研究人员探索对抗蛔虫感染的新途径

AS IT IS 2016-08-17 Researchers Exploring Ways to Fight Roundworm Infection 研究人员探索对抗蛔虫感染的新途径

Researchers in Ireland and England may have discovered a new way to fight roundworm parasites¹.

The researchers say they identified a method that could possibly turn an animal at risk for the disease into one that can fight the infection. Their findings were published in PLOS, the Public Library of Science.

More than 800 million people around the world are infected with the parasite². The highest infection rates are in parts of Asia, south-central Latin America and Africa, south of the Sahara.

The World Health Organization says roundworm is one of many neglected diseases in warm climates. In other words, not much research is being done to stop these diseases.

Roundworm is the most common of three diseases transmitted through soil. Most humans infected with roundworm do not show signs of the disease. People only realize they are infected after the parasite leaves the body in the person’s waste or vomit³.

Fertilized⁴ roundworm eggs are left in the soil from human waste. When the eggs enter the body, they hatch in the intestine⁵. The roundworm larvae⁶ then move into the liver where they grow larger. They then travel through the bloodstream into the lungs. After a few days, the worms leave the lungs and enter the throat, where they are either swallowed or expelled from the body.

If they return to the intestines⁷, the female worms can produce up to 200,000 eggs a day. The eggs are deposited into the soil when a person defecates. This restarts the cycle of infection.

Roundworms can be especially harmful to children. Adult worms can live in the body for up to two years, blocking the intestines. The larvae can also cause breathing problems when they enter the lungs.

The WHO fights the parasite by “deworming” people who live in areas with high rates of infection. Patients are given strong medicines designed to kill the parasites.

Graham Medley⁸ is a professor of Infectious Disease Modelling at the London School of Hygiene⁹ and Tropical Medicine. He noted¹⁰ that deworming is effective at stopping the disease from spreading, but it does not end the health threat.

His comments were published in the British medical journal The Lancet.

Medley told VOA that “roundworms are a major public health problem in low-income countries, and having a drug that prevents infection would be a major advance.”

Researchers have found that some people are more likely to be infected with roundworm than others. But it is costly¹¹ to study humans, so researchers use mice that have the same chance of being infected. When these animals are infected, a larger number of the parasites enter their lungs than enter those of mice that are resistant¹² to the parasites.

Earlier research suggested that the livers of these two genetically-different mice must be different.

Jim Carolan works at Maynooth University in Ireland. He told VOA that humans should be able to stop the parasite from entering our bodies.

“But it doesn’t,” he said, “because the [roundworms] have evolved ways to evade¹³ or suppress the system.”

Carolan wanted to learn how the organisms did that. So he studied the liver proteins of the two genetically-different mice. He and his team found that the liver cells of resistant mice had more copies of a protein than the mice that were more likely to be infected. The proteins create a chemical which the researchers believe could be toxic¹⁴ to the parasitic¹⁵ cells. But they are not sure.

Carolan notes that more research must be done before drugs can be developed and tested on humans. But he said the research is “pointing us in a direction that we need to focus on.”

Words in This Story

parasite – n. an animal or plant that lives in or on another animal or plant and gets food or protection from it

neglect – v. to fail to take care of or to give attention to (someone or something)

transmit – v. to cause (a virus, disease, etc.) to be given to others

vomit – n. the food, liquid, etc., that comes out of your body through your mouth when you vomit

hatch – v. of an egg: to break open as a young bird, insect, fish, etc., is born

larva – n. a very young form of an insect that looks like a worm

defecate – v. to pass solid waste from the body

cycle – n. a set of events or actions that happen again and again in the same order; a repeating series of events or actions

advance – n. progress in the development or improvement of something

evolve – v. to change or develop slowly often into a better, more complex, or more advanced state; to develop by a process of evolution

evade – v. to avoid doing

toxic – adj. containing poisonous substances

focus – v. to cause (something, such as attention) to be directed at something specific (usually + on)

