1. State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Institute for Viral Disease Control and Prevention, China CDC, Changping District, Beijing, P.R. China.
2. School of Public Health, Shandong University, Jinan, China.
3. School of Forensic and Laboratory Medicine, Jining Medical University, Jining, China.
4. Qinghai Center for Disease control and Prevention, Xining, China.
5. Geermu Center for Disease control and Prevention, Geermu, China.