1. Department of Preventive Veterinary Medicine, College of Animal Husbandry and Veterinary ScienceHenan Agricultural University, Zhengzhou 450002, Henan Province, China
2. Zhengzhou Zoo, Zhengzhou 450008, Henan Province, China
3. Department of Molecular Microbiology and Immunology, University of Missouri-Columbia, School of Medicine Bond Life Sciences Center, Columbia, MO 65211, USA