1. Institute of Preventive Veterinary Sciences & Department of Veterinary Medicine, Zhejiang University College of Animal Sciences, Hangzhou, P.R. China
2. Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA, USA
3. Zhejiang Provincial Key Laboratory of Preventive Veterinary Medicine, Hangzhou, P.R. China
4. State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, National Medical Center for Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, P.R. China
5. Hainan Institute of Zhejiang University, Sanya, P.R. China