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对抗兹卡病毒的新武器:以蚊攻蚊

更新时间:2016-2-3 9:55:53 来源:纽约时报中文网 作者:佚名

New Weapon to Fight Zika: The Mosquito
对抗兹卡病毒的新武器:以蚊攻蚊

Every weekday at 7 a.m., a van drives slowly through the southeastern Brazilian city of Piracicaba carrying a precious cargo — mosquitoes. More than 100,000 of them are dumped from plastic containers out the van’s window, and they fly off to find mates.

每个工作日的早晨7点,一辆载有宝贵货物的货车会从巴西东南部城市皮拉西卡巴缓缓驶过,里面装满了蚊子。塑料容器中的逾10万只蚊子会被从货车窗户放出。它们会飞走,去寻找配偶。

But these are not ordinary mosquitoes. They have been genetically engineered to pass a lethal gene to their offspring, which die before they can reach adulthood. In small tests, this approach has lowered mosquito populations by 80 percent or more.

但这些不是普通的蚊子。它们经过遗传工程处理,会将一种致死基因传给后代,如此一来,这些蚊子还没成年就会死亡。在小型试验中,这种方式将蚊子数量减少了80%或更多。

The biotech bugs could become one of the newest weapons in the perennial battle between humans and mosquitoes, which kill hundreds of thousands of people a year by transmitting malaria, dengue fever and other devastating diseases and have been called the deadliest animal in the world.

这种生物科技细菌可能会成为人类与蚊子之间的持续斗争中的最新武器。通过传播疟疾、登革热及其他恶劣疾病,蚊子每年杀死数以十万计的人类,因此被称为世界上最致命的动物。

“When it comes to killing humans, no other animal even comes close,” Bill Gates, whose foundation fights disease globally, has written.

“论及杀人,没有什么动物能与蚊子相提并论,”比尔·盖茨(Bill Gates)曾写道。盖茨的基金会在全球开展抵抗疾病的项目。

The battle has abruptly become more pressing by what the World Health Organization has called the “explosive” spread of the mosquito-borne Zika virus through Brazil and other parts of Latin America. Experts say that new methods are needed because the standard practices — using insecticides and removing the standing water where mosquitoes breed — have not proved sufficient.

世界卫生组织(World Health Organization)称蚊媒传播的兹卡病毒在巴西及拉丁美洲的其他地方出现“爆炸式”传播,从而使这场斗争突然变得更加紧迫。专家们表示,需要新方法,因为事实证明,使用杀虫剂及清除蚊子赖以繁衍的积水等常用作法不够有效。

“After 30 years of this kind of fight, we had more than two million cases of dengue last year in Brazil,” said Dr. Artur Timerman, an infectious disease expert in São Paulo. “New approaches are critically necessary.”

“在经过30年的斗争后,巴西去年还出现200万例登革热病例,”圣保罗传染病专家阿图尔·蒂莫尔曼(Artur Timerman)说。“新方法是极其必要的。”

But the new efforts have yet to be proved, and it would take some years to scale them up to a meaningful level. An alternative to mosquito control, a vaccine against Zika, is not expected to be available soon.

但新举措的效果还有待证明,尚需要几年的时间将这些措施扩展至能产生切实作用的水平。相对于控制蚊虫的方式,另一个选择就是预防兹卡病毒的疫苗,但那不会很快面世。

So for now, experts say, the best modes of prevention are to intensify use of the older methods of mosquito control and to lower the risk of being bitten using repellents and by wearing long sleeves.

专家们表示,迄今为止,最好的预防方式就是加强使用传统的蚊虫控制方式,通过喷洒防虫剂、穿长袖衣服,降低被蚊子叮咬的风险。

Women are being advised to not get pregnant and to avoid infested areas if pregnant, since the virus is strongly suspected of causing babies to be born with abnormally small heads and damaged brains.

相关人员建议女性不要怀孕,如果怀孕就要避开蚊子活动的区域,因为人们强烈怀疑这种病毒导致婴儿出生时头部小得不正常,大脑受损。

One old method that is not getting serious attention would be to use DDT, a powerful pesticide that is banned in many countries because of the ecological damage documented in the 1962 book “Silent Spring.” Still, it is being mentioned a bit, and some experts defend its use for disease control.

滴滴涕(DDT)是一个没有得到重视的旧方法,这种强效杀虫剂在很多国家遭禁,因为1962年出版的《寂静的春天》(Silent Spring)记录了这种杀虫剂导致的生态破坏情况。但这种方法多少被提到了,一些专家为利用这种杀虫剂控制疾病的做法进行了辩解。

“That concern about DDT has to be reconsidered in the public health context,” said Dr. Lyle R. Petersen, director of the division of vector-borne diseases at the Centers for Disease Control and Prevention. He said the damage to fish and wildlife stemmed from widespread outdoor use of DDT in agriculture, not the use of small amounts on walls inside homes to kill mosquitoes.

