* Correspondence: 
Li Guo, College of Animal Science and Technology, Jilin Agricultural Science and Technology University, Jilin 132101, China.
piaogl110@163.com
Yongzhi Wang, Jilin Academy of Agricultural Sciences, Changchun, 130033, China
E-mail: yzwang@126.com
Xiaocheng Li, Jilin DaBeiNong Agriculture and Animal Husbandry Technology Co., Ltd, Changchun 130102, China.
E-mail: lxch_215@yeah.net
Xuelian Liu, State Key Laboratory of Direct-Fed Microbial Engineering, Beijing DaBeiNong Science and Technology Group Co., Ltd. (DBN), Beijing 100192, China.
E-mail: liuxuelian@dbn.com.cn
Jinghui Zhao, Jilin DaBeiNong Agriculture and Animal Husbandry Technology Co., Ltd, Changchun 130102, China.
E-mail: zhaojinghui8791@163.com; zhaojinghui8791@hotmail.com
Yanlong Cong, Junfeng Li, Yixue Sun, Fengjie Wang and Lifeng Zhao contributed equally to this article, and all should be considered first author.
Keywords:  Serum bank; SARS-CoV-2; Serological survey; Emerging infectious diseases