1. Division of Animal Infectious Disease, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
2. Division of Animal Infectious Disease, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
3. State Key Laboratory for Molecular Virology and Genetic Engineering, Institute of Pathogen Biology, Chinese Academy of Medical Sciences, Beijing 100176, People's Republic of China