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
107
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.
From the description in the passage, we learn that
选项
A、monkeys are also susceptible to HTV.
B、AIDS has killed 25 million people in the last 25 years.
C、vaccine has been developed to prevent AIDS.
D、AIDS can be cured by drug cocktails.
答案
B
解析
从第4段第3句和第4句可得知B与其对应,为正确答案。
转载请注明原文地址:https://www.kaotiyun.com/show/X44O777K
0
专业英语八级
相关试题推荐
Ihavenostatisticsonthis,butconversationwithfriendsanddozensofperson-on-the-streetinterviewsIsawandheardlastmo
Childrentodayspendmoretimestareatcomputerand【M1】______TVscreensbothatschoolandathome.Scientific【M2】
Criticismofresearchlaysasignificantfoundationforfutureinvestigativework,butwhenstudentsbegintheirownprojects,t
IwasborninFeb.12,1809,inHardinCounty,Kentucky.MyparentswerebothborninVirginia,ofundistinguishedfamilies--secon
FormanyyearsitwascommonintheUnitedStatestoassociateChineseAmericanswithrestaurantsandlaundries.Peopledidnot
Mummiescaptureourimaginationsandourhearts.Fullofsecretsandmagic,theywereoncepeoplewholivedandloved,justasw
Arapidmeansoflong-distancetransportationbecameanecessityfortheUnitedStatesassettlementspreadfartherwestward
Intheschoolsofancienttimes,themostimportantexaminationswerespoken.Usuallythestudentsweresupposedtosaypoetrya
泊珍到偏远小镇的育幼院把生在那里养到一岁的孩子接回来。但泊珍看他第一眼,仿似一声雷劈头而来,令她晕头胀脑,这1岁的孩子脸型长得如此熟悉,她心里的第一道声音是,不能带回去痛苦纠聚心中,眉心发烫发热,胸口郁闷难展,胃里一股气冲喉而上。院长说这孩子发
InBritain,only2%ofthepopulationarefarmersbuttheymanage______ofthelandarea.
随机试题
现在很多人对于甜味和吃糖感到排斥和恐惧,因为他们很惧怕发胖,吃一小块糖果就会胖一圈似的,其实,真正使人发胖的并不是那一小块糖果,而是每天吃的食物所包含的能量超出了消耗的能量。馒头、面条、米饭或者玉米面窝头中都有淀粉,即不甜的糖。淀粉在人体内氧化所放出的热量
目前基因治疗主要采用的方法是
下列符合肺源性心脏病体征的有()。
世界500强企业关于优秀员工的12条核心标准:第一条,一个人的工作是他生存的基本权利,有没有权利在这个世界上生存,看他能不能认真地对待工作。如果一个人的本职工作做不好,应付工作,最终失去的是信誉,再找别的工作、做其他的事情都没有可信度。如果认真做好一个工作
按照实现全面建成小康社会奋斗目标新要求,到2020年,要实现文化改革发展奋斗目标,必须坚持把改革开放放在首位。()
因继承遗产纠纷提起的诉讼,由()人民法院管辖。
这些年来,审计盯得多的、民众关心得多的,往往是重点部门、关键科室,对于水务、林业这样的“冷衙门”,想当然地以为是“清水衙门”而缺乏监督热情。只是,无明确规定、无时间约束、无绩效考核,此类“三无”拨款可能遍及更多的“冷衙门”。事实上,这些容易被监督遗忘的角度
求
AnEnglishtouristfoundthathehadonlyenoughmoneyinhispockettobuytheticket.Asheknewthatittookonlytwodaysto
Wesometimesthinkhumansareuniquelyvulnerabletoanxiety,butstressseemstoaffecttheimmunedefensesofloweranimalsto
最新回复
(
0
)