山东省首起野生天鹅H5N8高致病性禽流感疫情的紧急调查及处置

2021年1月12—19日,山东黄河三角洲国家级自然保护区大汶流管理站出现35只死亡的野生疣鼻天鹅。经现场调查,市级和省级实验室检测,诊断为疑似H5N8亚型高致病性禽流感,经国家禽流感参考实验室进行病毒分离鉴定,最终确定为H5N8亚型高致病性禽流感疫情。疫情发生后,通过现场调查、座谈及实验室检测等方式,对此次疫情开展了紧急流行病学调查,追溯疫情的可能来源,分析疫情的扩散风险,继而提出针对性的应急处置措施。调查发现,此次疫情由迁徙候鸟带毒引入引起的可能性较大;野生鸟类未及时开展免疫,导致体内抗体水平低下是疫情暴发的内源因素。由于迅速采取了合理的应急处理措施,此次疫情得到迅速控制,避免了疫情扩散。本次疫情警示,必须切实做好禽流感的强制免疫和监测工作,高度重视自然保护区及其附近场所珍稀禽类的免疫,以降低疫情发生风险。

Emergency Investigation and Response to the First Outbreak of H5N8 HPAI in Wild Swans in Shandong Province

On January 12—19,2021,35 dead wild mute swans were found in Dawenliu Station in Shandong Yellow River Delta National Nature Reserve.Upon field investigation,a case suspicious of H5N8 subtype highly pathogenic avian influenza(HPAI)was detected by laboratories at municipal and provincial level,and confirmed as H5N8 subtype HPAI through virus isolation and identification by National Avian Influenza Reference Laboratory.Subsequently,an emergency epidemiological investigation was carried out through field investigation,interview and laboratory testing to trace any possible sources of the outbreak and analyze the risk of virus spreading,so as toput forward specific emergency response measures. It was investigated that the outbreak was likely caused by the virusintroduced by migratory birds;wild birds were not vaccinated in time,leading to low antibody level that was theinternal factor for the outbreak. However,the outbreak was rapidly controlled without any spreading under reasonableemergency measures. It was suggested that the risk of the outbreak should be reduced through compulsory vaccinationand monitoring,especially the vaccination in rare birds in the nature reserve and its surrounding premises.