Emergence of fatal avian influenza in New England harbor seals.
Emergence of fatal avian influenza in New England harbor seals.
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作者：
Anthony SJ;St Leger JA;Pugliares K;Ip HS;Chan JM;Carpenter ZW;Navarrete-Macias I;Sanchez-Leon M;Saliki JT;Pedersen J;Karesh W;Daszak P;Rabadan R;Rowles T;Lipkin WI
2011年9月至12月，162只新英格兰斑海豹死于肺炎爆发。尸检样本的序列分析显示存在一种禽类 H3N8 甲型流感病毒，类似于至少 2002 年以来在北美水禽中传播的病毒，但其突变表明最近已适应哺乳动物宿主。其中包括病毒PB2蛋白中的D701N突变，此前曾在感染人类的高致病性H5N1禽流感病毒中报道过这种突变。凝集素染色和凝集测定表明，海豹呼吸道中存在鸟类偏好的 SAα-2,3 和哺乳动物 SAα-2,6 受体，并且病毒具有凝集带有 SAα-2,3 或 SAα-2,6 受体的红细胞的能力。这种 A/斑海豹/马萨诸塞州/1/2011 病毒的出现可能预示着具有持久性和跨物种传播潜力的 H3N8 流感分支的出现。流感病毒新毒株的出现始终备受公众关注，特别是当新的哺乳动物宿主的感染有可能导致疾病大范围爆发时。在此，我们报告了新英格兰斑海豹中出现的禽流感病毒 (H3N8)，该病毒引起了肺炎的爆发，并导致了美国联邦政府认定的异常死亡事件 (UME)。这次疫情的爆发尤其重要，不仅因为它在海豹中引起了疾病，还因为该病毒自然获得了突变，已知这些突变会增加哺乳动物的传播性和毒力。如果我们要了解导致动物流行和人畜共患病出现的因素，监测鸟类病毒在哺乳动物物种中的溢出和适应至关重要。
From September to December 2011, 162 New England harbor seals died in an outbreak of pneumonia. Sequence analysis of postmortem samples revealed the presence of an avian H3N8 influenza A virus, similar to a virus circulating in North American waterfowl since at least 2002 but with mutations that indicate recent adaption to mammalian hosts. These include a D701N mutation in the viral PB2 protein, previously reported in highly pathogenic H5N1 avian influenza viruses infecting people. Lectin staining and agglutination assays indicated the presence of the avian-preferred SAα-2,3 and mammalian SAα-2,6 receptors in seal respiratory tract, and the ability of the virus to agglutinate erythrocytes bearing either the SAα-2,3 or the SAα-2,6 receptor. The emergence of this A/harbor seal/Massachusetts/1/2011 virus may herald the appearance of an H3N8 influenza clade with potential for persistence and cross-species transmission. The emergence of new strains of influenza virus is always of great public concern, especially when the infection of a new mammalian host has the potential to result in a widespread outbreak of disease. Here we report the emergence of an avian influenza virus (H3N8) in New England harbor seals which caused an outbreak of pneumonia and contributed to a U.S. federally recognized unusual mortality event (UME). This outbreak is particularly significant, not only because of the disease it caused in seals but also because the virus has naturally acquired mutations that are known to increase transmissibility and virulence in mammals. Monitoring the spillover and adaptation of avian viruses in mammalian species is critically important if we are to understand the factors that lead to both epizootic and zoonotic emergence.