Subtitles section Play video
-
In the summer of 1976,
-
a mysterious epidemic suddenly struck two central African towns,
-
killing the majority of its victims.
-
Medical researchers suspected
-
the deadly Marburg virus to be the culprit.
-
But what they saw in microscope images was an entirely new pathogen,
-
which would be named after the nearby Ebola river.
-
Like yellow fever or dengue,
-
the disease caused by the Ebola virus is a severe type of hemorrhagic fever.
-
It begins by attacking the immune system's cells
-
and neutralizing its responses,
-
allowing the virus to proliferate.
-
Starting anywhere from two to twenty days after contraction,
-
initial symptoms like high temperature,
-
aching,
-
and sore throat,
-
resemble those of a typical flu,
-
but quickly escalate to vomiting,
-
rashes,
-
and diarrhea.
-
And as the virus spreads,
-
it invades the lymph nodes and vital organs,
-
such as kidneys and liver, causing them to lose function.
-
But the virus itself is not what kills Ebola victims.
-
Instead, the mounting cell deaths trigger an immune system overload,
-
known as a cytokine storm,
-
an explosion of immune responses that damages blood vessels,
-
causing both internal and external bleeding.
-
The excessive fluid loss and resulting complications
-
can be fatal within six to sixteen days of the first symptoms,
-
though proper care and rehydration therapy
-
can significantly reduce mortality rates in patients.
-
Fortunately, while Ebola is highly virulent,
-
several factors limit its contagiousness.
-
Unlike viruses that proliferate through small, airborne particles,
-
Ebola only exists in bodily fluids,
-
such as saliva,
-
blood,
-
mucus,
-
vomit,
-
or feces.
-
in order to spread,
-
these must be transmitted from an infected person into another's body
-
through passageways such as the eyes, mouth, or nose.
-
And because the disease's severity
-
increases directly along with the viral load,
-
even an infected person is unlikely to be contagious
-
until they have begun to show symptoms.
-
While Ebola has been shown to survive on surfaces for several hours,
-
and transmission through sneezing or coughing is theoretically possible,
-
virtually all known cases of contraction have been through direct contact
-
with the severely ill,
-
with the greatest risk posed to medical workers
-
and friends or relatives of the victims.
-
This is why, despite its horrifying effects,
-
Ebola has been far less deadly overall than more common infections,
-
such as measles,
-
malaria,
-
or even influenza.
-
Once an outbreak has been contained,
-
the virus does not exist in the human population
-
until the next outbreak begins.
-
But while this is undoubtedly a good thing,
-
it also makes Ebola difficult to study.
-
Scientists believe fruit bats to be its natural carriers,
-
but just how it is transmitted to humans remains unknown.
-
Furthermore, many of the countries where Ebola outbreaks occur
-
suffer from poor infrastructure and sanitation,
-
which enables the disease to spread.
-
And the poverty of these regions,
-
combined with the relatively low amount of overall cases
-
means there is little economic incentive for drug companies to invest in research.
-
Though some experimental medicines have shown promise,
-
and governments are funding development of a vaccine,
-
as of 2014,
-
the only widespread and effective solutions to an Ebola outbreak remain
-
isolation,
-
sanitation,
-
and information.