1 parasites   

寄生物( parasite的名词复数 )； 靠他人为生的人； 诸虫

参考例句：

• These symptoms may be referable to virus infection rather than parasites. 这些症状也许是由病毒感染引起的，而与寄生虫无关。
• Kangaroos harbor a vast range of parasites. 袋鼠身上有各种各样的寄生虫。

2 parasite   

n.寄生虫；寄生菌；食客

参考例句：

• The lazy man was a parasite on his family.那懒汉是家里的寄生虫。
• I don't want to be a parasite.I must earn my own way in life.我不想做寄生虫，我要自己养活自己。

3 vomit   

v.呕吐，作呕；n.呕吐物，吐出物

参考例句：

• They gave her salty water to make her vomit.他们给她喝盐水好让她吐出来。
• She was stricken by pain and began to vomit.她感到一阵疼痛，开始呕吐起来。

4 Fertilized   

v.施肥( fertilize的过去式和过去分词 )

参考例句：

• The study of psychology has recently been widely cross-fertilized by new discoveries in genetics. 心理学研究最近从遗传学的新发现中受益匪浅。
• Flowers are often fertilized by bees as they gather nectar. 花常在蜜蜂采蜜时受粉。

5 intestine   

adj.内部的；国内的；n.肠

参考例句：

• This vitamin is absorbed through the walls of the small intestine.这种维生素通过小肠壁被吸收。
• The service productivity is the function,including external efficiency,intestine efficiency and capacity efficiency.服务业的生产率是一个包含有外部效率、内部效率和能力效率的函数。

6 larvae   

n.幼虫

参考例句：

• Larvae are parasitic on sheep.幼虫寄生在绵羊的身上。
• The larvae prey upon small aphids.这种幼虫以小蚜虫为食。

7 intestines   

n.肠( intestine的名词复数 )

参考例句：

• Perhaps the most serious problems occur in the stomach and intestines. 最严重的问题或许出现在胃和肠里。 来自辞典例句
• The traps of carnivorous plants function a little like the stomachs and small intestines of animals. 食肉植物的捕蝇器起着动物的胃和小肠的作用。 来自辞典例句

8 medley   

n.混合

参考例句：

• Today's sports meeting doesn't seem to include medley relay swimming.现在的运动会好象还没有混合接力泳这个比赛项目。
• China won the Men's 200 metres Individual Medley.中国赢得了男子200米个人混合泳比赛。

9 hygiene   

n.健康法，卫生学 （a.hygienic）

参考例句：

• Their course of study includes elementary hygiene and medical theory.他们的课程包括基础卫生学和医疗知识。
• He's going to give us a lecture on public hygiene.他要给我们作关于公共卫生方面的报告。

10 noted   

adj.著名的，知名的

参考例句：

• The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
• Jim is noted for arriving late for work.吉姆上班迟到出了名。

11 costly   

adj.昂贵的，价值高的，豪华的

参考例句：

• It must be very costly to keep up a house like this.维修这么一幢房子一定很昂贵。
• This dictionary is very useful,only it is a bit costly.这本词典很有用，左不过贵了些。

12 resistant   

adj.(to)抵抗的，有抵抗力的

参考例句：

• Many pests are resistant to the insecticide.许多害虫对这种杀虫剂有抵抗力。
• They imposed their government by force on the resistant population.他们以武力把自己的统治强加在持反抗态度的人民头上。

13 evade   

vt.逃避，回避；避开，躲避

参考例句：

• He tried to evade the embarrassing question.他企图回避这令人难堪的问题。
• You are in charge of the job.How could you evade the issue?你是负责人，你怎么能对这个问题不置可否？

14 toxic   

adj.有毒的，因中毒引起的

参考例句：

• The factory had accidentally released a quantity of toxic waste into the sea.这家工厂意外泄漏大量有毒废物到海中。
• There is a risk that toxic chemicals might be blasted into the atmosphere.爆炸后有毒化学物质可能会进入大气层。

15 parasitic   

adj.寄生的

参考例句：

• Will global warming mean the spread of tropical parasitic diseases?全球变暖是否意味着热带寄生虫病会蔓延呢？
• By definition,this way of life is parasitic.从其含义来说，这是种寄生虫的生活方式。