Disease Control and Prevention
7. Second People's Hospital of Fuyang City, Fuyang City, Anhhui 236030, China