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

Translator: Hui Zhong Reviewer: Thomas Tam

Some swear they’re cursed to be hunted by mosquitoes

有啲人覺得佢哋零舎受蚊蚊歡迎

while their close-by companions are regularly left unscathed.

響佢哋附近嘅 friend 就唔怕有蚊咬

But is this an illusion?

唔通呢個係幻覺？

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

如果唔係，又發生咗乜事呢？ 可以有咩搞作？

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

噉就要瞭解下蚊蚊係點樣 同埋點解揾到我哋

While male mosquitoes stick to nectar for sustenance,

蚊佬净係食花蜜

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

但蚊乸仲會吸血 來為蟲卵提供營養

唔同種類嘅蚊已經進化到 吸食唔同動物嘅血

Different mosquito species evolved to feed on different animals.

And, probably within the last 10,000 years,

響過去約一萬年

multiple mosquito lineages independently evolved a predilection for people.

多種系譜嘅蚊 都各自進化出對人類嘅偏愛

隨著人類嘅生存區域愈趨穩定

As human settlements became more permanent,

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

極度旱季都會有 大量靜止嘅水源

which supported mosquito reproduction year-round.

攪到啲蚊全年無休咁生仔

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

蚊乸嘅觸角度 有毛髮狀嘅物體

that contain odor-sensing receptors and neurons.

包含咗感應气味嘅 受體同神經元

These pick up on the signals of their preferred hosts,

呢樣嘢幫蚊蚊探測到 偏愛嘅宿主

And over thousands of years,

過去幾千年

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

偏愛人類嘅蚊蚊 已變得極度擅長追蹤我哋

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

佢哋仲會進攻 我哋難以察覺嘅身體部位

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

佢哋對光綫同空氣 變動十分敏感

總係響我哋出手時迅速避開

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

They even learn to avoid particularly defensive people altogether.

佢哋甚至識得 避開防禦意識高嘅人

But before these close encounters happen,

但響呢啲親密接觸發生前

several factors alert mosquitoes to people's presence.

蚊蚊仲會通過幾樣嘢 來感應我哋

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

蚊乸可以感應到 我哋持續呼出嘅二氧化碳

from about 10 meters away.

十米咁遠都感應到

Once they’ve gotten the CO2 cue,

一旦感應到啲二氧化碳

they become especially interested in dark, high-contrast objects

佢哋就會特別留心啲 巨型高對比嘅深色物體

and the hues found in human skin.

仲留意到人皮膚嘅顔色

As they follow the carbon dioxide plume to its source,

當佢哋追蹤到二氧化碳嘅源頭

they eventually sense body heat and odors.

就會感應到人身體嘅熱量同氣味

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

身上嘅氣味係由生活響 皮膚上嘅有機微生物產生

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

佢哋會分解身體分泌出來嘅嘢 比如汗液同皮脂

In doing so, our skin microbes create smaller organic compounds

然後就會產生更細嘅 有機化合物

that can vaporize and get picked up as smells—

呢啲有機化合物 會蒸發出氣味

smells that human-homing mosquitoes are especially attuned to.

而啲氣味就會吸引到 鍾意我哋嘅蚊蚊喇

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

出汗嘅我哋對蚊蚊來講 更加有魅力

as can ingesting alcohol or being pregnant.

飲酒或者懷孕都有同樣嘅效果

And the Plasmodium parasite that causes malaria

仲有，瘧原蟲 會喺瘧疾病人嘅皮膚上

makes the people it infects more appealing to mosquitoes by increasing

增加水果味嘅醛類化合物

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

更加吸引蚊蚊

This is extremely helpful to the parasite

呢種情況對瘧原蟲來講好有用

because it depends on both humans and mosquitoes to reproduce.

因爲佢哋就係透過人類 同蚊蚊先可以繁殖

But in addition to these temporary factors,

除咗上面提到嘅臨時因素以外

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

有 20% 人類被認為 天生比較「吸蚊」

or mosquito magnets,

甚至話係「蚊蚊攝石」

who are disproportionately targeted year after year.

呢啲人年年都特別受蚊蚊歡迎

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

如果你係呢種人 心裏就好清楚

Sorry about that.

真係辛苦曬喇

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

特別受蚊蚊歡迎 可能同肌膚嘅特徵有關

While carbon dioxide exhalations and body heat consistently signal the presence

除咗被呼出嘅二氧化碳 同身體熱量出賣咗

of warm-blooded animals,

我哋呢啲恆溫動物

human body odor is more distinctive.

人類嘅氣味仲好易認

And everyone hosts different microbial communities on their skin,

而每個人嘅肌膚上 都會有唔同嘅微生物郡

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

導致我哋每個人身上 都會有獨一無二嘅氣味

Researchers reveal that the receptors mosquitoes use to detect acidic compounds

研究表明蚊蚊嘅接收器 係用來探測酸性化合物

are especially important in helping them navigate towards humans.

令蚊蚊特別容易揾到我哋人類

And, indeed, humans with more abundant skin acids

事實上，人類肌膚含較多酸性

prove to be consistently more attractive to mosquitoes.

會對蚊蚊特別有吸引力

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

呢個情況唔係巧合 唔排除有啲基因做咗手腳

perhaps by helping determine the skin’s microbial composition.

比如決定咗肌膚上嘅微生物組成

Scientists have observed that mosquitoes demonstrate similar levels of attraction

科學家發現單卵性雙胞胎 對蚊蚊嘅吸引力相似

among identical twins while responding more variably to fraternal twins,

但異卵雙胞胎就唔同

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

呢個發現表明咗 基因可能有作用

But beyond confirming that mosquitoes are, in fact,

但除咗證明蚊蚊

conspiring against some of us specifically,

事實上特別中意某啲人類

understanding what makes people mosquito-magnets

瞭解到「蚊蚊攝石」嘅原理

has serious, large-scale implications.

具有嚴肅及廣泛性嘅影響

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

每一年，數十萬人死於 蚊媒傳染病

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

而最需要幫助嘅人卻沒有資源

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

呢個發現會幫助解決問題 通過控制皮膚上微生物組同氣味

that manipulate the skin's microbiome and odors.

來製作出更有效嘅驅蚊劑

And knowing that some people are especially strong mosquito attractors

又比如知道某D人特別受蚊蚊歡迎

could also help efforts to get them resources

就可以請距哋參與幫忙

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

研製驅蚊劑、蚊帳、疫苗、測試和治療

The results could not only be less itchy,

最终嘅研發成果除咗可以減少痕癢

they could break transmission cycles and save countless lives.

仲可以減少疾病傳播 同挽救無數生命