1. Key Laboratory of Zoonotic of Liaoning Province, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang 110866, Liaoning Province, P. R. China
2. Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, P. R. China
3. School of Public Health, Sun Yat-sen University, Guangzhou 510080, P. R. China
4. Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, P. R. China