VOA标准英语2011--E coli: Good Bacteria Gone Bad

E coli: Good Bacteria Gone Bad

As a major outbreak of a highly toxic¹ strain of E. coli bacteria continues to sicken residents of Europe, medical experts are racing² to find the source.
E. coli doesn't usually cause any trouble, says University of Minnesota microbiology professor Michael Sadowski. "E. coli is a normal inhabitant of the intestinal³ tract⁴ of warm-blooded animals."
That means you, me, our livestock⁵ and even wild animals are all carrying strains of E. coli around in our guts⁷. The types that cause disease are rare, Sadowski says.
"The majority of E. coli are in fact considered to be harmless. And they carry out various biochemical processes in your intestine⁸ and they help you digest food."
E. coli and how it is transmitted
E. coli is an abbreviation for Escherichia, which is a large and diverse group of bacteria. Most strains are harmless, others can cause illness. Symptoms include stomach cramps⁹, diarrhea and vomiting¹⁰. The major source is cattle, but other animals, foods and liquids may spread contamination to people.
?Shiga toxin-producing E. coli
This is a dangerous form of E. coli known by the acronym¹¹ STEC. The best known strain of this STEC (also called 0157) was identified in 1982. Transmission and symptoms are similar to the most common form of E. coli.
?EHEC
A very serious infection is enterohaemorrhagic E. coli known by the acronym EHEC. It produces toxins¹², known as verotoxins or Shiga-like toxins. It may lead to life threatening diseases such as hemolytic uremic syndrome¹³, or HUS.
?HUS
Scientists believe this is responsible for the European outbreak, originating from a potentially life threatening strain of STEC (0104). HUS afflicts¹⁴ the kidneys, blood and central nervous system.
And the majority have remained relatively¹⁵ harmless until fairly recently, says University of Minnesota food safety professor Francisco Diez. "We didn't have this type of organism before 1982."
That's when the first deadly strain of E. coli appeared in hamburger meat in the United States. Before then, Diez says, E. coli wasn't even considered a disease-causing germ.
According to Diez, it is not clear exactly how this new virulence¹⁶ developed. It may have been changes in the bacteria, or changes in the way food is produced or distributed. Whatever the cause, E. coli is now turning up in a growing number of fruits and vegetables including apples, lettuce¹⁷, and spinach¹⁸.
For a germ that was first found in meat, it seems like a long way to the produce aisle¹⁹. But Diez says there is a connection.
"We've seen an increase in cases of produce-associated outbreaks, but ultimately the source is cattle."
He says cattle-manure²⁰ fertilizer that has not been well composted may still carry live bacteria from the animals' gut⁶. Or manure may contaminate irrigation water. It could also be on the hands of someone picking or sorting the produce. Add storage, transportation, and preparation as other places between the farm and the fork where food can become contaminated with the bacteria.
That's part of why tracing an outbreak to its source is so difficult. In Europe, officials originally blamed Spanish-grown cucumbers, but now they are not so sure. Other suspects include tomatoes and lettuce.
The problem is, those are all common salad ingredients.
"It's hard to find enough people that only ate one, and only ate one once in the time period before their infection," says Christopher Braden, head of the foodborne disease section at the U.S. Centers for Disease Control and Prevention." They're commonly eaten. They're commonly eaten together. So to try to tease one apart as to which one is the culprit can be difficult."
Spain maintains that its cucumbers have been falsely accused. Spanish farmers are losing huge amounts of money, and they are furious.
The CDC was in a similar position in 2008 when it blamed tomatoes for a salmonella outbreak that ultimately was pinned on peppers.
Braden says it can be a hard decision to make when you have preliminary information that points to a suspect. "And in the meantime, people are getting ill and possibly dying in large numbers. Sometimes there's a real balancing act between being fast and being right. Often times it's really hard to do both."
He adds that, if their first suspicions proved correct, they could also be criticized if they did not act.
There are still a lot of unknowns about the current European outbreak, and it will likely be some time before they are all resolved.
In the meantime, the advice remains²¹ the same: wash your hands after using the toilet, and before preparing food and eating, and wash counters and utensils²² that come in contact with raw meat.
And if you are concerned about the cleanliness of raw vegetables, cook them well.

