应用透射电子显微镜观察致病性血清型带毒力质粒Ｙ．ｅ．Ｇ１５１及ＬＡＢ－Ｂ１８２菌株感染的家兔，其肠道及脾脏有微脓肿及菌落形成，在微脓肿形成的区域，组织细胞变性坏死严重．用ＬＡＢ—Ｂ１８２菌株感染的家兔，其肝脏可见局灶性凝固性坏死．在上述脏器无微脓肿及菌落形成的部位，肉眼观察正常，但在电子显微镜下．却呈现不同程度的组织细胞病变．细菌不在细胞内增殖．致病性血清型丢失毒力质粒的４３９—８０Ｖ－菌株感染的家兔，其肠道、肝脏及脾脏组织细胞无病理学改变． The pathogenic serotype virulence plasmid Y was observed by transmission electron microscopy. e. Rabbits infected with strains G151 and LAB-B182 had slight abscesses and colony formation in the gut and spleen. In the area formed by micro abscesses, the tissue degeneration and necrosis were serious. Rabbits infected with LAB-B182 strain showed focal coagulation necrosis in their liver. In the organs without micro-abscesses and colony formation site, the naked eye observed normal, but under the electron microscope. But showed varying degrees of histiocytosis. Bacteria do not proliferate in cells. Pathogenic serotypes of virulent plasmids infected 439-80V- strains of rabbits, intestinal, liver and spleen tissue cells without pathological changes.