1. College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, Heilongjiang, China.
2. College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, Shandong, China.
3. General Station for Surveillance of Wildlife-borne Infectious Diseases, State Forestry and Grassland Administration, Shenyang, Liaoning, China.