“从公共卫生方面来看,对滴滴涕的这一担忧需要重新考虑,”美国疾病控制与预防中心(Centers for DiseaseControl and Prevention,简称CDC)媒传疾病部主任莱尔·R·彼得森博士(Lyle R. Petersen)说。他表示,有害于鱼类和野生动物的是农业领域在室外广泛使用滴滴涕的做法,而不是向室内墙壁喷洒少量滴滴涕来消灭蚊子的行为。

Other experts say the old methods can work if applied diligently.

其他一些专家表示,如果坚持使用,老办法可以产生效果。

“We’ve had great success using old methods for the last 50, 60 years,” said Dr. Peter J. Hotez, dean of the National School of Tropical Medicine at the Baylor College of Medicine. “We just need to be very aggressive and exercise political will.”

“我们在过去五六十年中使用老方法取得了巨大成功,”美国贝勒医学院国家热带疾病学院(National School of Tropical Medicine the Baylor College of Medicine)院长彼得·J·霍特兹博士(Peter J. Hotez)说。“我们只需要非常积极地行动,践行政治意愿。”

The main mosquito that transmits Zika virus — and also dengue, chikungunya and yellow fever — is Aedes aegypti, a particularly wily foe.

传播兹卡病毒——及登革热、基孔肯雅热和黄热病——的主要蚊子是埃及伊蚊。这是一种特别狡猾的对手。

It prefers urban areas and bites mainly people, making it very efficient at spreading disease. It bites in the day, so bed nets, a common way to protect people against the night-biting malaria mosquitoes, have little effect. It breeds in small containers of water, such as flower pots, cans and tires that collect rainwater.

埃及伊蚊喜欢城市地区,主要叮咬人类,因此可以十分有效地传播疾病。这种蚊子在白天叮咬,所以蚊帐这种预防夜间遭到疟蚊叮咬的常用方式几乎没什么效果。埃及伊蚊在小容器的水中就能繁殖,比如花盆、饮料罐和积了雨水的轮胎。

“I’ve seen Aedes aegypti merrily breeding in discarded soda caps,” said Joseph M. Conlon, technical adviser to the American Mosquito Control Association.

美国控蚊协会(American Mosquito Control Association)技术顾问约瑟夫·M·康伦(Joseph M. Conlon)说,“我看到埃及伊蚊可以欢快地在汽水瓶盖里繁殖。”

Aedes aegypti is found in the southern part of the United States, so public health authorities say there will be some local transmission of Zika in this country, though it will be far less serious than in Latin America. Dr. Petersen of the C.D.C. said he envisioned “almost a SWAT team approach” in which resources would be rapidly deployed to areas of local transmission to control mosquitoes using conventional methods.

埃及伊蚊在美国南部有分布,因此公共卫生部门表示,兹卡病毒会在美国进行局部传播,但远没有拉丁美洲严重。CDC的彼得森博士表示,他设想的是“一种几乎与特警部队差不多的方法”,将资源迅速部署至局部传播的地区,利用传统方式控制蚊虫。

The genetically engineered Aedes aegypti mosquitoes were developed by Oxitec, a British company, to fight dengue, but would also work to curtail the spread of Zika.

通过遗传工程处理埃及伊蚊的技术由英国的Oxitec公司研发,目的是对抗登革热,但也可以用来遏制兹卡病毒的传播。

Since last April, the mosquitoes have been released in one neighborhood of Piracicaba populated by about 5,000 people. By the end of 2015, there was a reduction in wild mosquito larvae — as opposed to larvae inheriting the lethal gene — of 82 percent, the company said.

自去年4月以来,技术人员在皮拉西卡巴的一个大约有5000人口的社区释放这种蚊子。该公司表示,到2015年底,野生孑孓——相对于遗传了致死基因的孑孓——减少了82%。

But critics worry about the long-term effects of releasing genetically modified organisms. Oxitec has run into public opposition to a proposed test in the Florida Keys.

不过,批评人士担心释放转基因生物体可能带来长期影响。Oxitec提议在佛罗里达群岛开展试验,但遭到公众反对。

A Brazilian commission that oversees genetically engineered organisms declared the Oxitec mosquitoes safe to release into the environment in 2014. But Oxitec still does not have a license from Brazil’s health regulators that would allow it to actively market its approach to Brazilian cities.