1 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。

2 racing   

n.竞赛，赛马；adj.竞赛用的，赛马用的

参考例句：

• I was watching the racing on television last night.昨晚我在电视上看赛马。
• The two racing drivers fenced for a chance to gain the lead.两个赛车手伺机竞相领先。

3 intestinal   

adj.肠的；肠壁；肠道细菌

参考例句：

• A few other conditions are in high intestinal obstruction. 其它少数情况是高位肠梗阻。 来自辞典例句
• This complication has occasionally occurred following the use of intestinal antiseptics. 这种并发症偶而发生在使用肠道抗菌剂上。 来自辞典例句

4 tract   

n.传单，小册子，大片(土地或森林)

参考例句：

• He owns a large tract of forest.他拥有一大片森林。
• He wrote a tract on this subject.他曾对此写了一篇短文。

5 livestock   

n.家畜，牲畜

参考例句：

• Both men and livestock are flourishing.人畜两旺。
• The heavy rains and flooding killed scores of livestock.暴雨和大水淹死了许多牲口。

6 gut   

n.[pl.]胆量；内脏；adj.本能的；vt.取出内脏

参考例句：

• It is not always necessary to gut the fish prior to freezing.冷冻鱼之前并不总是需要先把内脏掏空。
• My immediate gut feeling was to refuse.我本能的直接反应是拒绝。

7 guts   

v.狼吞虎咽，贪婪地吃，飞碟游戏（比赛双方每组5人，相距15码，互相掷接飞碟）；毁坏（建筑物等）的内部( gut的第三人称单数 )；取出…的内脏n.勇气( gut的名词复数 )；内脏；消化道的下段；肠

参考例句：

• I'll only cook fish if the guts have been removed. 鱼若已收拾干净，我只需烧一下即可。
• Barbara hasn't got the guts to leave her mother. 巴巴拉没有勇气离开她妈妈。 来自《简明英汉词典》

8 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。

9 cramps   

n. 抽筋, 腹部绞痛, 铁箍 adj. 狭窄的, 难解的 v. 使...抽筋, 以铁箍扣紧, 束缚

参考例句：

• If he cramps again let the line cut him off. 要是它再抽筋，就让这钓索把它勒断吧。
• "I have no cramps." he said. “我没抽筋，"他说。

10 vomiting   

吐

参考例句：

• Symptoms include diarrhoea and vomiting. 症状有腹泻和呕吐。
• Especially when I feel seasick, I can't stand watching someone else vomiting." 尤其晕船的时候，看不得人家呕。”

11 acronym   

n.首字母简略词，简称

参考例句：

• That's a mouthful of an acronym for a very simple technology.对于一项非常简单的技术来说，这是一个很绕口的缩写词。
• TSDF is an acronym for Treatment, Storage and Disposal Facilities.TSDF是处理，储存和处置设施的一个缩写。

12 toxins   

n.毒素( toxin的名词复数 )

参考例句：

• The seas have been used as a receptacle for a range of industrial toxins. 海洋成了各种有毒工业废料的大容器。
• Most toxins are naturally excreted from the body. 大部分毒素被自然排出体外。 来自《简明英汉词典》

13 syndrome   

n.综合病症；并存特性

参考例句：

• The Institute says that an unidentified virus is to blame for the syndrome. 该研究所表示,引起这种综合症的是一种尚未确认的病毒。
• Results indicated that 11 fetuses had Down syndrome. 结果表明有11个胎儿患有唐氏综合征。

14 afflicts   

使受痛苦，折磨( afflict的名词复数 )

参考例句：

• Level 3-Afflicts a target with the Curse of the Silent. 三级-用静默诅咒折磨一个目标。
• Level 1-Afflicts a target with the Curse of the Silent. 一级-用静默诅咒折磨一个目标。

15 relatively   

adv.比较...地，相对地

参考例句：

• The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
• The operation was relatively painless.手术相对来说不痛。

16 virulence   

n.毒力，毒性；病毒性；致病力

参考例句：

• The virulence of the café owner's anger had appalled her.咖啡店老板怒气冲天，充满敌意，把她吓坏了。
• Medical authorities were baffled,both as to its causes and its virulence.医疗当局对其病因及有多致命都还不甚了解。

17 lettuce   

n.莴苣；生菜

参考例句：

• Get some lettuce and tomatoes so I can make a salad.买些莴苣和西红柿，我好做色拉。
• The lettuce is crisp and cold.莴苣松脆爽口。

18 spinach   

n.菠菜

参考例句：

• Eating spinach is supposed to make you strong.据说吃菠菜能使人强壮。
• You should eat such vegetables as carrot,celery and spinach.你应该吃胡萝卜、芹菜和菠菜这类的蔬菜。

19 aisle   

n.（教堂、教室、戏院等里的）过道，通道

参考例句：

• The aisle was crammed with people.过道上挤满了人。
• The girl ushered me along the aisle to my seat.引座小姐带领我沿着通道到我的座位上去。

20 manure   

n.粪，肥，肥粒；vt.施肥

参考例句：

• The farmers were distributing manure over the field.农民们正在田间施肥。
• The farmers used manure to keep up the fertility of their land.农夫们用粪保持其土质的肥沃。

21 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。

22 utensils   

器具，用具，器皿( utensil的名词复数 )； 器物

参考例句：

• Formerly most of our household utensils were made of brass. 以前我们家庭用的器皿多数是用黄铜做的。
• Some utensils were in a state of decay when they were unearthed. 有些器皿在出土时已经残破。