More Simon, Bicout Dominique, Bøtner Anette, Butterworth Andrew, Calistri Paolo, Depner Klaus, Edwards Sandra, Garin-Bastuji Bruno, Good Margaret, Gortázar Schmidt Christian, Michel Virginie, Miranda Miguel Angel, Nielsen Søren Saxmose, Raj Mohan, Sihvonen Liisa, Spoolder Hans, Thulke Hans-Hermann, Velarde Antonio, Willeberg Preben, Winckler Christoph, Breed Andrew, Brouwer Adam, Guillemain Matthieu, Harder Timm, Monne Isabella, Roberts Helen, Baldinelli Francesca, Barrucci Federica, Fabris Chiara, Martino Laura, Mosbach-Schulz Olaf, Verdonck Frank, Morgado Joana, Stegeman Jan Arend
EFSA J. 2017 Oct 16;15(10):e04991. doi: 10.2903/j.efsa.2017.4991. eCollection 2017 Oct.
Previous introductions of highly pathogenic avian influenza virus (HPAIV) to the EU were most likely via migratory wild birds. A mathematical model has been developed which indicated that virus amplification and spread may take place when wild bird populations of sufficient size within EU become infected. Low pathogenic avian influenza virus (LPAIV) may reach similar maximum prevalence levels in wild bird populations to HPAIV but the risk of LPAIV infection of a poultry holding was estimated to be lower than that of HPAIV. Only few non-wild bird pathways were identified having a non-negligible risk of AI introduction. The transmission rate between animals within a flock is assessed to be higher for HPAIV than LPAIV. In very few cases, it could be proven that HPAI outbreaks were caused by intrinsic mutation of LPAIV to HPAIV but current knowledge does not allow a prediction as to if, and when this could occur. In gallinaceous poultry, passive surveillance through notification of suspicious clinical signs/mortality was identified as the most effective method for early detection of HPAI outbreaks. For effective surveillance in anseriform poultry, passive surveillance through notification of suspicious clinical signs/mortality needs to be accompanied by serological surveillance and/or a virological surveillance programme of birds found dead (bucket sampling). Serosurveillance is unfit for early warning of LPAI outbreaks at the individual holding level but could be effective in tracing clusters of LPAIV-infected holdings. In wild birds, passive surveillance is an appropriate method for HPAIV surveillance if the HPAIV infections are associated with mortality whereas active wild bird surveillance has a very low efficiency for detecting HPAIV. Experts estimated and emphasised the effect of implementing specific biosecurity measures on reducing the probability of AIV entering into a poultry holding. Human diligence is pivotal to select, implement and maintain specific, effective biosecurity measures.
高致病性禽流感病毒（HPAIV）此前传入欧盟极有可能是通过野生候鸟。现已开发出一个数学模型，该模型表明，当欧盟境内足够数量的野生鸟类种群受到感染时，病毒可能会扩增和传播。低致病性禽流感病毒（LPAIV）在野生鸟类种群中可能达到与HPAIV相似的最高流行水平，但估计LPAIV感染家禽养殖场的风险低于HPAIV。已确定只有少数非野生鸟类传播途径引入禽流感的风险不可忽视。据评估，HPAIV在禽群内动物之间的传播率高于LPAIV。在极少数情况下，可以证明高致病性禽流感疫情是由LPAIV向HPAIV的内在突变引起的，但目前的知识水平尚无法预测这种情况是否会发生以及何时会发生。在家禽中，通过报告可疑临床症状/死亡率进行被动监测被确定为早期发现高致病性禽流感疫情的最有效方法。对于水禽的有效监测，除了通过报告可疑临床症状/死亡率进行被动监测外，还需要进行血清学监测和/或对死亡鸟类进行病毒学监测（桶式采样）。血清学监测不适用于单个养殖场低致病性禽流感疫情的早期预警，但可有效追踪受LPAIV感染的养殖场集群。在野生鸟类中，如果HPAIV感染与死亡率相关，被动监测是HPAIV监测的合适方法，而主动监测野生鸟类检测HPAIV的效率非常低。专家估计并强调了实施特定生物安全措施对降低禽流感病毒进入家禽养殖场可能性的作用。人为的勤勉对于选择、实施和维持特定、有效的生物安全措施至关重要。
