College of Wildlife and Protected Area, Northeast Forestry Universitygrid.412246.7, Harbin, China.
Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
J Virol. 2022 Feb 9;96(3):e0171721. doi: 10.1128/JVI.01717-21. Epub 2021 Nov 17.
A 2-year surveillance study of influenza A viruses in migratory birds was conducted to understand the subsequent risk during the migratory seasons in Dandong Yalu River Estuary Coastal Wetland National Nature Reserve, Liaoning Province, China, a major stopover site on the East Asian-Australasian flyway. Overall, we isolated 27 influenza A viruses with multiple subtypes, including H3N8 ( = 2), H4N6 ( = 2), H4N7 ( = 2), H7N4 ( = 9), H7N7 ( = 1), H10N7 ( = 7), and H13N6 ( = 4). Particularly, a novel reassortant influenza A(H7N4) virus was first identified in a woman and her backyard poultry flock in Jiangsu Province, China, posing a serious threat to public health. Here, we describe the genetic characterization and pathogenicity of the nine influenza A(H7N4) isolates. Phylogenetic analysis indicated that complex viral gene flow occurred among Asian countries. We also demonstrated a similar evolutionary trajectory of the surface genes of the A(H7N4) isolates and Jiangsu human-related A(H7N4) viruses. Our A(H7N4) isolates exhibited differing degrees of virulence in mice, suggesting a potential risk to other mammalian species, including humans. We revealed multiple mutations that might affect viral virulence in mice. Our report highlights the importance and need for the long-term surveillance of avian influenza virus in migratory birds combined with domestic poultry surveillance along migratory routes and flyways and, thereby, the development of measures to manage potential health threats. The H7 subtype avian influenza viruses, such as H7N2, H7N3, H7N4, H7N7, and H7N9, were documented as being capable of infecting humans, and the H7 subtype low pathogenicity avian influenza viruses are capable of mutating into highly pathogenic avian influenza; therefore, they pose a serious threat to public health. Here, we investigated the evolutionary history, molecular characteristics, and pathogenicity of shorebird-origin influenza A(H7N4) viruses, showing a similar evolutionary trajectory with Jiangsu human A(H7N4) viruses in HA and NA genes. Moreover, our isolates exhibited variable virulence (including moderate virulence) in mice, suggesting a potential risk to other mammalian species, including humans.
在中国辽宁省丹东鸭绿江口滨海湿地国家级自然保护区进行了为期两年的候鸟流感病毒监测研究，该保护区是东亚-澳大利西亚候鸟迁徙路线上的一个重要停歇地，旨在了解迁徙季节的后续风险。总的来说，我们从候鸟中分离出了 27 种具有多种亚型的流感病毒，包括 H3N8（2 株）、H4N6（2 株）、H4N7（2 株）、H7N4（9 株）、H7N7（1 株）、H10N7（7 株）和 H13N6（4 株）。特别是，在中国江苏省，我们首次从一名妇女及其后院家禽群中分离到一种新型重配流感 A(H7N4)病毒，这对公共卫生构成了严重威胁。在这里，我们描述了这 9 株流感 A(H7N4)分离株的遗传特征和致病性。系统进化分析表明，亚洲国家之间发生了复杂的病毒基因流。我们还证明了 A(H7N4)分离株和江苏人源相关 A(H7N4)病毒表面基因的相似进化轨迹。我们的 A(H7N4)分离株在小鼠中表现出不同程度的毒力，这表明它们可能对其他哺乳动物物种（包括人类）构成潜在风险。我们揭示了多个可能影响小鼠病毒毒力的突变。我们的报告强调了长期监测候鸟中禽流感病毒以及在迁徙路线和迁徙路线上监测家禽的重要性和必要性，并制定了管理潜在健康威胁的措施。H7 亚型禽流感病毒，如 H7N2、H7N3、H7N4、H7N7 和 H7N9，已被证明能够感染人类，而 H7 亚型低致病性禽流感病毒能够突变为高致病性禽流感病毒；因此，它们对公共卫生构成严重威胁。在这里，我们研究了滨鸟源流感 A(H7N4)病毒的进化史、分子特征和致病性，结果表明其 HA 和 NA 基因与江苏人源 A(H7N4)病毒具有相似的进化轨迹。此外，我们的分离株在小鼠中表现出不同的毒力（包括中度毒力），这表明它们对其他哺乳动物物种（包括人类）可能构成潜在风险。
