The contrasting phylodynamics of human influenza B viruses.
The contrasting phylodynamics of human influenza B viruses.
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DOI：
10.7554/elife.05055
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发表时间：
2015-01-16
期刊：
影响因子：
7.7
通讯作者：
Barr IG
中科院分区：
文献类型：
--
作者：
Vijaykrishna D;Holmes EC;Joseph U;Fourment M;Su YC;Halpin R;Lee RT;Deng YM;Gunalan V;Lin X;Stockwell TB;Fedorova NB;Zhou B;Spirason N;Kühnert D;Bošková V;Stadler T;Costa AM;Dwyer DE;Huang QS;Jennings LC;Rawlinson W;Sullivan SG;Hurt AC;Maurer-Stroh S;Wentworth DE;Smith GJ;Barr IG
病毒、宿主和生态因素的复杂相互作用塑造了人类流感病毒的时空发病率和演变。尽管甲型流感病毒受到了相当大的关注，但缺乏相应的数据意味着，尽管B型流感病毒造成了重大的疾病负担，但迄今为止还没有一个综合的进化和流行病学框架。通过对来自澳大利亚和新西兰的26，000多株流行病学收集的900多个全基因组的分析，我们揭示了两种共循环的B型流感病毒谱系（维多利亚和山形）的传播动力学的根本差异，表明它们的个体动力学由病毒传播、感染年龄和受体结合偏好之间的复杂关系决定。总之，这项工作确定了新的因素，是流感B演变和流行病学的重要决定因素。DOI：http://dx.doi.org/10.7554/eLife.05055.001为了开发针对病毒引起的感染的新疗法，重要的是要了解病毒的历史-在何处，何时以及为什么它会引起疾病以及它如何随着时间的推移而变化。例如，A型流感病毒的新人类毒株源自感染动物的毒株，并可迅速在人群中变得常见。相反，B型流感病毒株几乎专门感染人类，并持续存在于人群中。这两种类型的病毒都对全球健康产生不利影响，但对B型病毒的了解较少，部分原因是爆发没有得到广泛的记录。Vijaykrishna等人现在已经调查了两种B型流感病毒株的历史-称为维多利亚和Yamagata-目前在人类中传播。为了做到这一点，他们检查了13年来从澳大利亚和新西兰收集的确诊B型感染样本中提取的908种病毒的基因序列。同一毒株的单个病毒颗粒具有非常相似但不完全相同的基因序列。Vijaykrishna等人的研究表明，维多利亚菌株的遗传序列多样性在不同季节之间波动，维多利亚菌株的特定遗传变体仅在种群中持续1-3年。这表明维多利亚病毒在进化上面临很大压力，这导致了所谓的“瓶颈”，只有携带特定基因序列的病毒才能生存。这种波动模式类似于更好理解的A型季节性流感病毒株H3 N2。另一方面，在相同的13年期间采样的山形株的遗传多样性变化不大。山形病毒在很大程度上已经多样化，几种不同的病毒“变种”往往会在一起传播很长一段时间。例如，2013年流行的三种山形病毒是从大约10年前流行的一种共同的亲本病毒进化而来的。Vijaykrishna等人发现，在疾病爆发之间，维多利亚病毒在人类中传播的能力存在较大差异，但它们通常比山形病毒更容易传播。维多利亚病毒比山形病毒更容易感染年轻患者，这被认为是由于帮助病毒进入呼吸道细胞的分子不同。这些发现表明，通过使用现有疫苗的大规模疫苗接种计划，有可能根除进化较慢的B山形流感病毒。这将使研究人员能够专注于开发针对其他流感病毒株的有效疫苗。DOI：http://dx.doi.org/10.7554/eLife.05055.002网站
A complex interplay of viral, host, and ecological factors shapes the spatio-temporal incidence and evolution of human influenza viruses. Although considerable attention has been paid to influenza A viruses, a lack of equivalent data means that an integrated evolutionary and epidemiological framework has until now not been available for influenza B viruses, despite their significant disease burden. Through the analysis of over 900 full genomes from an epidemiological collection of more than 26,000 strains from Australia and New Zealand, we reveal fundamental differences in the phylodynamics of the two co-circulating lineages of influenza B virus (Victoria and Yamagata), showing that their individual dynamics are determined by a complex relationship between virus transmission, age of infection, and receptor binding preference. In sum, this work identifies new factors that are important determinants of influenza B evolution and epidemiology. DOI: http://dx.doi.org/10.7554/eLife.05055.001 To develop new therapies against infections caused by a virus, it is important to understand the virus's history—where, when, and why it has caused disease and how it has changed over time. For example, new human strains of the influenza type A virus originate from strains that infect animals and rapidly can become common in human populations. In contrast, influenza type B virus strains almost exclusively infect humans and are continuously present in human populations. Both types have a detrimental impact on global health, but the type B viruses are less well understood, partly because outbreaks have not been as extensively documented. Vijaykrishna et al. have now investigated the history of the two strains of the influenza type B virus—called Victoria and Yamagata—that currently circulate in humans. To do this, they inspected the genetic sequences of 908 viruses taken from samples of confirmed type B infections collected across Australia and New Zealand over 13 years. Individual virus particles of the same strain have genetic sequences that are very similar, but not completely identical. Vijaykrishna et al. showed that the diversity of the genetic sequences from the Victoria strain fluctuated between seasons, and particular genetic variants of Victoria only persisted in the population for 1–3 years. This indicates that Victoria viruses are under a lot of pressure to evolve, which results in so-called ‘bottlenecks’ whereby only the viruses carrying particular varieties of genetic sequence survive. This fluctuating pattern resembles that of the better-understood type A seasonal flu strain H3N2. On the other hand, there was little change in the genetic diversity of the Yamagata strains sampled over the same 13-year period. The Yamagata viruses have diversified to a greater extent and several different ‘varieties’ of the virus tend to circulate together for long periods of time. For example, the three varieties of Yamagata virus circulating in 2013 evolved from a common parent virus that was circulating around 10 years ago. Vijaykrishna et al. found that between disease outbreaks, there was greater variation in the ability of Victoria viruses to be transmitted in humans, but that they were generally more easily transmitted than the Yamagata viruses. Victoria viruses tend to infect younger patients than Yamagata viruses, which is thought to be due to differences in the molecules that help the viruses enter the cells of the respiratory tract. These findings suggests that it might be possible to eradicate the more slowly evolving influenza B Yamagata virus through mass vaccination programs using existing vaccines. This would then allow researchers to focus on developing effective vaccines to target the other strains of influenza virus. DOI: http://dx.doi.org/10.7554/eLife.05055.002