科学美国人60秒 SSS 蚊帐改变了疟蚊的叮咬时间

This is Scientific American's 60-second Science. I'm Jason Goldman.

这里是科学美国人——60秒科学。我是杰森·古德曼。

More than 200 million people get malaria¹ each year.

每年有超过2亿人感染疟疾。

And about half a million die—mostly in Africa, many of them children. And those staggering numbers are an improvement.

约50万人死亡，大多数是非洲人，其中有许多是儿童。而这些惊人的数字已是改善后的结果。

Malaria deaths have been cut in half since 2000.

自2000年以来，疟疾死亡人数减少了一半。

In many places, a remarkably² simple tool has led the fight:

在许多地方，一种非常简单的工具领导了这场斗争：

bed nets treated with a mild insecticide that stop mosquitoes from biting people in their sleep.

用温和杀虫剂处理过的蚊帐，可以防止蚊子叮咬睡梦中的人。

Both people and mosquitoes are pawns³ in the malaria transmission cycle.

人和蚊子都是疟疾传播周期的工具。

If an infected person gets bitten by a mosquito, the parasite⁴ gets picked up along within the blood meal.

如果蚊子叮咬被感染者，寄生虫就会顺着血管传染给蚊子。

That mosquito can then transfer the parasite to the next person it bites.

之后，蚊子会将寄生虫传染给它叮咬的下一个人。

Bed nets help stop mosquitoes from easy attacks on motionless sleepers⁵. But now some mosquitoes seem to be giving up the night shift.

蚊帐有助于阻止蚊子轻易攻击静止不动的睡眠者。但现在有些蚊子似乎要放弃“夜班”了。

"Malaria mosquitos in Africa tend to shift their biting behavior."

“非洲疟蚊很容易改变其叮咬行为。”

Entomologist Eunho Suh from Penn State University's Center for Infectious Disease Dynamics⁶.

宾夕法尼亚州立大学传染病动力学中心的昆虫学家Eunho Suh说到。

"Normally they tend to bite people during the night,

“它们一般在夜间叮咬人，

but because of extensive use of bed nets, these mosquitoes started biting in the early evening or in the morning."

但由于蚊帐的广泛使用，这些蚊子开始在傍晚或早晨开始叮咬。”

The assumption is that the bed nets are weeding out the nighttime biters, while not affecting the mosquitos prefer feeding at other times.

这一设想认为，蚊帐清除了夜间叮咬者，但未影响偏爱在其他时间叮咬的蚊子。

So those mosquitos are thriving.

因此这些蚊子开始繁衍兴盛。

Suh and his team wanted to know whether observed change in biting time had any impact on malaria transmission.

Suh和团队想知道，他们观察到的叮咬时间变化是否会对疟疾传播产生影响。

Back in the lab, they presented Anopheles mosquitoes with the opportunity to feed on blood at 6 P.M., at midnight and at 6 A.M.

回到实验室后，他们给按蚊提供了在晚上6点、午夜和早上6点进食的机会。

When the laboratory was kept at an even 80 degrees Fahrenheit⁷,

当实验室温度保持在80华氏度时，

evening and morning biters were no more or less likely to become infectious than the midnight biters.

在晚上和早上叮咬蚊子的传染性类似或低于在午夜叮咬的蚊子。

But in the real world of the warm and humid tropics, nighttime is slightly cooler than daytime.

但在温暖潮湿的现实世界中，夜晚只比白天稍微凉快一点。

And when the researchers introduced that temperature variation, the evening biters were a lot more likely to have potent⁸ malaria parasites⁹.

研究人员变化室温后，晚上叮咬的蚊子携带疟原虫的可能大大增加。

The results are in the journal Nature Ecology & Evolution.

这项研究发表在《自然·生态和进化》期刊上。

"Not all mosquito bites are equal.

