[1] China Agr Univ, Coll Vet Med, Beijing 100094, Peoples R China
[2] Chinese Acad Sci, Inst Microbiol, Beijing 100080, Peoples R China
[3] Chinese Acad Sci, Inst Zool, Beijing 100101, Peoples R China
[4] Chinese Acad Sci, Grad Sch, Beijing, Peoples R China
[5] Acad Mil Med Sci, Inst Microbiol & Epidemiol, Beijing 100071, Peoples R China
[6] Chinese Acad Sci, Beijing Genom Inst, Beijing 101300, Peoples R China