It has been seven months since the current Ebola outbreak started, with the first cases reported in Guinea and Liberia back in March.
As the the death toll surpasses 4,500 we take a look back at the timeline of events which led to the current health epidemic:
1976 - The first documented person with the Ebola virus, a schoolteacher in Zaire (now the Democratic Republic of Congo) dies
1976-2013 Numerous small outbreaks are recorded in West Africa, with the highest death toll for any one outbreak reaching 250
December 2013 - An unidentified fever claims the lives of a handful of people in Guinea, it is later confirmed they died of Ebola
March 2014 - A major Ebola outbreak in Guinea is reported by the World Health Organisation and Liberia identifies its first case. In teh following months the virus spreads to neighbouring Sierra Leone
July 20, 2014 - Patrick Sawyer, a Liberian government employee, sparks fears that the virus could cross borders when he travels to Lagos, Nigeria, where he dies of Ebola
August 8, 2014 - An "international health emergency" is declared by the World Health Organisation just four days before the death toll exceeds 1,000.
August 24, 2014 - William Pooley, a British volunteer nurse, is urgently flown to London for treatment after contracting the virus. He has since made a full recovery and said he will return to West Africa
September 17, 2014 - The first healthy human volunteer is injected with an experimental Ebola vaccine in Oxford as part of a fast-tracked British trial
September 19, 2014 - The outbreak is described as a "social crisis, a humanitarian crisis, an economic crisis" by the World Health Organisation. Cases double around every four weeks and the death toll reaches over 2,500.
October 6, 2014 - Spanish nurse Teresa Romero becomes the first person known to have caught the disease outside the outbreak zone in West Africa
October 8, 2014 - Thomas Eric Duncan becomes the first person to die on American soil after it is believed he contracted the disease in Liberia. Two nurses at the hospital, in Texas, where he was treated are also infected.
October 9, 2014 - The UK Government announces screening for passengers arriving at Gatwick and Heathrow airports.
October 17, 2014 - David Cameron says Britain is "leading the way" in its efforts to tackle the outbreak, committing "well over £100 million, 750 troops, training 800 members of health staff, providing 700 beds" to the region.