It's filled with dead skin cells, dust, and around 200,000 different species of bug, bacteria, and fungus.

到處都充滿了死掉的皮膚細胞、灰塵，還有大約 200,000 種不同的蟲、細菌和真菌。

Now, it's tempting to assume that most of them live in your toilet.

我們一般都會認為上述這些髒東西藏匿在廁所。

After all it's where, you know.

畢竟，那裡是用來......你知道的。

But here's the thing, the dirtiest place in your house isn't your toilet.

但重點是你家最髒的地方並不是廁所。

It's actually you.

其實是你。

Household microbes lurk in the most unlikely of places.

居家的微生物常埋伏在最讓人意想不到的地方。

Take a heat loving bacteria called Thermus aquaticus.

以喜愛高溫的水生棲熱菌為例。

These guys can only be found in two environments, blisteringly hot geysers like Old Faithful at Yellowstone and your hot water heater.

這種細菌只能在兩種環境中發現，第一種是極熱的間歇泉，像是黃石國家公園的老忠實間歇泉，第二個就是你家的熱水器。

Another example is Penicillium fungi.

另一個例子是青黴菌。

They creep into your air conditioner from outdoors and when you switch on the AC their spores get blasted around the house.

他們會悄悄從外面鑽進你的冷氣機，當你打開冷氣時，他的孢子就會在你家四處飛散。

They're known to cause allergies in 2-6% of people.

有 2-6% 的人會對這些孢子過敏。

So when you notice a funny musty smell coming from your AC, it's probably the fungus.

所以如果你聞到冷氣傳來奇怪的發霉味，那很有可能就是青黴菌。

But before you start eyeing your central air suspiciously, think about this, you dump microbes all over your body every time you shower.

但在你疑神疑鬼地檢查你的空調前，你先想想這件事，當你每次沖澡的時候，其實你根本就是把微生物倒在自己身上。

It turns out trillions of organisms live in your shower head, pilled on top of each other in a slimy layer half a millimeter thick.

好幾兆隻的微生物就住在你的蓮蓬頭裡面，一隻堆著一隻，黏呼呼地堆了半毫米這麼厚。

But that's not necessarily a problem.

但這不是什麼問題。

Researchers found that a type of shower dwelling mycobacterium actually boosts levels of serotonin.

研究人員發現有一種住在蓮蓬頭裡的分枝杆菌能夠增加你的血清素。

That's a neurotransmitter thought to lower stress and increase happiness.

這種神經傳遞介質可以降低壓力、提升快樂的情緒。

And when those arrant microbacteria land on you, they join the tens of thousands of other microbe species that live in the dirtiest place around, your body.

當這些分枝杆菌落在你身上，他們也只是加入了數萬隻細菌的行列，住進這個房子裡最髒的地方。

Like Corynebacterium, the microbes that give your armpits that stinky odor and simultaneously fight off harmful pathogens like E. Coli.

像是棒狀桿菌這種微生物會讓你的腋下發出汗臭味，但同時也會擊退對人體有害的病原體，如大腸桿菌。

Meanwhile, 300 to 500 species of microbe colonize your gut and are thought to play a role in maintaining your immune system, digestive system and even mental health.

於此同時，你的腸胃裡也至少被 300 到 500 種微生物佔領，他們扮演了維持免疫系統、消化系統和心理健康的重要角色。

In the non bacteria category microbes, you've got such guests as microscopic mites that live on your face and mold that colonizes into your toes.

而談到非細菌的微生物，你的臉上也有許多顯微等級的小客人—蟎，以及被黴菌佔領的腳指頭。

While the idea of them might give you chills, microbes like these help keep you safe.

雖然這個事實可能會讓你一陣雞皮疙瘩，但其實這些微生物可以讓你保持健康。

You see the number of harmless microbial species in the world outnumber harmful ones, by a trillion to one.

你會發現無害的微生物數量遠遠超過有害的，比例大概是一兆比一。

In fact, less than 0.00000001% of microbial species account for nearly all infectious diseases in the world.

其實，世界上會造成傳染性疾病的微生物少於總體的一億分之一。

And all these harmless bacteria crawling on your skin means less room and resources for pathogens like antibiotic resistant microbes,

有許多無害的細菌攀附在你身上也就意味著，那些對抗生素具有抗藥性的微生物分不到資源、搶不到一席之地。

which also means they have less opportunity to take over and make you sick.

也就表示他們攀附在你身上的機會較小，你也比較不會生病。

So even when antibiotics fail, it could be all those other microbes crawling in and on you that keep you safe.

所以如果抗生素無效，那些依附在你身上的微生物還是可以讓你頭好壯壯。

So in a way, you need to get a little dirty to stay healthy.

所以其實你要有點髒髒的才會健康。

But full disclosure, that's not an excuse to swear off your shower.

但話先說在前頭，這可不是你拒絕洗澡的好藉口。

Besides, you don't wanna miss out on that feel good mycobacterium.

而且你也不會想錯過來場「分枝杆菌浴」的好機會。

This video was made in large part thanks to Rob Dunn and the information in his new book Never Home Alone.

非常感謝 Rob Dunn，他的新書《Never Home Alone》提供我們這支影片許多資訊。