Funding for this research was provided by:
Excellent Young Talents Fund Program of Higher Education Institutions of Anhui Province (2017jk002)
National grand program on key infectious disease control (Grant#2017ZX10201101)
Jiangsu provincial high-level talents programs in health (LGY2016021)
Gaofeng Clinical Medicine Grant Support (2017269)
Text and Data Mining valid from 2019-06-28
Received: 17 September 2018
Accepted: 4 June 2019
First Online: 28 June 2019
Ethics approval and consent to participate
: This study was approved by the Medical Ethics Committee of Anhui Provincial Center for Disease Control and Prevention. All subjects signed informed consent form before collecting samples and epidemiology investigation.
: Not applicable.
: The authors declare that they have no competing interests.