VOA慢速英语2011--Way to Stop Dengue

Health Report - Trying a New Way to Stop Dengue

This is the VOA Special English Health Report.
Dengue fever feels like a severe case of the flu, including pain in the muscles and joints¹. The World Health Organization says there may be fifty million dengue infections every year. Deaths are rare, fewer than thirteen thousand a year. But dengue has spread sharply² since the nineteen seventies.
The disease is found mostly in cities. The WHO says forty percent of the world’s population is now at risk in more than one hundred countries. Southeast Asia and the Western Pacific are the most affected³. Dengue is also found in Africa, the Americas and the eastern Mediterranean⁴.
There is no vaccine⁵ against dengue and no special treatment.
Scott Ritchie of James Cook University in Queensland, Australia, says control efforts target the mosquitoes that spread dengue.
SCOTT RITCHIE: “And the only way to control it is through the use of pesticides⁶ and perhaps community education, and some of the mosquitoes are getting resistant⁷ to those pesticides, so we need something novel and different.”
Something different is what he and other scientists from Australia and the United States are working on. They blocked the growth of dengue virus in mosquitoes by infecting them with a kind of bacteria called Wolbachia pipientis. Wolbachia is commonly found in fruit flies and is safe for people.
The researchers released mosquitoes infected with Wolbachia into an indoor test area filled with uninfected mosquitoes. The infected ones mated with the uninfected ones and successfully spread the bacteria.
The researchers then tried their experiment outdoors. Over a two-month period they released more than three hundred thousand infected mosquitoes in two Australian towns far from large cities.
Scott O’Neill at Monash University in Melbourne says the mosquitoes quickly infected wild populations just as they had in the indoor test.
SCOTT O’NEILL: “And then, most importantly, once the release has stopped, the Wolbachia continued to increase until the experiments came to a conclusion at the end of the wet season. And about that time we can see that we have almost complete penetration⁸ of the Wolbachia infection into the mosquito population at these sites.”
Next, the plan is to do tests over the next two to three years in an area where many people are infected with dengue. Ary Hoffman at the University of Melbourne says the tests will show if the idea can actually prevent the disease.
ARY HOFFMAN: "You know, at the moment we’re very hopeful. But before we get to the stage where we can say 'Hey, Wolbachia can control dengue,' that’s a different matter. That’s a bit down the track.”
The researchers described their work in two papers last week in the journal Nature.
Mosquitoes also spread malaria⁹. The kind of mosquito that injects the malaria parasite¹⁰ into the people it bites is most active around sunset and sunrise. So bed nets can help protect people while they sleep. But the mosquito that spreads dengue, Aedes aegypti, is most active during the day.
And that’s the VOA Special English Health Report. I’m Shirley Griffith.
___
Contributing: Art Chimes

1 joints   

接头( joint的名词复数 )； 关节； 公共场所（尤指价格低廉的饮食和娱乐场所） （非正式）； 一块烤肉 （英式英语）

参考例句：

• Expansion joints of various kinds are fitted on gas mains. 各种各样的伸缩接头被安装在煤气的总管道上了。
• Expansion joints of various kinds are fitted on steam pipes. 各种各样的伸缩接头被安装在蒸气管道上了。

2 sharply   

adj.锐利地，急速；adv.严厉地，鲜明地

参考例句：

• The plane dived sharply and rose again.飞机猛然俯冲而后又拉了起来。
• Demand for personal computers has risen sharply.对个人电脑的需求急剧增长。

3 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

4 Mediterranean   

adj.地中海的；地中海沿岸的

参考例句：

• The houses are Mediterranean in character.这些房子都属地中海风格。
• Gibraltar is the key to the Mediterranean.直布罗陀是地中海的要冲。

5 vaccine   

n.牛痘苗，疫苗；adj.牛痘的，疫苗的

参考例句：

• The polio vaccine has saved millions of lives.脊髓灰质炎疫苗挽救了数以百万计的生命。
• She takes a vaccine against influenza every fall.她每年秋季接种流感疫苗。

6 pesticides   

n.杀虫剂( pesticide的名词复数 )；除害药物

参考例句：

• vegetables grown without the use of pesticides 未用杀虫剂种植的蔬菜
• There is a lot of concern over the amount of herbicides and pesticides used in farming. 人们对农业上灭草剂和杀虫剂的用量非常担忧。 来自《简明英汉词典》

7 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。

8 penetration   

n.穿透，穿人，渗透

参考例句：

• He is a man of penetration.他是一个富有洞察力的人。
• Our aim is to achieve greater market penetration.我们的目标是进一步打入市场。

9 malaria   

n.疟疾

参考例句：

• He had frequent attacks of malaria.他常患疟疾。
• Malaria is a kind of serious malady.疟疾是一种严重的疾病。

10 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。