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A new front has been opened up in the battle against malaria with the
release of the first ever genetically modified mosquitoes in Africa.

  Scientists are hoping to eliminate malaria(疟疾)by developing a
genetically modified mosquito that cannot transmit the disease. Malaria
has long troubled the populations of South America, Africa, and Asia,
where mosquito bites infect up to 500 million people a year with this
serious and sometimes fatal parasitic blood disease. For generations,
scientists have been trying to eliminate malaria by developing new drugs
and using pesticides(杀虫剂)to wipe out local mosquito populations. But
these measure aren’t working — and some scientists, like Greg Lanzaro,
say that because of drug resistance and population changes, malaria is
actually more prevalent now than it was 20 years ago. Lanzaro says he
has a better way to stop the spread of malaria: genetically modifying
mosquitoes so they are unable to carry the disease.

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有史以来第一批转基因蚊子将在非洲释放,开辟了抗击疟疾的新战线。

  Lanzaro and his colleagues are planning a multi-year project to
produce malaria-resistant mosquitoes — and he thinks they can do it
within five years. “We can get foreign genes into mosquitoes and they go
where they’re supposed to go,” Lanzaro says, pointing out that
scientists have already succeeded in genetically engineering mosquitoes
that cannot transmit malaria to birds and mice. And, he says, scientists
are quickly making progress on genes that block transmission of the
disease to humans as well.

皇家88平台 3为什么蚊子会咬你

Some 10,000 sterile male mosquitoes will be released in Burkina Faso, a
country at the front line of the war against the disease. Last year
there were 9.8m cases of malaria here, resulting in almost 4,000 deaths.

  The most difficult part scientifically, Lanzaro says, is figuring
out how to get the lab-engineered mosquitoes to spread their genes into
natural populations. After all, he points out, it’s useless to engineer
mosquitoes in the lab that can’t transmit malaria when there are
millions out in the wild that can. To solve this problem, Lanzaro wants
to load up a mobile piece of DNA with the malaria-resistant gene, and
then insert it into a group of mosquito embryos. The malaria-resistant
gene would be integrated directly into the mosquitoes’ DNA, making it
impossible for those mosquitoes to transmit the parasite that causes
malaria.In this way a small group of lab-raised mosquitoes could be
released into the wild, and by interbreeding with wild mosquitoes,
eventually transmit the beneficial gene to the entire population.

Mosquitoes have an extraordinary ability to target humans far away and
fly straight to their unprotected skin.Regrettably, mosquitoes can do
more than cause an itchy wound.Some mosquitoes spread several serious
diseases, including Dengue, yellow fever and malaria.

约一万只不育雄蚊将在抗击疟疾的第一线——布基纳法索释放。去年这个国家发生了980万例疟疾,造成近4000人丧生。

  46.One reason for malaria to be widespread now is that .

蚊子具有惊人的能力,可以从远处瞄准目标人群,直接叮向人们裸露的肌肤。不幸的是,蚊子叮咬不仅仅是引起瘙痒这么简单。一些蚊子还会传播致命疾病,如登革热、黄热病以及疟疾等等。

皇家88平台,Malaria is the biggest killer of children under five in Africa and the
most up-to-date figures show that there were 216 million malaria cases
worldwide, and an estimated 445,000 malaria deaths.

  A.more people have moved to malaria-infected areas

Over one million people worldwide die from these mosquito-borne diseases
each year.New research now shows how mosquitos choose who to bite。

疟疾是非洲5岁以下儿童的最大杀手,最新数据显示,全世界发生的疟疾病例有2.16亿,预计导致的死亡人数大44.5万。

  B.mosquitoes have become resistant to pesticides

每年世界上有100多万人死于由蚊子传播的疾病。最新一项研究表明了蚊子是如何选择人群进行叮咬的。

This is the first step in a program to dramatically reduce the mosquito
population in the country, and hopefully beyond. The initial release of
the mosquitoes will enable researchers to gather more data about the
longevity and dispersal of the insects, as well as how they interact
with the natural insect population.

  C.genetically modified mosquitoes still transmit the disease

Mosquitoes need blood to survive.They are attracted to human skin and
breath.They smell the carbon dioxide gas — which all mammals breathe
out.This gas is how mosquitoes know that a warm-blooded creature is
nearby。

这是该国计划大幅减少蚊子数量并借此抗击疟疾项目的第一步。第一批释放的蚊子将能帮助研究人员收集到有关蚊子寿命和分布的更多数据,以及它们同天然蚊子相互影响的情况。

  D.mosquitoes bite as many as 500 million people a year

蚊子依靠血液存活。人类的皮肤和呼吸能够吸引蚊子。它们能够闻到二氧化碳的味道,而一切哺乳动物都会呼出二氧化碳。这种味道通常会帮助蚊子发现附近存在的热血动物。

Researchers also hope to gain operational experience and improve
understanding of their work among regulators and locals.

  47.Lanzaro is hopeful that in a few years man can .

But mosquitoes also use their eyes and sense of touch.Michael Dickinson
is a professor at the California Institute of Technology.His research
shows how these small insects, with even smaller brains, use three
senses to find a blood meal。

研究人员还希望从中获得操作经验,增进监管部门和当地人对他们工作的理解。

  A.start to eliminate malaria

然而,蚊子也会利用它们的视觉和触觉来搜寻目标人群。Michael
Dickinson是加州理工学院的一位教授。他的研究表明了蚊子这种小型昆虫虽然脑袋很小,但它们却可以利用三种感官来发现吸食目标。

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