【摘要】 用大肠杆菌K₉₉遗传工程活疫苗,按100亿活菌/只剂量于产前6周给149只妊娠杂交绵羊皮下接种,有28.86％的羊只出现临床反应,但所有免疫母羊均正常分娩,其所产羔羊均发育正常。对免疫母羊所产羔羊（66只）吮吸初乳后,给口服250亿强毒菌攻击,死亡率为4.55％,其发生腹泻持续期平均为1.78天,排菌持续期平均为2.94天。与未免疫对照组比较,差异极显著。本试验初步证明该疫苗对绵羊的安全性与免疫原性良好.更多还原

【Abstract】 When 149 crossbred pregnant sheep had been subcutaneously inoculated with the genetic engineering live E.coli K99 vaccine at dose of 10¹⁰ live bacteria per sheep, 28.86% of animals inoc-uted showed clinical symptoms, but all these sheep laboured normally and their newborn lambs were developing normally. After the lambs sucked colostrum,they were perorally administrated 2.5×10¹⁰ virulent live E.coli that 4.55% the lambsdied, the average persistent periods of diarrhea and discharge of bacteria were 1.78 days and 2.94 days, respectively, which differences were obvious in comparison with nor-ino-culated control group.更多还原