首页
登录
职称英语
An epidemic of swine flu (猪流感) has recently developed in Mexico and the Unit
An epidemic of swine flu (猪流感) has recently developed in Mexico and the Unit
游客
2024-05-22
2
管理
问题
An epidemic of swine flu (猪流感) has recently developed in Mexico and the United States, says the CDC. Swine flu has killed many people, and the outbreak has features that suggest it could become a global pandemic (瘟疫). A pandemic is an epidemic that spreads around the whole world. Pandemics also often cause more severe disease than epidemics.
Flu is a disease caused by the influenza virus. Humans, pigs, birds and other animals all can be infected by influenza viruses. Typically, influenza viruses can infect only one species, so the influenza viruses of humans are different from those of pigs and birds. However, sometimes a virus can infect more than one species. For examples, pigs sometimes can be infected not only with pig influenza viruses, but also with human and bird influenza viruses. Then these viruses can come up to one another secretly and swap (交换) genes, creating new viruses that have a mix of genes -- from human, pig, and bird viruses. That is what has happened with this new swine flu virus.
Sometimes this swapping of genes allows a virus that was originally able to infect only pigs or only birds to also infect humans. When that happens, we refer to the illness as "swine flu" or "bird flu". This current virus could actually be called "swine/bird flu", since it has some genes from pig flu viruses and other genes from bird flu viruses.
Most viruses that cause swine flu or bird flu are very hard to pass from one human to another: they don’t cause epidemics. Sometimes, however, further changes in genes create a virus that can spread rapidly among humans, and can produce a more severe illness. One reason this illness is more severe is that the virus is so new. The regular flu that comes each year is caused by a regular human influenza virus that often has similarities to the viruses that have caused the flu in years past, so people have some degree of immunity to the latest virus. The unusual swine flu or bird flu viruses that develop the ability for person-to-person spread are so different that people have little or no immunity to them.
The worst global pandemic in modem times was the influenza pandemic of 1918 to 1919. It affected about a third of the human race, and killed at least 40 million people in less than a year -- more than those who have been killed by AIDS in three decades. The world economy went into a deep recession. The average length of life dropped for 10 years.
Unfortunately, the new swine flu virus can be transmitted between humans. It is not clear yet how easily it is transmitted, nor how it is transmitted. Almost surely it is transmitted by sneezing and coughing, and by skin-to-skin contact with an infected person. [br] Which of the following is true about the present swine flu viruses?
选项
A、The viruses can infect different species.
B、The genes of the viruses come from pigs.
C、The viruses mix genes from different species.
D、The genes of the viruses were made artificially.
答案
A
解析
题干问的是目前的猪流感病毒的情况。原文从第二段开始对这种新流感病毒分析描述。第三句说,通常情况下,流感病毒只感染一个物种。第四句说,有时一种病毒却可能感染多个物种。然后举例,最后一句说这次的新型猪流感病毒就属于这种情况。由后文也可知道,这种新型猪流感病毒能感染人、猪和鸟类。所以[A]项正确。
转载请注明原文地址:https://tihaiku.com/zcyy/3606527.html
相关试题推荐
Huntedasthewildturkeyis,ithasdevelopedadegreeofinevadingitspursue
DuringtheIceAges,mandevelopedtheuseoftools,andthusawayofprotectin
Topreventthespreadoftheepidemic,thepublichealthorganizationcarriesou
Contrarytopopularbelief,epidemicsdonotoccur________afteranaturaldisa
Recently,greatadvanceshavebeenmadeinthestudyofVenus’surfacebytheus
[originaltext]Recentlyafive-yearstudywasconductedbytheCenterforCh
[originaltext]Recentlyafive-yearstudywasconductedbytheCenterforCh
[originaltext]Irecentlyturnedfifty,whichisyoungforatree,midlifefo
[originaltext]Irecentlyturnedfifty,whichisyoungforatree,midlifefo
Anepidemicofswineflu(猪流感)hasrecentlydevelopedinMexicoandtheUnit
随机试题
形状不一beindifferentshapes
Whenaconsumerfindsthatanitemsheorheboughtisfaultyordoesnotli
阳和汤的组成药物除麻黄、白芥子外,其余是A、熟地、鹿角胶、炮姜炭、肉桂、生甘草
(2013年)下列各项中,可能表明被审计单位存在值得关注的内部控制缺陷的有(
下列除了哪类人,其余人引起的医疗纠纷均适用医疗事故处理办法处理A.注册医疗机构中
按照《药品说明书和标签管理规定》,下列说法错误的是A.药品说明书的具体格式、内容
关于巨噬细胞在机体抗肿瘤免疫中的作用,下列叙述正确的是A:患者肿瘤组织周围有明显
有关体循环与肺循环的说法,哪项是错误的A.体循环又称大循环 B.肺循环始于体循
泄压设施的材质宜采用轻质屋面板、轻质墙体和易于泄压的门、窗等,并采用安全玻璃等在
经济总是处于在周期性运动中,股价波动是不固定的。()
最新回复
(
0
)