关注社会:H7N9病毒或可在空气中高效传播

A new bird flu virus that has infected 132 people in recent months and killed 43 is capable of spreading from mammal to mammal through the air, a study by a team of Chinese virologists has found, rekindling fears that the virus could eventually pass from person to person.

中国一个病毒学家团队的研究报告发现，近几个月感染132人并导致43人死亡的新型禽流感病毒可在哺乳动物之间通过空气传播，这再次引发了对于这种病毒最终可能在人际传播的担忧。

The study, published online Thursday by the journal Science, found that one strain of the H7N9 virus isolated from a human subject in eastern China's Anhui province was 'highly transmissible' between ferrets by respiratory droplets, according to a summary posted to Science's website.

该研究报告上周四发布在《科学》(Science)杂志的网站上。据发布在《科学》杂志网站上的研究摘要说，研究发现，从中国安徽省一位感染了H7N9禽流感病毒的患者体内分离出来的毒株可在雪貂之间通过飞沫高效传播。

Led by Chen Hualan, one of China's top virologists, researchers tested the ability of multiple strains of the virus to spread by placing three healthy ferrets in one cage next three infected ferrets in another cage. In most cases, only one of the healthy ferrets became infected, but in the case of the Anhui strain, all three of the healthy ferrets became infected with the virus. A repeat of the experiment with the Anhui strain produced the same result.

在中国主要病毒学家陈化兰的带领下，研究人员测试了H7N9禽流感病毒多个毒株的传播能力，方法是将三只健康的雪貂放在一个笼子里，旁边的一个笼子里放入三只感染了病毒的雪貂。在大部分情况下，只有一只健康的雪貂感染了病毒，但对于从安徽患者体内分离出来的毒株，三只健康雪貂全部感染。用安徽的毒株重复实验产生的结果相同。

Ferrets respond to flu viruses similarly to humans and thus are often used to test the potential of avian flu viruses in infect and spread between people.

雪貂对流感病毒做出的反应与人类相似，因此常常被用来测试禽流感病毒感染人类及人际传播的可能。

H7N9 was confirmed to have made the jump from birds to humans for the first time in March, when state media revealed that two people in Shanghai had died after being infected with the virus the previous month. Other deaths soon followed, prompting officials to shut down wet markets and slaughter poultry in a number of cities amid fears of a potential epidemic.

今年3月，中国证实H7N9禽流感病毒首次出现禽类向人类传播的病例，当时中国国有媒体披露说，上海有两人此前一个月感染了H7N9病毒，之后死亡。很快有其他感染者死亡，由于担心可能爆发大范围的疫情，官员们关闭了多个城市的活禽市场，并扑杀了大量禽鸟。

Despite discovering a handful of 'family clusters' or infections of multiple family members health authorities have yet to turn up evidence that H7N9 is capable human-to-human transmission, which would make it far more dangerous.

尽管发现有一些“家庭集群式”感染（即多个家庭成员感染）的情况，但卫生主管部门尚未找到证据证明H7N9能够发生人与人之间的传播。如果出现人际传播，这种病毒的危险性就大得多。

But the new study reinforces earlier warnings from the World Heath Organization and Chinese authorities that the virus has a higher potential for human-to-human transmission than any other known bird-flu virus.

但上述新的研究印证了早些时候世界卫生组织(World Health Organization)和中国有关部门发出的警告，他们曾警告说，相比其他任何一种已知的禽流感病毒，H7N9病毒有更高的人际传播的可能。

'The findings suggest that only a few amino acid changes would be needed to make the avian H7N9 viruses highly transmissible,' the official Xinhua news agency quoted Ms. Chen as saying on Friday.

新华社上周五援引陈化兰的话说，研究结果表明，H7N9病毒株可能只需要几个氨基酸的突变，就会具有高度传播性。

In its summary of the new study, Science notes that the results conflict with an earlier study by the U.S. Centers for Disease Control featuring a similar experiment using the same Anhui strain of the virus. In that experiment the virus spread to only two of six healthy ferrets, leading researchers to conclude that the virus did not spread readily through the air.

在对上述新的研究的总结中，《科学》杂志指出，研究结果与早些时候美国疾病控制与预防中心(U.S. Centers for Disease Control and Prevention)使用同样的安徽毒株进行的类似研究得出的结果不一致。在美国疾病控制与预防中心的实验中，病毒只传染给了六只健康雪貂中的两只，研究人员由此得出结论，病毒不易通过空气传播。

A third study led by virologist Yoshihiro Kawaoka produced similar results to the CDC. The researchers concluded nevertheless that H7N9 respresented a significant public health threat.

另外一项由病毒学家河冈义裕(Yoshihiro Kawaoka)主持的研究得出的结果与美国疾病控制与预防中心得出的结果类似。不过研究人员仍得出结论说，H7N9可能给公众健康带来严重威胁。

The number of human H7N9 infections has dropped off significantly in recent months, though Ms. Chen warned in her interview with Xinhua the virus continues to exist in animals. The fact that the virus doesn't produce symptoms in birds means it can 'replicate silently' and transmit to unsuspecting humans, providing multiple chances for it to mutate and potentially become more dangerous, she said.

人感染H7N9禽流感病毒的病例近几个月大幅减少，不过陈化兰在接受新华社采访时警告说，这种病毒仍存在于动物体内。她说，这种病毒在禽类身上并不会出现症状，这一事实意味着，它可以沉默地复制而不引人注意，这增加了它传染给人并获得更多变异成为致病、传播能力更强病毒的机会。