West Africa's Ebola Outbreak Becomes the Largest in History
A single spillover in rural Guinea spreads to national capitals within months and infects more people than every prior Ebola outbreak combined
Quick facts
- Pathogen
- Ebola virus
- Origin
- Rural southeastern Guinea, confirmed March 2014
- Toll
- Over 28,600 infected, over 11,300 dead
- Scale
- More than 11 times larger than all previous known Ebola outbreaks combined
- Healthcare worker toll
- 874 infected, 509 dead by July 2015
What happened
An Ebola virus outbreak began in the forested rural region of southeastern Guinea, confirmed by the World Health Organization in March 2014, and spread to the capital cities of Guinea, Liberia, and Sierra Leone within months, making this the largest Ebola outbreak since the virus was first identified in 1976. In August 2014, WHO declared it a Public Health Emergency of International Concern. By the time the outbreak was declared over in June 2016, more than 28,600 people had been infected and over 11,300 had died, a toll more than eleven times larger than all previously known Ebola outbreaks combined. The disease also spread to Mali, Nigeria, Senegal, and, through travel, to Italy, Spain, the United Kingdom, and the United States, with limited secondary transmission in several of those countries. Healthcare workers were hit especially hard: by July 2015, WHO reported 874 infected and 509 dead among health workers alone.
Why it matters
The scale of this outbreak, reaching national capitals rather than staying confined to remote villages as previous Ebola outbreaks had, exposed how fragile healthcare systems in Guinea, Liberia, and Sierra Leone could turn a regional spillover into a transnational crisis, and it prompted lasting changes to how WHO funds and triggers emergency outbreak response.
How we know
WHO situation reports and CDC's MMWR document case counts, geographic spread, and healthcare worker infections throughout the outbreak's two-year course, drawing on national health ministry surveillance data from the affected countries.
Sources
- World Health Organization. Ebola outbreak 2014-2016, West Africa · Reputable sourcewho.int · The domain "who.int" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
- PMC (National Library of Medicine). The Ebola outbreak, 2013-2016: old lessons for new epidemics · Peer-reviewed (author-declared)pmc.ncbi.nlm.nih.gov · Cited as a "journal" source (no stronger domain match). · Link is live and its text matches the event's key terms (Jul 2026)
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