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VOA标准英语2015--Carnivores Spread Distemper to Lions

时间:2015-01-30 14:20来源:互联网 提供网友:nan   字体: [ ]
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Carnivores Spread Distemper to Lions

New research shows that dogs are no longer the primary source of a disease that has infected and killed lions in Tanzania. Canine1 distemper now appears to be spread mostly by other carnivores, such as hyenas2, jackals and foxes.

In 1994, about 30 percent of the lions in Serengeti National Park died from – what was then – a mysterious neurological disease. It was later identified as canine distemper.

Veterinarian Felix Lankester said that “the dynamics3 of the distemper virus are extremely complex….Canine distemper is an infectious disease that’s caused by a virus called the canine distemper virus, which is in the same family as measles4 and rinderpest. So it’s a viral infection that affects dogs, commonly, but it can also infect wild carnivore species.”

In the ’94 outbreak, domestic dogs were responsible.

“There are lots of domestic dogs living in human communities around the national park. And there’s one particular area in the northwest of the national park where there’s a lot of people and quite a high density5 of dogs,” he said.

Since then, blood samples of various animals have been tested for signs of canine distemper.

“What we found is that there have been peaks in antibodies in the lion population. So the virus has come into the population since the 1994 outbreak. And what we were expecting to see is that those peaks would be related to peaks of antibodies in the domestic dog population – showing that the domestic dog population had an outbreak of distemper and that that would then be followed by an outbreak in the lion population,” Lankester said.

However, the antibody peak in lions did not correspond to a peak in domestic dogs. So, the dogs were not the primary source.

Lankester said the canine distemper virus is spread by physical contact.

“Social contact within a social group, like a lion or domestic dog bite -- dogs licking each other or grooming6 each other, fighting, mating. But it’s also spread from species to species we think at points of contact like when carnivores scavenge at a carcass and you get multiple species at that carcass. And they might fight with each other or they might eat a bit of meat or bone that’s already been contaminated with the saliva7 from one animal. That is an area where disease can move from one species to another.”

And animals eat one another. Hyenas, for example, may prey8 on domestic dogs around Serengeti National Park. However, there hasn’t been much evidence the canine distemper virus has affected9 hyenas much. Sometimes the virus can even pass through a lion population with few if any symptoms.

“It’s a very curious disease. Sometimes it causes outbreaks that are clinically apparent with lots of death and diseased animals. And other times it passes through and you don’t see any symptoms whatsoever,” Lankester said.

The canine distemper, he said, virus now may be established in the wild among several carnivore species rather than the domestic dog population. A big reason for that may be domestic dogs around Serengeti National Park are being vaccinated10 for distemper, rabies and the parva virus.

“It’s probably reduced the intensity11 of transmission of the virus into the national park and into lion populations. But what we’re seeing is that it hasn’t prevented the lions from becoming infected completely. And so there is clearly some other transmission going on that the vaccination12 campaign has not managed to prevent.”

Lankester said evidence of it spreading into other animals can be found in Eastern Russia where Siberian tigers are now becoming infected and dying.

“There’s a lot more work to be done to understand really how the virus is working. How it’s changing. How it’s mutating. How new species are becoming infected with this and what the implications are of those species becoming infected,” he said.

Lankester is a clinical assistant professor at the Paul G. Allen School for Global Animal Health at Washington State University. However, he’s based full time in Arusha, Tanzania. While research continues into canine distemper, he also focuses on rabies, which is widespread in Africa and Asia.

“Rabies is what we call a neglected tropical disease. It’s causing fatalities13 all around the world. Every year, approximately 69,000 people are dying of rabies. Almost half of those are children under the age of 16. As we all know, it’s a horrific disease. It’s one of the most lethal14 diseases known to mankind, which means once somebody becomes infected and symptomatic they nearly invariably die,” he said.

He said in Africa and Asia the disease is nearly always transmitted by domestic dogs. It’s entirely15 preventable with vaccines16. Lankester and his colleagues are campaigning for funds to establish national canine vaccination campaigns to eliminate rabies on those continents. In the United States, the rabies reservoir is usually wild animals, such as raccoons and skunks17.


