Ebola Outbreaks


Image credit: CDC

This database covers all outbreaks of the Ebola Virus Disease (EVD) as reported by the World Health Organization (WHO) and the US Centers for Disease Control and Prevention (CDC).

How to Use This Silk: Browse the charts and maps below. Click "Explore" anywhere on the site to go into visualization and filtering mode. Search for individual pages or entities in the top search box. 

The Outbreaks So Far

So far, the most deadly outbreaks have been in Central Africa with fatality percentages in the 90%. While the fatality rate of the 2014 West African outbreak overall is still relatively low, this can be expected to be much higher once all confirmed cases will have a definitive outcome (recovery or death): fatality in the 3 most affected countries for cases with a definitive outcome was last reported to be between 53% and 60%.

All reported outbreaks plotted by fatality percentage

Showing all outbreaks of the Ebola Virus Disease (EVD) between 1976 and 2015. Source: CDC and WHO.

The 2014 West African Outbreak

The growth rate has peaked in all 3 countries with widespread transmissions; Sierra Leone's growth rate of new cases was the last of the 3 countries to peak (in December 2014). Due to underreporting, in particular in Liberia, the actual number of new cases may be considerably higher still.

Timeline of cases in the past 21 days

Showing a timeline of the number of cases during a 21-day period during the outbreak. The steady drop in all 3 countries indicates a slower growth in new (reported) cases, but due to underreporting this has to be considered with a grain of salt.

While the number of Ebola patients has been growing linear in Guinea, growth has been exponential in Liberia and Sierra Leone since August but it has been slowing down after December 2014. 

Timeline of total reported cases in Guinea, Liberia and Sierra Leone

Total cases include confirmed, probable and suspect cases. Note that the peak on October 29 is the result of a more comprehensive assessment by the WHO of their data, meaning that these additional cases occurred throughout the epidemic period and not only since October 22. The subsequent decline in cases on November 5 is due to a change in the use of datasources by the WHO.

Percentage of cases in the past 21 days

Showing the number of cases during a 21-day period as a percentage of the total number of cases during the outbreak. Note that the data relating to Liberia is incomplete and is currently missing figures for several dates. The actual number of cases in the past 21 days is expected to be higher than currently recorded.

Timeline of percentage of cases in the past 21 days

Showing a timeline of the number of cases during a 21-day period as a percentage of the total number of cases during the outbreak. The steady drop in all 3 countries indicates a slower growth in new (reported) cases, but due to underreporting this has to be considered with a grain of salt.

Ebola cases outside West Africa

Showing all known EVD patients that have received or are receiving treatment outside West Africa, including those that were infected in West Africa. Click on any header to sort the table.

Aid directly committed to the 3 most affected countries has been rising similar to the number of Ebola cases: linear for Guinea and exponential for Liberia and Sierra Leone. While a total of $3.2 billion has been committed for all Ebola-stricken regions, the economies of the affected countries will face a multi-billion $ disruption.

Financial aid ($) for Ebola-stricken countries

Showing international financial aid in US$ contributed or committed directly to one of the countries with widespread transmission. These amounts do not include aid contributed or committed to the West African region in general. Graph is plotted by date of decision to contribute. Source: Financial Tracking Service.

While total aid directly committed to Guinea lags the other two hard-hit countries (see above), Sierra Leone is actually receiving the least aid per patient: currently about half of the per capita amount for Liberia.

Financial aid ($) for Ebola-stricken countries - proportional to number of cases

Showing international financial aid in US$ contributed or committed directly to one of the countries with widespread transmission divided by each country's number of reported cases of EVD. These amounts do not include aid contributed or committed to the West African region in general. Graph is plotted by date of decision to contribute. Source: Financial Tracking Service.

Ebola outbreaks compared: 1976 - 2015

Before 2015:

* Leaving out the outbreak of 1977 in the Democratic Republic of Congo, when the fatality rate was 100% but only one person had been infected.

Number of Ebola Outbreaks by Country of Origin


Ebola cases outside West Africa

Showing all countries with Ebola patients, including those where the location of infection was in West Africa.

All reported outbreaks since 1976 plotted by number of reported deaths


All reported outbreaks since 1976 plotted by number of reported human cases


All countries with reported outbreaks since 1976 plotted by number of separate outbreaks


About this site

This site was created with Silk, a platform for collections of information. The database will be continuously updated as long as the WHO provides new figures on the 2014 outbreak that started in West Africa. Pages, visualizations and collections on this site may therefore change over time.