1 College of Life Sciences, Sichuan University, Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, Chengdu, 610064, China.
2 Sichuan Provincial Center for Animal Disease Control and Prevention, Chengdu, 610041, China.
3 College of Life Sciences, Sichuan University, Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, Chengdu, 610064, China. whongning@163.com.