Funding for this research was provided by:
National Natural Science Foundation of China (81602904)
Received: 15 May 2017
Accepted: 28 February 2018
First Online: 7 March 2018
Ethics approval and consent to participate
: The data of this study was collected from web-source, so the ethics and participatory consent was not required, and this was approved by National Institute of Parasitic Diseases, Chinese Center for Diseases Control and Prevention.
: Not applicable.
: The authors declare that they have no competing interests.
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