1. State Key Laboratory of Agricultural Microbiology, Wuhan, China (Cao, Li, Fang, Chen, Xiao)
2. Public Laboratory of Electron Microscopy, Wuhan, China (Cao)
3. Laboratory of Animal Virology, College of Veterinary Medicine, Wuhan, China (Li, Fang, Chen, Xiao)
4. Huazhong Agricultural University, Wuhan, Hubei, PR China and Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu Province, China (Li)