Random Analytics: Ebola 2014 (update to 23 Apr 2014)

by Shane Granger

“This study demonstrates the emergence of a new EBOV strain in Guinea,” New England Journal of Medicine (22 April 2014).

The latest outbreak of Ebola Zaire, which is ongoing, has now reached 242-clinical cases and taken the lives of 147. Guinea has borne the brunt of the disease with 208-clinical cases (136-deaths) and Liberia 34 clinical cases (11-deaths, revised down from 13). Previously reported cases in Mali and Sierra Leone have either been confirmed as Lassa fever or Ebola Virus Disease (EVD) negative. Although recent cases are tapering off these numbers are still likely to change.

The World Health Organisation has a comprehensive update issued on the 22 April 2014.

As part of a post-graduate program I am undertaking I have built a five-minute Ebola Virus Disease (EVD) lesson utilising just four graphs and six-dot points.

1. Ebola Virus Disease Outbreak (Guinea/Liberia 2014) * UPDATED *

01 - Ebola_GuineaOutbreak_140423

***** Please note that this infographic of the EVD was updated with public source information to 2000hrs 23 April 2014 (EST) *****

From the World Health Organisation. Ebola virus disease, West Africa (Situation as of 22 April 2014). Excerpt:

As of 18:00 on 20 April, the Ministry of Health (MOH) of Guinea has reported a cumulative total of 208 clinical cases of Ebola Virus Disease (EVD), including 136 deaths. To date, 169 patients have been tested for ebolavirus infection and 112 cases have been laboratory confirmed, including 69 deaths.  In addition, 41 cases (34 deaths) meet the probable case definition for EVD and 55 cases (33 deaths) are classified as suspected cases.  Twenty-five (25) health care workers (HCW) have been affected (18 confirmed), with 16 deaths (12 confirmed).

Clinical cases of EVD have been reported from Conakry (53 cases, including 23 deaths), Guekedou (122/87), Macenta (22/16), Kissidougou (6/5), Dabola (4/4) and Djingaraye (1/1). Laboratory confirmed cases and deaths have been reported from Conakry (37 cases, including 19 deaths), Guekedou (60/38), Macenta (13/10), Kissidougou (1/1) and Dabola (1/1). These updated figures include 3 new cases isolated on 20 April from Conakry and Guekedou, 2 of whom are laboratory confirmed.  Five new deaths have also been reported among existing cases; all 5 of the deaths were patients with confirmed EVD.  Twenty-one (21) patients were in isolation in Conakry (12), Guekedou (8) and Macenta (1), while 16 patients who recovered from their illness were discharged from hospital.

Notes: The map graphic was taken from Wikipedia (then amended).

2. Ebola across Africa * UPDATED *

02 - Ebola_AcrossAfrica_140423

***** Please note that this infographic of the EVD was updated with public source information to 0800hrs 23 April 2014 (EST). EBOV = Ebola Zaire, SUDV = Ebola Sudan, BDBV = Ebola Bundibugyo and TAFV = Ebola Ivory Coast *****

The Ebola across Africa infographic details the country specific outbreaks of the EVD since it was first discovered in 1976 (with a 1972 retrospective case from Zaire included). As the map shows the bulk of the outbreaks have occurred within central Africa and the most deadly, Ebola Zaire causing the most cases in the Democratic Republic of Congo (formally Zaire). The most recent outbreak has actually occurred in West Africa, originating from Guinea and is a new isolate of Ebola Zaire (Gueckedou and Kissidougou).

As an additional point of interest I have also added the Health Expenditure per capita for each country in 2012 $USD (source: World Bank).

Notes: The 1976 – 2004 outbreaks of Ebola Sudan occurred in the bottom half of Sudan (now South Sudan). Zaire was renamed the Democratic Republic of Congo in 1997.

3. Ebola (Top 10 Outbreaks by Case Numbers) * UPDATED *

03 - Ebola_Top10OutbreaksByCaseNo_140423

***** Please note that this infographic of the EVD was updated with public source information to 0800hrs 23 April 2014 (EST) *****

The next chart displays the top 10 outbreaks in order of case numbers and each horizontal bar is filled with the flag of the country where the outbreak occurred. With clinical cases reaching 208 in Guinea and 34 in Liberia the EBOV17 coded outbreak has now become sixth largest (242) based on case numbers. The largest outbreak (SUDV4) was of Ebola Sudan in Uganda (2000) when 425 became infected and 224 died. The only other recording of an EVD that jumped borders prior to this outbreak was the 10th worst outbreak (EBOV8) when a doctor caught the disease in Gabon and subsequently took an international flight to South Africa where he became ill and infected other health workers.

Notes: In order from lowest to highest. 10th: EBOV8 (Gabon/South Africa), 9th: EBOV9 (Gabon), 8th: EBOV11 (Republic of Congo), 7th: BDBV01 (Uganda), 6th: EBOV17 (Guinea/Liberia/Mali), 5th: EBOV15 (Democratic Republic of Congo), 4th: SUDV1 (technically Sudan but would now be South Sudan), 3rd: EBOV6 (Zaire but now the DRC), 2nd: EBOV2 (Zaire but now the DRC) and 1st: SUDV4 (Uganda).

4. Ebola (Cases by Classification and Year) * UPDATED *

04 - Ebola_CasesbyClassYear_140423

***** Please note that this infographic of the EVD was updated with public source information to 0800hrs 23 April 2014 (EST) *****

The final chart shows cases by classification (Ebola Zaire, Sudan, Bundibugyo, Reston and Ivory Coast) by year and then split into those recovered or those deceased (following in a red variant). As you can see the initial outbreak in 1976 of the both Ebola Zaire and Ebola Sudan was the most significant year with 603 cases and 431 deaths (a combined Case Fatality Rate of 71.5%). With up to 242 clinical cases so far the 2014 Ebola Zaire outbreak is now the fifth worst in terms of case numbers.

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). The 2014 numbers are currently provisional.

Key Facts: (source: Fact Sheet 103, WHO, last updated March 2014)

  • The Ebola virus causes Ebola virus disease (EVD; formerly known as Ebola haemorrhagic fever) in humans;
  • EVD outbreaks have a case fatality rate of up to 90%;
  • EVD outbreaks occur primarily in remote villages in Central and West Africa, near tropical rainforests;
  • The virus is transmitted to people from wild animals and spreads in the human population through human-to-human transmission;
  • Fruit bats of the Pteropodidae family are considered to be the natural host of the Ebola virus;
  • No specific treatment or vaccine is available for use in people or animals.

Acknowledgements:Data for this infographic was sourced from official reports from the World Health Organisation. I have also utilised resources from the CDC, CIDRAP, H5N1, Virology Down Under and National Geographic.