1. Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiaotong University, Shanghai 200240, China
2. Division of Swine Infectious Diseases, National Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute of Chinese Academy of Agricultural Sciences, Harbin 150001, China
3. College of Veterinary, Inner Mongolia Agriculture University, Huhhot 010018, China