1. Xi’an Centers for Disease Control and Prevention, Xi’an, Shaanxi, PR China
2. Department of Immunology and Pathogenic Biology, Key Laboratory of Environment and Genes Related to Diseases, Chinese Ministry of Education, School of Medicine, Xi’an Jiaotong University, Xi’an, Shaanxi, PR China
3. Department of Microbiology, Faculty of Veterinary Sciences, University of Veterinary and Animal Sciences, Lahore, Pakistan
4. State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, PR China
5. Shaanxi Animal Research Institute, Xi’an, Shaanxi, PR China