MPAIV、NDV Lasota株分别与较低致病性禽源E.coli的联合感染试验

Combination Infection of Chickens with Mildly Pathogenic Avian Influenza Virus or Newcastle Disease Virus Lasota Strain and Lowly Pathogenic Escherichia Coli Isolates of Chicken Origin

以 2× 1 0 5EID50 的低致病性禽流感病毒 ( mildly pathogenic avian influenza virus,MPAIV)、2× 1 0 6 EID50 新城疫病毒 L asota株( Newcastle disease virus Lasota strain,NDVL asota)气管内注射 1 0日龄 SPF鸡 ,2 4h后 ,同剂量、同法重复感染一次 ;48h后 ,分别气管内注射较低致病性禽病原性大肠杆菌 1 2 0( O1 8)和 1 73( O2 6 )株 ,2× 1 0 7CFU/羽 ,2 4h后同剂量、同法重复攻毒一次 ,连续观察 1 0d。结果 :MPAIV单独感染组死亡率为 53% ;NDV Lasota株单独攻毒组未见死亡 ;大肠杆菌 1 2 0株单独攻毒组死亡率为 40 % ,1 73株单独攻毒组死亡率为 7% ;MPAIV与大肠杆菌1 2 0株联合攻毒组的死亡率为 87% ,NDV L a-sota株与 1 2 0株联合攻毒组的死亡率为 40 % ;MPAIV与大肠杆菌 1 73株联合攻毒组的死亡率为 80 % ,NDV Lasota株与 1 73株联合攻毒组的死亡率为 2 0 %。

By twice inoculating 10 day old specific pathogen free(SPF) chickens intratracheally with 2×10 5 EID 50 mildly pathogenic avian influenza virus or 2×10 6 EID 50 Newcastle disease virus Lasota strain at an interval of 24 hours, two days after the second inoculation,2×10 7 c. f. u. of Lowly pathogenic Escherichia coli strain 120(O18) and 173(O26) was inoculated by the same way respectively.The results suggested that the MPAIV alone infected group experienced the mortality rate of 53.33 per cent.Mortality rates of groups of the pathogenic E.coli isolates alone were as follows: strain 120?173 exhibited motality rate of 40.00 per cent and 6.67 per cent respectively; MPAIV was implicated in the mortality rates that occurred in the groups of chickens of the Escherichia coli strain 120 and strain 173 in combine with MPAIV, which mortality rate was 86.67 per cent and 80.00 per cent respectively. The synergic pathogenesis between NDV Lasota and E.coli strain 120 was not obvious,and that between NDV Lasota and E.coli strain 173 was clear.