 | | Alex | 等级：轻骑兵
管理等级：管理团队
贡献积分：57
帖子水平：未见精华
虚拟学会：无门无派 |
| 〖删除〗〖版主编辑〗〖转移帖子〗〖顶〗〖精〗[回复][短消息][编辑] | | [译］关于禽流感 | Instant Expert: Bird Flu
我们常说的禽流感，H5N1品系的流感病毒，第一次得知可以在鸡和人之间传播是在1997年。从2004年它开始从亚洲的禽养殖场爆发,并且在最先报道感染的的70人中有70％的死亡率。健康权威很害怕这种病毒以及其变种，会引起一次致命的新流感流行，这可能会杀死数十亿的人。
The H5N1 strain of influenza - often referred to as bird flu - was first known to have jumped from chickens to humans in 1997. Since 2004 it has ripped through Asian poultry farms, and had a 70% mortality rate in the first 70 people it is known to have infected. Health authorities fear this strain, or its descendents, could cause a lethal new flu pandemic with the potential to kill billions.
流感已经困扰了人类几千年。流感病毒是一个大的家族，每一个成员在它的RNA上只含有十个基因。所有这16个家族都是来源于水鸟，尤其是鸭子和海鸥。并对非常适应它们的免疫系统，而且不会引起强烈的反应。这使得这些动物可以自由移动并散播病毒—这正是病毒需要维持的条件。
Flu has been a regular scourge of humanity for thousands of years. The flu viruses are a large family, each possessing a mere 10 genes encoded in RNA. All of the 16 known groups originate in water birds, especially ducks and gulls. The virus is well adapted to their immune systems, and does not usually make them very sick. This leaves the animals free to move around and spread the virus - just what it needs to persist.
病毒爆发
但是不管过去还是以后，每一种禽流感病毒到那些免疫系统不适应的动物当中。在来自于森林而驯养的鸡类中，病毒引起了适中的的疾病但是逐渐的变异成更严重的毒株.正如H5N1病毒株,它的命名来自于病毒的表面蛋白,已经在东亚的大型养鸡场爆发.
Rampaging virus
But every now and then a bird flu virus jumps to an animal whose immune system it is not adapted to. In chickens, a forest bird originally and not a natural host, it causes a moderate disease but can readily mutate to a more severe strain. Just such a strain of H5N1 flu, named after its surface proteins, has been rampaging through large chicken farms in east Asia.
这事关重要，因为在1997年，科学家们第一次发现H5流感可以感染人。 18个人发现感染，其中6人死亡。为了阻止威胁香港屠杀了所有家禽。但是禽流感仍在流行，特别是在中国。
That is of concern because, in 1997, scientists found for the first time that H5 flu is capable of infecting humans. It was found in 18 people, six of whom died. All the poultry in Hong Kong were destroyed to stop the threat. But it continued to circulate, especially in China.
2003年在中国发生了更进一步的人类感染。在2004年初越南报道了禽流感的爆发以及一些人类的病例。在最初否定之后，柬埔寨和台湾也承认有禽流感的爆发，紧接着中国也有报道。这一切恰恰发生在中国否定New Scientist报道科学家强烈怀疑中国禽流感爆发之后。
There were further human cases in China in 2003. Then in early 2004 Vietnam reported widespread poultry outbreaks and some human cases. After initial denials, Cambodia and Thailand admitted they had outbreaks too, followed by China. That was immediately after China had denied a New Scientist report that scientists strongly suspected Chinese outbreaks.
2004年三月一场大的家禽筛选阻止了禽流感的爆发，截至此时已有23人死亡。但是病毒仍然流行，尤其可能在鸭子中。科学家对试图破坏其在野生鸟类中存在和传播行为表示怀疑。2004年夏 禽流感再次爆发截至到2005年四月中旬总共引起了51人死亡，全部发生在台湾和越南。
A mass poultry cull stopped the outbreaks by March 2004, by which time 23 people had died. But the virus persisted, most probably in ducks. Attempts to blame its persistence and spread in the region on wild birds are widely discounted by scientists. The outbreaks started again in summer 2004, and by mid-April 2005 had caused a total of 51 human deaths, all in Thailand and Vietnam.
种间传播
有两三种流感家族已经传染到人类，大都引起了轻度疾病，因为他们已经适应了我们的免疫系统。每年冬天的流感流行折磨着世界大多数地方。但是并没有总爆发。全世界大约700000人死亡，大都是老人小孩和身体孱弱的人。
Making the jump
The two or three flu virus families that have made the jump to humans mostly cause mild disease, because they have adapted to our immune systems. A yearly winter flu epidemic afflicts most of the world. But it is not totally benign. About 700,000 people around the world die of it each year, mainly the very old, very young and the infirm.
普通流感疫苗整逐步普及，即便是流感病毒变异非常快以至于每年我们都需要换新的注射剂。2004年美国一个意想不到的疫苗缺陷突出了疫苗供应的脆弱,这些疫苗只是由非常有限的几个厂家生产.正如New Scientist预料的,为防止过多的死亡，限制正常的供应使得在那些严重疾病的风险下的人更加雪上加霜。
Common flu vaccines are increasing in popularity, although flu evolves so fast that we need new shots every year. In 2004 an unexpected shortage of vaccine in the US underscored the fragility of the vaccine supply, which is produced by very few manufacturers. As New Scientist predicted, it took strenuous efforts to limit available supplies to those most at risk of serious illness, preventing excess deaths.
