【作者】 闻志丹；

【导师】 王晶钰； 杨小平；

【作者基本信息】 西北农林科技大学 ， 兽医， 2011， 硕士

【摘要】 禽流感(Avianinfluenza,Al)是由属于正粘病毒科的A型流感病毒引起的一种禽类传染病,该病在世界上多数国家都有流行历史。禽流感流行会造成巨大的经济损失,特别是高致病性禽流感一旦暴发将给养殖业带来毁灭性的打击,因此世界卫生组织将禽流感列入必须报告的疾病之一。自2004年我国暴发高致病性禽流感以来,全国对禽流感的防控高度重视,实践证明采用疫苗主动免疫是预防禽流感最经济、最有效的手段,然后对鸡群禽流感病毒免疫后状况进行检测可以及时了解其免疫效果或病毒感染情况,且所得检测结果将为以后的防控工作提供数据支持。本试验对陕西省一家大型养鸡场鸡群禽流感病毒疫苗免疫的抗体水平进行了检测与分析。从1日龄开始,每隔4d检测一次雏鸡母源抗体水平。结果显示,雏鸡的母源抗体水平随日龄增大而不断下降,12～16日龄时雏鸡的母源抗体水平下降到4log2以下,且只有50%的雏鸡母源抗体水平达到合格标准,确定在12～16日龄时进行首次免疫。选取4个鸡群从7周龄时开始每隔4周采血样一次。用血凝抑制试验检测禽流感病毒灭活疫苗免疫后的抗体水平。检测结果显示,种鸡场禽流感病毒H5亚型和H9亚型疫苗免疫均取得较好的效果。首次免疫后鸡群抗体水平小幅度升高,免疫后3周,其抗体水平可达到4log2以上,但是鸡群的抗体效价离散度较高。经过二免、三免后,禽流感病毒H5亚型疫苗免疫鸡群抗体效价均值最高可达9.1log2;禽流感病毒H9亚型疫苗免疫鸡群抗体水平均值最高达到10.79log2;从离散度来看,除蛋鸡场成5舍外,其它舍鸡群禽流感病毒疫苗免疫的效价分布比较整齐均匀,且种鸡场鸡群抗体效价离散度要小于蛋鸡场鸡群。从持续时间上来看,鸡群经过禽流感病毒H5疫苗两次免疫后其抗体滴度保持在6log2以上并持续9周左右,鸡群经过禽流感病毒H9疫苗三次免疫后其抗体滴度保持在8log2以上并持续约11周。更多还原

【Abstract】 Avian influenza (AI) was caused by type A influenza viruses in Orthomyxoviridae family, and has prevailed in many countries in the world. AI can be divided into highly pathogenic AI (HPAI) and low pathogenic AI (LPAI) based on the pathogenicity of AIVs. Because of the destructive consequences caused by HPAI, it was listed as notifiable disease by OIE. Chinese government has posed great concern on the control on HPAI since 2004, and vaccination has been the important component in the strategy used for the control of HPAI because of the national situation. Surveillance and analysis of HI antibody titers of vaccinated chickens are needed to provide theoretical basement for the prevention and control of HPAI.In the current study, we conducted a continuous surveillance of HI antibody titers of avian influenza vaccines-vaccinated chickens in a large chicken field in Shanxi province.we tested the matrnal antibodies of chicks, samples were colleted every 4 days.The results showed that its maternal antibodies decreaed when the chicks grew up.We should be vaccinating for the first in 12～16 days.The antisera samples were got from two ripe breeding birds flocks and two layer chicken flocks at the 7 weeks old on the first time and went on with a interval of 4 weeks. The HI antibody titers were calculated by HI tests.Our data showed that both the H5 and H9 vaccines can induce good HI antibody responses. All HI titers were low at 7 weeks, which were lower than the protective critical value. HI titers increased after first vaccination and reached protective value 3 weeks post vaccination, but with great varying. HI titers can reach high levels after the second and third vaccination, the HI titers against H5 AIVs can reach 9.1 log2 while the HI titers against H9 AIVs can reach 10.79 log2. As for the lay chicken flocks, the HI titers induced by H5 vaccine were well-distributed except the 5th flock. The H9 vaccine induced HI titers in breeding flocks were better than that in layer chicken flocks based on the dispersity.The H9 HI titers, which were higher than the protective critical value, can persist for 11 weeks with 8 log2 in the four flocks. The H5 HI titers, can persist for 8 weeks with 6 log2 in the four flocksSome vaccinated chickens had low HI titers, that may caused by artificial operation in the vaccination, the health situation of the flocks and the breeding situation. Improvement of these factors and complement vaccination may be needed. The vaccination times can be reduced to minimize the vaccine stress to the layer flocks.更多还原