In 2008, something incredible happened:
2008年发生了一件不可思议的事情：
a man was cured of HIV.
一名HIV患者被治愈了
In over 70 million HIV cases,
在超过七千万病例中
that was a first and, so far, a last.
这是第一例 也是目前为止最后一例被治愈的
We don’t yet understand exactly how he was cured.
我们仍未掌握他到底是如何被治愈的
We can cure people of various diseases,
我们可以治愈各种各样的疾病
such as malaria and hepatitis C,
如疟疾 丙型肝炎
so why can’t we cure HIV?
但为何无法治愈艾滋病？
Well,first let’s examine how HIV infects people
那么 首先我们来看HIV是如何感染
and progresses into AIDS.
并发展成为艾滋病的
HIV spreads through exchanges of bodily fluids.
HIV通过体液交换传播
Unprotected sex and contaminated needles are the leading cause of transmission.
不安全性行为和污染的针头是HIV传播的首要途径
It艾滋病治愈, fortunately, cannot spread through air, water, or casual contact.
万幸的是 它无法通过空气 水和日常接触传播
Individuals of any age, sexual orientation, gender and race
但任何年龄 性取向 性别和种族的人
can contract HIV.
都可能感染HIV
Once inside the body,
一旦进入体内
HIV infects cells that are part of the immune system.
HIV就会感染免疫系统细胞
It particularly targets helper T cells,
专门攻击能抵抗细菌和真菌感染的
which help defend the body against bacterial and fungal infections.
辅助T细胞
HIV is a retrovirus,
HIV是一种逆转录酶病毒
which means it can write its genetic code
意味着它可以将自己的基因编码
into the genome of infected cells,
写入被感染细胞的基因组
co-opting them into making more copies of itself.
令它们复制出更多带HIV基因的细胞
During the first stage of HIV infection,
在HIV感染的第一阶段
the virus replicates within helper T cells,
病毒在辅助T细胞内复制
destroying many of them in the process.
并在此过程中摧毁大量T细胞
During this stage, patients often experience flu-like symptoms,
此阶段 患者会经常出现流感症状
but are typically not yet in mortal danger.
但不会有性命危险
However, for a period ranging from a few months to several years,
在几个月甚至几年的一段时间内
during which time the patient may look and feel completely healthy,
患者可能看起来很健康
the virus continues to replicate and destroy T cells.
但病毒持续复制并摧毁T细胞
When T cell counts drop too low,
当T细胞数量降至过少
patients are in serious danger of contracting deadly infections
患者就会陷入感染致命疾病的危险中
that healthy immune systems can normally handle.
而这些感染原本可被健康的免疫系统抵抗
This stage of HIV infection is known as AIDS.
感染的这个阶段被称为艾滋病
The good news is
好消息是
there are drugs that are highly effective at managing levels of HIV
有药物可以有效控制HIV的发展进度
and preventing T cell counts from getting low enough
防止T细胞数量降到过低
for the disease to progress to AIDS.
以避免发展成为艾滋病
With antiretroviral therapy,
通过抗逆转录病毒治疗
most HIV-positive people can expect to live long and healthy lives,
大多数HIV阳性病人可以获得长期的正常生活
and are much less likely to infect others.
并且也没那么容易感染他人
However, there are two major catches.
然而目前有两个主要的难点
One is that HIV-positive patients
一是HIV阳性病人
must keep taking their drugs for the rest of their lives.
余生必须坚持服药
Without them, the virus can make a deadly comeback.
一旦停止服药 病毒可能再度恶化
So, how do these drugs work?
那么 这些药物是如何起效的呢？
The most commonly prescribed ones
最常使用的临床药物
prevent the viral genome from being copied
能够阻止HIV基因组
and incorporated into a host cell’s DNA.
复制并编入宿主细胞的DNA中
Other drugs prevent the virus from maturing or assembling,
其他的药物可以阻止病毒的成熟和组装
causing HIV to be unable to infect new cells in the body.
使HIV病毒无法感染体内新的细胞
But HIV hides out somewhere our current drugs cannot reach it:
但HIV会隐藏在目前药物无法到达的地方
inside the DNA of healthy T cells.
那就是健康T细胞的DNA中
Most T cells die shortly after being infected with HIV.
多数T细胞在感染HIV不久后死亡
But in a tiny percentage,
但有很小部分
the instructions for building more HIV viruses lies dormant,
被控制用来繁殖复制更多HIV病毒
sometimes for years.
有时长达数年
So even if we could wipe out every HIV virus from an infected person’s body,
所以尽管我们可以清除感染者体内的每一个HIV病毒
one of those T cells could activate and start spreading the virus again.
但上述一个T细胞就可以激活并重新在体内传播病毒
The other major catch is that not everyone in the world
另一个难题是 不是世界上每个患者
has access to the therapies that could save their lives.
都能获得这些挽救生命的治疗
In Sub-Saharan Africa,
撒哈拉以南非洲地区
which accounts for over 70% of HIV patients worldwide,
生活着全球70%以上的艾滋病患者
antiretrovirals reached only about one in three
但在2012年 仅有三分之一患者
HIV-positive patients in 2012.
获得了抗逆转录病毒治疗
There is no easy answer to this problem.
这个问题很难解决
A mix of political, economic and cultural barriers
因为政治 经济和文化的三重障碍
makes effective prevention and treatment difficult.
使本地区有效的预防和治疗难上加难
And even in the U.S.,
甚至在美国
HIV still claims more than 10,000 lives per year.
HIV每年夺去超过一万人的生命
However, there is ample cause for hope.
不过 我们仍抱有希望
Researchers may be closer than ever to developing a true cure.
研究人员已经非常接近真正的治愈方式
One research approach involves using a drug
一项研究通过使用一种药物
to activate all cells harboring the HIV genetic information.
激活所有隐藏HIV遗传信息的细胞
This would both destroy those cells
破坏这些细胞
and flush the virus out into the open,
同时将病毒暴露出来
where our current drugs are effective.
这样现有的药物就可以起效了
Another is looking to use genetic tools
另一项研究希望借由基因工具
to cut the HIV DNA out of cells genomes altogether.
将HIV的DNA从人体细胞基因组上切割下来
And while one cure out of 70 million cases
尽管七千万病例中仅治愈一例
may seem like terrible odds,
似乎只是个意外
one is immeasurably better than zero.
但这一例意义是不可估量的
We now know that a cure is possible艾滋病治愈,
因为我们现在知道艾滋病是能治愈的
and that may give us what we need to beat HIV for good.
可能有助于我们最终战胜HIV病毒