巴西的一个负责监管基因工程生物体的委员会在2014年宣告,Oxitec的蚊子可以安全地释放到环境中。但公司仍未获得巴西卫生监管部门授予的许可证,有了该许可证,它才可以积极向巴西各大城市推销这种方式。

Still, said Hadyn Parry, the company’s chief executive, with the outbreak of Zika, “We’ve had a huge amount more interest from different municipalities.”

然而,随着兹卡疫情的爆发,公司首席执行官哈迪恩·帕里(Hadyn Parry)表示,“一些市政当局对此兴趣猛增。”

Another approach, being tested in one Rio de Janeiro neighborhood, is to infect the mosquitoes with Wolbachia, a bacterium that does not infect them naturally. Once infected, the mosquitoes do not pick up and transmit viruses as easily.

里约热内卢的一个地区正在试验另一种方式,即向蚊子体内注入沃尔巴克氏菌。蚊子并不会自然感染这种细菌,不过一旦感染上,它们就不会轻易携带并传播病毒了。

The bacteria can be passed to the next generation through eggs, so they spread through the mosquito population.

这种细菌可以通过卵传给下一代,因此能够在蚊子种群中传播。

“The beauty of it is it is a sustainable method — once you put it out it sustains itself in the environment and gives ongoing protection,” said Scott O’Neill, dean of science at Monash University in Australia. He is the leader of Eliminate Dengue, a Wolbachia project supported by the Bill & Melinda Gates Foundation and others.

“这种方法好就好在它的可持续性,一旦释放,就可以在环境中延续下去,不断给予保护,”澳大利亚莫纳什大学(Monash University)科学院院长斯科特·奥尼尔(Scott O’Neill)说。他是“消除登革热”(Eliminate Dengue)项目的带头人。该项目利用沃尔巴克氏菌,获得了比尔及梅林达·盖茨基金会(Bill and Melinda Gates Foundation)等机构的支持。

Tests are now underway in Indonesia and Vietnam to see if the technique can reduce the number of people getting dengue fever.

印度尼西亚和越南正在开展试验,看看这种技术能否减少登革热患病人数。

Dr. Paulo Gadelha, president of the Oswaldo Cruz Foundation, a scientific institute under the Brazilian Ministry of Health, said initial results in his country were good and there were plans to try it on a larger scale, in Niterói, a municipality across Guanabara Bay from Rio.

巴西卫生部旗下科研机构奥斯瓦尔多·克鲁兹基金会(Oswaldo Cruz Foundation)的主席保罗·贾德勒哈博士(Paulo Gadelha)表示,在他们国家开展的试验的初步结果较好,有在尼泰罗伊进行更大规模试验的计划。这座自治市与里约隔着瓜纳巴拉湾相望。

“We are planning to scale this up,” he said. “The mayor has already agreed.”

“我们计划扩大规模,”他说。“市长已经同意了。”

A new and even more powerful tool may be gene drives, which are genetic mechanisms that rapidly propagate a trait through a wild population. Just in the last few months, scientists have made gene drives that work in mosquitoes in the laboratory.

一种新的乃至更加强大的工具或许是基因驱动技术。这种遗传机制可以在野生种群中迅速传播一种性状。就在过去几个月中,科学家们在实验室中进行了作用于蚊子的基因驱动。

Anthony A. James, a professor at the University of California, Irvine, said it would be straightforward to use a gene drive to spread something like a sterility trait through the Aedes aegypti population to kill them off.

加州大学欧文分校(University of California, Irvine)教授安东尼·A·詹姆斯(Anthony A. James)表示,通过基因驱动在埃及伊蚊群体中传播不育性状以消灭蚊子的做法直截了当。

“We have all the blueprints and have demonstrated proofs of principle,” he said. “It’s just public will to do this.”

“我们掌握了蓝图,也展示了相关原理的证据,”他说。“就看公众愿不愿意这么做了。”

The public might not be ready to deploy gene drives outside the laboratory because once a new trait is let loose to spread through the population, it would be difficult to reverse it if something went wrong.

公众可能还没准备好在实验室外进行基因驱动,因为一旦新性状得以在生物种群中传播,如果出了问题,就很难逆转。

Dr. Petersen of the C.D.C. said of all the new approaches, “We don’t know about the efficacy of any of them on a wide enough scale.” He added, “For now, we’ve got to deal with what we have.”

提到这些新方法时,CDC的彼得森博士说,“我们并不知道大规模使用其中任何一种方法的功效。”他还表示,“目前,我们需要用手头的方法来加以应对。”

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