How did the 2014 Ebola epidemic in West Africa grow, and how did it end?
A child who died in a Guinean village in December 2013 is generally believed to be the first case of an epidemic that infected more than 28,600 people.
In 2014 Ebola spread from one village in Guinea into the largest outbreak ever recorded, helped by months of delay, dysfunctional healthcare systems and distrust, and it declined from October 2014 as substantial international resources were committed. By the time it was declared over in June 2016, more than 28,600 people had been infected and 11,325 had died, according to the WHO.
The first cases were recorded in Guinea in December 2013. A boy of one or two, later identified as Emile Ouamouno, who died in December 2013 in the village of Méliandou, is generally believed to have been the , the first known person infected. His case and the early ones after it were diagnosed as other conditions more common in the area, so the disease had several months to spread before anyone recognised it as Ebola. From Guinea it moved to neighbouring Liberia and Sierra Leone, with smaller outbreaks in Nigeria and Mali.
Several things made it hard to stop: extreme poverty, dysfunctional healthcare systems, distrust of government after years of armed conflict, and a delay of several months in responding. The key number was R, the average number of people each case infects. In September 2014 the estimated was 1.71 for Guinea, 1.83 for Liberia and 2.02 for Sierra Leone. Above 1, an epidemic keeps growing, exponentially.
Estimated R0 in September 2014
| R0 estimate | |
|---|---|
| Guinea | 1.71 R0 |
| Liberia | 1.83 R0 |
| Sierra Leone | 2.02 R0 |
Cases peaked in October 2014 and then began to decline, after substantial international resources were committed. In Liberia the drop was believed to be related to an integrated strategy: isolation and treatment together with community behaviour change, including safe burial practices, case finding and . The epidemic was finally declared over on 9 June 2016, and it left about 17,000 survivors.
Try it
What R does over eight rounds
y = 1 · 1.8ˣ
Challenge · Set R to 2.0, close to Sierra Leone's estimate in September 2014, and read the cases in round 8 starting from one. Then pull R below 1.
Quiz me
0/3
Recap
The epidemic grew because R stayed above 1 after a months-long delay, and it shrank when isolation, safe burials and tracing brought it down.
💡 A trick to remember it · A late start, a number above one: each round multiplies the last, until the chain is cut.
Surprising fact · The estimated R0 in September 2014 was only about 1.7 to 2.0, yet that was enough for exponential growth.
Connects to
- 🧬 What is Ebola, and how does it spread?
- 🦇 Where did Ebola come from, and who discovered it?
- 🕊️ Why did funerals and mistrust help Ebola spread?
- 📈 What does it mean when an epidemic's R number is above one?
- 🪷 Why does something that doubles daily look harmless until the last moment?
- Public health emergency of international concern
Sources (2)
No source, no claim. Every fact in this lesson (16 claims) cites at least one of these.