- [Instructor] Back in 2011, I'm gonna write it down here,
our world's population was about 6.9 billion.
That's a pretty large number and sometimes,
you know, when I'm thinking about big numbers,
they all kind of melt into each other,
so I thought I'd be helpful to just write it out
so you could see it, 6.9 billion people,
and that's what I tried to represent here
with these little black circles.
That's my best attempt at showing
all the people on the planet,
and you just have to take my word for it
that it's roughly representative.
So what I wanted to point out is
that the WHO, the World Health Organization,
has said that about one in three people
living on our planet, so just divide this number by three,
one in three people, has latent TB infection.
So this is an enormous number of people, right.
I mean, when you read that, you might not think about it,
but that's actually 2.3 billion people
with latent TB infection.
And remember, when I say latent TB infection,
what I mean is that the bacteria
is either dormant inside of someone's lungs,
or it's dead, but it's really hard to tell the difference,
so we always kind of hedge on the side of being cautious
and we treat them as if they have
dormant bacteria in their lungs.
And sometimes you might even see the term LTBI.
So now keep your eye on the map
and what I'm gonna do is show you
what that would actually look like.
So if I actually erased two-thirds of the people,
this is what you'd basically have left, something like this,
and these people are the ones that
we can imagine then have latent TB infections.
Still a lot of people, right?
So the WHO found that in 2011,
there were also about nine million
individuals that had active disease.
So this is actually people that are coughing,
and having chest pain, maybe having bloody sputum,
all sorts of signs and symptoms of active disease.
So that's a huge number of people,
and we know that a lot of those folks with active disease,
they're actually coming from this pool
of latent TB infection.
Now about 10% of these folks
that have latent TB infection,
will actually go on to get active disease,
and you can break that down further
and say, well 5% will be in the first couple of years
after they get the latent TB infection,
and another 5% will be over a lifetime,
will be in their lifetime.
So you can split it up
so you can see that most of that risk,
that 10% risk, is coming in the first couple years,
but in general, if you think about 10%
of that enormous number, 2.3 billion,
that's a lot of sick folks, right.
Let me actually draw in here
what 10% of these people would look like,
just so you get a visual idea.
Maybe this person in Brazil would be sick,
maybe another person out here,
perhaps this person over here,
maybe someone in America and maybe someone in Mexico.
We've got five, maybe a Canadian gets six.
We've got six people over there, maybe seven, eight,
a couple in India, nine, 10,
a couple of folks in China, 11,
12, 13...
14, 15, I mean, it's a lot of folks, right?
17, 18, maybe a Nigerian,
maybe an Ethopian, something like this.
And let me just make sure I did the math right really quick.
A couple more, let's just do one here and one there.
So, this is 10%.
That's what 10% visually looks like,
so you get a sense for how many people
are actually gonna get sick and have active disease.
And we know that there are a couple of other groups
of folks that are also gonna get active disease.
Some would be the folks that had primary infection.
Right, cause you can get primary infection,
then immediately have what we call
primary progressive disease.
Or you might have secondary infection, right.
You might have latent TB infection
and then you get another person coughing on you,
and we would call that secondary infection.
So these are the different ways
that you might get to be part of that nine million
who have active disease.
But I wanna point out that this is a huge pool, right.
This is a large number of people,
and so many, many, many people are gonna contribute
to that nine million with active disease.
Now you might be thinking, wait a second,
the math doesn't add up, you know, because you have,
if you just take 10% of this enormous number,
that's actually way more than nine million people,
so how does that make sense.
But just remember that this is a risk in a lifetime,
or in a couple of years,
and this is actually looking at how many people are sick
with active disease in one given year.
And to extend a little bit further,
I just wanna make a little bit of space,
those folks are gonna go on to,
actually some of them are gonna go on to die.
So you're gonna have, in 2011 we had
about 1.4 million people that died.
And ultimately that's really
what we're trying to avoid, right?
We're trying to avoid people dying of TB
and we wanna avoid people getting active disease,
because you know, it's a horrible illness.
And so you can see why there's such pressure
to try to find people that have latent TB infection
and really intervene
before they actually go on to get sick.
So the final thing I wanna show you
is actually another picture.
I think you'll find this interesting.
This is where, this is actually 22 countries,
where 80% of the disease is.
So go on and take a look at this map.
We've got 22 countries in total, right, 22 countries,
and these account for 80% of the cases of TB.
So these together account for 80%.
So the majority of the disease in the world
is coming from these places, so TB cases.
So it's actually quite interesting, right?
You can take a look at this and say okay,
so you can see that you've got some African countries,
you've got countries in Asia, and you've got Russia,
and you've got Brazil out here.
And these countries combined make up the majority
of where people are sick with TB.