Ebola: what is it and how does it spread?

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By Tim Leslie, illustrations by Lucy Fahey

Almost 700 people in West Africa have died in the worst Ebola outbreak on record. What is Ebola, and how does this highly contagious and deadly disease spread?

First discovered in 1976, the virus has periodically spread through parts of Africa, killing thousands in the process.

There is currently no vaccine, and due to its fast onset and horrific symptoms it has become one of the world’s most feared diseases.

How does it spread?

There are five strains of Ebola: Zaire, Sudan, Tai Forest, Bundibugyo and Reston. The Zaire strain, which is involved in the latest outbreak, is the most lethal with a fatality rate of up to 90 per cent.

Humans can catch the virus from animals through close contact with infected animals’ blood, secretions, organs or other bodily fluids.

The virus is thought to reside within the region’s fruit bat population, with the bats carriers of Ebola, but unaffected by it.

The bushmeat trade (the catching and eating of wild animals, including primates such as gorillas and chimpanzees), is thought to play a role in outbreaks of the disease.

While cooking infected meat kills the virus, handling of the meat beforehand can cause infection.

Human-to-human transmission happens through direct contact with blood, secretions, organs or other bodily fluids of infected humans.

The World Health Organisation has specifically noted traditional healing and burial practices in rural regions as a factor in the spread of the disease.

How does it affect the body?

Why is containing Ebola proving difficult?

In West Africa, the man-made elements of conflict, confusion and culture have all combined to create a perfect-storm for Ebola.

The scientist who first identified Ebola in 1976 gives direct and simple advice on how to contain this latest outbreak:

“Soap, gloves, isolating patients, not reusing needles and quarantining the contacts of those who are ill – in theory it should be very easy to contain Ebola,” Dr Peter Piot told the BBC.

In practice, this is a much tougher proposition. The latest outbreak has emerged in war ravaged West Africa, where much of the health care infrastructure has been totally destroyed.

Poverty has combined with fear, ignorance and superstition, particularly in remote communities, where distrust of government is understandably high, and belief in witchcraft and sorcery is interwoven into everyday life.

Testing for Ebola often requires multiple blood tests – which is difficult to conduct in areas where strong cultural beliefs prohibit collection of a “life force”.

In Liberia, some communities believe the outbreak is a hoax, and that health care workers have been sent to kill them. In one town, health care workers spraying chlorine – a cheap and effective counter to the spread of the disease – were attacked.

In Guinea, Medicines Sans Frontiers (MSF) doctors and medics were attacked by villagers who believed the clinical team had brought Ebola to their country.

Governmental response has been heavy handed. Liberia’s president threatened to jail anyone sheltering or hiding suspected Ebola cases.

An un-coordinated rush by the international community to assist can also complicate efforts, says African governance expert Kim Yi Dionne, especially when it appears that no one is in charge.

Already involved in the Ebola response are the local ministries of health for Liberia, Guinea and Sierra Leone, the World Health Organisation, MSF, UNICEF and many other agencies.