unit10 中英对照翻译

Viruses and viral diseasesViruses are the smallest of the pathogens, being approximately 1/500th the size of bacteria. Because of their small size, they are visible only under an electron microscope and were identified in humans only in the 1930s. Not until the1960s were viruses effectively grown outside of the body in tissue cultures.病毒和病毒性疾病病毒是最小的病原体，大小只有细菌的1 /500。

由于其体积小，它们只在电子显微镜下可见和在1930年代的被人们鉴定出来。

直到20世纪60年代，人们才得以在人体之外用组织培养的方式使病毒生长。

At the present time over 150 viruses are known to cause diseases in humans. The role of viruses in the development of various cancers and chronic disease is still unclear. In fact, viruses themselves are perhaps the most unusual of the microorganisms that infect humans.目前有150以上种病毒是已知的能导致人类疾病的。

病毒在各种癌症和慢性疾病的发展中的作用仍不清楚。

事实上，病毒本身也许是最不寻常的能感染人类的微生物。

Essentially, a virus consists of a protein structure that contains the nucleic acids ribonucleic acid (RNA) or deoxyribonucleic acid (DNA). They have no capacity for carrying the normal cell functions of respiration and metabolism. Some scientists even question whether or notviruses should be considered living organisms. Viruses cannot reproduce on their own; rather, they must exist in a parasitic relationship with the cells they invade.基本上，一个病毒是由一个蛋白质结构包含核酸的核糖核酸（RNA）或脱氧核糖核酸（DNA）构成。

它们没有携带呼吸和代谢的正常细胞功能的能力。

一些科学家甚至质疑病毒是不是应该归类为生物。

病毒自身不能繁殖；确切来说，它必须与被其入侵的细胞形成寄生的关系而存在。

Once viruses attach themselves to host cells, they inject their own RNA and DNA,causing the host cells to begin reproducing new viruses. Once they take control of the cell, these new viruses overrun it until it fills to capacity and bursts, putting thousands of new viruses into circulation to begin the process all over again. This whole reproduction process may take as little as 20 seconds!一旦病毒附着到宿主细胞，它们会注入自己的RNA和DNA，造成宿主细胞开始复制新的病毒。

一旦它们控制了细胞，这些新的病毒会大量蔓延，直至整个细胞无法包容而破裂，成千上万的新病毒进入循环，开始新一轮的扩张。

这整个复制过程可能只需花20秒！Because viruses cannot reproduce outside of living cells, they are particularly difficult to culture in a laboratory, making detection and study of the organism extremely time-consuming. Treatment is also difficult because many viruses withstand heat, formaldehyde, and large doses ofradiation with little effect on their structure. In addition, some viruses may have incubation period (the length of time required to develop fully) measured in years rather than hours or days. Termed slow viral infections, these viruses infect the host and remain in a semidormant state for years, causing a slowly developing illness. AIDS is the most recent deadly example of a slow-acting virus.因为病毒不能再活体细胞以外繁殖，在实验室中培养特别困难，使得对病毒的发现和研究非常耗时。

（疾病）治疗也很困难，因为许多病毒耐热，耐甲醛，大剂量的辐射对它们的结构影响不大。

此外，有些病毒有潜伏期（完全成熟需要的时间）不是以小时或天来计算，是以年为单位来计算。

（它们）被称为慢性病毒感染，这些病毒感染宿主并且(在宿主中)保持在一个半休眠状态多年，造成一个缓慢发展的疾病。

艾滋病是一种最致命的慢性疾病例子。

Drug treatment for viral infections is limited. Drug that are powerful enough to kill viruses also kill the host cells. However , some drugs are available that block stages in viral reproduction and do not damage the host cells.病毒感染的（疾病的）治疗是有限的。

药物是强大到足以杀死的病毒（同时）也杀死宿主细胞。

然而，还是有一些药物能阻断病毒的繁殖阶段，而不对宿主细胞造成伤害。

Another form of virus protection exists within our own bodies. When exposed to certain viruses, the body begins to produce a proteinsubstance known as interferon. Although interferon does not destroy the invading microorganisms themselves, it sets up a protective mechanism to aid healthy cells in their struggle against the invaders. Although interferon offers a promising new area of antiviral activities, it should be noted that not all viruses stimulate interferon production.另一种形式的病毒防御方式存在于我们自己的身体。

当（身体）暴露给某些病毒，身体开始产生一种蛋白质的物质称为干扰素。

虽然干扰素不消灭入侵的微生物本身，它建立了一个保护机制，帮助健康细胞抗击侵略者的斗争。

虽然干扰素提供了一个很有前景的抗病毒活性研究的新领域，但值得注意的是，并非所有的病毒都能刺激干扰素的产生。

Here , let’s take a look at some of the most common viral infection.现在，让我们来看一看一些最常见的病毒感染（例子）。

The Common ColdOn an everyday basis, perhaps no ailment is as bothersome as the runny nose, itchy eyes, and generally uncomfortable feeling associated with the common cold. Cold-related symptoms are responsible for more days lost from work and more uncomfortable days spent at work than any other ailment.普通伤风就日常的情况来说，也许没有那一种疾患比伴随伤风而来的流涕，眼部发痒和整个身体的不适感更令人苦恼；因伤风相关的症状引发的病假和工作中的不适比其他疾患都要多。

Cause by any number of viruses (some experts claim there may be over 100 different viruses responsible for the common cold itself), colds are endemic (present to some degree) among people throughout the world. Current research indicates that otherwise healthy people carry cold viruses in their noses and throats a majority of the time. These viruses are held in cleck until a person’s resistance is lowered. Thus, in the true sense of the word, it is possible to “catch” a cold from the air-borne droplets of another person’s sneeze or from skin to skin or mucous membrane contact. In fact, recent studies indicate that the hands may be the greatest avenue of cold and other viral transmission. It should be obvious that covering your mouth with a tissue or handkerchief when sneezing is better than covering it with your bare hand, particularly if you next use your hand to touch food in a restaurant, shake your friend’s hand , or open the door.引起伤风的病毒为数众多（一些专家称可能会有超过100种不同的病毒可以引起普通伤风），在世界各地，伤风都是困扰人群的地方病（一定程度上持续存在）。