1. Research Center for Swine Diseases, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
2. Sichuan Science-Observation Experimental Station for Veterinary Drugs and Veterinary Diagnostic Technology, Ministry of Agriculture, Chengdu, China
3. Engineering Research Center of Southwest Animal Disease Prevention and Control Technology, Ministry of Education of the People’s Republic of China, Chengdu, China
4. Sichuan Center for Disease Control and Prevention, Chengdu, China