摘要：考研英语作为一门考研公共课，虽然大家都学了英语十几年，却仍经常有总分过线挂在英语上的情况，因此英语复习不单单是单词、做题。阅读作为考研英语的大头，仅仅做考研真题或许没法满足你的阅读量，因此帮帮之后会不定时推出一篇英文美文，这些文章都与考研英语阅读同源，多读必有好处。

　　An estimated 37 million people worldwide are living with HIV, with just under 2 million of those people having recently contracted the virus. In the United States, around 1.1 million people live with HIV, but as many as 15% (or roughly 1 in 7) of those infected do not know they carry the virus. Some groups bare more of the burden of the HIV risk than others, especially racial minorities and men who have sex with other men.

　　全世界大概有3700万人携有HIV病毒，其中不到200万人是最近新增的病毒感染者。在美国，HIV病毒携带者约110万人，但是其中15%的感染者（大概七分之一的人）根本不知道自己携有该病毒。有些群体的病毒感染率高于其他人，特别是那些少数族裔以及与同性存在性关系的男性。

　　HIV is considered rare in the US with less than 200,000 new infections per year. But for those living with HIV, treatment of the virus becomes a lifelong commitment to medication and maintenance because a reliable cure remains elusive. What makes HIV so hard to eradicate? And how close has science brought us to a cure?

　　美国的HIV病例发生率还算比较低，每年新出现的HIV感染者不到20万。但是对于那些已经患上HIV的病人来说，对付这种病毒的方法只有一辈子药不离身，苟延残喘，因为目前为止仍未出现可靠的根治方案。到底是什么让HIV如此难根治？到底还要多久科学家才能发现胜利的曙光？

　　What Is HIV?

　　什么是HIV？

　　The human immunodeficiency virus, or HIV, is a virus that targets the body’s immune system. Within a few weeks of contracting the virus, known as the acute infection stage, people typically experience what feels like a very bad case of the flu as the virus works hard to replicate itself throughout the body. Once this initial surge is over, HIV transitions into a clinical latency stage which means people carrying the virus can go for years without experiencing any symptoms at all.

　　人类免疫缺陷病毒，也就是我们常说的HIV，这种病毒能直接摧毁我们体内的免疫系统。在感染该病毒的前几个星期，即急性感染期，由于体内的病毒处于疯狂的自我复制阶段，患者通常会表现出非常严重的流感症状。一旦这种伴随着病毒数量激增的感染初期一过去，HIV就会进入临床潜伏期，这也就意味着患者会一直携带着这种病毒，并且不会有任何症状出现。

　　If left untreated, however, HIV can lead to acquired immunodeficiency syndrome, or AIDS. This occurs once the immune system has become sufficiently damaged or has been weakened enough to allow the contraction of what are called opportunistic illnesses.

　　但是如果直接听之任之，那么HIV就会发展成获得性免疫缺陷综合征，也就是艾滋病。一旦免疫系统受到了很大程度上的损坏，或是由于太过脆弱而让机会性疾病趁虚而入，HIV就会变成艾滋病。

　　Why Is HIV So Hard to Cure?

　　为什么HIV如此难以根治？

　　The first cases of clinically-reported AIDS in the United States occurred in 1981 in Los Angeles. Since then, despite extensive study, we are still without a standard cure. HIV is particularly difficult to combat because it attacks the body’s immune system, the very system meant to fight off infections like HIV.

　　美国首例临床诊断的艾滋病出现在1981年的洛杉矶。尽管关于艾滋病的深入研究一直在进行着，但是这些年来我们依旧没有研究出一个标准的医疗方案。HIV之所以很难攻克，是因为它破坏的是人体的免疫系统，而免疫系统恰恰就是原本能抵抗像HIV一类的感染病毒的保护墙。

　　The virus first hijacks a protein called CD4 found on the cells of our immune system to replicate itself and then eventually kills those cells off. Among those under attack are T cells, the cells typically tasked with seeking out and destroying cells infected with viruses or cancers.

　　这种病毒一旦进入体内，就会先通过免疫细胞里的蛋白质CD4进行自我复制，然后再将这些细胞全部消灭。包括T细胞也会受到攻击破坏，而人体T细胞本身承担的责任就是找出并摧毁那些已经感染上病毒或癌症的变异细胞。

　　HIV is also be able to kill off immune system cells that it hasn’t even infected yet. The loss of those uninfected cells further leads to the decline in the immune system’s ability to do its job and thus the body’s ability to fight off future infections.

　　HIV病毒还会杀掉那些未曾感染的免疫细胞。而这些功能完整的细胞一旦消失，就会进一步导致免疫系统功能的崩溃，人体也就无法抵御后续的各种病毒感染。

　　As if all of that weren’t challenging enough, HIV is found to have an extremely high mutation rate in the first 10 days of infection, meaning researchers looking for a cure are chasing down a moving target.

　　HIV一入侵人体，似乎就能“势如破竹”，科学家发现这种病毒的变异率在感染前10天极其地高，这就意味着科学家在研究治疗方法的时候就仿佛在追赶一个移动的目标（研究变量太多）。

　　We’ve discussed before how challenging it is to come up each year with the vaccine to fend off the ever-adapting flu virus, and the rapidly mutating HIV is at least an order of magnitude worse.

　　我们之前讨论过每年成功研究出对抗一直不断适应环境的流感病毒的疫苗有多么困难，而对于这种不断变异的HIV，更是难上加难。

　　The virus at work on the body has been likened to an arsonist setting fire to the local firehouse: there is no way to fight the blaze when the tools for that fight are the ones under attack.

　　这种病毒对人体的感染就好比纵火犯在地方小城镇的消防站里放火：当陷入火海的恰恰就是你能灭火的工具，这场大火你根本无从灭起。

　　(全文共520个词：科学美国人)

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