This is the most common way to get head lice - Nazzy Pakpour

翻译人员: enxi xie 校对人员: Marie Li

The six-legged creature creeps down the canopy,

这只六条腿的生物爬下树冠，

extends its slender trunk, and pierces the ground.

伸出纤细的躯干，刺穿地面。

Up comes blood.

血开始流。

This is no regular forest.

这不是普通的森林。

Living where the scalp meets the hair,

生活在头皮与头发交汇的地方，

these nightmarish figures are, in fact, sesame seed-sized insects,

这些噩梦般的人物实际上是 芝麻籽大小的昆虫，

otherwise known as head lice.

也称为头虱。

The earliest archaeological evidence of humans’ close-knit relationship with lice

人类与虱子紧密关系的最早考古证据

is a fully preserved egg,

是一个保存完好的卵，

discovered in the hair of a 10,000-year-old Brazilian mummy.

它是在一个有10,000年历史的巴西木乃伊 的头发中被发现。

And it seems that for as long as we’ve had lice,

看来只要我们有虱子，

we’ve fought hard to get rid of them.

我们一直在努力消灭它们。

Nit combs, the fine-tooth brushes used to remove lice

在全球古老的文化遗迹中发现

and their sticky eggs

了虱子梳子。它们是用来去除虱子

have been found among the ancient remains of cultures across the globe.

及其粘蛋的细齿刷子。

This battle continues today,

这场战斗至今仍在继续，

as it's estimated we spend billions of dollars each year treating infestations.

据估计，我们每年花费数十亿 美元治疗虫害。

So, why are lice so difficult to get rid of?

那么，为什么虱子很难消灭呢？

There are at are at least several thousand louse species,

至少有数千种虱子，

as nearly all mammals deal with these parasites.

因为几乎所有的哺乳动物都 与这些寄生虫有关。

Humans are pestered by three different types,

人类被三种不同的类型所困扰，

each specialized to roam its own unique bodily terrain.

每种类型都专门在 自己独特的身体地形中漫游。

Pediculus humanus capitis live exclusively on heads

头虱（Pediculus humanus capitis） 仅生活在头上，

and are equipped with hook-like claws that are perfectly fitted to human scalp hair.

并配有钩状爪子， 非常适合人类头皮的头发。

Pediculus humanus humanus, or body lice,

体虱（Pediculus humanus humanus），一生中大部分

spend most of their lives embedded in clothing and bedding,

时间都在衣服和床上用品中度过，

and crawling onto any nearby body part for their feedings.

爬到身体附近的任何部位进行喂食。

In order to thrive in these changing environments,

为了在这些不断变化的环境中茁壮成长，

body lice are more resilient to fluctuations in temperatures and humidity.

体虱更能抵御温度和湿度的波动。

Meanwhile, pubic lice, also known as crab lice,

同时，阴虱，也称为蟹虱，

are an entirely different species.

是一种完全不同的物种。

While they also live on hair,

虽然它们也生活在头发上，

their claws are larger than head lice,

但它们的爪子比头虱大，

as they’re fitted to grasp onto the thicker cuticles found in pubic areas.

因为它们适合抓住阴部较厚的角质层。

Among these three varieties, head lice are the most common.

在这三个品种中，头虱是最常见的。

In the US alone, it’s estimated 6 to 12 million children

仅在美国，估计每年就有 600万至1200万儿童

deal with infestation each year.

遭受虫害。

Contrary to popular fears about catching lice from hats or hairbrushes,

与人们普遍担心从帽子或发刷上抓 虱子的担忧相反，

most cases spread through direct head-to-head contact.

大多数病例是通过直接的头对 头接触传播的。

You see, head lice can only survive about 24 hours without a host to feed on.

你看，没有宿主可以吃的头虱 只能存活大约24 小时。

They’re wingless and they can’t jump,

它们没有翅膀也无法跳跃，

so the only way they can infest a new head is to crawl.

所以它们感染新头部的唯一方法就是爬行。

They can detect a new host by using their antenna to home in on body heat

他们可以通过使用天线捕获体温

and other chemical compounds that naturally emanate from the scalp.

和头皮自然散发的其他 化合物来检测新宿主。

Once they arrive on a new head, they're ready to eat.

一旦他们有了新的头脑， 他们就可以开始吃东西了。

A louse pierces the scalp with a retractable tube-like mouth

虱子用可伸缩的管状嘴刺穿头皮，

and releases a special saliva

并释放出 一种特殊的唾液， 其中含有打开血管并

that contains factors that open up blood vessels and help prevent clotting.

有助于防止凝血的因子。

This chemical cocktail is also what makes the scalp feel itchy.

这种化学混合物也是 使头皮感到发痒的原因。

Symbiotic bacteria living in louse’s gut complement this blood meal,

生活在虱子肠道中的共生细菌

by providing the additional vitamins and minerals that the louse needs to survive.

通过提供虱子存活所需的额外维生素和 矿物质来补充这种血餐。

The scalp is also where lice mate.

头皮也是虱子交配的地方。

Once mated, female lice can lay up to 8 eggs, called nits, per day.

一旦交配，雌性虱子每天 最多可以产下8个卵，称为幼虫。

She deposits each egg on the hair,

她将每个卵子沉积在头发上，

just a few millimeters above the scalp, and coats it with a sticky nit sheath,

仅在头皮上方几毫米处， 然后在头发上覆盖一层粘稠的尼特护套，

which provides hydration and other factors the egg needs to survive.

为卵子提供水分和其他生存所需的因素。

This sheath hardens,

这种护套会变硬，将针头

tightly cementing the nit to the hair until it hatches 8 to 9 days later.

紧紧地粘在头发上， 直到 8到 9 天后孵化。

You can’t get rid of a lice infestation

如果不解决这个粘蛋问题，

without taking care of this sticky egg problem.

你就无法摆脱虱子侵扰。

While insecticide shampoos kill hatched lice,

虽然杀虫剂洗发水可以杀死孵化的虱子，

they’re ineffective against eggs.

但它们对卵子无效。

And nit sheaths are strong, waterproof, and resistant to chemical breakdown.

而且 nit 护套坚固、防水、 耐化学分解。

Scientists hope to bring some new tools to this old battle

科学家们希望通过找出能够分解卵子鞘

by identifying treatments that can dismantle individual components

中单个成分的治疗方法，

in the nit sheath,

例如那些能给卵子补水 和维持卵子存活的治疗方法

like those that hydrate the egg and keep it alive.

为这场古老的战斗带来一些新工具。

But until then, there’s only one tool that’s been shown

但是在那之前，只有一种工具被证明

to effectively remove eggs,

可以有效去除卵子，

and it’s the same one that was used by ancient cultures:

它与古代文化使用的工具相同：

a fine-toothed nit comb.

细齿的虱子梳子。

Lice are certainly stubborn survivors,

虱子当然是顽固的幸存者，

but perhaps one day, with the help of science,

但也许有一天，在科学的帮助下，

these ancient parasites will haunt our nightmares— and scalps— no more.

这些古老的寄生虫将不再困扰我们的 噩梦和头皮。