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What is Ebola?
Ebola, also known as Ebola haemorrhagic fever or Ebola virus disease, is an potentially fatal, infectious disease. It is caused by a virus, named after a river in the Democratic Republic of Congo, where it was first identified in 1976 and has since caused several outbreaks of disease. The virus spreads through contact with an infected person's bodily fluids.
Ebola is a serious disease causing high mortality rates. However, the risk of infection is reduced if sensible precautions are taken.
The condition is caused by the Ebola virus. The virus can be found in non-human animals; it is most likely passed to humans from infected bats.
There are five known strains of the virus, four of which cause serious disease. Some strains are more virulent than others. The fifth strain, known as the Ebola-Reston virus, was detected in pigs in the Philippines in 2008, but does not cause illness.
How the Ebola virus causes disease
After the virus enters the body, it can infect many types of cells, including liver cells and cells of the immune system. It then multiplies rapidly, often overwhelming the body's immune defences.
Also, the virus infects and damages the cells that make up the blood vessels, leading to blood-vessel damage and severe bleeding. The virus can also interfere with the body's blood-clotting mechanism. The most common cause of death is uncontrolled bleeding.
The Ebola virus passes from person to person via bodily fluids, including blood, saliva, semen or vaginal secretions, urine, faeces, vomit, mucus, sweat and tears. You can also become infected through contact with infected animals or eating their meat.
It is worth noting that the virus can remain in the testes for a long period. An infected male can sexually transmit the virus for up to seven weeks after their recovery.
Ebola virus is not known to spread from person to person via droplets from coughs and sneezes.
Since Ebola can cause severe bleeding, touching and handling a person infected with Ebola can cause infection. This poses a particular problem for health workers, who are at great risk of infection. In addition, risk of infection is high in cultures where customs involve grooming the deceased person before burial.
The two most major risk factors for catching Ebola are:
- Living in a region where Ebola is present, and;
- Coming into contact with the bodily fluids of an infected person or animal. The virus in the bodily fluid generally has to pass through a breach in the skin such as a cut or through mucous membranes such as the linings of the mouth, nose, rectum or vagina.
Ebola was first identified in 1976 when an outbreak occurred in Sudan (now Southern Sudan) and Zaire (now Democratic Republic of the Congo). The initial outbreak ended in 1979 and Ebola did not resurface for 15 years. Since then, Ebola outbreaks have occurred every few years, all of them in Africa. The 2014-15 outbreak is by far the largest, with more people infected than all the previous outbreaks combined. 
As well as the cost in human lives and suffering, an outbreak such as the 2014-15 Ebola outbreak can have far-reaching implications. A country experiencing an outbreak must shoulder the direct costs of controlling the outbreak. These include loss of income from trade and travel restrictions. In already struggling economies, this can cause food shortages and increased poverty - which may sometimes have an even larger impact on the population's health than the outbreak itself.
Signs and symptoms
Signs and symptoms of Ebola initially resemble those of influenza and usually appear any time from 2 to 21 days after infection, though the most common time frame is 8 to 10 days.
Symptoms of Ebola can include:
- Sore throat;
- Stiff, painful muscles and joints, and;
- Weakness and loss of appetite.
As the disease progresses, further symptoms appear, including:
Methods for diagnosis
Ebola cannot be diagnosed by its symptoms alone. A blood sample is tested in the laboratory for the presence of the virus and/or antibodies to it.
Types of treatment
At present, there is no specific treatment for Ebola. A person suspected of being infected will be quarantined to prevent further spread and will receive intensive supportive treatment.
It is particularly important to seek treatment as early as possible - early treatment of Ebola significantly increases your chances of survival and recovery.
Supportive treatment of Ebola will usually include rehydration and treating the symptoms as they appear. Blood transfusions may be required to replace lost blood.
An Ebola infection will normally run its course within 2 to 3 weeks. Recovery can be slow, as the infected person is often weak and unwell. Hair loss, eye inflammation and skin shedding can be seen at this stage.
Ebola is a very serious disease. During previous outbreaks, about 90% of all infected people died of the disease.  However, during the 2014-15 outbreak the mortality rate had dropped to about 50%.  If, and when, new treatments and vaccines are approved for use, the mortality rate will likely drop further.
There is also hope that the virus is becoming less dangerous as it spreads, a common natural process known as viral attenuation.
A person who has recovered from Ebola is immune to that strain of the virus.
Ebola is currently restricted to specific regions in Africa. Unless you are living in or travelling to one of these regions, you will not be exposed to Ebola.
If you are in an area where Ebola is active, steps you can take to reduce your chance of catching Ebola include:
- Avoiding physical contact with people or animals who have been infected with the virus, including those who have died of the disease;
- Washing your hands frequently and thoroughly with soap and water, and;
- Avoiding 'bushmeat' (meat of wild animals), especially fruit bats.
There is currently no vaccine to protect against Ebola, but several vaccine candidates are being fast-tracked towards approval. If successful, an Ebola vaccine may be available in the not-too-distant future.