“并不是所有蚊子叮咬的影响都是相同的。

So mosquitoes biting in the evening can have the highest transmission potential, compared to mosquitoes biting at midnight or in the morning."

因此，与在午夜或早晨叮咬的蚊子相比，在晚上叮咬的蚊子传播可能性最高。”

Suh thinks that the difference in the likelihood of mosquitoes becoming infectious has to do with the way that the malaria parasite matures.

Suh认为蚊子的传染可能性差异与疟原虫成熟的方式有关。

The parasites have a tougher time developing when mosquitoes are too warm.

蚊子体温过高时，疟原虫很难发育。

But if a mosquito picks up the parasites from blood at around dusk,

但是，如果蚊子在黄昏前后传染上疟原虫，

those parasites have more hours of cooler nighttime temps to complete their development.

这些寄生虫就有更多更凉爽的夜间时间来完成发育。

Next, Suh wants to conduct a similar study of wild mosquitoes and wild malaria parasites in Africa to see if the results from his lab mosquitoes hold up.

接下来，苏想对非洲野生蚊子和野生疟原虫进行类似的研究，看看其实验室蚊子的结果是否成立。

Either way, bed nets will remain an important tool. But understanding the enemy's behavior is always crucial information in any battle.

不管怎样，蚊帐仍是重要工具。但在任何战斗中，了解敌人的行为都是至关重要的信息。

Thanks for listening for Scientific American's 60-second Science. I'm Jason Goldman.

谢谢大家收听科学美国人——60秒科学。我是杰森·古德曼。

1 malaria   

n.疟疾

参考例句：

• He had frequent attacks of malaria.他常患疟疾。
• Malaria is a kind of serious malady.疟疾是一种严重的疾病。

2 remarkably   

ad.不同寻常地，相当地

参考例句：

• I thought she was remarkably restrained in the circumstances. 我认为她在那种情况下非常克制。
• He made a remarkably swift recovery. 他康复得相当快。

3 pawns   

n.（国际象棋中的）兵( pawn的名词复数 )；卒；被人利用的人；小卒v.典当，抵押( pawn的第三人称单数 )；以（某事物）担保

参考例句：

• The hostages are being used as political pawns. 人质正被用作政治卒子。
• The allies would fear that they were pawns in a superpower condominium. 这个联盟担心他们会成为超级大国共管的牺牲品。 来自《简明英汉词典》

4 parasite   

n.寄生虫；寄生菌；食客

参考例句：

• The lazy man was a parasite on his family.那懒汉是家里的寄生虫。
• I don't want to be a parasite.I must earn my own way in life.我不想做寄生虫，我要自己养活自己。

5 sleepers   

n.卧铺（通常以复数形式出现）；卧车( sleeper的名词复数 )；轨枕；睡觉（呈某种状态）的人；小耳环

参考例句：

• He trod quietly so as not to disturb the sleepers. 他轻移脚步，以免吵醒睡着的人。 来自辞典例句
• The nurse was out, and we two sleepers were alone. 保姆出去了，只剩下我们两个瞌睡虫。 来自辞典例句

6 dynamics   

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。

7 Fahrenheit   

n./adj.华氏温度；华氏温度计(的)

参考例句：

• He was asked for the boiling point of water in Fahrenheit.他被问到水的沸点是华氏多少度。
• The thermometer reads 80 degrees Fahrenheit.寒暑表指出华氏80度。

8 potent   

adj.强有力的，有权势的；有效力的

参考例句：

• The medicine had a potent effect on your disease.这药物对你的病疗效很大。
• We must account of his potent influence.我们必须考虑他的强有力的影响。

9 parasites   

寄生物( parasite的名词复数 )； 靠他人为生的人； 诸虫

参考例句：

• These symptoms may be referable to virus infection rather than parasites. 这些症状也许是由病毒感染引起的，而与寄生虫无关。
• Kangaroos harbor a vast range of parasites. 袋鼠身上有各种各样的寄生虫。