同期online两篇Science：骆驼中的MERS病毒不同的变异及一种疫苗

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鉴于最近爆发的中东呼吸综合征-冠状病毒（MERS-CoV），两项研究对这种威胁生命的病原体提出了新的看法：第一项研究发现了在人和骆驼之间传播的5个不同的病毒世系，而第二项研究评估了用于骆驼的MERS-CoV疫苗，它或能作为一种抢先发制的措施来减少该病原体的传播。

在过去的3年中，中东地区报告了数起MERS爆发，而最近的爆发出现在韩国，其死亡率大约为35%。阿拉伯骆驼是MERS-CoV的一种常见宿主，在其体内，该病毒常常会产生变化并接着传染给人类。为了更多地了解这种病毒的本质，香港大学新发传染性疾病国家重点实验室管轶教授领导的研究小组在2014年5月至2015年4月间对沙特阿拉伯1300多头骆驼进行了采样；沙特是受到MERS影响最重的国家。在这些样本中检测出MERS-CoV的总体百分比为12%。他们用基因测序方法确认了5种不同世系的MERS-CoVs，它们都含有人类和骆驼的MERS-CoV序列，表明种系间传播的屏障效应低下。广泛的CoVs范围以及它们能感染多个物种的资质表明，未来会出现该病毒的更多变异。作者们得出结论，尽管人群密度、气候条件和社会因素等的变化可能促成MERS-CoVs在其它地区（如最近在韩国的爆发）的扩散，但防止其在动物-人界面的传播可能会是遏制这类病毒威胁的最有效措施。

在第二项研究中，来自荷兰鹿特丹大学的Bart Haagmans等人对一种在阿拉伯骆驼中表达MERS-CoV突起蛋白的疫苗功效进行了测试，该疫苗是通过一种修饰的痘病毒进行输送的。在同时通过鼻腔吸入和肌肉内注射给予该疫苗后，所有的骆驼都在3周内产生了针对MERS-CoV的可检测得到的抗体浓度。在感染MERS-CoV后，与对照组相比，这些接种了MERS-CoV疫苗的骆驼只出现了轻微的临床症状，且它们体内的病毒浓度显著降低。在接种MERS-Cov疫苗的骆驼中，其受到保护的程度与骆驼体内含有的中和抗体浓度相关。由于这种疫苗所用的是一种修改的骆驼痘病毒，接种疫苗的骆驼也出现了针对该骆驼痘病毒的抗体及得到保护程度的增加，该病原体也常常会感染阿拉伯病毒。

来源：生物360

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Co-circulation of three camel coronavirus species and recombination of MERS-CoVs in Saudi Arabia

Jamal S. M. Sabir1,*, Tommy T.-Y. Lam2,3,4,*, Mohamed M. M. Ahmed1,6,*, Lifeng Li3,4,*, Yongyi Shen3,4, Salah E. M. Abo-Aba1,7, Muhammad I. Qureshi1, Mohamed Abu-Zeid1,7, Yu Zhang2,3,4, Mohammad A. Khiyami8, Njud S. Alharbi1, Nahid H. Hajrah1, Meshaal J. Sabir1, Mohammed H. Z. Mutwakil1, Saleh A. Kabli1, Faten A. S. Alsulaimany1, Abdullah Y. Obaid9, Boping Zhou2, David K. Smith4, Edward C. Holmes5, Huachen Zhu2,3,4,†, Yi Guan1,2,3,4,†

Outbreaks of Middle East respiratory syndrome (MERS) raise questions about the prevalence and evolution of the MERS coronavirus (CoV) in its animal reservoir. Our surveillance in Saudi Arabia in 2014 and 2015 showed that viruses of the MERS-CoV species and a human CoV 229E–related lineage co-circulated at high prevalence, with frequent co-infections in the upper respiratory tract of dromedary camels. Including a betacoronavirus 1 species, we found that dromedary camels share three CoV species with humans. Several MERS-CoV lineages were present in camels, including a recombinant lineage that has been dominant since December 2014 and that subsequently led to the human outbreaks in 2015. Camels therefore serve as an important reservoir for the maintenance and diversification of the MERS-CoVs and are the source of human infections with this virus.

http://www.sciencemag.org/conten ... cience.aac8608.full

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An orthopoxvirus-based vaccine reduces virus excretion after MERS-CoV infection in dromedary camels

Bart L. Haagmans1,*, Judith M. A. van den Brand1, V. Stalin Raj1, Asisa Volz2, Peter Wohlsein3, Saskia L. Smits1, Debby Schipper1, Theo M. Bestebroer1, Nisreen Okba1, Robert Fux2, Albert Bensaid4, David Solanes Foz4, Thijs Kuiken1, Wolfgang Baumgärtner3, Joaquim Segalés5,6, Gerd Sutter2,*, Albert D. M. E. Osterhaus1,7,8,*

Middle East respiratory syndrome coronavirus (MERS-CoV) infections cause an ongoing outbreak in humans fueled by multiple zoonotic MERS-CoV introductions from dromedary camels. Besides implementing hygiene measures to limit further camel-to-human and human-to-human transmissions, vaccine-mediated reduction of MERS-CoV spread from the animal reservoir may be envisaged. Here, we show that a modified vaccinia virus Ankara (MVA) virus vaccine expressing the MERS-CoV spike protein confers mucosal immunity in dromedary camels. Significant reduction of excreted infectious virus and viral RNA transcripts was observed in vaccinated animals upon MERS-CoV challenge as compared to controls. Protection correlated with the presence of serum neutralizing antibodies to MERS-CoV. Induction of MVA-specific antibodies that cross-neutralize camelpox virus, would also provide protection against camelpox.

http://www.sciencemag.org/conten ... c-b7cf-cc92e43d5ff5