Bublot Michel, Le Gros François-Xavier, Nieddu Daniela, Pritchard Nikki, Mickle Thomas R, Swayne David E
Merial SAS, R&D, Lyon 69007, France.
Avian Dis. 2007 Mar;51(1 Suppl):332-7. doi: 10.1637/7623-042706R.1.
The objective of this study was to compare the efficacy of two avian influenza (AI) H5-inactivated vaccines containing either an American (A/turkey/Wisconsin/68 H5N9; H5N9-WI) or a Eurasian isolate (A/chicken/Italy/22A/98 H5N9; H5N9-It). Three-week-old specific pathogen-free chickens were vaccinated once and challenged 3 wk later with a H5N1 highly pathogenic AI (HPAI) virus isolated from a chicken in Thailand in 2004. All unvaccinated challenged birds died within 2 days, whereas 90% and 100% of chickens vaccinated with H5N9-WI and H5N9-It, respectively, were protected against morbidity and mortality. Both vaccines prevented cloacal shedding and significantly reduced oral shedding of the challenge HPAI virus. Additional chickens (vaccinated or unvaccinated) were placed in contact with the directly challenged birds 18 hr after challenge. All unvaccinated chickens in contact with unvaccinated challenged birds died within 3 days after contact, whereas unvaccinated chickens in contact with vaccinated challenged birds either showed a significantly delayed mortality or did not become infected. All vaccinated contacts were protected against clinical signs, and most chickens did not shed detectable amount of HPAI virus. Altogether, these data indicate that both vaccines protected very well against morbidity and mortality and reduced or prevented shedding induced by direct or contact exposure to Asian H5N1 HPAI virus.
本研究的目的是比较两种禽流感(AI)H5灭活疫苗的效力,这两种疫苗分别含有一株美国毒株(A/火鸡/威斯康星/68 H5N9;H5N9-WI)和一株欧亚毒株(A/鸡/意大利/22A/98 H5N9;H5N9-It)。对3周龄的无特定病原体鸡只进行一次疫苗接种,3周后用2004年从泰国一只鸡分离出的H5N1高致病性禽流感(HPAI)病毒进行攻毒。所有未接种疫苗而攻毒的鸡只在2天内死亡,而分别接种H5N9-WI和H5N9-It疫苗的鸡只中,90%和100%受到保护,未出现发病和死亡。两种疫苗均能防止泄殖腔排毒,并显著减少攻毒HPAI病毒的口腔排毒。在攻毒后18小时,将额外的鸡只(已接种或未接种疫苗)与直接攻毒的鸡只接触。所有与未接种疫苗且攻毒的鸡只接触的未接种疫苗鸡只在接触后3天内死亡,而与接种疫苗且攻毒的鸡只接触的未接种疫苗鸡只要么死亡明显延迟,要么未被感染。所有接种疫苗的接触鸡只均受到保护,未出现临床症状,且大多数鸡只未排出可检测量的HPAI病毒。总之,这些数据表明,两种疫苗均能很好地预防发病和死亡,并减少或防止因直接接触或接触暴露于亚洲H5N1 HPAI病毒而导致的排毒。