点击收听单词发音收听单词发音  

1 canine Lceyb     
adj.犬的,犬科的
参考例句:
  • The fox is a canine animal.狐狸是犬科动物。
  • Herbivorous animals have very small canine teeth,or none.食草动物的犬牙很小或者没有。
2 hyenas f7b0c2304b9433d9f69980a715aa6dbe     
n.鬣狗( hyena的名词复数 )
参考例句:
  • These animals were the prey of hyenas. 这些动物是鬣狗的猎物。 来自辞典例句
  • We detest with horror the duplicity and villainy of the murderous hyenas of Bukharinite wreckers. 我们非常憎恨布哈林那帮两面三刀、杀人破坏,干尽坏事的豺狼。 来自辞典例句
3 dynamics NuSzQq     
n.力学,动力学,动力,原动力;动态
参考例句:
  • In order to succeed,you must master complicated knowledge of dynamics.要取得胜利,你必须掌握很复杂的动力学知识。
  • Dynamics is a discipline that cannot be mastered without extensive practice.动力学是一门不做大量习题就不能掌握的学科。
4 measles Bw8y9     
n.麻疹,风疹,包虫病,痧子
参考例句:
  • The doctor is quite definite about Tom having measles.医生十分肯定汤姆得了麻疹。
  • The doctor told her to watch out for symptoms of measles.医生叫她注意麻疹出现的症状。
5 density rOdzZ     
n.密集,密度,浓度
参考例句:
  • The population density of that country is 685 per square mile.那个国家的人口密度为每平方英里685人。
  • The region has a very high population density.该地区的人口密度很高。
6 grooming grooming     
n. 修饰, 美容,(动物)梳理毛发
参考例句:
  • You should always pay attention to personal grooming. 你应随时注意个人仪容。
  • We watched two apes grooming each other. 我们看两只猩猩在互相理毛。
7 saliva 6Cdz0     
n.唾液,口水
参考例句:
  • He wiped a dribble of saliva from his chin.他擦掉了下巴上的几滴口水。
  • Saliva dribbled from the baby's mouth.唾液从婴儿的嘴里流了出来。
8 prey g1czH     
n.被掠食者,牺牲者,掠食;v.捕食,掠夺,折磨
参考例句:
  • Stronger animals prey on weaker ones.弱肉强食。
  • The lion was hunting for its prey.狮子在寻找猎物。
9 affected TzUzg0     
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。
10 vaccinated 8f16717462e6e6db3389d0f736409983     
[医]已接种的,种痘的,接种过疫菌的
参考例句:
  • I was vaccinated against tetanus. 我接种了破伤风疫苗。
  • Were you vaccinated against smallpox as a child? 你小时候打过天花疫苗吗?
11 intensity 45Ixd     
n.强烈,剧烈;强度;烈度
参考例句:
  • I didn't realize the intensity of people's feelings on this issue.我没有意识到这一问题能引起群情激奋。
  • The strike is growing in intensity.罢工日益加剧。
12 vaccination bKGzM     
n.接种疫苗,种痘
参考例句:
  • Vaccination is a preventive against smallpox.种痘是预防天花的方法。
  • Doctors suggest getting a tetanus vaccination every ten years.医生建议每十年注射一次破伤风疫苗。
13 fatalities d08638a004766194f5b8910963af71d4     
n.恶性事故( fatality的名词复数 );死亡;致命性;命运
参考例句:
  • Several people were injured, but there were no fatalities. 有几个人受伤,但没有人死亡。
  • The accident resulted in fatalities. 那宗意外道致多人死亡。 来自《简明英汉词典》
14 lethal D3LyB     
adj.致死的;毁灭性的
参考例句:
  • A hammer can be a lethal weapon.铁锤可以是致命的武器。
  • She took a lethal amount of poison and died.她服了致命剂量的毒药死了。
15 entirely entirely     
ad.全部地,完整地;完全地,彻底地
参考例句:
  • The fire was entirely caused by their neglect of duty. 那场火灾完全是由于他们失职而引起的。
  • His life was entirely given up to the educational work. 他的一生统统献给了教育工作。
16 vaccines c9bb57973a82c1e95c7cd0f4988a1ded     
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。
17 skunks 0828a7f0a6238cd46b9be5116e60b73e     
n.臭鼬( skunk的名词复数 );臭鼬毛皮;卑鄙的人;可恶的人
参考例句:
  • Slim swans and slender skunks swim in the slippery slime. 苗条的天鹅和纤细的臭鼬在滑滑的黏泥上游泳。 来自互联网
  • But not all baby skunks are so lucky. -We're coming down. 但不是所有的臭鼬宝宝都会如此幸运。-我们正在下来。 来自互联网
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