Emergence of a Highly Pathogenic Avian Influenza Virus from a Low-Pathogenic Progenitor
Emergence of a Highly Pathogenic Avian Influenza Virus from a Low-Pathogenic Progenitor
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DOI：
10.1128/jvi.03181-13
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发表时间：
2014-04-01
影响因子：
5.4
通讯作者：
Cattolia, Giovanni
中科院分区：
文献类型：
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作者：
Monne, Isabella;Fusaro, Alice;Cattolia, Giovanni
H7亚型禽流感（AI）病毒有可能演变成高致病性（HP）病毒，这是家禽业的主要经济问题和对全球健康的威胁。然而，目前对低致病性（LPAI）祖病毒中出现高致病性（HPAI）病毒的了解还很少。为了研究欧洲最重要的禽流感流行病之一的起源和演变，我们研究了1999年3月至2001年2月意大利H7N1爆发期间收集的109株H7N1（46株LPAI和63株HPAI）病毒全基因组的演变和空间动态。系统发育分析表明，LPAI和HPAI流行病有一个共同的祖先，HPAI毒株在没有重配的情况下从LPAI病毒进化而来，并且在HPAI和后来的LPAI谱系中平行出现突变。值得注意的是，超深度测序分析表明，从LPAI H7N1流行开始，一些表征HPAI病毒簇的氨基酸变化已经以低频率存在于几个单独的病毒群体中。贝叶斯地理分析显示，LPAI爆发期间的空间结构更强，反映了HPAI出现后病毒的传播速度更快。本研究中生成的数据提供了迄今为止对流行病学交织的高致病性和低致病性病毒进行的最完整的进化和地理学分析，并强调了对LPAI实施及时根除措施的重要性，以防止出现具有适应性优势和不可预测的致病特性的病毒。
Avian influenza (AI) viruses of the H7 subtype have the potential to evolve into highly pathogenic (HP) viruses that represent a major economic problem for the poultry industry and a threat to global health. However, the emergence of HPAI viruses from low-pathogenic (LPAI) progenitor viruses currently is poorly understood. To investigate the origin and evolution of one of the most important avian influenza epidemics described in Europe, we investigated the evolutionary and spatial dynamics of the entire genome of 109 H7N1 (46 LPAI and 63 HPAI) viruses collected during Italian H7N1 outbreaks between March 1999 and February 2001. Phylogenetic analysis revealed that the LPAI and HPAI epidemics shared a single ancestor, that the HPAI strains evolved from the LPAI viruses in the absence of reassortment, and that there was a parallel emergence of mutations among HPAI and later LPAI lineages. Notably, an ultradeep-sequencing analysis demonstrated that some of the amino acid changes characterizing the HPAI virus cluster were already present with low frequency within several individual viral populations from the beginning of the LPAI H7N1 epidemic. A Bayesian phylogeographic analysis revealed stronger spatial structure during the LPAI outbreak, reflecting the more rapid spread of the virus following the emergence of HPAI. The data generated in this study provide the most complete evolutionary and phylogeographic analysis of epidemiologically intertwined high- and low-pathogenicity viruses undertaken to date and highlight the importance of implementing prompt eradication measures against LPAI to prevent the appearance of viruses with fitness advantages and unpredictable pathogenic properties.