Why mosquitoes bite some people more than others - Maria Elena De Obaldia

翻译人员: Jing Quan 校对人员: Sophia Ye

Some swear they’re cursed to be hunted by mosquitoes

有些人笃定他们被蚊子咬 是因为受到了诅咒，

while their close-by companions are regularly left unscathed.

而他们身边的同伴却总是毫发无伤。

But is this an illusion?

但这是一种幻觉吗？

If it's not, what's going on? And what can we do about it?

如果不是，究竟是怎么回事？ 我们能采取哪些措施呢？

It all comes down to how— and why— mosquitoes find us.

这一切取决于蚊子是如何找到我们的， 以及为什么它们会找到我们。

While male mosquitoes stick to nectar for sustenance,

雄性蚊子靠吸食花蜜来维持生存， 而雌性蚊子则

females also seek out blood to provide the nutrients they need for their eggs.

寻找血液以提供卵发育所需的营养。

Different mosquito species evolved to feed on different animals.

不同种类的蚊子以不同动物的血液为食。

And, probably within the last 10,000 years,

而且，可能在过去一万年内，

multiple mosquito lineages independently evolved a predilection for people.

多个蚊子谱系独立 地进化出了对人类的偏好。

As human settlements became more permanent,

随着人类定居点持续更长时间，

they provided plenty of standing water, even through intense dry seasons,

即使在严重的旱季，也有充沛的水量

which supported mosquito reproduction year-round.

支持蚊子全年繁殖。

Female mosquitoes are equipped with antennae covered in hair-like appendages

雌蚊的触角上覆盖着毛发状的附属物，

that contain odor-sensing receptors and neurons.

这些附属物含有气味感应受体和神经元。

These pick up on the signals of their preferred hosts,

它们接收其偏好物种的信号，

And over thousands of years,

而数千年来，

the mosquitoes that target humans have gotten extremely good at tracking us down.

以人类为目标的蚊子非常擅长追踪我们，

They also target parts of our bodies where we’re less likely to notice them.

甚至以我们忽略的身体部位为目标。

And they’re sensitive to visual cues and changes in airflow,

它们对视觉提示和气流变化很敏感，

so when we try to defend ourselves, they can make swift escapes.

所以当我们试图保护自己时， 它们可以迅速逃跑。

They even learn to avoid particularly defensive people altogether.

它们甚至学会完全避开那些 具有强烈防御性的人。

But before these close encounters happen,

但在这些亲密接触发生之前，

several factors alert mosquitoes to people's presence.

有几个因素可以提醒蚊子 注意人类的存在。

Female mosquitoes can pick up on the carbon dioxide humans constantly exhale

雌蚊可以从约 10 米外感应 到人类不断呼出的二氧化碳，

from about 10 meters away.

Once they’ve gotten the CO2 cue,

一旦它们感知到二氧化碳，

they become especially interested in dark, high-contrast objects

它们就会对深色、高对比度的物体

and the hues found in human skin.

和人类肤色尤其感兴趣。

As they follow the carbon dioxide plume to its source,

当它们跟随一缕二氧化碳到达其源头后，

they eventually sense body heat and odors.

最终会感知到体温和气味。

These smells are generated by the many microorganisms that live on our skin.

这些气味是由生活在 我们皮肤上的微生物产生的，

They break down the secretions our bodies produce, like sweat and sebum.

它们分解我们身体产生的分泌物， 如汗水和皮脂。

In doing so, our skin microbes create smaller organic compounds

在此过程中，我们的皮肤微生物会 产生小分子有机化合物，

that can vaporize and get picked up as smells—

这些化合物可以挥发并 以气味的形式被察觉—

smells that human-homing mosquitoes are especially attuned to.

寄食人类的蚊子特别喜欢这种气味。

Getting extra sweaty can temporarily make people more attractive to mosquitoes—

出汗过多会暂时让人对蚊子更有吸引力—

as can ingesting alcohol or being pregnant.

饮酒或怀孕的人也是如此。

And the Plasmodium parasite that causes malaria

引发疟疾的疟原虫也

makes the people it infects more appealing to mosquitoes by increasing

会提升感染者对蚊子的吸引力，

the amounts of certain fruit-smelling aldehyde compounds on their skin.

是因为其增加了皮肤 上的某种果香的醛类化合物。

This is extremely helpful to the parasite

这对寄生虫非常有好处，

because it depends on both humans and mosquitoes to reproduce.

因为它的繁殖依赖于人类和蚊子。

But in addition to these temporary factors,

但除了这些暂时性因素外，

about 20% of people are thought to be naturally high attractors,

大约 20% 的人被认为 天生具有强吸引力，

or mosquito magnets,

就像“吸蚊器”。

who are disproportionately targeted year after year.

他们常年是蚊子重点攻击的目标，

If you’re one of them, you’re probably well aware.

如果您是其中之一，您可能很清楚，

Sorry about that.

抱歉。

Why this is seems to come down to some skin-specific characteristics.

原因可能是一些皮肤特征，

While carbon dioxide exhalations and body heat consistently signal the presence

虽然二氧化碳呼出和体温不断提醒

of warm-blooded animals,

温血动物的存在，

human body odor is more distinctive.

但人体气味更为独特。

And everyone hosts different microbial communities on their skin,

每个人的皮肤上都有不同的微生物群落，

which contribute to unique body odors that likewise vary from person to person.

这会导致独特的体味， 并且同样存在个体差异。

Researchers reveal that the receptors mosquitoes use to detect acidic compounds

研究人员发现蚊子用来 检测酸性化合物的受体

are especially important in helping them navigate towards humans.

对于帮助它们定向人类尤其重要。

And, indeed, humans with more abundant skin acids

确实，皮肤酸化合物更丰富的人类

prove to be consistently more attractive to mosquitoes.

被证明一直以来对蚊子更具吸引力。

Because it’s such a persistent trait, certain genes may play a role,

因为这是一个持久的特征， 某些基因可能发挥作用，

perhaps by helping determine the skin’s microbial composition.

比如帮助确定皮肤的微生物组成。

Scientists have observed that mosquitoes demonstrate similar levels of attraction

科学家观察到同卵双胞胎对 蚊子有相似程度的吸引力，

among identical twins while responding more variably to fraternal twins,

而异卵双胞胎的吸引程度则不同。

which supports that there may be some genetic basis at play.

这表明可能有一些遗传基础在起作用。

But beyond confirming that mosquitoes are, in fact,

但实际上，除了能确认蚊子为什么

conspiring against some of us specifically,

特别针对我们中的一些人外，

understanding what makes people mosquito-magnets

了解是什么因素让人们对蚊子有吸引力

has serious, large-scale implications.

对我们生活还有重要且广泛的影响。

Every year, hundreds of thousands of people die from mosquito-borne diseases.

每年，数十万人死于蚊媒疾病，

And resources aren’t reaching those who need them most.

而物资也没有到达最需要它的人手中。

This knowledge can help inspire solutions, like more effective insect repellents

这些知识可以提示解决手段，例如更有效的驱虫剂、

that manipulate the skin's microbiome and odors.

改变皮肤的微生物群落和气味。

And knowing that some people are especially strong mosquito attractors

并且知道哪类人对蚊子有致命吸引力，

could also help efforts to get them resources

也可以帮助他们尽快获得资源，

like repellents, bed nets, vaccines, tests, and treatments.

例如驱虫剂、蚊帐、疫苗、测试和治疗。

The results could not only be less itchy,

结果不仅可以减少蚊子叮咬，

they could break transmission cycles and save countless lives.

还可以破坏疾病传播周期并拯救无数生命。