1. Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu City, Sichuan, China
2. Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu City, Sichuan, China
3. Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu City, Sichuan, China
4. Sinopharm Yangzhou VAC Biological Engineering Co., Ltd., Yangzhou City, China