1. Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
2. Research Center of Avian Disease, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, China
3. Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, China