首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Researchers who picked up and analyzed wild chimp droppings said on Thursday they had shown how the AIDS virus originated in wil
Researchers who picked up and analyzed wild chimp droppings said on Thursday they had shown how the AIDS virus originated in wil
admin
2013-08-05
70
问题
Researchers who picked up and analyzed wild chimp droppings said on Thursday they had shown how the AIDS virus originated in wild apes in Cameroon and then spread in humans across Africa and eventually the world. Their study, published in the journal Science, supports other studies that suggest people somehow caught the deadly human immunodeficiency virus (HIV) from chimpanzees, perhaps by killing and eating them.
"It says that the chimpanzee group that gave rise to HIV... this chimp community resides in Cameroon," said Beatrice Hahn of the University of Alabama, who led the study. "But that doesn’t mean the epidemic originated there because it didn’t," Hahn, who has been studying the genetic origin of HIV for years, said in a telephone interview.
"We actually know where the epidemic took off. The epidemic took off in Kinshasa, in Brazzaville." Kinshasa is in the Democratic Republic Congo, formerly Zaire, and faces Brazzaville, in Congo, across the Congo River. Studies have traced HIV to a man who gave a blood sample in 1959 in Kinshasa, then called Leopoldville. Later analysis found the AIDS virus.
In people, HIV leads to AIDS but chimps have a version called simian immune deficiency virus (SIV) that causes them no harm. Humans are the only animals naturally susceptible to HTV. AIDS was only identified 25 years ago. The virus now infects 40 million people around the world and has killed 25 million. Spread in blood, sexual contact and from mother to child during birth or breastfeeding, HTV has no cure and there is no vaccine, although drug cocktails can control it.
And like so many new infections, AIDS appears to have been passed to humans from animals they slaughtered. SIV has been found in captive chimps but Hahn wanted to show it could be found in the wild too. Her international team got the cooperation of the government in Cameroon and they hired skilled trackers.
"The chimps in that area are hunted. It’s certainly impossible to see them. It is hard to track them and find these materials," she said. But the trackers managed to collect 599 samples of droppings. Hahn’s lab found DNA, identified each individual chimp and then found evidence of the virus.
"We went to 10 field sites and we found evidence of infection in five. We were able to identify a total of 16 infected chimps and we were able to get viral sequences from all of them," Hahn said. Up to 35 percent of the apes in some communities were infected. Not only that, they could find different varieties, called clades, of the virus.
"We found some of the clades were really, really very closely related to the human virus and others were not," she said. Chimps separated by a river were infected with different clades, Hahn said. And a river may have carried the virus into the human population. "So how do you get from southern Cameroon to the Democratic Republic of Congo?" Hahn asked. "Some human must have done so. There is a river that goes from that southeastern comer of Cameroon down to the Congo River."
Ivory and hardwood traders used the Sangha River in the 1930s, when the original human-to-human transmission is believed to have happened. Hahn’s study suggests the virus passed from chimpanzees to people more than once. "We don’t really know how these transmissions occurred," Hahn said.
"We know that you don’t get it petting a chimp, or from a toilet seat, just like you can’t get HTV from a toilet seat. It requires exposure to infected blood and infected body fluids. So if you get bitten by an angry chimp while you are hunting it, which could do it."
Hahn’s study only applies the HTV group M, which is the main strain of the virus responsible for the AIDS pandemic. "It’s quite possible that still other (chimpanzee SIV) lineages exist that could pose risks for human infection and prove problematic for HTV diagnostic and vaccines," her team wrote.
The word "lineage" in the last paragraph means
选项
A、transmission.
B、catastrophe.
C、strain.
D、virus.
答案
C
解析
根据该词前面的other可知该句应与前一句并列,上文提到HIV的M群是导致艾滋病传染的主要菌株(main strain of the virus),再结合修饰lineages的定语从句that could pose risks.…可知lineage在此处是strain之意,故选C。
转载请注明原文地址:https://kaotiyun.com/show/U44O777K
0
专业英语八级
相关试题推荐
Childrentodayspendmoretimestareatcomputerand【M1】______TVscreensbothatschoolandathome.Scientific【M2】
WhichofthefollowingisthelargestprovinceinCannada?
WhichofthefollowingabbreviationsisNOTsoassociatedwiththeU.S.astheotherthree?
ThefollowingcanbeusedtointroducetheU.K.EXCEPT______.
WhichofthefollowingisconsideredanAmericanmasterpiece?
Duringtheearlyyearsofthiscentury,wheatwasseenastheverylifebloodofWesternCanada.Peopleoncitystreetswatched
InBritain,only2%ofthepopulationarefarmersbuttheymanage______ofthelandarea.
芙蓉镇街面不大。十几家铺子、几十户住家紧紧夹着一条青石板街。铺子和铺子是那样的紧密,以至一家煮狗肉,满街闻香气;以至谁家娃儿跌跤碰脱牙,扛了碗,街坊邻里心中都有数;以至姐妹家的私房活,年轻夫妻的打情骂俏,都常常被隔壁邻居听了去,传为一镇的的秘闻趣事,笑料谈
这地方是个长潭的转折处,两岸是高大壁立千丈的山,山头上长着小小竹子,长年翠色逼人。这时节两山只剩余一抹深黑,赖天空微明勾画出一个轮廓。但在黄昏里看来如一种奇迹的,都是两岸高处去水已三千丈上下的吊脚楼。这些房子莫不俨然悬挂在半空中,借着黄昏的余光,还可以把这
随机试题
现代管理以()为中心。
微需氧茵的培养条件为
杏苏散与败毒散方中相同药物是
A.心气不足B.肝气郁结C.脾气下陷D.胃气上逆E.肺气上逆太息表示()
能全面反映项目资金活动全貌的报表是()。
某公司拟招聘一名技术工人。在众多应聘者中,老王脱颖而出,原因是在面试过程中,老王对工作充满热情的态度打动了总经理,总经理相信老王在日后的工作中一定会有出色的表现。事实也证明了总经理的判断。一年之后,老王成为公司的技术骨干。但是由于经常需要出差,老王萌生了离
战国琴曲()可谓中国音乐史上的千古绝唱。
数列1,1,2,3,5,8,13,21,…的规律是从第三个数开始,每个数是它前面两个数之和。在考生目录下有一个工程文件sjt5.vbp。窗体中已经给出了所有控件,如图3-87所示。请编写适当的事件过程实现以下功能:在Text1中输入整数40,单击“计算”按
A、Tolivetogetherwiththeirfamily.B、Tobringtheirskillstocities.C、Tobuildabettercountryside.D、Tosearchabetterc
Itseemslogical:Collegegraduateshavelowerunemploymentandearnmorethanlesseducatedworkers,so,thethinkinggoes,the
最新回复
(
0
)