Over the past couple of years the largest outbreak of avian influenza (H5N1) in recorded history has torn across the planet. The virus, which is deadly to birds, has devastated wild and domesticated flocks alike. Attempts to stop transmission have seen hundreds of millions of birds culled on farms since the strain was first identified in 1996. Wild bird deaths are probably in their millions at least. The danger is that, as the virus mutates, a bird pandemic becomes a human one. Precisely how H5N1 will adapt and spread is impossible to predict. But the time to prepare is now.

过去几年，有记录以来最大规模的禽流感（H5N1）疫情席卷了地球。这种病毒对鸟类是致命的，已经夺走了许多野生鸟类和家养鸟类的生命。自1996年首次发现该毒株以来，为了阻止传播，农场已经扑杀了数亿只鸟类。野生鸟类死亡数量至少有数百万只。危险在于，随着病毒变异，鸟类疫情会演变成人类疫情。H5N1将如何适应和传播是无法准确预测的。但现在是时候做好准备应对了。



In the past year the virus has spread in a range of mammals, and it is now rife among dairy cattle in America. This has led to several confirmed infections in farm workers. So far, these have been mild and isolated. However, many more cases in cows and people are thought to be going undetected, because of gaps in surveillance.

去年，该病毒在一系列哺乳动物中传播，现在在美国的奶牛中盛行。这导致多名农场工人确诊感染。到目前为止，相关疫情程度较轻且未造成大范围感染。然而，由于监测存在缺陷，很多牛和人的病例都并未被检测出来。

For now there are no known cases of the virus being passed from one person to another. Nor is there evidence of airborne transmission from dairy cattle to humans. But that is no cause for complacency. Each infection is a chance for new mutations to arise. Scientists have found the virus has acquired many adaptations, including some that may help it spread more easily. There is a risk that it could become a highly dangerous airborne human pathogen.

目前还没有已知的病毒人传人的病例。也没有证据表明奶牛通过空气将病毒传播给人类。但我们不能因此就放松警惕。每次感染都是出现新突变的机会。科学家发现该病毒已经进行过多次突变以适应环境，其中包括可能有助于其传播的变化。它有可能成为一种高度危险的空气传播人类病原体。

In many respects the world is better prepared for an influenza pandemic than it was in 2020 when covid-19 began to spread. It is not starting from scratch. Influenza viruses frequently circulate among humans, providing some degree of immunity. Antiviral drugs can help treat those who are infected. A limited supply of vaccines already exists; efforts to produce more, and to develop better jabs, are ramping up.

在许多方面，与2020年新冠疫情流行时的情况相比，世界对疫情做好了更充足的准备。这不是从零开始的挑战。流感病毒经常在人类中传播，提供一定程度的免疫力。抗病毒药物可以帮助治疗感染者。已存在小规模的疫苗供应；生产更多疫苗和开发更好疫苗的努力正在加大。

Yet more needs to be done to ensure that governments can react speedily, should signs emerge that the virus is spreading from person to person. Countries, including America, need to strengthen their surveillance of infections. More targeted testing needs to take place on farms. Wastewater sampling, to help detect outbreaks, needs to be expanded. Standards of hygiene on farms could be checked and improved. Where stocks exist, vaccines should be deployed to the most exposed people, such as farm workers.

然而，需要采取更多措施来确保政府能够在出现病毒在人际传播的迹象时迅速做出反应。包括美国在内的各国需要加强对感染的监测。需要在农场进行更有针对性的测试。需要扩大废水采样以帮助检测疫情爆发。可以检查和提高农场的卫生标准。在疫苗有库存保障的情况下，应将疫苗接种给风险最高的人，例如农场工人。

Now is also a good time for governments to dust off their pandemic plans and check that their stockpiles of diagnostic kits, vaccines and protective equipment are in good order. Countries need to work together, too, to share genetic sequences and outbreak data more readily. One big lesson of covid-19 was that transparency and cross-border collaboration can save a lot of lives. Secrecy and selfishness tend to have the opposite effect.

现在也是各国政府制定疫情计划并检查其诊断试剂盒、疫苗和防护设备库存是否处于良好状态的好时机。各国也需要共同努力让共享基因序列和疫情数据更便利。新冠疫情的一个重要教训是，透明度和跨境合作可以拯救很多生命。保密和自私往往会适得其反。

Preparing for H5N1 will be helpful even if the virus does not become a threat to humanity. Better monitoring of wastewater, for instance, is an investment in monitoring a whole range of infections in human and animal populations. Human influenza pandemics have been common for centuries, occurring three times in the 20th century alone. Another one at some point is highly likely, perhaps even inevitable. Improvements in detection, surveillance and vaccines will help the world cope when it comes.

即使该病毒没有对人类构成威胁，为H5N1做好准备也会有所帮助。例如，更好地监测废水是一项投资，可以监测人类和动物群体一系列感染状况。几个世纪以来，人类流感疫情一直很常见，仅在20世纪就发生了三次。在某种程度上说，新的一场疫情正暗流涌动，甚至很可能是不可避免的。检测、监测和疫苗的改进，将帮助世界应对危机。