What is Ebola?
Ebola virus disease, which used to be
called Ebola haemorrhagic fever, was
named after the river in the Democratic
Republic of the Congo, where one of the
first two villages to report cases in 1976
was located. The other was in Sudan.
Ebola is a severe viral illness with a
sudden onset that comes from direct
contact with infected living or dead
rainforest animals, including chimpanzees,
gorillas, monkeys, fruit bats, forest
antelope and porcupines. It kills up to
90% of those who are infected.
How is it transmitted?
The virus is passed from one human to
another, carried in blood and bodily fluids
and secretions, but also beds, sheets,
clothes or other surfaces that a sick
person has touched. Burial ceremonies
that involve touching the body are also a
risk. The virus enters the body through
broken skin or mucous membrane.
The group at highest risk are health
workers, caring for those with Ebola. They
have to wear full protective clothing,
including facemasks and goggles, and
should change their gloves between one
patient and the next.
What are the symptoms?
The early signs are sudden fever, intense
weakness, muscle pain, headache and a
sore throat. Vomiting and diarrhoea
follow, raising the chances that the sick
man or woman will infect somebody else.
The kidney and liver are affected and
there can be both internal and external
bleeding, which is why it was originally
called Ebola haemorrhagic fever. Patients
are infectious once the symptoms show,
which is two to 21 days after they have
contracted the virus.
What is the treatment?
There is very little treatment. Patients
will need intensive supportive care, with
intravenous fluids or oral rehydration
salts. They must be kept in isolation and
their nurses and visitors must wear full
protective suits. If people are to be nursed
at home, their carers need instructions
and equipment to safeguard themselves.
There are no drugs to treat the disease or
vaccine to prevent it, although research on
a vaccine is under way.
Why is there no cure?
It has proved very hard to find drugs to
treat viral diseases from animals, from
influenza to HIV. Although the death rate
is high, outbreaks of ebola are infrequent
and have so far been contained each time.
As with many of the so-called neglected
tropical diseases, there is not a potentially
lucrative market for drug companies, so
they will be reluctant to invest in research
and development.
If outbreaks can be contained and
brought to a halt with good infection
control, why do they return?
They can be contained in human
populations but the viral reservoir still
exists in animals. There will always be a
risk that hunters will kill infected animals
or that people will pick up those that have
died of the infection in the forest and the
virus will be reintroduced to the human
population.
Will closing borders help?
Containment is key to the strategy against
ebola. Quarantine has been used in some
outbreaks for the relatives of people who
become sick. Because people are not
infectious until they become obviously ill,
it should in theory be possible to focus
efforts on the community where the
outbreak began. In the past, that has
usually been villages in close proximity to
rainforests.
Confirmation of a case in a city such as
Lagos is a real concern, but transmission
must involve direct contact with a sick
individual, so is more likely in a family
setting or a hospital. The biggest worry is
probably that somebody showing
symptoms will be taken to hospital where
nursing staff are unprotected, because the
disease is not recognised, sparking an
outbreak that spreads to their families in
turn.
Closing borders may not help keep the
disease out because borders are
permeable in much of Africa. The World
Health Organisation says closures may
hinder travel and trade without detecting
cases.
Is the rest of the world threatened by
ebola?
Clearly somebody infected with the virus
could theoretically get on a plane and
spark an outbreak – probably in a hospital
– anywhere in the world.

Source
www.theguardian.com/science/2014/jul/28/ebola-outbreak-africa-key-questions