Random Analytics: The West African Ebola Outbreak (to 4 Aug 2014)

by Shane Granger

Here are some updated charts and infographics of the 2014 Ebola Virus Disease outbreak using a number of primary sources including the most recent World Health Organisation Disease Outbreak News (DON) released 6 August 2014.

***** Please note that all EVD infographics in this series were updated with public source information to 4 August 2014 *****

01 - Ebola_Top10OutbreaksByCaseNos_140808

Ebola (Top 10 Outbreaks by Case Numbers)

The first chart displays the top 10 outbreaks in order of case numbers. Each horizontal bar is filled with the flag(s) of the country where the outbreak occurred.

With clinical cases reaching 691 in Guinea, 516 in Liberia, 495 in Liberia and nine in Nigeria the West African outbreak has now become largest Ebola outbreak in history based on both case numbers (1711) and fatalities (932). The second largest outbreak was of the Ebola Sudan strain which occurred in Uganda (2000) when 425 became infected and 224 died. The recent outbreak is the first to migrate across international land borders. The only other recording of an EVD that jumped borders prior to this outbreak was the Gabon/RSA (1996) outbreak. In that instance a doctor caught the disease in Gabon and subsequently took an international flight to South Africa where he became ill and infected other Health Care Workers (HCWs).

02 - Ebola_CasesbyClassYear_140808

Ebola (Cases by Classification and Year)

The second chart shows cases by classification (in order they are Ebola Zaire, Sudan, Bundibugyo, Reston and Ivory Coast) by year and then split into those recovered or those deceased (which follows in a red variant). The West African outbreak has become the most significant in terms of case numbers, eclipsing the 1976 dual outbreaks which saw 603 cases and 431 deaths (a combined Case Fatality Rate of 71.5%).

Currently the provisional Western African outbreak has seen 1711 cases and 932 deaths (a CFR of 54.5%).

Notes: Several years had just one case. They are 1972 (a retrospective fatality of Ebola Zaire in Zaire), 1977 (a single case of Ebola Zaire in Zaire), 1988 (an accidental infection of Ebola Zaire in Porton Down, UK) and 2011 (a single fatality of Ebola Sudan in Uganda).

 03 - WestAfrica_Cases~FatalitiesMonth_140808

The West African Outbreak – Cases & Fatalities by Month

The final chart shows both case numbers and fatalities by month. Each column is split into the current four impacted countries with data represented by the varying national flags.

The very interesting data point that springs out from this chart is that the DON I utilised for this only had data for the first four days of the month yet cases are already 271 and fatalities are 106. It should be noted that those figures are not exact as the DON that covered the month rollover between July and August had to be estimated (using a 50/50% split).


Acknowledgements: Data for this infographic was sourced from official reports from the World Health Organisation. I have also utilised resources from the CDC, CIDRAP, FluTrackers, and H5N1. I’m also a big fan of the analytical work of Virology Down Under (Ian Mackay) and Mens et Manus (Maia Majumder).