Hongyan Bao1, Xiangdong Li2,3. 1. College of Continuing Education, Yangzhou University, Yangzhou, China. 2. Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, China. 3. Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou, China.