Compliance with Ethical Standards
Acknowledgements: This work was supported by the National Natural Science Foundation of China (31702271), the Guangdong Provincial Natural Science Foundation (2017A030310367),the Special Fund for Agro-scientific Research in the Public Interest (201303042), the National Key Research and Development Program of China (2016YFD0501004, 2016YFD0501010), the Promote Scientific and Technological Development Program (2013B040200032), and the Guangdong Provincial Key Laboratory of Prevention and Control for Severe Clinical Animal Diseases (2013A061401013).
Conflict of Interest Statement: The authors declare no conflicts of interest.
Ethical Approval: No studies involving human participants or animals performed by any of the authors are described in this article.
Data Availability Statement: The data that support the findings of this study are available from the corresponding author upon reasonable request.