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LINA MOSES: We first
started hearing these rumors
about a mysterious
hemorrhagic disease in Guinea.
And honestly, I wasn't
thinking Ebola at all.
The biggest concern
was that there
was some evolutionary
selection going on there.
The virus could be changing
into something really scary.
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PARDIS SABETI: The Ebola
outbreak in West Africa
is believed to have started
sometime in late 2013,
with cases coming up
in a village in Guinea.
LINA MOSES: The epidemic started
when a bat came in contact
with a human, and the virus
passed from that animal
to that person.
Ebola spreads through
direct contact
with body fluids of someone
that's infected with Ebola.
They start to get a high fever,
develop vomiting and diarrhea,
bleeding.
Blood pressure goes down.
You go into a shock and
systematic organ failure.
And that's how people die.
PARDIS SABETI: The virus in
that time began to spread.
It moved over into neighboring
Liberia and Sierra Leone.
Then before you know, there
were 28,000 cases at least,
with 11,000 reported deaths.
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When outbreaks happen,
we have to stop them
right away because there is this
possibility that the virus will
accidentally have
a change that could
make an outbreak escalate.
I'm a computational
geneticist, which
is someone who uses computers
to look at data from biology,
from our genomes.
The genome of a virus is
so incredibly important
to all aspects of its
intervention, prevention,
understanding.
It's basically a blueprint
that every organism on earth
has that defines it.
Every time a virus replicates,
it just reproduces its genome.
And when that happens,
sometimes an accidental change
can happen.
A new mutation changes
that genome sequence
just a little bit.
Most of those
mutations either have
no effect or a detrimental
effect and get cleared out.
Very rarely, it's possible
they can pick up a change that
somehow is beneficial to them.
One of the major drivers of
evolution is natural selection.
And in the context of
viruses, you see that,
that if a virus basically
has some mutation that
makes it spread more quickly
or infect more people,
and then it will become more
common in the population.
And that's why it's a
real issue when you're
talking about an
outbreak of something
like Ebola that's not believed
to happen in humans that often
is you're giving it more
and more opportunities
in this new environment in human
infection to mutate and change
and to have a widespread impact.
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LINA MOSES: I'm a disease
ecologist and epidemiologist.
And my nightmare outbreak
scenario actually happened.
I got to live it last year.
Sierra Leone and
Liberia are just
recovering from some very
brutal, brutal civil wars.
85% of the health
clinics in Sierra Leone
were destroyed
during the civil war.
And West Africa has a very
high population density.
They have some very good roads.
So if you take a health
system that's in shambles
and you add an Ebola
outbreak and a rapidly moving
population, then you
have the perfect storm.
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PARDIS SABETI: When the
outbreak hit Sierra Leone,
Kenema Government
Hospital was really
the only hospital that was
prepared to deal with patients
of hemorrhagic fever.
And Kenema was
extraordinary and prepared
for one or two or three cases.
But before you knew it,
there were hundreds.
And at a certain point,
everybody has their threshold,
and they were overwhelmed.
And what happened was one of
the nurses became infected,
and then that spread
through the clinical staff.
LINA MOSES: One of
the tragedies of Ebola
is that it spreads through love
and through people taking care
of people that they care about.
PARDIS SABETI: In this
outbreak, we had 11,000 deaths.
But what's really shocking
is that 800 of those deaths
are health care workers.
It's estimated there
was a 20-fold increased
risk of a health care worker.
My team also lost a number
of our clinical care workers.
All clinicians, all
health care workers, all
loved ones of
individuals who are sick
are putting themselves
at risk every time
they go to care for somebody
who's ill like this.
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The Ebola outbreak
we saw in West Africa
was by far the largest outbreak
we've ever seen of Ebola.
As opposed to small
numbers of cases,
you're giving the virus
many opportunities
to replicate and to pass
from human to human.
And each of those
is an opportunity
for an accidental mutation
to allow it to adapt.
And there is new evidence
there was a mutation that
occurred early in the
outbreak, a few months
into the outbreak,
that changed one
of the important genes
of the Ebola genome.
And that mutation likely not
only increased infectivity,
but did so in a way that
was more specific to humans
and primates.
But the story to
be told is not one
that is answered by
genomics, it's just
answered by faster response.
The more time you
give it to change,
the more chance it will.
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LINA MOSES: I do think
that the world is not
prepared for a long and
sustained disease pandemic.
The main reason why is because
you see such disparities
in quality of health.
It's no accident that
the epidemic happened
the way it did in Sierra Leone.
If Sierra Leone had the
health system and the health
infrastructure that
we had in the US,
you would have seen two
cases, like we saw in the US,
instead of thousands
and thousands of cases
that we saw here.
As long as there
are countries that
do not have proper health
systems, everyone in the world
is vulnerable.
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PARDIS SABETI: This outbreak
did provide an opportunity
to learn a lot more.
But while there's tremendous new
information that came to light,
it didn't have to
happen that way,
and it shouldn't have
happened that way.
We can get much, much better at
picking up cases as they emerge
and stopping these
outbreaks from happening.
And so to me actually, to
think like a scientist is
to be creative,
to be open-minded,
to be curious, to get
ideas from all over,
and then to identify ways of
systematically proving out
what you've done.
I love that, that balance
between the creativity
and the rigor.
And I think as long as
we're on this earth,
the viruses will be, too.
And so I think that's
really why it's
important to understand the
biology, to appreciate it,
to not assume that we need
to completely eradicate them,
but just to understand
how to control them
and how to respond when
something gets out of control.
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