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
35
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】
Oncefound"almostentirelyinthewesternUnitedStatesandinAsia,dinosaurfossilsarenowbeingdiscoveredonallsevencon
WhichofthefollowingabbreviationsisNOTsoassociatedwiththeU.S.astheotherthree?
Materialculturereferstothetouchable,material"things"--physicalobjectsthatcanbeseen,held,felt,used--thataculture
Intheschoolsofancienttimes,themostimportantexaminationswerespoken.Usuallythestudentsweresupposedtosaypoetrya
Duringtheearlyyearsofthiscentury,wheatwasseenastheverylifebloodofWesternCanada.Peopleoncitystreetswatched
Untiltheverylatestmomentofhisexistence,manhasbeenboundtotheplanetonwhichheoriginatedanddeveloped.Nowh
Untiltheverylatestmomentofhisexistence,manhasbeenboundtotheplanetonwhichheoriginatedanddeveloped.Nowh
Unlikeanearthquake,ademographicdisasterdoesnotstrikewithoutwarning.Japan’spopulationof127mispredictedtofallto
Unlikeanearthquake,ademographicdisasterdoesnotstrikewithoutwarning.Japan’spopulationof127mispredictedtofallto
随机试题
全国范围内农业税的最终取消在()
可出现下肢浮肿的证候有
治疗痄腮一般以哪条经脉的穴位为主
以变性为主的炎症性疾病是
淋巴管瘤的主要治疗方法是
城市规划行政主管部门与其他行政主管部门之间的关系是()。
在上《风景摄影的取景》一课时,肖老师将教学难点设定为“学会运用‘近中远’三层次取景方法,拍摄出既有内涵又有美感的摄影作品”。上课时,肖老师首先展示了山川、河流、植物等照片,让学生感受自然之美。接下来,肖老师着重引导学生动手操作光圈与快门,学生们都很投入,一
3,64,35,126,91,()
Whatcanbeinferredaboutthebaggageboys?Whatdoesthefather’sadviceimply?
Itisbadmannersto______otherpeoplebehindtheirbacks.
最新回复
(
0
)