Funding for this research was provided by:
National Natural Science Foundation of China-Yunnan Joint Fund (81773493)
Anhui provincial Program of Prevent medicine & Public Health (2017jk002)
National Grand Program on Key Infectious Disease Control (2017ZX10201101)
State Key Laboratory of Pathogen and Biosecurity
Received: 22 February 2019
Accepted: 12 June 2019
First Online: 27 June 2019
Ethics approval and consent to participate
: This study was reviewed and approved by the ethics committees of the Beijing Institute of Microbiology and Epidemiology and the Anhui Center for Disease Prevention and Control. All participants signed written informed consents prior to sample donations.
: Not applicable.
: The authors declare that they have no competing interest.