VOA标准英语2012--Reptiles, Amphibians in US Succumbing to Deadly Ranavirus
时间：2019-01-13 作者：英语课 分类：VOA标准英语2012年(四月)
英语课
Reptiles 1, Amphibians 2 in US Succumbing 3 to Deadly Ranavirus
Tracking the virus
A few years ago, Scott Farnsworth, a graduate student at Towson University in Maryland, was sent to a wooded park in Maryland to relocate box turtles safely away from a new highway.
Farnsworth and his team tagged 100 turtles with radio transmitters. But then the reptiles started turning up dead. And not just turtles. They began seeing massive die-offs of toads 4, young frogs called tadpoles 5 and salamanders. Lab analyses showed the culprit was the ranavirus, a class of viruses that mostly infect cold blooded animals.
“It’s pretty quick. We can go from seeing no outer signs," he explained. "To having complete mortality for all of the ones in the pond within a few days.”
While amphibians die within hours of infection, box turtles can survive as long as a month. A lab test showed the animal died struggling to breathe. Ranavirus often infects amphibians during their egg and juvenile 6 stages, leaving them unable to swim. But it affects only adult turtles. “It could send them on a glide 7 path towards extinction,” said Farnsworth.
Farnsworth carefully checks for signs of life at a pond where all the animals died last year.
A device records water temperature in the pond every hour so scientists can correlate the temperature to evidence of the virus. Nearby, Farnsworth finds salamanders developing their legs.
For now, they look fine, but in a few weeks the virus could show up again. Scientists don’t know much about ranavirus, or how to eliminate it. “If this continues the way we’ve seen it, this could be devastating 8 to several species,” Farnsworth noted 9.
When a group of animals dies in large numbers, the animals that feed on them also decline. And the species that were food for them - such as mosquitoes and insects - flourish.
Ranavirus spreading
"Ranavirus infection in wild and captive amphibians is a very serious disease," said David Green is an animal disease specialist at the National Wildlife Health Center of the U.S. Geological Survey. "When the infection shows up in a wetland, we expect nearly 100 percent of the animals to be killed in that wetland."
Green says scientists have reported ranavirus in 25 US states and in several other countries. He predicts it will take years before scientists are able to control it.
Meanwhile, after a long day of study, Scott Farnsworth heads home. On his way, he checks on the red back salamanders. For now, they look okay.
n.爬行动物，爬虫( reptile的名词复数 )
- Snakes and crocodiles are both reptiles. 蛇和鳄鱼都是爬行动物。 来自《简明英汉词典》
- Birds, reptiles and insects come from eggs. 鸟类、爬虫及昆虫是卵生的。 来自《现代汉英综合大词典》
两栖动物( amphibian的名词复数 )； 水陆两用车； 水旱两生植物； 水陆两用飞行器
- The skin of amphibians is permeable to water. 两栖动物的皮肤是透水的。
- Two amphibians ferry them out over the sands. 两辆水陆两用车把他们渡过沙滩。
不再抵抗（诱惑、疾病、攻击等）( succumb的现在分词 )； 屈从； 被压垮； 死
- Mrs. Smith washed and ironed clothes for him, succumbing to him. 史密斯太太被他迷住了，愿意为他洗衣烫衣。
- They would not in the end abandon their vital interests by succumbing to Soviet blandishment. 他们最终决不会受苏联人的甜言蜜语的诱惑，从而抛弃自己的切身利益。
n.蟾蜍，癞蛤蟆( toad的名词复数 )
- All toads blink when they swallow. 所有的癞蛤蟆吞食东西时都会眨眼皮。 来自《简明英汉词典》
- Toads have shorter legs and are generally more clumsy than frogs. 蟾蜍比青蛙脚短，一般说来没有青蛙灵活。 来自辞典例句
n.蝌蚪( tadpole的名词复数 )
- The pond teemed with tadpoles. 池子里有很多蝌蚪。 来自《简明英汉词典》
- Both fish and tadpoles have gills. 鱼和蝌蚪都有鳃。 来自《现代汉英综合大词典》
n.青少年，少年读物；adj.青少年的，幼稚的
- For a grown man he acted in a very juvenile manner.身为成年人，他的行为举止显得十分幼稚。
- Juvenile crime is increasing at a terrifying rate.青少年犯罪正在以惊人的速度增长。
n./v.溜，滑行；(时间)消逝
- We stood in silence watching the snake glide effortlessly.我们噤若寒蝉地站着，眼看那条蛇逍遥自在地游来游去。
- So graceful was the ballerina that she just seemed to glide.那芭蕾舞女演员翩跹起舞，宛如滑翔。
adj.毁灭性的，令人震惊的，强有力的
- It is the most devastating storm in 20 years.这是20年来破坏性最大的风暴。
- Affairs do have a devastating effect on marriages.婚外情确实会对婚姻造成毁灭性的影响。