Life on Us: A Microscopic Safari

Hidden on you is a world you have never seen

overrun with bizarre creatures that live on and in

every part of your body.

It's an animal.

It's on your face and we don't know very much about it.

Yet they are affecting us

in ways we never imagined

but now for the first time

we can explore this unknown world.

- They're an absolutely essential component of what we are.

This is a struggle of life and death.

- If we got rid of all of the microbes on us

and inside us we would die.

- So doctors are even reintroducing bugs into our bodies.

Larvae are alive.

They're going through the skin.

It's Judy plus hookworm.

You are more than human.

Each and everyone of us is a collection

of different life forms that call us home.

This is Life on Us.

You are mostly not you.

Come on.

You are home to an astounding array

of life forms.

Some creatures hide inside your bowels.

Others prefer the view from your eye brows.

There are gardens of fungi on your feet.

Alien tribes inhabit the jungle of your hair.

Tiny mites borrow into your face

and you host more bacteria

than there are stars in the milky way.

You and your bugs form a web of life.

In fact bugs are us.

Everyday this typical family is home

to 100 trillion hitchhikers

on their skin and inside their body.

These invisible colonizers keep them healthy.

Sometimes make them ill.

Hey!

- Mine! - You played yesterday.

No it's breakfast.

And even influence their behavior.

Wait!

Stop fighting!

Yet until recently we understood very little

about our microscopic residents.

Germs have a bad reputation.

We think of them as the cause of disease

but paradoxically we couldn't survive without them.

We have our tunnel vision.

Bacteria are bad.

The archaeans are bad.

All this stuff growing on me is bad.

Let's just nuke it.

And the majority of those organisms

are actually good for us.

They're assisting us.

They're not our enemies.

Our obsession with bad bugs

left us blind to the good,

but now genetic tools allow us to see

what we've been missing.

Molecular tools, sequencing DNA,

have allowed us to get a true picture

of what organisms are there

and there's a far richer picture than we had previously

appreciated for our culturing microorganisms.

By decoding the genes

of these microscopic creatures

we can reveal a new microbial world.

- The genetic tools are kind of like the new telescope.

- Think of it as a geographer that might have

just been studying the fields

around Norway their whole career

and then somebody says, "Oh by the way

"we just discovered the Americas and Australia,"

and nobody had ever heard of it before.

For the first time we can see the microbes

that live on us and inside us.

- It's a bit like a gold rush at the moment.

It really is a very thrilling thing.

Scientists have embarked on a journey

into the unexplored world of our own body.

They are discovering how we are all shaped and kept alive

by the bugs that live on us.

As the crust covers planet Earth

the skin covers the body,

an impermeable barrier between us and invading germs.

But we only realize just how important it is

when it's compromised.

I see people's lives changed

in an instant on a daily basis.

But that tissue on the corner right

is not gonna stay.

Fiona Wood is a world leading burn specialist.

Her struggle to save lives is all about beating pathogens.

The microbes that cause infections.

We have bacteria and pathogens

all over us all the time.

When you have a breach in your skin there's a way in

and that way in is going to be there

until we seal the wound.

So the longer the wound is open

the greater the risk of getting infected.

So what we want to do is close that surface.

Seal the surface of the wound as quickly as possible

while the waves of infection keep coming over.

If you waterproof you will survive.

And central to that survival

is the layer of microbes that live on our skin.

Like the atmosphere that protects our planet

our microbes form a shield against alien invaders.

If some pathogen arrives on your skin

it's not your immune system that rises up to greet it.

The first thing that greets it is this microbial layer.

This hairy invisible cloak.

But where do these bugs come from?

The answer lies in the miracle of birth.

For the baby the womb is a solitary world,

but outside an army of microbes awaits its arrival.

The moment you're born you're colonized

with your mother's microbes.

Until then you can be called 100% human

but after that moment you're really

just 10% human and 90% microbes.

- Which as a scientist is very very exciting,

but as a parent is terrifying.

Towards the end of pregnancy

the bacteria that live in the mother's gut

migrate to the vagina

ready for the baby to pick them up

as it slides through the birth canal.

Being covered in vagina microbes

may not seem much of a trait,

but it's a gift that lasts a lifetime.

These bugs not only protect us from infections

they're essential for our overall health.

They also have an important role

in regulating the immune system.

The immune system never rests.

Its cells constantly patrol our bodies

to eliminate pathogens,

but this power can also be dangerous.

- It can potentially damage your own tissues

and therefore it must be controlled.

It must be turned down.

It must be regulated.

The immune system has an internal police force

keeping it under constant surveillance.

- If you don't have a properly regulated immune system

it becomes trigger happy.

It's attacking people's brains.

It's attacking people's joints and giving them arthritis

or it's attacking the contents of the gut

and then you have inflammatory bowel disease,

or it's attacking trivial quantities of pollen

or dog dandruff or whatever in the air

and that gives you allergic airway disorders.

And what keeps our immune system in check

is our microbes.

- So that if you have that organism in the gut

you have more, more policemen.

More regulation.

More control of the immune system

so it doesn't get trigger happy and do crazy things.

The supply of these microbial regulators

doesn't stop at birth.

The mother continues to deliver hundreds

of species of bacteria in her breast milk.

- And it's only very recently that it's become clear

that breast milk comes with a whole suite of microbes

that have moved up through the mother's body,

through the lymph, into the milk,

and come as part of what goes

into the baby with the breast milk.

Breast milk also contains sugars

that the infant can't digest.

These are like fertilizer for the baby's

rapidly developing gut flora.

- And the breast milk becomes this really amazing example

of the way in which our bodies actually evolved

to help these microbes to the next generation.

By the time a child is two and a half

it will have developed a fully mature microscopic community.

Collectively they're known as our microbiome.

They're as much apart of us as any of our own organs.

We shouldn't think of them as a scary

part of our machinery.

They're an absolutely essential component of what we are.

Every one of us is a finely tuned society