The Ebola outbreak in West Africa is the world’s deadliest to date and the World Health Organization has declared an international health emergency as more than 3,850 people have died of the virus in Guinea, Liberia, Sierra Leone and Nigeria this year.
What is Ebola?
Ebola is a viral illness of which the initial symptoms can include a sudden fever, intense weakness, muscle pain and a sore throat, according to the World Health Organization (WHO). And that is just the beginning: subsequent stages are vomiting, diarrhoea and – in some cases – both internal and external bleeding.
The disease infects humans through close contact with infected animals, including chimpanzees, fruit bats and forest antelope.
It then spreads between humans by direct contact with infected blood, bodily fluids or organs, or indirectly through contact with contaminated environments. Even funerals of Ebola victims can be a risk, if mourners have direct contact with the body of the deceased.
The incubation period can last from two days to three weeks, and diagnosis is difficult. The human disease has so far been mostly limited to Africa, although one strain has cropped up in the Philippines.
Healthcare workers are at risk if they treat patients without taking the right precautions to avoid infection. People are infectious as long as their blood and secretions contain the virus – in some cases, up to seven weeks after they recover.
Where does it strike?
Ebola outbreaks occur primarily in remote villages in Central and West Africa, near tropical rainforests, says the WHO.
It was first discovered in the Democratic Republic of Congo in 1976 since when it has mostly affected countries further east, such as Uganda and Sudan.
Ebola deaths since 1976
This year’s outbreak is unusual because it started in Guinea, which has never before been affected, and it quickly spread to urban areas.
From Nzerekore, a remote area of south-eastern Guinea, the virus spread to the capital, Conakry, and neighbouring Liberia and Sierra Leone.
There have been 20 cases of Ebola being imported by someone travelling from a country of widespread transmission to Nigeria, with eight confirmed deaths. The US and Senegal have both confirmed one case each. The US Centers for Disease Control and Prevention (CDC) said in September that the virus might have been successfully contained in Nigeria and Senegal.
In October, a nurse in Spain became the first person to contract the deadly virus outside of West Africa, after treating two Spanish missionaries who had eventually died of Ebola in Madrid.
The medical charity Medecins Sans Frontieres (MSF) says the outbreak is “unprecedented” in the way the cases were scattered in multiple locations across Guinea, hundreds of kilometres apart, and says it is a “race against time” to check people who come into contact with sick people in neighbouring Sierra Leone.