Abstract: In order to better evaluate the effectiveness of preventative vaccines and therapeutic drugs，we aimed to establish a stable dairy cow mastitis model，which may provide a reliable way to verify the concept of“human disease and animal prevention”for extensively infectious diseases. Milk samples from dairy cows with clinical mastitis were collected from different regions of China. Different strains of E.coli were used to infect 6-8 weeks old Balb/c mice and 2- 6 years old healthy susceptible cows in late stage of lactation respectively after bacterial isolation and identification. The infectivity and pathogenicity of the different strains against mice and dairy cows were determined， and strong virulent strains with high pathogenicity for both species were chosen for in vivo infection. The susceptible cows were inoculated with the selected candidate virulent strains，and the differences of clinical manifestations，daily milk yields，milk bacterial counts and somatic cell counts were recorded. Meanwhile，the mice were infected by the same strains，and the clinical symptoms and death of mice were recorded to establish a stable animal model of E.coli infection. Results：Three virulent E.coli strains（LZ06，ESH05，EHL11） of different serotypes were obtained，which could induce typical clinical mastitis in dairy cows and death in mice. The mastitis models in dairy cows and a lethal model in mice were finally established using virulent strain LZ06. Conclusion：The virulent strains of E.coli causing mastitis were successfully screened，and the animal mastitis model was successfully established，which could be used to evaluate the protective effects of vaccines or medicine. This study provided the new method and strategy for evaluating the concept of“human disease and animal prevention”for zoonosis.

Key words: Escherichia coli； Bovine mastitis； Animal model； Human disease and animal prevention

摘要： 为了给预防疫苗和治疗药物的有效性评价提供参考依据，该试验建立了稳定的乳 房炎奶牛模型，可为广泛感染性疾病“人病兽防”理念的验证提供可靠途径。自全国不同地区 取奶牛临床型乳房炎乳样，经细菌分离鉴定后，将大肠杆菌不同菌株感染6—8周龄Balb/c小 鼠和2—6岁泌乳后期健康易感奶牛，通过测定不同菌株对小鼠、奶牛的感染力和致病力，筛选 出对两者均具有较强致病性的强毒株；使用强毒株攻击易感奶牛，记录奶牛攻毒前后临床表 现，及日产奶量、乳汁细菌数和体细胞数的变化情况；攻击小鼠，记录小鼠攻毒前后临床表现 和死亡情况，以建立稳定的大肠杆菌感染致病实验动物模型。结果表明：筛选到3株不同血清 型的强毒株大肠杆菌LZ06（O6）、ESH05（O8）、EHL11（O81），能够致死小鼠并导致奶牛乳房炎 疾病；建立稳定的大肠杆菌乳房炎模型和小鼠致死性模型。该试验成功筛选到导致奶牛乳房 炎的大肠杆菌强毒株，建立的实验动物模型可用于大肠杆菌疫苗和治疗药物的有效性评价， 为大肠杆菌引起的人兽共患病“人病兽防”理念和策略提供新的评估途径。

关键词: 大肠杆菌； 奶牛乳房炎； 动物模型； 人病兽防