1. Beijing Key Laboratory of Animal Genetic Improvement College of Animal Science and Technology China Agricultural University Beijing China
2. College of Animal Science and Veterinary Medicine Henan Institute of Science and Technology Xinxiang China
3. Key Laboratory of Animal Epidemiology of Ministry of Agriculture College of Veterinary Medicine China Agricultural University Beijing China
4. National Institute for Viral Disease Control and Prevention Collaboration Innovation Center for Diagnosis and Treatment of Infectious Diseases Chinese Center for Disease Control and Prevention Key Laboratory for Medical Virology National Health and Family Planning Commission Beijing China