a few weeks ago we gave you a primer on
Ebola a virus responsible for nearly
5,000 deaths this year in West Africa
now with isolated cases popping up in
the US and Spain the question on
everybody's mind is how do we stop the
spread people in the media have been
profer all kinds of sensible sounding
suggestions that turn out to be not so
sensible like why not screen everybody
who's traveling out of the hottest of
the Ebola hot zones but also what about
treating the people who are already
infected and where's the vaccine the
fact is we're working on all of these
things but like science is hard
sometimes in airports around the world
first of all Health officials are
screening high-risk passengers traveling
from the epicenter of the outbreak
Liberia Guinea and Sierra Leon they do
this using simple infrared thermometers
like the kind in your doctor's office
fever is one of the earliest symptoms of
Ebola infection so any passenger found
to have a temperature higher than 100.4
de fhe is then tested for Ebola virus
through a blood test but obviously
stopping thousands of Travelers just to
take their temperature leaves loopholes
that are big enough to fly jumbo Jets
through for one thing the Ebola virus
can incubate in a person's body for up
to 21 days that means a passenger can be
infected with ebola and not show any
symptoms for up to 3 weeks and of course
if someone happens to feel a little bit
warm and takes a Tylenol or something it
will reduce the fever thereby masking
the symptom that's being screened for so
if a fever isn't a reliable indicator of
infection what is we can always skip to
the second step of the screening a
polymerous chain reaction or PCR test
it's like basically DNA photocopying PCR
works by finding Trace Amounts of Ebola
DNA in a blood sample and replicating it
over and over again until there's enough
DNA to be detected by a microscope
because PCR can magnify tiny Trace
Amounts of Ebola DNA it's really good at
detecting Ebola in patients that aren't
showing symptoms yet so why not just
test everybody's blood who's coming out
of West Africa it's because it's
extremely impractical test costs around
$100 to conduct each sample of blood
needs to be transferred on Ice to a lab
where lab workers computers and other
Hardware can test it and even then it
takes several hours to analyze each
sample also it isn't perfect it has a
false negative rate of 4% that means
that out of every 1,000 people four
could have Ebola but test negative for
it the good news though is that if a
person has Ebola but they are not
showing symptoms they are not contagious
so even if you're on a flight with
somebody who has Ebola but they don't
have the symptoms they're not going to
give it to you it's not going to keep
Ebola out of another country but it is
going to prevent everyone on the plane
from getting it but we do live in a
world where some people are going to get
Ebola so we have to start looking at how
we can treat them can we help them
recover again we have options and we're
using them Nina fam the Dallas nurse who
contracted Ebola was able to recover in
part because she was given what's known
as a convalescent serum a serum obtained
from someone who had recovered from the
same infection in fam's case she was
given blood plasma from Dr Ken Brantley
an American doctor who survived Ebola
earlier this year and Brantley in turn
survived partly because he received
serum from a 14-year-old boy he had
treated in Liberia these serums work
because a survivor's blood is rich in
antibodies that know how to fight the
virus for those individual cases it was
an elegant solution but convalescent
serums don't always work and they also
run the risk of transmitting other
bloodborne diseases like HIV or
hepatitis to the recipients plus there
are the enormous challenges of finding a
way that's both safe and feasible to
bank the blood of people who have
survived Ebola unsurprisingly this is
much easier to do in America where we
have complicated medical infrastructure
than it is in like West Africa for
example which is just one of the reasons
why Ebola is actually pretty survivable
if you have it in America unfortunately
the vast majority of people infected
with ebola are not in places with
complicated medical infrastructure so
drug companies are developing other
therapeutic medicines like the
experimental treatment called zmap zmap
is made by injecting mice with a protein
from the Ebola virus the mice then
produce antibodies to the or
protein and scientists then genetically
modify those antibodies for human use by
combining them with fragments of human
antibodies so far this technique has
successfully treated primates infected
with ebola and preliminary results
suggest that it's effective in people
too but still as promising as all of
these treatments sound we haven't found
that silverest of silver bullets that
everybody's looking for a vaccine there
are actually lots of Ebola vaccines in
development right now but the one that's
farthest along is being engineered by a
pharmaceutical company glos Smith Klein
with the National Institutes of Health
this vaccine takes a non lethal virus
and splices an ebola gene into it when
the immune system responds to this
non-lethal virus it develops antibodies
that will work against a living Ebola
virus so far this approach has proven
successful in protecting primates and
other animals as for people NIH
scientists just began testing it on
humans last month and won't have the
results until November meanwhile
Canada's public health agency has a
similar vaccine that's ready for human
testing but the crazy thing is their
vaccine has been sitting on a shelf for
nearly a decade scientists tested it
successfully on primates and 2005 and
published a report about it in the
journal Nature it was all ready for
human testing but there wasn't enough
money to fund the trials because ebolo
just wasn't that common in 2005 now that
this year's outbreak has killed nearly
5,000 people the World Health
Organization has put these vaccines on
The Fast Track the Canadian government
has shipped 800 vials of its vaccine to
the who in Geneva for testing and glos
Smith Klein estimates that it could
begin a large scale human trial
involving 12,000 liberians and 8,000
Sierra leonian in January if the trial
is successful the first vaccine for
Ebola could be ready for release by
April thanks for watching this episode
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