1. Laboratory of Virology and Immunology, Institute of Preventive Veterinary Medicine, Zhejiang University, 268 Kaixuan Road, Hangzhou, Zhejiang 310029, People's Republic of China
2. College of Life Sciences, Zhejiang University, 268 Kaixuan Road, Hangzhou, Zhejiang 310029, People's Republic of China
3. National Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, People's Republic of China
4. Key Laboratory of Poultry Raising and Disease Control of Ministry of Agriculture, Southern China Agricultural University, Guangzhou 510642, People's Republic of China
5. Key Laboratory of Preventive Veterinary Medicine of Ministry of Agriculture, China Agricultural University, Beijing 100094, People's Republic of China