Marangon S, Capua I
OIE and National Reference Laboratory for Newcastle Disease and Avian Influenza, Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Padova, Italy.
Dev Biol (Basel). 2006;124:109-15.
Since 1997, north-eastern Italy has been repeatedly challenged by avian influenza (AI) infections caused by viruses of the H5 and H7 subtypes. The penetration of such infections in the industrial circuit in densely populated poultry areas (DPPAs) resulted in massive spread, and early attempts to control AI only by stamping-out and restriction policies resulted in death or culling of millions of birds. The re-emergence or the introduction of AI viruses in the same DPPA resulted in the development of an emergency vaccination programme based on the use of heterologous vaccination and a companion discriminatory test. By enabling the detection of field exposure in vaccinated animals, the application of this system, in conjunction with a monitoring programme and a well-defined territorial strategy has resulted in the eradication of H7N1 and H7N3 epidemics that occurred between 2000 and 2004. Retrospective analysis of the AI outbreaks in north-eastern Italy coupled with surveillance programmes in wild birds and in hobby flocks indicating that certain areas are at continuous high risk of infection, was the rationale for developing and implementing a bivalent H5/H7 pilot vaccination programme in a restricted area of the DPPA. Laboratory and field evidence indicate that vaccinated animals are more resistant to challenge and shed lower amounts of virus, thus acting as a tool for both prevention and control, thus limiting the impact of AI infections.
自1997年以来，意大利东北部多次受到H5和H7亚型病毒引起的禽流感（AI）感染的挑战。此类感染在人口密集的家禽养殖区（DPPAs）的产业循环中的渗透导致了大规模传播，而早期仅通过扑杀和限制政策来控制禽流感的尝试导致数百万只禽类死亡或被扑杀。在同一DPPA中禽流感病毒的再次出现或引入导致了基于使用异源疫苗接种和配套鉴别检测的紧急疫苗接种计划的制定。通过能够检测接种动物的野外暴露情况，该系统的应用与监测计划和明确的区域战略相结合，导致了2000年至2004年间发生的H7N1和H7N3疫情的根除。对意大利东北部禽流感疫情的回顾性分析，以及对野生鸟类和业余养殖禽群的监测计划表明，某些地区持续面临高感染风险，这是在DPPA的一个受限区域制定和实施H5/H7二价试点疫苗接种计划的依据。实验室和现场证据表明，接种疫苗的动物对病毒攻击更具抵抗力，且排出的病毒量更少，因此可作为预防和控制的工具，从而限制禽流感感染的影响。
