1. Institute of Animal Health, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China
2. Key Laboratory for Prevention and Control of Avian Influenza and Other Major Poultry Diseases, Ministry of Agriculture and Rural Affairs, Guangzhou 510640, China
3. Key Laboratory of Livestock Disease Prevention of Guangdong Province, Guangzhou 510640, China
4. Shanwei Academy of Agricultural Sciences, Shanwei 516699, China