We selected the bacteria which have strong virulence by test and studied on the chiasm of the antigen of the principal pathogen bacteria by agglutination test and two-way agar diffusion test. 对主要的病原菌进行细菌毒力试验,根据毒力试验结果,选择毒力较强的主要病原菌进行凝集试验和双向琼扩试验对其抗原交叉性进行分析。