VOA标准英语2009年-Scientists Seek Better Treatment For Dengu

By Greg Flakus
San Antonio, Texas
13 October 2009

 
Dengue carrying mosquitos
According to the World Health Organization, there are around 50 million cases of dengue fever around the world every year.  About two and a half billion people, two fifths of the world's population, are at risk. The disease is now spreading, along with the mosquitoes that carry it, into areas like Texas, in the United States -- far from the virus's tropical breeding grounds.   Scientists at an independent research foundation in San Antonio, Texas have developed a new line of study they say shows promise in fighting the often deadly disease.

This mouse has a lot in common with its handler because it carries some human cells that allow it to be infected with dengue fever, just like people.

These so-called humanized mice were injected with human stem cells from umbilical cords discarded after women gave birth at local hospitals.

They are a crucial part of the dengue study being carried out by Rebecca Rico-Hesse and her colleagues here at the Southwest Foundation for Biomedical Research.  "We have basically reconstituted the human immune system in these mice and it is only because they have these immune system cells that they can get infected and show symptoms of dengue fever," she says.

By infecting the mice with strains of the dengue virus, investigators¹ can study how the disease takes hold and what factors might cause the more serious and often deadly dengue hemorrhagic fever.

In people, the disease found in tropical and subtropical climates causes an uncomfortable rash, fever, headaches.  The more serious cases will include bleeding under the skin, shock and death.  There is no treatment or cure.

Rico-Hesse and her colleague, Javier Mota, just published a report showing how their study method can help lead to better treatments by identifying the specific viral strains that are most dangerous. "In this report we present results of eight different virus strains and we show that the ones that have been associated with the more severe epidemics² and the ones that cause hemorrhagic fever in patients are actually of a specific genetic³ variant," she says.

Mosquitoes normally spread dengue.  When they bite, they inject certain proteins into the skin which does not happen when mice are artifically injected in the lab.  So, the scientists are breeding mosquitoes that will bite the mice and transmit the disease. "If you are just, you know, injecting it in with a syringe, you are missing out on all those salivary⁴ gland⁵ factors and all the things that happen during a natural infection that might either speed up the infection rate or decrease the infection rate," she says.

Rebecca Rico-Hesse has worked extensively among those stricken by dengue fever in Latin America. "I have had the opportunity to go to many of the countries and see the patients, even children dying in the hospitals…. So it has given me a sense of urgency to work more," she says.

Although effective vaccines⁶ or antiviral drugs for dengue may still be a long way off, researchers here say they are taking important steps that they hope will one day minimize the suffering caused by this illness.

1 investigators   

n.调查者，审查者( investigator的名词复数 )

参考例句：

• This memo could be the smoking gun that investigators have been looking for. 这份备忘录可能是调查人员一直在寻找的证据。
• The team consisted of six investigators and two secretaries. 这个团队由六个调查人员和两个秘书组成。 来自《简明英汉词典》

2 epidemics   

n．流行病

参考例句：

• Reliance upon natural epidemics may be both time-consuming and misleading. 依靠天然的流行既浪费时间，又会引入歧途。
• The antibiotic epidemics usually start stop when the summer rainy season begins. 传染病通常会在夏天的雨季停止传播。

3 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

4 salivary   

adj. 唾液的

参考例句：

• Small doses depress salivary and bronchial secretion and sweating. 小剂量可抑制唾液分泌、支气管分泌及出汗。
• The five pairs of salivary glands open into the mouth. 有五对唾液腺通向口腔。

5 gland   

n.腺体，(机)密封压盖，填料盖

参考例句：

• This is a snake's poison gland.这就是蛇的毒腺。
• Her mother has an underactive adrenal gland.她的母亲肾上腺机能不全。

6 vaccines   

疫苗，痘苗( vaccine的名词复数 )

参考例句：

• His team are at the forefront of scientific research into vaccines. 他的小组处于疫苗科研的最前沿。
• The vaccines were kept cool in refrigerators. 疫苗放在冰箱中冷藏。