Timeline of the Ebola virus: 1976–2014

1976 — A school teacher in Zaire, now the Democratic Republic of Congo, becomes the first documented person to contract the Ebola virus and later dies.

1976–2013 — A number of small outbreaks affect West Africa, with the highest death toll at one time reaching just over 250.

December 2013 — A handful of people in Guinea die of an unidentified fever, which is later confirmed as Ebola.

March 2014 — The World Health Organisation (WHO) reports a major Ebola outbreak in Guinea, while Liberia identifies its first case and over the next few months the virus spreads to neighbouring Sierra Leone.

July 20th, 2014 — Liberian government employee Patrick Sawyer travels to Lagos, Nigeria, where he dies of Ebola, sparking fears that the virus could cross wider borders.

August 8th, 2014 — The WHO declares Ebola an "international health emergency". Four days later, the death toll exceeds 1,000.

August 24, 2014 — British volunteer nurse William Pooley is urgently flown to London for treatment after contracting the virus. The 29-year-old makes a full recovery and makes plans to return to west Africa.

September 17th — The first healthy human volunteer is injected with an experimental Ebola vaccine in Oxford as part of a fast-tracked British trial.

September 19th — The WHO describes the outbreak as a "social crisis, a humanitarian crisis, an economic crisis", with cases doubling around every four weeks and a death toll of over 2,500.

October 6th — Spanish nurse Teresa Romero becomes the first person known to have caught the disease outside the outbreak zone in West Africa.

October 8th — 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 Texas hospital where he was treated are also infected.

October 9th — The Government announces screening for passengers arriving at Gatwick and Heathrow airports, and warns some Ebola cases will reach the UK.

October 17th — 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.

UN Chief Ban Ki-moon launches another urgent appeal for funds as the death toll hits 4,500.