London (CNN)More than 6,000 people have died as the virus spread from Guinea to other countries in West Africa. International flights took the disease as far as Spain and the United States, and international organizations have mobilized to contain it.
Worst Ebola outbreak in history: What you need to know
Explore the outbreak and its effects through the graphics below. The outbreak began in Guinea at the end of 2013 with a 2-year-old boy who may have gotten the virus from eating the meat of infected monkeys, antelope or squirrels. From him, the virus spread to his family and then out in four separate chains.
The virus exploded in neighboring Sierra Leone, where hundreds of deaths can be traced to the funeral of a widely respected traditional healer who died of Ebola after people came from Guinea seeking treatment from her. (The World Health Organization does not know her name.)
International organizations including the United Nations, Medecins Sans Frontieres and the World Health Organization have raced to fight the outbreak.