1. College of Veterinary Medicine; Shandong Agricultural University; Tai'an Shandong China
2. Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention; Tai'an Shandong China
3. Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention; Tai'an Shandong China
4. China Animal Health and Epidemiology Center; Qingdao Shandong China