美、瑞称联合发现麻风病传染源
文章来源:未知 文章作者:enread 发布时间:2011-05-04 07:19 字体: [ ]  进入论坛
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Using advanced DNA1 analysis and extensive field work, an international research team has confirmed the link between leprosy(麻风病) infection in Americans and direct contact with armadillos(一种动物,犰狳,中南美产)). In a joint2 collaboration3 between the Global Health Institute at EPFL in Switzerland and Louisiana State University, clear evidence was found that a never-before-seen strain of Mycobacterium(分枝杆菌属) leprae has emerged in the Southern United States and that it is transmitted through contact with armadillos carrying the disease. The results will be published on April 28th in the New England Journal of Medicine. There are only around 150 cases of leprosy in the United States each year. Most of these victims have worked abroad in areas in which leprosy is endemic, making it likely that they may have acquired the disease while outside the US. But, to the alarm of health authorities, a third of all patients infected appear to have contracted the disease locally. The hypothesis that the disease is transmitted though contact with armadillos—aside from humans, the only other known carriers of the leprosy-causing bacteria—was confirmed by fine-grained DNA analysis of both armadillo and human samples done at EPFL.

Leprosy bacilli found in armadillos

It has been known since the 1970s that armadillos are potential carriers of the disease, most likely introduced by European immigrants 500 years ago. But the current study shows inter-species contamination and the presence of a unique strain. "There is a very strong association between the geographic4 location of the presence of this particular strain of M. leprae and the presence of armadillos in the Southern US," explains Stewart Cole, head of the Global Health Institute in Lausanne and world-leader in the field of genomics of leprosy bacilli. "Our research provides clear DNA evidence that the unique strain found in armadillos is the same as the one in certain humans."

The study included 33 wild armadillos known to have the disease and 50 leprosy patients. The new strain of the bacteria, named 3I, was found in 28 armadillos and in 22 patients who reported no foreign residence. The researchers used genome sequencing to identify the new strain and cross check it with other known strains from Europe, Brazil and Asia, and used genotyping to identify and classify the population infected. It became clear that leprosy patients who never travelled outside the US but lived in areas where infected armadillos are prevalent were infected with the same strain as the armadillos. These findings prompted the researchers to state in the article that "Frequent direct contact with armadillos and cooking and consumption of armadillo meat should be discouraged." The study also suggests that armadillo range expansion should be monitored.

It is not known exactly why armadillos contract and carry leprosy. While their low body temperature (89° F / 32° C) makes them perfect incubators for the bacteria, which grow in temperatures between 86° F and 89° F (30° C to 32° C), there are almost certainly other factors such as immune deficiency that also play a role. Similarly, the bacteria attack the extremities5 of humans because our core body temperature is too high for a generalized infection, and over 90% of humans who come into direct contact with the disease spontaneously fight it off. "The last thing we want is to induce panic in the population and incite6 a slaughter7 of armadillos. The best way to combat further infection is though education and prudence," says Cole.

The stigma8 of leprosy

José Ramirez, a former migrant worker from Houston who contracted the disease after hunting and eating armadillo meat and took part in the study, has consecrated9(奉献) his life to combating social stigmas10. He hopes that the study brings to light the stigma attached to leprosy. "We need to take this opportunity to give leprosy patients a voice and to learn to not use the word 'leper' that has negative connotations around the world, a stigma that should be replaced with an understanding of the disease and its causes." Ramirez, who struggled over five years with the disease before it was properly diagnosed, is now disease-free after receiving antibiotic11 treatment. Proving what few know to be true—that leprosy is a bacterial12 infection that can be cured.

 



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1 DNA 4u3z1l     
(缩)deoxyribonucleic acid 脱氧核糖核酸
参考例句:
  • DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
  • Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。
2 joint m3lx4     
adj.联合的,共同的;n.关节,接合处;v.连接,贴合
参考例句:
  • I had a bad fall,which put my shoulder out of joint.我重重地摔了一跤,肩膀脫臼了。
  • We wrote a letter in joint names.我们联名写了封信。
3 collaboration bW7yD     
n.合作,协作;勾结
参考例句:
  • The two companies are working in close collaboration each other.这两家公司密切合作。
  • He was shot for collaboration with the enemy.他因通敌而被枪毙了。
4 geographic tgsxb     
adj.地理学的,地理的
参考例句:
  • The city's success owes much to its geographic position. 这座城市的成功很大程度上归功于它的地理位置。 来自《简明英汉词典》
  • Environmental problems pay no heed to these geographic lines. 环境问题并不理会这些地理界限。 来自英汉非文学 - 环境法 - 环境法
5 extremities AtOzAr     
n.端点( extremity的名词复数 );尽头;手和足;极窘迫的境地
参考例句:
  • She was most noticeable, I thought, in respect of her extremities. 我觉得她那副穷极可怜的样子实在太惹人注目。 来自辞典例句
  • Winters may be quite cool at the northwestern extremities. 西北边区的冬天也可能会相当凉。 来自辞典例句
6 incite kx4yv     
v.引起,激动,煽动
参考例句:
  • I wanted to point out he was a very good speaker, and could incite a crowd.我想说明他曾是一个非常出色的演讲家,非常会调动群众的情绪。
  • Just a few words will incite him into action.他只需几句话一将,就会干。
7 slaughter 8Tpz1     
n.屠杀,屠宰;vt.屠杀,宰杀
参考例句:
  • I couldn't stand to watch them slaughter the cattle.我不忍看他们宰牛。
  • Wholesale slaughter was carried out in the name of progress.大规模的屠杀在维护进步的名义下进行。
8 stigma WG2z4     
n.耻辱,污名;(花的)柱头
参考例句:
  • Being an unmarried mother used to carry a social stigma.做未婚母亲在社会上曾是不光彩的事。
  • The stigma of losing weighed heavily on the team.失败的耻辱让整个队伍压力沉重。
9 consecrated consecrated     
adj.神圣的,被视为神圣的v.把…奉为神圣,给…祝圣( consecrate的过去式和过去分词 );奉献
参考例句:
  • The church was consecrated in 1853. 这座教堂于1853年祝圣。
  • They consecrated a temple to their god. 他们把庙奉献给神。 来自《简明英汉词典》
10 stigmas 6fa32ac806aa8569ec97b1ba9261533f     
n.耻辱的标记,瑕疵( stigma的名词复数 )
参考例句:
  • Wind may affect the set of fruit by desiccating the stigmas. 风可影响座果,因为风吹干了柱头。 来自辞典例句
  • Monterey's transpiration of pistils and stigmas are lowest. Monterey的柱头和雌蕊的失水速率均较低。 来自互联网
11 antibiotic KNJzd     
adj.抗菌的;n.抗生素
参考例句:
  • The doctor said that I should take some antibiotic.医生说我应该服些用抗生素。
  • Antibiotic can be used against infection.抗菌素可以用来防止感染。
12 bacterial dy5z8q     
a.细菌的
参考例句:
  • Bacterial reproduction is accelerated in weightless space. 在失重的空间,细菌繁殖加快了。
  • Brain lesions can be caused by bacterial infections. 大脑损伤可能由细菌感染引起。
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