1. Department of Diagnosis, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
2. Office for Disease Control and Emergency Response, Chinese Center for Disease Control and Prevention, Beijing, China.
3. Center for Disease Control and Prevention in Changchun, Jilin, China.
4. National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
5. Enteric Diseases Laboratory Branch, Centers for Disease Control and Prevention, Atlanta, Georgia.