但是流感第一次传染到人就有很高的死亡率，已经没有机会把它自己适应我们的免疫系统。伴随着明显的高死亡率，H5N1就象在禽类中爆发一样已经在持续的感染人类。就目前为止禽流感还不容易感染，而且不容易在人与人之间传播。如果病毒株得到传播能力，它将变成致命流行，在世界范围内传播流行。
But flu is at its most deadly when it first makes the jump to people, having had no opportunity to adapt itself to our immune systems. H5N1 has continued to infect humans as the outbreak in poultry has raged, with an apparently high fatality rate. It has so far has been hard to contract, and has not spread readily between people. If this viral strain should acquire that ability, it could become a lethal pandemic - the name for an epidemic that spreads worldwide.
致命流行
正如1918年发生的，一个病毒株在人中传播，并在短短的几个月中杀死了五千万人。
Deadly pandemic
That is what happened in 1918, when a virulent flu strain appeared in humans and killed 50 million people within a few months.
还有两次比那一次稍微好一点的大流行。1957年所谓的“亚洲的”流感导致了一百万到四百万的死亡而1968年的“香港”流感，估计大概“亚洲的”流感致死一半，引起了一百万到两百万的死亡。这两次都是人类流感病毒重组了鸟类流感病毒,导致了人类免疫系统对其的不可识别。因为偶然的因素1957病毒株险些在2005年流行。
There have also been two less catastrophic pandemics. The so-called "Asian" flu of 1957 caused between one and four million deaths, while 1968's "Hong Kong" flu - with about half the estimated deadliness of the Asian flu - caused one to two million deaths. Both of these were human flu viruses which had recombined with bird flu viruses, rendering them unrecognisable to the human immune system. The 1957 strain was nearly released by accident in 2005.
病毒学家基本同意我们将迎来一场传染病大流行。因此他们非常担心H5N1的，以为它很像1918事件他似乎正在演化的对哺乳动物更具致死力。New Scientist揭示，这很有可能在中国，很可能在接种过疫苗的鸡中出现。
Virologists generally agree that we are due for another pandemic. So they are very worried about H5N1, because - like the 1918 event - it seems to be evolving to become more deadly to mammals. This is largely in China and, possibly, as New Scientist revealed, in vaccinated chickens.
它可能通过上述方法演化出潜在的流行，或通过重组人类流感，特别是在远东并没有注射疫苗预防普通流感。
It could evolve into a potential pandemic that way, or by recombining with human flu, especially as most people in the Far East are not vaccinated against ordinary flu strains.
缓和方法
幸运的是制作H5N1病毒株的疫苗，即便是我们为准备流行及时的检测和生产疫苗的能力还存在质疑。一旦有效的疫苗得以生产,另一种屏障将很快的控制流感。如果进程的每个方面都失败，最后的支持将使抗病毒药物。一些新药即将问世，但是现有的药供应紧张。
Mitigation measures
Fortunately we can make vaccines for the H5N1 strain, although our ability to get them tested and manufactured in time for a pandemic is in doubt. Once an effective vaccine is produced, yet another hurdle would be administering it swiftly. If either aspect of that process should fail, the only backup would be antiviral drugs. A few new ones are on the horizon, but existing drugs are in short supply.
如果流感病毒发生遗传变化，它将降低致死性。但是，没有理由考虑这种可能，并且一种70％致死率的高传染性病毒是一种非常恐怖的场景，尤其是在现代国际间流动速度的今天。还有一种可能就是演化出一种全新的疾病，在它传播之前我们可能都不能完全认识它。
If the flu virus changes genetically, it may become less deadly. However, there is no reason to think this will happen, and a highly contagious virus with a 70% death rate is a terrifying prospect, particularly given the speed of modern international travel. There is also a chance that it could evolve into a completely new disease, which we could fail to spot before it spreads.
甚至即使H5不扣动下一次传染病的扳机，它的兄弟姐妹H7和H9也可能引起流行。H7出现在相同的地域并且在它2003年爆发时传染了大量的荷兰人。虽然它引起了少量的的症状但只有一例死亡，这种禽流感病毒与人类流感形成交叉种并变得更加危险的担心依然存在。
Even if H5 does not trigger the next pandemic, its cousins H7 and H9 could. H7 is present in the same region and also infected large numbers of Dutch people in an outbreak in 2003. Although it caused few symptoms, and only one death, fears remain that such a poultry virus could cross-breed with a human flu, making it even more dangerous.
一些科学家不愿静观变化。他们试图培育的H5N1传染性来验证它是否会产生。另一些科学家从受害者身上的样品复制1918病毒来研究是什么让其具有如此高的致死性。但是有些人感到病毒有从实验室泄漏的危险，这将把我们推向很高的风险，这种风险和病毒的自然演化带来的风险相差无几。
Some scientists are not willing to wait and see. They are trying to breed contagiousness into H5N1 to see if it is likely to happen. Others are breeding replicas of the 1918 virus - from samples recovered from victims - to see just what made it so deadly. But some feel that those experiments, because of the potential for escape from the lab, put us at as much risk as the natural evolution of the virus.
Debora Mackenzie, 6 May 2005
| 最初发表时间：2005-12-16 |  | | 未填 |
|
