1. Division of Animal Infectious Diseases, State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
2. TEDA School of Biological Sciences and Biotechnology, Nankai University, Tianjin 300457, People's Republic of China
3. Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, People's Republic of China